@article{miguez2025urban,
title = {Urban greenspaces benefit both human utility and biodiversity},
author = {Miguez, Nataly G and Mason, Brittany M and Qiu, Jiangxiao and Cao, Haojie and Callaghan, Corey T},
journal = {Urban Forestry \& Urban Greening},
pages = {128791},
year = {2025},
publisher = {Elsevier},
file = {Miguez_et_al_2025-Urban greenspaces benefit both human utility and biodiversity.pdf},
doi = {10.1016/j.ufug.2025.128791}
}
Urban greenspaces are essential for both human well-being and biodiversity, with their importance continually growing in the face of increasing urbanization. The dual role of these spaces raises questions about how their planning and management can best serve the diverse needs of both people and biodiversity. Our goal was to quantify the synergies and tradeoffs between human utility and biodiversity benefits in urban greenspaces. Through a detailed inventory, we mapped 639 urban greenspaces throughout Broward County, Florida — one of the most populous counties in the United States. We identified and categorized various physical attributes (N=8 in total), including playgrounds, athletic facilities, and picnic areas and derived a ‘human utility index’. Concurrently, we assessed biodiversity by estimating relative species richness within an urban greenspace. We found little relationship between our human utility index and biodiversity. More specifically, when the index was broken down to its parts, we found a positive correlation between some attributes such as playgrounds, bodies of water, nature preserves, and dog parks with biodiversity, indicating potential synergies rather than tradeoffs. This alignment between our human utility index and biodiversity suggests that urban parks can effectively serve multiple values without necessarily sacrificing one for the other. Both the human utility index and biodiversity correlate with greenspace size, emphasizing the significance of larger greenspaces in accommodating diverse values. Our results offer insights for optimizing planning and management of urban greenspaces to simultaneously benefit local communities and ecosystems, highlighting the potential for harmonizing human and biodiversity to foster sustainable cities.
@article{barrattheitmann2025land,
title = {Land cover and area influence bird biodiversity in geographically isolated wetlands},
author = {Barratt Heitmann, Jackson and Mason, Brittany M and Callaghan, Corey T},
journal = {Diversity and Distributions},
pages = {e70012},
volume = {31},
number = {3},
year = {2025},
publisher = {Wiley Online Library},
file = {Barratt Heitmann_et_al-2025-Land cover and area influence bird biodiversity in geographically isolated wetlands.pdf},
doi = {10.1111/ddi.70012}
}
Aim Geographically isolated wetlands, wetlands surrounded by upland habitat, harbour high amounts of bird biodiversity but are rapidly being lost across the United States. Yet, we do not know which characteristics, such as wetland area or land cover, influence the level of bird biodiversity supported. We assessed the influence of wetland area and local (size of the wetland, 0.001–4.20km2) and landscape (25km) land cover on bird biodiversity in geographically isolated wetlands. Location Conterminous United States. Methods We quantified the impacts of the wetland area and different land cover on overall bird species richness and richness estimates within five functional groups. We integrated 207 geographically isolated wetlands, selected based on eBird sampling locations with over 100 total checklists. We computed land cover metrics within wetland sites and landscape buffers (25km) around each site. Using a generalised linear modelling approach, we examined how species richness was impacted by area and six remotely sensed land cover variables. Results Species richness increased with area for all species and functional groups of birds, but aquatic (e.g., ducks) and terrestrial (e.g., wading birds) functional groups had the steepest species–area slopes. Constructed wetlands exhibited a steeper species–area relationship slope compared to natural wetlands. Species richness was negatively correlated with built land cover at the local and landscape scales and was positively associated with flooded vegetation at the local scale and grass cover at the local and landscape scales. All functional group richness estimates responded negatively to build land cover but showed unique responses in their associations with other land cover variables. Main Conclusions Anthropogenic disturbance at the local and landscape scales significantly reduces species richness. Land managers looking to create or restore wetlands, which have steeper species–area curves, should consider local-scale management changes in flooded vegetation or grass cover to improve habitat for birds.
@article{callaghan2025citizen,
title = {Citizen science as a valuable tool for environmental review},
author = {Callaghan, Corey T and Winnebald, Carly and Smith, Blaze and Mason, Brittany M and L{\'o}pez-Hoffman, Laura},
journal = {Frontiers in Ecology and the Environment},
pages = {e2808},
volume = {23},
number = {1},
year = {2025},
publisher = {Wiley Online Library},
file = {Callaghan_et_al-2025-Citizen science as a valuable tool for environmental review.pdf},
doi = {10.1002/fee.2808}
}
Human development and population growth are placing immense pressure on natural ecosystems, necessitating the establishment of a balance between development and biodiversity preservation. Citizen science may serve as a valuable resource for monitoring biodiversity and informing decision-making processes, but its use has not been investigated within the realm of environmental review. We sought to quantify the extent to which citizen science data are currently being used, mentioned, or suggested in environmental impact statements (EISs) by analyzing more than 1300 EISs produced under the US National Environmental Policy Act. Among the sampled EISs, we found increasing incorporation of citizen science within the environmental review process, with 40% of EISs in 2022 using, mentioning, or suggesting use of such information, as compared with just 3% in 2012. Citizen science offers substantial potential to enhance biodiversity monitoring and conservation efforts within environmental review, but numerous considerations must be broadly discussed before citizen science data can be widely adopted.
@article{bowler2025evidence,
title = {Evidence-base for urban green-blue infrastructure to support insect diversity},
author = {Bowler, Diana E and Callaghan, Corey T and Felappi, J{\'e}ssica F and Mason, Brittany M and Hutchinson, Robin and Kumar, Prashant and Jones, Laurence},
journal = {Urban Ecosystems},
volume = {28},
number = {1},
pages = {1--14},
year = {2025},
publisher = {Springer},
file = {Bowler_et_al-2025-Evidence-base for urban green-blue infrastructure to support insect diversity.pdf},
doi = {10.1007/s11252-024-01649-4}
}
Green-blue urban infrastructures potentially offer win-win benefits for people and nature in urban areas. Given increasing evidence of widespread declines of insects, as well as their ecological importance, there is a need to better understand the potential role of green-blue urban infrastructure for insect conservation. In this review, we evaluated 201 studies about the ability of green-blue infrastructure to support insect diversity. Most studies were focused on the role of local and landscape-level characteristics of green-blue infrastructure. Fewer studies explicitly compared one type of infrastructure to another, and even fewer compared insect communities between green-blue infrastructure and traditional infrastructure. Overall, the body of research highlights the importance of plant diversity and reduced intensity of management (e.g., mowing) for most insect taxon groups. While local characteristics seem to be generally more important than landscape factors, insect communities within green-blue infrastructures can also depend on their connectivity and landscape context. Some infrastructure types are generally more beneficial than others; for instance, ground-level habitats tend to support more insects than green roofs. Few studies simultaneously studied synergies or trade-offs with other services provided by green-blue infrastructure, but environmental variables, such as tree cover and plant diversity, that affect insects are likely to also affect the provision of other services such as improving thermal comfort and the well-being of people. Our review offers some initial evidence for how green-blue infrastructure could be designed for multifunctionality with insects in mind.
@article{backstrom2025estimating,
title = {Estimating sampling biases in citizen science datasets},
author = {Backstrom, Louis J and Callaghan, Corey T and Worthington, Hannah and Fuller, Richard A and Johnston, Alison},
journal = {Ibis},
year = {2025},
volume = {167},
number = {1},
pages = {73--87},
publisher = {Wiley Online Library},
file = {Backstrom_et_al-2025-Estimating sampling biases in citizen science datasets.pdf},
doi = {10.1111/ibi.13343}
}
The rise of citizen science (also called community science) has led to vast quantities of species observation data collected by members of the public. Citizen science data tend to be unevenly distributed across space and time, but the treatment of sampling bias varies between studies, and interactions between different biases are often overlooked. We present a method for conceptualizing and estimating spatial and temporal sampling biases, and interactions between them. We use this method to estimate sampling biases in an example ornithological citizen science dataset from eBird in Brisbane City, Australia. We then explore the effects of these sampling biases on subsequent model inference of population trends, using both a simulation study and an application of the same trend models to the Brisbane eBird dataset. We find varying levels of sampling bias in the Brisbane eBird dataset across temporal and spatial scales, and evidence for interactions between biases. Several of the sampling biases we identified differ from those described in the literature for other datasets, with protected areas being undersampled in the city, and only limited seasonal sampling bias. We demonstrate variable performance of trend models under different sampling bias scenarios, with more complex biases being associated with typically poorer trend estimates. Sampling biases are important to consider when analysing ecological datasets, and analysts can use this method to ensure that any biologically relevant sampling biases are detected and given due consideration during analysis. With appropriate model specification, the effects of sampling biases can be reduced to yield reliable information about biodiversity.
@article{moon2024relational,
title = {The relational nature of citizen science},
author = {Moon, Katie and Yates, Sophie and Callaghan, Corey T and Thompson, Maureen},
journal = {People and Nature},
volume = {6},
number = {5},
pages = {2060--2076},
year = {2024},
publisher = {Wiley Online Library},
file = {Moon_et_al-2024-The relational nature of citizen science.pdf},
doi = {10.1002/pan3.10709}
}
1. Most citizen science research inherently separates the observer (citizen science participant) from the observation (e.g. data point), placing artificial boundaries around what matters and how it comes to matter. We apply three elements of the philosophical framework of agential realism to reveal a more complex picture of how data arise within citizen science programmes, and its meaning to both the practice of science and the citizen science participant: ‘intra-action’ (all entities have agency and are entangled with one another); ‘material becoming’ (what comes to matter); and ‘responsibility’ (accountability for what comes to matter and what is excluded from mattering). 2. We draw on a case study of FrogID—an Australia-wide citizen science program focused on calling frogs, with over 42,000 participants and over 1 million frog records. We conducted semi-structured interviews with 30 FrogID users, completing two rounds of thematic and relational coding. 3. Our findings reveal that as a consequence of their recording behaviours, FrogID participants become increasingly entangled with the nocturnal environment, with sound and with their own self. Expanding and reciprocal relationships and experiences shape the nature and frequency of their recordings. 4. Second, meaning influences what comes to matter (i.e. what is recorded and submitted) for FrogID participants. We reveal meaning related to feedback (recognition and thus reciprocity), others (social networks and participation with family and friends) and the self (physical and mental well-being and identity formation/becoming). These different forms of meaning influenced engagement with app use. 5. Third, participants communicated responsibilities related to their involvement in citizen science, including responsibilities to create knowledge (e.g. longitudinal data collection), to conserve (e.g. actively conserving frog, formally committing areas to conservation) and to educate self and others (e.g. skills and competencies required for environmental action). 6. Synthesis and applications: By recognizing a more comprehensive set of intra-actions, beyond the observer and the observation, agential realism can reveal when, why and how citizen science observations are made; what observations come to matter and why; and how people can create a more just world. Agential realism can shape how citizen science participation, retention and biodiversity data generation are founded. We propose three opportunities for citizen science programs based on these findings.
@article{oh2024enhancing,
title = {Enhancing the health and wellbeing benefits of biodiversity citizen science},
author = {Oh, Rachel RY and Fuller, Richard A and Peters, Birte and Dean, Angela J and Pachana, Nancy A and Callaghan, Corey T and Sockhill, Nicola J and Bonn, Aletta and Suarez-Castro, Andres F},
journal = {Frontiers in Environmental Science},
volume = {12},
pages = {1444161},
year = {2024},
publisher = {Frontiers Media SA},
file = {Oh_et_al-2024-Enhancing the health and wellbeing benefits of biodiversity citizen science.pdf},
doi = {10.3389/fenvs.2024.1444161}
}
Engagement in biodiversity citizen science initiatives can confer health and wellbeing benefits to individuals and communities. Yet, few biodiversity citizen science initiatives are explicitly planned to optimize health and wellbeing as a potential co-benefit, leading to missed opportunities for biodiversity conservation and human health. In this perspective, we use a dose-response approach to discuss the components that determine how engagement in biodiversity citizen science initiatives map onto opportunities to foster health and wellbeing benefits. We considered aspects related to the duration and frequency of contact with nature, and the intensity of interactions with nature and between individuals to highlight the different health benefits across the variety of citizen science initiatives. To illustrate these aspects, we use a sample of 95 citizen science initiatives from seven English and non-English-speaking countries and show how careful project design can increase the potential to confer health and wellbeing benefits to participants. We conclude with considerations on how to enhance the health and wellbeing benefits from citizen science initiatives, and propose potential research avenues to assess synergies and trade-offs between benefits to biodiversity and human health from these initiatives.
@article{bowler2024treating,
title = {Treating gaps and biases in biodiversity data as a missing data problem},
author = {Bowler, Diana E and Boyd, Robin J and Callaghan, Corey T and Robinson, Robert A and Isaac, Nick JB and Pocock, Michael JO},
journal = {Biological Reviews},
year = {2024},
publisher = {Wiley Online Library},
file = {Bowler_et_al-2024-Treating gaps and biases in biodiversity data as a missing data problem.pdf},
doi = {10.1111/brv.13127}
}
Big biodiversity data sets have great potential for monitoring and research because of their large taxonomic, geographic and temporal scope. Such data sets have become especially important for assessing temporal changes in species’ populations and distributions. Gaps in the available data, especially spatial and temporal gaps, often mean that the data are not representative of the target population. This hinders drawing large-scale inferences, such as about species’ trends, and may lead to misplaced conservation action. Here, we conceptualise gaps in biodiversity monitoring data as a missing data problem, which provides a unifying framework for the challenges and potential solutions across different types of biodiversity data sets. We characterise the typical types of data gaps as different classes of missing data and then use missing data theory to explore the implications for questions about species’ trends and factors affecting occurrences/abundances. By using this framework, we show that bias due to data gaps can arise when the factors affecting sampling and/or data availability overlap with those affecting species. But a data set per se is not biased. The outcome depends on the ecological question and statistical approach, which determine choices around which sources of variation are taken into account. We argue that typical approaches to long-term species trend modelling using monitoring data are especially susceptible to data gaps since such models do not tend to account for the factors driving missingness. To identify general solutions to this problem, we review empirical studies and use simulation studies to compare some of the most frequently employed approaches to deal with data gaps, including subsampling, weighting and imputation. All these methods have the potential to reduce bias but may come at the cost of increased uncertainty of parameter estimates. Weighting techniques are arguably the least used so far in ecology and have the potential to reduce both the bias and variance of parameter estimates. Regardless of the method, the ability to reduce bias critically depends on knowledge of, and the availability of data on, the factors creating data gaps. We use this review to outline the necessary considerations when dealing with data gaps at different stages of the data collection and analysis workflow.
@article{sheard2024emerging,
title = {Emerging technologies in citizen science and potential for insect monitoring},
author = {Sheard, Julie Koch and Adriaens, Tim and Bowler, Diana E and B{\"u}ermann, Andrea and Callaghan, Corey T and Camprasse, Elodie CM and Chowdhury, Shawan and Engel, Thore and Finch, Elizabeth A and von G{\"o}nner, Julia and others},
journal = {Philosophical Transactions of the Royal Society B},
volume = {379},
number = {1904},
pages = {20230106},
year = {2024},
publisher = {The Royal Society},
file = {Sheard_et_al-2024-Emerging technologies in citizen science and potential for insect monitoring.pdf},
doi = {10.1098/rstb.2023.0106}
}
Emerging technologies are increasingly employed in environmental citizen science projects. This integration offers benefits and opportunities for scientists and participants alike. Citizen science can support large-scale, long-term monitoring of species occurrences, behaviour and interactions. At the same time, technologies can foster participant engagement, regardless of pre-existing taxonomic expertise or experience, and permit new types of data to be collected. Yet, technologies may also create challenges by potentially increasing financial costs, necessitating technological expertise or demanding training of participants. Technology could also reduce people’s direct involvement and engagement with nature. In this perspective, we discuss how current technologies have spurred an increase in citizen science projects and how the implementation of emerging technologies in citizen science may enhance scientific impact and public engagement. We show how technology can act as (i) a facilitator of current citizen science and monitoring efforts, (ii) an enabler of new research opportunities, and (iii) a transformer of science, policy and public participation, but could also become (iv) an inhibitor of participation, equity and scientific rigour. Technology is developing fast and promises to provide many exciting opportunities for citizen science and insect monitoring, but while we seize these opportunities, we must remain vigilant against potential risks.
@article{chowdhury2024standard,
title = {A standard protocol for harvesting biodiversity data from Facebook},
author = {Chowdhury, Shawan and Ahmed, Sultan and Alam, Shofiul and Callaghan, Corey T and Das, Priyanka and Di Marco, Moreno and Di Minin, Enrico and Jari{\'c}, Ivan and Labi, Mahzabin Muzahid and Rokonuzzaman, Md and others},
journal = {Conservation Biology},
volume = {38},
number = {4},
pages = {},
year = {2024},
publisher = {Wiley},
file = {Chowdhury_et_al-2024-A protocol for harvesting biodiversity data from Facebook.pdf},
doi = {10.1111/cobi.14257}
}
The expanding use of community science platforms has led to an exponential increase in biodiversity data in global repositories. Yet, understanding of species distributions remains patchy. Biodiversity data from social media can potentially reduce the global biodiversity knowledge gap. However, practical guidelines and standardized methods for harvesting such data are nonexistent. Following data privacy and protection safeguards, we devised a standardized method for extracting species distribution records from Facebook groups that allow access to their data. It involves 3 steps: group selection, data extraction, and georeferencing the record location. We present how to structure keywords, search for species photographs, and georeference localities for such records. We further highlight some challenges users might face when extracting species distribution data from Facebook and suggest solutions. Following our proposed framework, we present a case study on Bangladesh’s biodiversity—a tropical megadiverse South Asian country. We scraped nearly 45,000 unique georeferenced records across 967 species and found a median of 27 records per species. About 12% of the distribution data were for threatened species, representing 27% of all species. We also obtained data for 56 DataDeficient species for Bangladesh. If carefully harvested, social media data can significantly reduce global biodiversity knowledge gaps. Consequently, developing an automated tool to extract and interpret social media biodiversity data is a research priority.
@article{callaghan2024population,
title = {Population abundance estimates in conservation and biodiversity research},
author = {Callaghan, Corey T and Santini, Luca and Spake, Rebecca and Bowler, Diana E},
journal = {Trends in Ecology \& Evolution},
volume = {39},
number = {6},
pages = {515--523},
year = {2024},
publisher = {Elsevier},
file = {Callaghan_et_al-2024-Population abundance estimates in conservation and biodiversity research.pdf},
doi = {10.1016/j.tree.2024.01.012}
}
Measuring and tracking biodiversity from local to global scales is challenging due to its multifaceted nature and the range of metrics used to describe spatial and temporal patterns. Abundance can be used to describe how a population changes across space and time, but it can be measured in different ways, with consequences for the interpretation and communication of spatiotemporal patterns. We differentiate between relative and absolute abundance, and discuss the advantages and disadvantages of each for biodiversity monitoring, conservation, and ecological research. We highlight when absolute abundance can be advantageous and should be prioritized in biodiversity monitoring and research, and conclude by providing avenues for future research directions to better assess the necessity of absolute abundance in biodiversity monitoring.
@article{backstrom2024assessing,
title = {Assessing adequacy of citizen science datasets for biodiversity monitoring},
author = {Backstrom, Louis J and Callaghan, Corey T and Leseberg, Nicholas P and Sanderson, Chris and Fuller, Richard A and Watson, James EM},
journal = {Ecology and Evolution},
volume = {14},
number = {2},
pages = {e10857},
year = {2024},
publisher = {Wiley Online Library},
file = {Backstrom_et_al-2024-Assessing adequacy of citizen science datasets for biodiversity monitoring.pdf},
doi = {10.1002/ece3.10857}
}
Tracking the state of biodiversity over time is critical to successful conservation, but conventional monitoring schemes tend to be insufficient to adequately quantify how species’ abundances and distributions are changing. One solution to this issue is to leverage data generated by citizen scientists, who collect vast quantities of data at temporal and spatial scales that cannot be matched by most traditional monitoring methods. However, the quality of citizen science data can vary greatly. In this paper, we develop three metrics (inventory completeness, range completeness, spatial bias) to assess the adequacy of spatial observation data. We explore the adequacy of citizen science data at the species level for Australia’s terrestrial native birds and then model these metrics against a suite of seven species traits (threat status, taxonomic uniqueness, body mass, average count, range size, species density, and human population density) to identify predictors of data adequacy. We find that citizen science data adequacy for Australian birds is increasing across two of our metrics (inventory completeness and range completeness), but not spatial bias, which has worsened over time. Relationships between the three metrics and seven traits we modelled were variable, with only two traits having consistently significant relationships across the three metrics. Our results suggest that although citizen science data adequacy has generally increased over time, there are still gaps in the spatial adequacy of citizen science for monitoring many Australian birds. Despite these gaps, citizen science can play an important role in biodiversity monitoring by providing valuable baseline data that may be supplemented by information collected through other methods. We believe the metrics presented here constitute an easily applied approach to assessing the utility of citizen science datasets for biodiversity analyses, allowing researchers to identify and prioritise regions or species with lower data adequacy that will benefit most from targeted monitoring efforts.
@article{wu2024effect,
title = {The effect of grain size on the relationship between urbanization and bird diversity},
author = {Wu, Jiayu and Chen, Guanyi and Callaghan, Corey T and Ren, Qiang},
journal = {Applied Geography},
volume = {162},
pages = {103154},
year = {2024},
publisher = {Elsevier},
file = {Wu_et_al-2023-The effect of grain size on the relationship between urbanization and bird diversity.pdf},
doi = {10.1016/j.apgeog.2023.103154}
}
The intensifying urbanization markedly influences bird diversity, frequently with negative repercussions but also yielding mixed outcomes. Our hypothesis posits that the variability in results often arises from methodological choices in measuring both bird diversity and urbanization. We investigated whether the effects of urbanization on bird diversity are influenced by the grain size of the measurements. Selected urban areas in China from 2000 to 2020 were analyzed, and bird diversity distributions were derived from citizen science data. Urbanization levels rose by approximately 30%, resulting in the loss of around 17 urban bird species. Panel data analyses at different grain sizes showed that urbanization negatively affected bird diversity, while taxonomic diversity was more resilient at the grain size (1–10 km). Furthermore, our findings indicate a grain effect on the urbanization-bird diversity relationship, revealing instability at various measurement grains. Functional diversity requires finer grains (1 km), reflecting feature redundancy. Our analytical approach enhances understanding of the mechanisms and cross-grain relationships through which urbanization impacts bird communities, and underscores the significance of grain in urban ecology.
@article{mitchell2023fighting,
title = {Fighting the flames: site-specific effects determine species richness of Australian frogs after fire},
author = {Mitchell, Brittany A and Gorta, Simon BZ and Callaghan, Corey T and Kingsford, Richard T and Rowley, Jodi JL},
journal = {Wildlife Research},
year = {2023},
publisher = {CSIRO Publishing},
file = {Mitchell_et_al-2023-Fighting the flames site-specific effects determine species richness of Australian frogs after fire.pdf},
doi = {10.1071/WR22175}
}
Context Fire has played an integral role in regulating patterns of biodiversity for millions of years. However, anthropogenic disturbance and climate change has altered fire activity – driving increases in both fire severity and scale. The effect fire now has on the persistence of biodiversity is poorly known, especially for frogs. Studies examining frog responses to fire usually have small sample sizes, focus upon small geographic areas and are based on low-severity fires, which can mean results are not applicable to high-severity fires, such as those expected under future climate change. Aims Our aims were to examine (1) persistence of frog species, measured by species richness, up to 18 months post-fire, and (2) the effects of varying fire severity on frog species richness and recovery, where we expected higher fire severity to lead to lower species richness after fire. Methods Using large-scale citizen science data from the Australian Museum’s FrogID project, coupled with remotely sensed fire data, we present a spatially and taxonomically broad analysis examining post-fire recovery responses for Australian frog species after the 2019/2020 ‘Black Summer’ bushfires. Key results We reveal no overall decrease in the species richness of Australian frogs both in the short- and long-term post-fire. Furthermore, species richness did not decline with increasing fire severity. Instead, species richness and its response to fire was highly site-specific. Conclusions We provide evidence that widespread and common Australian frog species have persisted post-fire in most sites and concluded that this is potentially due to their ability to shelter from fire adequately and/or La Niña-driven high rainfall offering conditions conducive to breeding activity and persistence. Implications We show how citizen science provides critical data for conservation, especially in response to unprecedented disturbance events, such as the 2019/2020 megafires. Our research also highlights the need for ongoing and targeted scientific monitoring, especially for less common or threatened species.
@article{backstrom2023using,
title = {Using citizen science to identify Australia’s least known birds and inform conservation action},
author = {Backstrom, Louis J and Leseberg, Nicholas P and Callaghan, Corey T and Sanderson, Chris and Fuller, Richard A and Watson, James EM},
journal = {Emu-Austral Ornithology},
pages = {1--7},
year = {2023},
publisher = {Taylor \& Francis},
file = {Backstrom_et_al-2023-Using citizen science to identify Australias least known birds and inform conservation action.pdf},
doi = {10.1080/01584197.2023.2283443}
}
Citizen science is a popular approach to biodiversity surveying, whereby data that are collected by volunteer naturalists may help analysts to understand the distribution and abundance of wild organisms. In Australia, birdwatchers have contributed to two major citizen science programs, eBird (run by the Cornell Lab of Ornithology) and Birdata (run by Birdlife Australia), which collectively hold more than 42 million records of wild birds from across the country. However, these records are not evenly distributed across space, time, or taxonomy, with particularly significant variation in the number of records of each species in these datasets. In this paper, we explore this variation and seek to determine which Australian bird species are least known as determined by rates of citizen science survey detections. We achieve this by comparing the rates of survey effort and species detection across each Australian bird species’ range, assigning all 581 species to one of the four groups depending on their rates of survey effort and species observation. We classify 56 species into a group considered the most poorly recorded despite extensive survey effort, with Coxen’s Fig Parrot Cyclopsitta coxeni, Letter-winged Kite Elanus scriptus, Night Parrot Pezoporus occidentalis, Buff-breasted Buttonquail Turnix olivii and Red-chested Buttonquail Turnix pyrrhothorax having the very lowest numbers of records. Our analyses provide a framework to identify species that are poorly represented in citizen science datasets. We explore the reasons behind why they may be poorly represented and suggest ways in which targeted approaches may be able to help fill in the gaps.
@article{callaghan2023unveiling,
title = {Unveiling global species abundance distributions},
author = {Callaghan, Corey T and Borda-de-{\'A}gua, Lu{\'\i}s and van Klink, Roel and Rozzi, Roberto and Pereira, Henrique M},
journal = {Nature Ecology \& Evolution},
pages = {1--10},
year = {2023},
publisher = {Nature Publishing Group UK London},
file = {Callaghan_et_al-2023-Unveiling global species abundance distributions.pdf},
doi = {10.1038/s41559-023-02173-y}
}
Whether most species are rare or have some intermediate abundance is a long-standing question in ecology. Here, we use more than one billion observations from the Global Biodiversity Information Facility to assess global species abundance distributions (gSADs) of 39 taxonomic classes of eukaryotic organisms from 1900 to 2019. We show that, as sampling effort increases through time, the shape of the gSAD is unveiled; that is, the shape of the sampled gSAD changes, revealing the underlying gSAD. The fraction of species unveiled for each class decreases with the total number of species in that class and increases with the number of individuals sampled, with some groups, such as birds, being fully unveiled. The best statistical fit for almost all classes was the Poisson log-normal distribution. This strong evidence for a universal pattern of gSADs across classes suggests that there may be general ecological or evolutionary mechanisms governing the commonness and rarity of life on Earth.
@article{chowdhury2023using,
title = {Using social media records to inform conservation planning},
author = {Chowdhury, Shawan and Fuller, Richard A and Ahmed, Sultan and Alam, Shofiul and Callaghan, Corey T and Das, Priyanka and Correia, Ricardo A and Di Marco, Moreno and Di Minin, Enrico and Jari{\'c}, Ivan and others},
journal = {Conservation Biology},
pages = {e14161},
year = {2023},
publisher = {Wiley Online Library},
file = {Chowdhury_et_al-2023-Using social media records to inform conservation planning.pdf},
doi = {10.1111/cobi.14161}
}
Citizen science plays a crucial role in helping monitor biodiversity and inform conservation. With the widespread use of smartphones, many people share biodiversity information on social media, but this information is still not widely used in conservation. Focusing on Bangladesh, a tropical megadiverse and mega-populated country, we examined the importance of social media records in conservation decision-making. We collated species distribution records for birds and butterflies from Facebook and Global Biodiversity Information Facility (GBIF), grouped them into GBIF-only and combined GBIF and Facebook data, and investigated the differences in identifying critical conservation areas. Adding Facebook data to GBIF data improved the accuracy of systematic conservation planning assessments by identifying additional important conservation areas in the northwest, southeast, and central parts of Bangladesh, extending priority conservation areas by 4,000–10,000 km2. Community efforts are needed to drive the implementation of the ambitious Kunming–Montreal Global Biodiversity Framework targets, especially in megadiverse tropical countries with a lack of reliable and up-to-date species distribution data. We highlight that conservation planning can be enhanced by including available data gathered from social media platforms.
@article{callaghan2023anthropogenic,
title = {Anthropogenic habitat modification causes nonlinear multiscale bird diversity declines},
author = {Callaghan, Corey T and Chase, Jonathan M and McGlinn, Daniel J},
journal = {Ecography},
pages = {e06759},
year = {2023},
publisher = {Wiley Online Library},
file = {Callaghan_et_al-2023-Anthropogenic habitat modification causes nonlinear multiscale bird diversity declines.pdf},
doi = {10.1111/ecog.06759}
}
Anthropogenic habitat modification is a leading contributor to biodiversity change, but it is unclear what factors, including scale, influence the magnitude of change. Changes in species richness and its scaling relationship across an anthropogenic gradient can be influenced by changes in the total number of individuals in each sample, the species abundance distribution, and/or the spatial arrangement of conspecific individuals. Here, we integrated continental-scale citizen science data on bird occurrences across the contiguous United States – from eBird – with an analytical framework capable of dissecting the aforementioned biodiversity components to quantify bird diversity changes along an anthropogenic landscape habitat modification gradient. We found an overall decline in bird diversity along an anthropogenic modification gradient, with peak levels of bird diversity at low to moderate levels of modification. The magnitude of biodiversity change was greater at gamma than at alpha scales and was most strongly associated with a declining number of individuals along the anthropogenic gradient. Spatial species turnover was lower at higher impacted sites, but this was also due to the sampling of fewer individuals rather than changes in spatial species patchiness. Our results suggest that local-scale management can promote bird diversity, especially at the natural–rural–suburban interface. Management efforts (e.g. managing natural habitat or preserving urban greenspaces against development) should be focused on creating, restoring, and preserving resources (e.g. nesting habitat, foraging resources) necessary for a large number of individuals, as this is the primary influence of diversity change along an anthropogenic gradient.
@article{gorta2023multi,
title = {Multi-taxon biodiversity responses to the 2019--2020 Australian megafires},
author = {Gorta, Simon BZ and Callaghan, Corey T and Samonte, Fabrice and Ooi, Mark KJ and Mesaglio, Thomas and Laffan, Shawn W and Cornwell, Will K},
journal = {Global Change Biology},
year = {2023},
publisher = {Wiley Online Library},
file = {Gorta_et_al-2023-Multi-taxon biodiversity responses to the 2019-2020 Australian megafires.pdf},
doi = {10.1111/gcb.16955}
}
Conditions conducive to fires are becoming increasingly common and widespread under climate change. Recent fire events across the globe have occurred over unprecedented scales, affecting a diverse array of species and habitats. Understanding biodiversity responses to such fires is critical for conservation. Quantifying post-fire recovery is problematic across taxa, from insects to plants to vertebrates, especially at large geographic scales. Novel datasets can address this challenge. We use presence-only citizen science data from iNaturalist, collected before and after the 2019–2020 megafires in burnt and unburnt regions of eastern Australia, to quantify the effect of post-fire diversity responses, up to 18 months post-fire. The geographic, temporal, and taxonomic sampling of this dataset was large, but sampling effort and species discoverability were unevenly spread. We used rarefaction and prediction (iNEXT) with which we controlled sampling completeness among treatments, to estimate diversity indices (Hill numbers: q = 0–2) among nine broad taxon groupings and seven habitats, including 3885 species. We estimated an increase in species diversity up to 18 months after the 2019–2020 Australian megafires in regions which were burnt, compared to before the fires in burnt and unburnt regions. Diversity estimates in dry sclerophyll forest matched and likely drove this overall increase post-fire, while no taxon groupings showed clear increases inconsistent with both control treatments post-fire. Compared to unburnt regions, overall diversity across all taxon groupings and habitats greatly decreased in areas exposed to extreme fire severity. Post-fire life histories are complex and species detectability is an important consideration in all post-fire sampling. We demonstrate how fire characteristics, distinct taxa, and habitat influence biodiversity, as seen in local-scale datasets. Further integration of large-scale datasets with small-scale studies will lead to a more robust understanding of fire recovery.
@article{headland2023smaller,
title = {Smaller Australian raptors have greater urban tolerance},
author = {Headland, Taylor and Colombelli-N{\'e}grel, Diane and Callaghan, Corey T and Sumasgutner, Shane C and Kleindorfer, Sonia and Sumasgutner, Petra},
journal = {Scientific Reports},
volume = {13},
number = {1},
pages = {11559},
year = {2023},
publisher = {Nature Publishing Group UK London},
file = {Headland_et_al-2023-Smaller Australian raptors have greater urban tolerance.pdf},
doi = {10.1038/s41598-023-38493-z}
}
Urbanisation is occurring around the world at a rapid rate and is generally associated with negative impacts on biodiversity at local, regional, and global scales. Examining the behavioural response profiles of wildlife to urbanisation helps differentiate between species that do or do not show adaptive responses to changing landscapes and hence are more or less likely to persist in such environments. Species-specific responses to urbanisation are poorly understood in the Southern Hemisphere compared to the Northern Hemisphere, where most of the published literature is focussed. This is also true for raptors, despite their high diversity and comparably high conservation concern in the Southern Hemisphere, and their critical role within ecosystems as bioindicators of environmental health. Here, we explore this knowledge gap using community science data sourced from eBird to investigate the urban tolerance of 24 Australian raptor species at a continental scale. We integrated eBird data with a global continuous measure of urbanisation, artificial light at night (ALAN), to derive an urban tolerance index, ranking species from positive to negative responses according to their tolerance of urban environments. We then gathered trait data from the published literature to assess whether certain traits (body mass, nest substrate, habitat type, feeding guild, and migratory status) were associated with urban tolerance. Body size was negatively associated with urban tolerance, as smaller raptors had greater urban tolerance than larger raptors. Out of the 24 species analysed, 13 species showed tolerance profiles for urban environments (positive response), and 11 species showed avoidance profiles for urban environments (negative response). The results of this study provide impetus to conserve native habitat and improve urban conditions for larger-bodied raptor species to conserve Australian raptor diversity in an increasingly urbanised world.
@article{rowley2023tracking,
title = {Tracking the spread of the eastern dwarf tree frog (Litoria fallax) in Australia using citizen science},
author = {Rowley, Jodi JL and Callaghan, Corey T},
journal = {Australian Journal of Zoology},
year = {2023},
publisher = {CSIRO Publishing},
file = {Rowley_and_Callaghan-2023-Tracking the spread of the eastern dwarf tree frog.pdf},
doi = {10.1071/ZO23012}
}
An increasing number of species are establishing populations outside of their native ranges, often with negative ecological and economic impacts. The detection and surveillance of invasive species presents a huge logistical challenge, given the large spatial regions in which new populations can appear. However, data collected through citizen science projects are increasingly recognised as a valuable source for detection and monitoring of invasive species. We use data from a national citizen science project, FrogID, to quantify the spread of the eastern dwarf tree frog (Litoria fallax) outside its historical native range in Australia. Of 48012 records of L. fallax in the FrogID database, 485 were located far outside the historical native range of the species. L. fallax has established geographically large populations hundreds of kilometres away from its native range, and these appear to be spreading in extent over time. These populations have resulted in novel species co-occurrences, with L. fallax now co-occurring with at least two frog species not present in their native range. Although the impacts of the invasive populations of L. fallax remain unknown, our work highlights the value in leveraging citizen science projects to detect and monitor native species that can become invasive far outside their historical range.
@article{chowdhury2023increasing,
title = {Increasing biodiversity knowledge through social media: A case study from tropical Bangladesh},
author = {Chowdhury, Shawan and Aich, Upama and Rokonuzzaman, Md and Alam, Shofiul and Das, Priyanka and Siddika, Asma and Ahmed, Sultan and Labi, Mahzabin Muzahid and Marco, Moreno Di and Fuller, Richard A and others},
journal = {BioScience},
pages = {biad042},
year = {2023},
publisher = {Oxford University Press},
file = {Chowdhury_et_al-2023-Increasing biodiversity knowledge through social media.pdf},
doi = {10.1093/biosci/biad042}
}
Citizen science programs are becoming increasingly popular among naturalists but remain heavily biased taxonomically and geographically. However, with the explosive popularity of social media and the near-ubiquitous availability of smartphones, many post wildlife photographs on social media. Here, we illustrate the potential of harvesting these data to enhance our biodiversity understanding using Bangladesh, a tropical biodiverse country, as a case study. We compared biodiversity records extracted from Facebook with those from the Global Biodiversity Information Facility (GBIF), collating geospatial records for 1013 unique species, including 970 species from Facebook and 712 species from GBIF. Although most observation records were biased toward major cities, the Facebook records were more evenly spatially distributed. About 86% of the Threatened species records were from Facebook, whereas the GBIF records were almost entirely Of Least Concern species. To reduce the global biodiversity data shortfall, a key research priority now is the development of mechanisms for extracting and interpreting social media biodiversity data.
@article{yang2023birds,
title = {How do birds with different traits respond to Urbanization? A phylogenetically controlled analysis based on citizen science data and a diverse urbanization measurement},
author = {Yang, Mengxia and Callaghan, Corey T and Wu, Jiayu},
journal = {Landscape and Urban Planning},
volume = {237},
pages = {104801},
year = {2023},
publisher = {Elsevier},
file = {Yang_et_al-2023-How do birds with different traits respond to urbanization.pdf},
doi = {10.1016/j.landurbplan.2023.104801}
}
The acceleration of urbanization has globally threatened bird diversity. Understanding how birds respond to the urban environment, and what, if any, traits predict this response to urban environments, is crucial in mitigating these declines. However, existing research often focuses on local or regional scales, utilizes restricted measures of urban tolerance, and does not always consider the interaction between evolutionary relatedness and traits, resulting in an unsettled relationship between some traits and urban tolerance. Our analyses aimed to test whether there is generalizability in previous results with that of the results in China, integrating 947,030 citizen science observations of birds with a continuous measure of urbanization. We synthesized an urbanization index for 874 species, representing their tolerance to urbanization by accounting for stressors such as built-up land, population density, and night-light intensity. First, we aimed to quantify which traits were positively and negatively associated with urban tolerance in Chinese birds, when considering all possible ecological and life history traits. Second, we tested specific hypotheses, based on a priori literature. Third, we tested whether the results from above change when phylogenetic relatedness is included in the models. The findings reveal that passage migrants or species with multiple main migration types with larger clutch sizes and more generalist diets are the most common in urban environments. Moreover, the evolutionary relationship between species conceals the expression of several traits in urban tolerance that omnivorous species that nest on architectural buildings or cliffs showed higher urban tolerance within clades. Our findings highlight the challenges in identifying consistent patterns in the relationships between species traits and their tolerance of urban environments. To optimize urban design and reduce the negative influence on birds from rapid urbanization, protecting existing trees and buildings where birds nest, increasing the proportion of shrubs to compensate for sources of ground-dwelling birds, and controlling the predation risk of the ground nests are beneficial.
@article{callaghan2023experimental,
title = {Experimental evidence that behavioral nudges in citizen science projects can improve biodiversity data},
author = {Callaghan, Corey T and Thompson, Maureen and Woods, Adam and Poore, Alistair GB and Bowler, Diana E and Samonte, Fabrice and Rowley, Jodi JL and Roslan, Nadiah and Kingsford, Richard T and Cornwell, William K and others},
journal = {BioScience},
volume = {73},
number = {4},
pages = {302--313},
year = {2023},
publisher = {Oxford University Press},
file = {Callaghan_et_al-2023-Experimental evidence that behavioral nudges in citizen science projects can improve biodiversity data.pdf},
doi = {10.1093/biosci/biad012}
}
One way to improve the value of citizen science data for a specific aim is through promoting adaptive sampling, where the marginal value of a citizen science observation is dependent on existing data collected to address a specific question. Adaptive sampling could increase sampling at places or times—using a dynamic and updateable framework—where data are expected to be most informative for a given ecological question or conservation goal. We used an experimental approach to test whether the participants in a popular Australian citizen science project—FrogID—would follow an adaptive sampling protocol aiming to maximize understanding of frog diversity. After a year, our results demonstrated that these citizen science participants were willing to adopt an adaptive sampling protocol, improving the sampling of biodiversity consistent with a specific aim. Such adaptive sampling can increase the value of citizen science data for biodiversity research and open up new avenues for citizen science project design.
@article{thompson2023citizen,
title = {Citizen science participant motivations and behaviour: Implications for biodiversity data coverage},
author = {Thompson, Maureen M and Moon, Katie and Woods, Adam and Rowley, Jodi JL and Poore, Alistair GB and Kingsford, Richard T and Callaghan, Corey T},
journal = {Biological Conservation},
volume = {282},
pages = {110079},
year = {2023},
publisher = {Elsevier},
file = {Thompson_et_al-2023-Citizen science participant motivations and behaviour.pdf},
doi = {10.1016/j.biocon.2023.110079}
}
1. Increasingly, citizen science data are becoming a significant source of information on the distribution of biodiversity. Their value is affected by many biases, especially gaps and redundancies in citizen science data. Reducing or minimizing those biases remains an important task, with an important first step being an understanding of whether, and to what extent, participants are willing to alter their behaviour for the benefit of a project. 2. We surveyed participants of a popular citizen science project focused on frog biodiversity to understand how their motivations and behaviour relate to their willingness to change when and where they collect data. 3. Most respondents contributed seasonally and close to home. Both their motivations and interest in changing behaviour strongly aligned with the project aims: conserving frogs and contributing to science. Willingness to change behaviour varied little with reported motivations, and respondents displayed a high level of willingness to change when or where they collect data when presented with opportunities for less biased sampling. 4. Our results indicate there is interest among participants to sample biodiversity in a more meaningful way, potentially reducing some biases in how citizen science data are collected. Creating citizen science projects that encourage participants to collect optimal data may satisfy both participant and organizers’ goals, and work towards science-driven conservation with improved biodiversity data.
@article{santini2023global,
title = {Global patterns and predictors of avian population density},
author = {Santini, Luca and Tobias, Joseph A and Callaghan, Corey and Gallego-Zamorano, Juan and Ben{\'\i}tez-L{\'o}pez, Ana},
journal = {Global Ecology and Biogeography},
year = {2023},
publisher = {Wiley Online Library},
file = {Santini_et_al-2023-Global patterns and predictors of avian population density.pdf},
doi = {10.1111/geb.13688}
}
Aim How population density varies across animal species in the context of environmental gradients, and associated migratory strategies, remains poorly understood. The recent influx of avian trait data and population density estimates allows these patterns to be described and explored in unprecedented detail. This study aims to identify the main macroecological drivers of population density in birds. Location Global. Time period 1970–2021. Major taxa studied Birds (Aves). Methods We collated a dataset of 5072 local population density estimates for 1853 species and modelled population density as a function of trait and environmental predictors in a Bayesian framework accounting for phylogenetic and spatial autocorrelation. We explored the influence of body mass, diet, primary lifestyle, mating system, nesting behaviour, territoriality, and migratory behaviour on population density, accounting for a range of environmental variables, including preferred habitat type, primary productivity, precipitation and temperature. Based on this empirical baseline, we then predicted the mean population density for 9089 species of birds and estimated global geographic patterns of bird population density. Results Population density was lower in species with larger body mass and higher trophic levels, and also declined in territorial species, migratory species, brood parasites and species inhabiting resource-poor habitat types (e.g., deserts). Conversely, population density increased in cooperative breeders. Environmental drivers were most influential for migratory birds, with precipitation and temperature both associated with higher population density. Overall, bird population densities were higher at lower latitudes. Main conclusions Our results support previous findings on the role of body mass, diet and environmental gradients, but also reveal novel species-specific drivers of avian densities related to reproduction, migration and resource-holding behaviour. Substantial fine-scale variation remains unexplained. We provide a global dataset of population density predictions for use in macroecological analyses and conservation assessments.
@article{ferretto2023optimising,
title = {Optimising the restoration of the threatened seagrass Posidonia australis: plant traits influence restoration success},
author = {Ferretto, Giulia and Glasby, Tim M and Poore, Alistair GB and Callaghan, Corey T and Sinclair, Elizabeth A and Statton, John and Kendrick, Gary A and Verg{\'e}s, Adriana},
journal = {Restoration Ecology},
year = {2023},
volume = {31},
pages = {e13893},
publisher = {Wiley Online Library},
file = {Ferretto_et_al-2023-Optimizing the restoration of the threatened seagrass Posidonia australis.pdf},
doi = {10.1111/rec.13893}
}
Restoration is an important activity to assist the recovery of damaged or degraded ecosystems. Accessing healthy donor material can be challenging when restoring threatened ecological communities, but careful selection of donor material may improve the success and cost-effectiveness of restoration projects. We aim to optimize restoration of the threatened seagrass Posidonia australis by identifying the traits of donor material that best predict survival and establishment. To avoid collecting donor material from threatened populations, a recent restoration method focuses on using naturally detached fragments of P. australis collected from the shoreline, which are stored in outdoor tanks prior to planting. Here, we examine 10 morphological traits of P. australis fragments and other variables relating to collection method to identify which traits best predicted survival after replanting. Fragments with more shoots and less dead tissue (necrosis) in their leaves had higher survival 1 year after planting. Fragments that were stored longer in tanks prior to replanting had significantly higher survival rates. These results can refine the selection for donor material used in restoration and optimize the recently developed restoration technique for P. australis using beach-cast seagrass material.
@article{spake2023understanding,
title = {Understanding ‘it depends’ in ecology: a guide to hypothesising, visualising and interpreting statistical interactions},
author = {Spake, R and Bowler, D and Callaghan, CT and Blowes, SA and Doncaster, CP and Antao, LH and Nakagawa, S and McElreath, R and Chase, JM},
journal = {Biological Reviews},
year = {2023},
publisher = {Wiley},
file = {Spake_et_al-2023-Understanding it depends in ecology a guide to hypothesising visualising and interpreting statistical interactions.pdf},
doi = {10.1111/brv.12939}
}
Ecologists routinely use statistical models to detect and explain interactions among ecological drivers, with a goal to evaluate whether an effect of interest changes in sign or magnitude in different contexts. Two fundamental properties of interactions are often overlooked during the process of hypothesising, visualising and interpreting interactions between drivers: the measurement scale – whether a response is analysed on an additive or multiplicative scale, such as a ratio or logarithmic scale; and the symmetry – whether dependencies are considered in both directions. Overlooking these properties can lead to one or more of three inferential errors: misinterpretation of (i) the detection and magnitude (Type-D error), and (ii) the sign of effect modification (Type-S error); and (iii) misidentification of the underlying processes (Type-A error). We illustrate each of these errors with a broad range of ecological questions applied to empirical and simulated data sets. We demonstrate how meta-analysis, a widely used approach that seeks explicitly to characterise context dependence, is especially prone to all three errors. Based on these insights, we propose guidelines to improve hypothesis generation, testing, visualisation and interpretation of interactions in ecology.
@article{szabo2023large,
title = {Large biodiversity datasets conform to Benford's law: Implications for assessing sampling heterogeneity},
author = {Szabo, Judit K and Forti, Lucas R and Callaghan, Corey T},
journal = {Biological Conservation},
pages = {109982},
year = {2023},
publisher = {Elsevier},
file = {Szabo_et_al-2023-Large biodiversity datasets conform to Benfords law implications for assessing sampling heterogeneity.pdf},
doi = {10.1016/j.biocon.2023.109982}
}
Inadequate sampling can cause biased estimates of species diversity, as species occurrence generally follows a log-normal distribution with a long tail. Understanding this sampling bias is fundamental to inform biodiversity conservation actions. However, currently available tests to assess data quality, such as fitting species abundance distribution (SAD) models and rarefaction curves are computationally costly and can still lead to erroneous conclusions. We evaluated Benford’s law (first digit distribution) as a complementary method to assess data heterogeneity and survey coverage in large biodiversity datasets, including eBird data for 157 countries and three non-avian GBIF datasets. We also tested conformity to Benford’s law of four simulated communities with different SAD models and four corrupted datasets with log-normal SAD. Finally, we evaluated the effect of including rare species in three datasets on the conformity to Benford’s law and also compared Benford fit to the results of traditional methods to estimate survey completeness in seven datasets. Species-rich datasets with a large number of observations tended to obtain a good fit. Benford conformity can be a simple and sensitive measure of sampling evenness, complementing traditional methods to assess quality data in large-scale studies. Benford’s test can reflect species abundance heterogeneity, especially in log-normally distributed data, but was not ideal to evaluate surveys completeness, as its results diverged from those of traditional methods. As the contribution of citizen science continues to increase in biodiversity monitoring, this fast and efficient method can play a critical role to assess the quality of datasets.
@article{valdez2023undetectability,
title = {The undetectability of global biodiversity trends using local species richness},
author = {Valdez, Jose W and Callaghan, Corey T and Junker, Jessica and Purvis, Andy and Hill, Samantha LL and Pereira, Henrique M},
journal = {Ecography},
pages = {e06604},
year = {2023},
publisher = {Wiley Online Library},
file = {Valdez_et_al-2023-The undetectability of global biodiversity trends using local species richness.pdf},
doi = {10.1111/ecog.06604}
}
Although species are being lost at alarming rates, previous research has provided conflicting results on the extent and even direction of global biodiversity change at the local scale. Here, we assessed the ability to detect global biodiversity trends using local species richness and how it is affected by the number of monitoring sites, sampling interval (i.e. time between original survey and re-survey of the site), measurement error (error of the measurement of the local species richness), spatial grain of monitoring (a proxy for the taxa mobility) and spatial sampling biases (i.e. site-selection biases). We use PREDICTS model-based estimates as a proxy for the real-world distribution of biodiversity and randomly selected monitoring sites to calculate local species richness trends. We found that while a monitoring network with hundreds of sites could detect global change in species richness within a 30-year period, the number of sites for detecting trends doubled for a decade, increased 10-fold within three years and yearly trends were undetectable. Measurement errors had a non-linear effect on statistical power, with a 1% error reducing statistical power by a slight margin and a 5% error drastically reducing the power to reliably detect any trend. The ability to detect global change in local species richness was also related to spatial grain, making it harder to detect trends for sites sampled at smaller plot sizes. Spatial sampling biases not only reduced the ability to detect negative global biodiversity trends but sometimes yielded positive trends. We conclude that detecting accurate global biodiversity trends using local richness may simply be unfeasible with current approaches. We suggest that monitoring a representative network of sites implemented at the national level, combined with models accounting for errors and biases, can help improve our understanding of global biodiversity change.
@article{benedetti2023evi,
title = {EVI and NDVI as proxies for multifaceted avian diversity in urban areas},
author = {Benedetti, Yanina and Callaghan, Corey T and Ulbrichov{\'a}, Iva and Galanaki, Antonia and Kominos, Theodoros and Abou Zeid, Farah and Ib{\'a}{\~n}ez-{\'A}lamo, Juan Diego and Suhonen, Jukka and D{\'\i}az, Mario and Mark{\'o}, G{\'a}bor and others},
journal = {Ecological Applications},
pages = {e2808},
year = {2023},
publisher = {Wiley Online Library},
file = {Benedetti_et_al-2023-EVI and NDVI as proxies for multifaceted avian diversity in urban areas.pdf},
doi = {10.1002/eap.2808}
}
Most ecological studies use remote sensing to analyze broad-scale biodiversity patterns, focusing mainly on taxonomic diversity in natural landscapes. One of the most important effects of high levels of urbanization is species loss (i.e., biotic homogenization). Therefore, cost-effective and more efficient methods to monitor biological communities’ distribution are essential. This study explores whether the Enhanced Vegetation Index (EVI) and the Normalized Difference Vegetation Index (NDVI) can predict multifaceted avian diversity, urban tolerance, and specialization in urban landscapes. We sampled bird communities among 15 European cities and extracted Landsat 30-meter resolution EVI and NDVI values of the pixels within a 50-m buffer of bird sample points using Google Earth Engine (32-day Landsat 8 Collection Tier 1). Mixed models were used to find the best associations of EVI and NDVI, predicting multiple avian diversity facets: Taxonomic diversity, functional diversity, phylogenetic diversity, specialization levels, and urban tolerance. A total of 113 bird species across 15 cities from 10 different European countries were detected. EVI mean was the best predictor for foraging substrate specialization. NDVI mean was the best predictor for most avian diversity facets: taxonomic diversity, functional richness and evenness, phylogenetic diversity, phylogenetic species variability, community evolutionary distinctiveness, urban tolerance, diet foraging behavior, and habitat richness specialists. Finally, EVI and NDVI standard deviation were not the best predictors for any avian diversity facets studied. Our findings expand previous knowledge about EVI and NDVI as surrogates of avian diversity at a continental scale. Considering the European Commission’s proposal for a Nature Restoration Law calling for expanding green urban space areas by 2050, we propose NDVI as a proxy of multiple facets of avian diversity to efficiently monitor bird community responses to land use changes in the cities.
@article{mesaglio2023recognition,
title = {Recognition and completeness: two key metrics for judging the utility of citizen science data},
author = {Mesaglio, Thomas and Callaghan, Corey T and Samonte, Fabrice and Gorta, Simon BZ and Cornwell, William K},
journal = {Frontiers in Ecology and the Environment},
year = {2023},
publisher = {Wiley Online Library},
file = {Mesaglio_et_al-2023-Recognition and completeness_two key metrics for judging the utility of citizen science data.pdf},
doi = {10.1002/fee.2604}
}
Biodiversity citizen science data are being collected at unprecedented scales, and are key for informing conservation and research. Species-level data typically provide the most valuable information, but recognition of specimens to species level from photographs varies among taxa. We examined a large dataset of Australian photographic observations of terrestrial invertebrates uploaded to iNaturalist to quantify recognition to species across different taxa. We also quantified the proportion of Australian species that have been uploaded to iNaturalist. Across 1,013,171 observations covering 14,663 species (17.8% completeness), 617,045 (60.9%) were recognized to species. Dragonflies/damselflies and butterflies were the best-recognized and most complete taxa, and therefore represent the best groups for researchers and managers intending to use existing iNaturalist data at large spatial and temporal scales. The recruitment of additional experts to identify records, and enhanced support for accessible resources for hard-to-identify taxa, will likely increase recognition for other taxa.
@article{gorta2023habitat,
title = {Habitat associations of dryland avian communities during an extended dry period},
author = {Gorta, Simon BZ and Callaghan, Corey T and Pedler, Reece D and Read, John L and West, Rebecca S and Kingsford, Richard T},
journal = {Austral Ecology},
volume = {48},
number = {1},
pages = {56--80},
year = {2023},
publisher = {Wiley Online Library},
file = {Gorta_et_al-2023-Habitat associations of dryland avian communities during an extended dry period.pdf},
doi = {10.1111/aec.13251}
}
The influence of resource availability on ecosystem function varies spatially and temporally, among and within ecosystems. Dramatic shifts in moisture-driven resources can drive bottom-up effects on animal behaviours and distributions. Further, complexity arises when landscapes are influenced by large mammalian grazers and predator-induced trophic cascades, such as those mediated by the dingo (Canis familiaris (Dingo)) in the eastern arid Strzelecki Desert in Australia. During the driest two-year period on record for this region, we investigated the persistence of avian communities associated with structurally distinct dunes and swale habitats, and across two different land management regimes (pastoral land with livestock and dingoes, and Sturt National Park managed for conservation without these animals). We grouped all birds into dietary functional groups to infer patterns of habitat use associated with available resources. We also compared incidental observations of the ‘winter’ bird community in part of the study region between the extended dry period of 2018/2019 and wet period of 2020/2021. Despite habitat partitioning, the avian community did not differ between land management regimes except in species richness during the dry period, likely driven by the low numbers of birds present during the surveys. Incidental observations indicated that insectivorous and omnivorous species dominated the bird community in the dry period, with granivorous species forming a greater proportion of the bird community during wet times. Birds with completely or partially insectivorous diets dominated avian species composition on surveys in the dry period, but there were distinct structural vegetation associations among functional groups, indicating that heterogeneity in vegetation structure was likely important for the conservation of refuges, which enable the persistence of avifauna during extended dry periods. Distinct habitat type, structure and available resources shaped avian communities in this landscape, during the extremely resource-limited extended dry period, with implications for conservation and management, particularly given the increasing drying effects of climate change.
@article{lee2023using,
title = {Using citizen science to measure recolonisation of birds after the Australian 2019--2020 mega-fires},
author = {Lee, Joshua S and Callaghan, Corey T and Cornwell, William K},
journal = {Austral Ecology},
volume = {48},
pages = {31--40},
year = {2023},
file = {Lee_et_al-2023-Using citizen science to measure recolonisation of birds after fire.pdf},
doi = {10.1111/aec.13105}
}
Large and severe fires (‘mega-fires’) are increasing in frequency across the globe, often pushing into ecosystems that have previously had very long fire return intervals. The 2019–2020 Australian bushfire season was one of the most catastrophic fire events on record. Almost 19 million hectares were burnt across the continent displacing and killing unprecedented numbers of native fauna, including bird species. Some bird species are known to thrive in post-fire environments, while others may be absent for an extended period from the firegrounds until there is sufficient ecosystem recovery. To test for systematic patterns in species use of the post-fire environment, we combined citizen science data from eBird with data on sedentism, body size, range size and the specialisation of diet and habitat. Using generalised additive models, we modelled the responses of 76 bird species to the 2019–2020 Australian mega-fires. Twenty-two species decreased in occurrence after the fire; 30 species increased; and no significant effect was found for the remaining 24 species. Furthermore, diet specialists, and birds with smaller body sizes and range sizes were less likely to be found in burnt areas after the fire event compared to before, a result which generates testable hypotheses for recovery from other mega-fires across the globe. Being displaced from the firegrounds for an event of this geographic magnitude may have severe consequences for population dynamics and thus warrant considerable conservation attention in pre-fire planning and in the post-fire aftermath.
@article{callaghan2023large,
title = {Large-scale spatial variability in urban tolerance of birds},
author = {Callaghan, Corey T and Palacio, Facundo X and Benedetti, Yanina and Morelli, Federico and Bowler, Diana E},
journal = {Journal of Animal Ecology},
volume = {92},
number = {2},
pages = {403--416},
year = {2022},
publisher = {Wiley Online Library},
file = {Callaghan_et_al-2023-Large‐scale spatial variability in urban tolerance of birds.pdf},
doi = {10.1111/1365-2656.13862}
}
1. Quantifying intraspecific and interspecific trait variability is critical to our understanding of biogeography, ecology and conservation. But quantifying such variability and understanding the importance of intraspecific and interspecific variability remain challenging. This is especially true of large geographic scales as this is where the differences between intraspecific and interspecific variability are likely to be greatest. 2. Our goal is to address this research gap using broad-scale citizen science data to quantify intraspecific variability and compare it with interspecific variability, using the example of bird responses to urbanization across the continental United States. 3. Using more than 100 million observations, we quantified urban tolerance for 338 species within randomly sampled spatial regions and then calculated the standard deviation of each species’ urban tolerance. 4. We found that species’ spatial variability in urban tolerance (i.e. standard deviation) was largely explained by the variability of urban cover throughout a species’ range (R2= 0.70). Variability in urban tolerance was greater in species that were more tolerant of urban cover (i.e. the average urban tolerance throughout their range), suggesting that generalist life histories are better suited to adapt to novel anthropogenic environments. Overall, species differences explained most of the variability in urban tolerance across spatial regions.5. Together, our results indicate that (1) intraspecific variability is largely predicted by local environmental variability in urban cover at a large spatial scale and (2) interspecific variability is greater than intraspecific variability, supporting the common use of mean values (i.e. collapsing observations across a species’ range) when assessing species–environment relationships. Further studies, across
@article{callaghan2022benefits,
title = {The benefits of contributing to the citizen science platform iNaturalist as an identifier},
author = {Callaghan, Corey T and Mesaglio, Thomas and Ascher, John S and Brooks, Thomas M and Cabras, Analyn A and Chandler, Mark and Cornwell, William K and Crist{\'o}bal R{\'\i}os-M{\'a}laver, Indiana and Dankowicz, Even and Urfi Dhiya’ulhaq, Naufal and others},
journal = {PLoS biology},
volume = {20},
number = {11},
pages = {e3001843},
year = {2022},
publisher = {Public Library of Science San Francisco, CA USA},
file = {Callaghan_et_al-2022-The benefits of contributing to the citizen science platform iNaturalist as an identifier.pdf},
doi = {10.1371/journal.pbio.3001843}
}
As the number of observations submitted to the citizen science platform iNaturalist continues to grow, it is increasingly important that these observations can be identified to the finest taxonomic level, maximizing their value for biodiversity research. Here, we explore the benefits of acting as an identifier on iNaturalist.
@article{spake2022detecting,
title = {Detecting thresholds of ecological change in the Anthropocene},
author = {Spake, Rebecca and Barajas-Barbosa, Martha Paola and Blowes, Shane A and Bowler, Diana E and Callaghan, Corey T and Garbowski, Magda and Jurburg, Stephanie D and van Klink, Roel and Korell, Lotte and Ladouceur, Emma and others},
journal = {Annual Review of Environment and Resources},
volume = {47},
year = {2022},
pages = {797--821},
publisher = {Annual Reviews},
file = {Spake_et_al-2022-Detecting thresholds of ecological change in the Anthropocene.pdf},
doi = {10.1146/annurev-environ-112420-015910}
}
Ecological thresholds comprise relatively fast changes in ecological conditions, with respect to time or external drivers, and are an attractive concept in both scientific and policy arenas. However, there is considerable debate concerning the existence, underlying mechanisms, and generalizability of ecological thresholds across a range of ecological subdisciplines. Here, we usethe general concept of scale as a unifying framework with which to systematically navigate the variability within ecological threshold research. We review the literature to show how the observational scale adopted in any one study, defined by its organizational level, spatiotemporal grain and extent, and analytical method, can influence threshold detection and magnitude. We highlight a need for nuance in synthetic studies of thresholds, which could improve our predictive understanding of thresholds. Nuance is also needed when translating threshold concepts into policies, including threshold contingencies and uncertainties.
@article{palacio2022protocol,
title = {A protocol for reproducible functional diversity analyses},
author = {Palacio, Facundo X and Callaghan, Corey T and Cardoso, Pedro and Hudgins, Emma J and Jarzyna, Marta A and Ottaviani, Gianluigi and Riva, Federico and Graco-Roza, Caio and Shirey, Vaughn and Mammola, Stefano},
journal = {Ecography},
volume = {},
number = {11},
pages = {e06287},
year = {2022},
publisher = {Wiley Online Library},
file = {Palacio_et_al_2022-A protocol for reproducible functional diversity analyses.pdf},
doi = {10.1111/ecog.06287}
}
The widespread use of species traits in basic and applied ecology, conservation and biogeography has led to an exponential increase in functional diversity analyses, with > 10 000 papers published in 2010–2020, and > 1800 papers only in 2021. This interest is reflected in the development of a multitude of theoretical and methodological frameworks for calculating functional diversity, making it challenging to navigate the myriads of options and to report detailed accounts of trait-based analyses. Therefore, the discipline of trait-based ecology would benefit from the existence of a general guideline for standard reporting and good practices for analyses. We devise an eight-step protocol to guide researchers in conducting and reporting functional diversity analyses, with the overarching goal of increasing reproducibility, transparency and comparability across studies. The protocol is based on: 1) identification of a research question; 2) a sampling scheme and a study design; 3–4) assemblage of data matrices; 5) data exploration and preprocessing; 6) functional diversity computation; 7) model fitting, evaluation and interpretation; and 8) data, metadata and code provision. Throughout the protocol, we provide information on how to best select research questions, study designs, trait data, compute functional diversity, interpret results and discuss ways to ensure reproducibility in reporting results. To facilitate the implementation of this template, we further develop an interactive web-based application (stepFD) in the form of a checklist workflow, detailing all the steps of the protocol and allowing the user to produce a final ‘reproducibility report’ to upload alongside the published paper. A thorough and transparent reporting of functional diversity analyses ensures that ecologists can incorporate others’ findings into meta-analyses, the shared data can be integrated into larger databases for consensus analyses, and available code can be reused by other researchers. All these elements are key to pushing forward this vibrant and fast-growing field of research.
@article{thompson2022citizen,
title = {Citizen science reveals meteorological determinants of frog calling at a continental scale},
author = {Thompson, Maureen M and Rowley, Jodi JL and Poore, Alistair GB and Callaghan, Corey T},
journal = {Diversity and Distributions},
volume = {28},
number = {11},
pages = {2375--2387},
year = {2022},
publisher = {Wiley Online Library},
file = {Thompson_et_al-2022-Citizen science reveals meteorological determinants of frog calling at a continental scale.pdf},
doi = {10.1111/ddi.13634}
}
Aim Here we investigate the strength of the relationships between meteorological factors and calling behaviour of 100 Australian frog species using continent-wide citizen science data. First, we use this dataset to quantify the meteorological factors that best predict frog calling. Second, we investigate the strength of interactions among predictor variables. Third, we assess whether frog species cluster into distinct groups based on shared drivers of calling. Location Australia. Method To assess the relationship between calling and meteorological traits, we used spatio-temporal subsampling (daily data fitted to 10 km2 grid cells) of call and meteorological data as inputs to a boosted regression tree. We scaled the model outputs, which created a descriptive ranking of predictor importance. For strongly day-driven species, we conducted further analyses to examine the influences of meteorological factors within the breeding season. Results We found a strong seasonal signal, with day of year the strongest relationship to calling in 67 out of our 100 species, moderate relationships between temperature and calling, and weak relationships between rainfall and calling. Despite the common narratives, we found that frogs did not group into distinct categories based upon the influence of meteorological factors. For strongly day-driven species, we found similar patterns within the breeding season. Main conclusions We demonstrate the importance of day of year and temperature thresholds in predicting frog calling behaviour in Australia. Understanding how meteorological conditions influence phenological events, such as breeding, will be increasingly important considering the rapid changes in environmental conditions and stability throughout most of the world, and how important breeding is to species survival.
@article{liu2022anthropogenic,
title = {Anthropogenic habitat modification alters calling phenology of frogs},
author = {Liu, Gracie and Kingsford, Richard T and Callaghan, Corey T and Rowley, Jodi JL},
journal = {Global Change Biology},
volume = {28},
number = {21},
pages = {6194--6208},
year = {2022},
publisher = {Wiley Online Library},
file = {Liu_et_al_2022-Anthropogenic habitat modifications alters calling phenology of frogs.pdf},
doi = {10.1111/gcb.16367}
}
Anthropogenic habitat modification significantly challenges biodiversity. With its intensification, understanding species’ capacity to adapt is critical for conservation planning. However, little is known about whether and how different species are responding, particularly among frogs. We used a continental-scale citizen science dataset of >226,000 audio recordings of 42 Australian frog species to investigate how calling—a proxy for breeding—phenology varied along an anthropogenic modification gradient. Calling started earlier and breeding seasons lengthened with increasing modification intensity. Breeding seasons averaged 22.9 ± 8.25 days (standard error) longer in the most modified compared to the least modified regions, suggesting that frog breeding activity was sensitive to habitat modification. We also examined whether calls varied along a modification gradient by analysing the temporal and spectral properties of advertisement calls from a subset of 441 audio recordings of three broadly distributed frog species. There was no appreciable effect of anthropogenic habitat modification on any of the measured call variables, although there was high variability. With continued habitat modification, species may shift towards earlier and longer breeding seasons, with largely unknown ecological consequences in terms of proximate and ultimate fitness.
@article{spake2022improving,
title = {Improving quantitative synthesis to achieve generality in ecology},
author = {Spake, Rebecca and O’Dea, Rose E and Nakagawa, Shinichi and Doncaster, C Patrick and Ryo, Masahiro and Callaghan, Corey T and Bullock, James M},
journal = {Nature Ecology \& Evolution},
volume = {6},
pages = {1818--1828},
year = {2022},
publisher = {Nature Publishing Group},
file = {Spake_et_al-2022-Detecting thresholds of ecological change in the Anthropocene.pdf},
doi = {10.1038/s41559-022-01891-z}
}
Synthesis of primary ecological data is often assumed to achieve a notion of ‘generality’, through the quantification of overall effect sizes and consistency among studies, and has become a dominant research approach in ecology. Unfortunately, ecologists rarely define either the generality of their findings, their estimand (the target of estimation) or the population of interest. Given that generality is fundamental to science, and the urgent need for scientific understanding to curb global scale ecological breakdown, loose usage of the term ‘generality’ is problematic. In other disciplines, generality is defined as comprising both generalizability—extending an inference about an estimand from the sample to the population—and transferability—the validity of estimand predictions in a different sampling unit or population. We review current practice in ecological synthesis and demonstrate that, when researchers fail to define the assumptions underpinning generalizations and transfers of effect sizes, generality often misses its target. We provide guidance for communicating nuanced inferences and maximizing the impact of syntheses both within and beyond academia. We propose pathways to generality applicable to ecological syntheses, including the development of quantitative and qualitative criteria with which to license the transfer of estimands from both primary and synthetic studies.
@article{benedetti2022distribution,
title = {Distribution and protection of avian specialization in Europe},
author = {Benedetti, Yanina and Morelli, Federico and Callaghan, Corey T and Fuller, Richard},
journal = {Global Ecology and Biogeography},
volume = {31},
number = {1},
pages = {10--24},
year = {2022},
file = {Benedetti_et_al-2022-Distribution and protection of avian specialization in Europe.pdf},
doi = {10.1111/geb.13405}
}
Aim We assessed the spatial distribution of four different types of avian specialization throughout Europe, identifying landscape features associated with specialization and quantifying where the Natura 2000 network intersects with areas of high avian specialization. Location Europe. Time period Present day. Taxa studied European breeding birds. Methods We used the European Atlas of breeding birds and four avian specialization measures (diet, foraging behaviour, foraging substrate and habitat). We calculated specialization richness and identified geographical hotspots for each of these ecological traits. We tested whether elevational gradient, landscape heterogeneity or dominant land use predicted each type of specialization richness. We determined which types of European protected areas are most associated with higher specialization richness. Results Diet and foraging substrate specialists increased with elevation, whereas richness of foraging behavioural specialists decreased. There was a greater richness of dietary and habitat specialists in forests than in other environments. The Natura 2000 areas declared under Bird and both directives (Birds and Habitats) intersected with a high dietary, foraging substrate and habitat specialist richness. The richness of foraging behaviour specialists was high in Birds directive areas. Single and multiple hotspots of specialization were greater in protected than non-protected areas. However, almost 30% of specialization hotspots did not intersect with protected areas. Main conclusions Our findings suggest that higher levels of avian specialization in Europe are positively associated with elevation and forested land cover. Importantly, we found that the Natura 2000 network supports all types of avian ecological specialization, albeit mainly in areas declared under both directives.
@article{mansur2022nature,
title = {Nature futures for the urban century: Integrating multiple values into urban management},
author = {Mansur, Andressa V and McDonald, Robert I and G{\"u}neralp, Burak and Kim, HyeJin and de Oliveira, Jose A Puppim and Callaghan, Corey T and Hamel, Perrine and Kuiper, Jan J and Wolff, Manuel and Liebelt, Veronika and others},
journal = {Environmental Science \& Policy},
volume = {131},
pages = {46--56},
year = {2022},
publisher = {Elsevier},
file = {Mansur_et_al_2022-Nature futures for the urban century.pdf},
doi = {10.1016/j.envsci.2022.01.013}
}
There is an emerging consensus that the health of the planet depends on the coexistence between rapidly growing cities and the natural world. One strategy for guiding cities towards sustainability is to facilitate a planning process based on positive visions for urban systems among actors and stakeholders. This paper presents the Urban Nature Futures Framework (UNFF), a framework for scenario building for cities that is based on three Nature Futures perspectives: Nature for Nature, Nature for Society, and Nature as Culture. Our framework engages stakeholders with envisioning the three Nature Futures perspectives through four components using participatory methods and quantitative models: identification of the socio-ecological feedbacks in cities, assessment of indirect impacts of cities on biodiversity, development of multi-scale indicators, and development of scenarios. Stakeholders in cities may use this framework to explore different options for integrating nature in its various manifestations within urban areas and to assess how different community preferences result in various cityscapes and distribution of associated benefits from nature among urban dwellers across multiple scales.
@article{schilling2022economic,
title = {Economic value of regional spearfishing competitions},
author = {Schilling, Hayden T and Riley, Indiana J and Puckeridge, Aaron C and Milne-Muller, Alexandra and Callaghan, Corey T},
journal = {Fisheries Research},
volume = {250},
pages = {106289},
year = {2022},
publisher = {Elsevier},
file = {Schilling_et_al-2022-Economic value of regional spearfishing competitions.pdf},
doi = {10.1016/j.fishres.2022.106289}
}
Large-scale surveys have been used to estimate the value of recreational fishing over large areas and time periods in the past, but there is a lack of information regarding the value of smaller event based recreational fishing activities. Using the travel-cost method, we estimate the overall value generated by two regional spearfishing competitions in eastern Australia and the adjusted value per competitor. The 2021 Bluewater Classic was valued between 32,874 and 39,492 AUD, with past values up to 100,364. The 2021 Eden 3-way Championships was valued between 102,461 and 118,747. On a per-competitor basis, the adjusted mean expenditure was between 1,090 and $1,649. Both competitions generated substantial economic activity within the towns that hosted them, as we estimated that localised expenditure constituted 60 – 71% of a competition’s overall value. These estimates demonstrate the value of recreational competitions for regional areas and the importance for economic surveys to consider smaller events.
@article{roberts2022many,
title = {Many cameras make light work: opportunistic photographs of rare species in iNaturalist complement structured surveys of reef fish to better understand species richness},
author = {Roberts, Christopher J and Verg{\'e}s, Adriana and Callaghan, Corey T and Poore, Alistair GB},
journal = {Biodiversity and Conservation},
pages = {1--19},
year = {2022},
publisher = {Springer Netherlands},
file = {Roberts_et_al_2022-Many camera make light work.pdf},
doi = {10.1007/s10531-022-02398-6}
}
Citizen science is on the rise, with growing numbers of initiatives, participants and increasing interest from the broader scientific community. iNaturalist is an example of a successful citizen science platform that enables users to opportunistically capture and share biodiversity observations. Understanding how data from such opportunistic citizen science platforms compare with and complement data from structured surveys will improve their use in future biodiversity research. We compared the opportunistic fish photographs from iNaturalist to those obtained from structured surveys at eight study reefs in Sydney, Australia over twelve years. iNaturalist recorded 1.2 to 5.5 times more fish species than structured surveys resulting in significantly greater annual species richness at half of the reefs, with the remainder showing no significant difference. iNaturalist likely recorded more species due to having simple methods, which allowed for broad participation with substantially more iNaturalist observation events (e.g., dives) than structured surveys over the same period. These results demonstrate the value of opportunistic citizen science platforms for documenting fish species richness, particularly where access and use of the marine environment is common and communities have the time and resources for expensive recreational activities (i.e., underwater photography). The datasets also recorded different species composition with iNaturalist recording many rare, less abundant, or cryptic species while the structured surveys captured many common and abundant species. These results suggest that integrating data from both opportunistic and structured data sources is likely to have the best outcome for future biodiversity monitoring and conservation activities.
@article{callaghan2022quantifying,
title = {Quantifying effort needed to estimate species diversity from citizen science data},
author = {Callaghan, Corey T and Bowler, Diana E and Blowes, Shane A and Chase, Jonathan M and Lyons, Mitchell B and Pereira, Henrique M},
journal = {Ecosphere},
volume = {13},
number = {4},
pages = {e3966},
year = {2022},
publisher = {John Wiley \& Sons, Inc. Hoboken, USA},
file = {Callaghan_et_al-2022-Quantifying effort needed to estimate species diversity from citizen science data.pdf},
doi = {10.1002/ecs2.3966}
}
Broad-scale biodiversity monitoring relies, at least in part, on the efforts of citizen, or community, scientists. To ensure robust inferences from citizen science data, it is important to understand the spatial pattern of sampling effort by citizen scientists and how it deviates from an optimal pattern. Here, we develop a generalized workflow to estimate the optimal distribution of sampling effort for inference of species diversity (e.g., species richness, Shannon diversity, and Simpson’s diversity) patterns using the relationship between species diversity and land cover. We used data from the eBird citizen science project that was collected across heterogeneous landscapes in Florida (USA) to illustrate this workflow across different grain sizes. We found that a relatively small number of samples are needed to meet 95% sampling completeness when diversity estimation is focused on dominant species: 43, 64, 96, 123, 172, and 176 for 5 × 5, 10 × 10, 15 × 15, 20 × 20, 25 × 25, and 30 × 30-km2 grain sizes, respectively. In contrast, three to five times more samples are necessary to infer species diversity when estimation is focused on rare species. However, in both cases, the optimal distribution of effort was spatially heterogeneous, with more effort needed in regions of higher diversity. Our results highlight the potential of citizen science data to make informed comparisons of species diversity in space and time, as well as how sampling effort inherently depends on monitoring goals, such as whether dominant or rare species are targeted. Our general workflow allows for the quantification of sampling effort needed to estimate species diversity with citizen science data and can guide future adaptive sampling by citizen science participants.
@article{bolt2022using,
title = {Using the background of fish photographs to quantify habitat composition in marine ecosystems},
author = {Bolt, Madison H and Callaghan, Corey T and Poore, Alistair GB and Verg{\'e}s, Adriana and Roberts, Christopher J},
journal = {Marine Ecology Progress Series},
volume = {688},
pages = {167--172},
year = {2022},
file = {Bolt_et_al_2022-Using the background of fish photographs to quantify habitat composition in marine ecosystems.pdf},
doi = {10.3354/meps14027}
}
Citizen science initiatives that collect opportunistic photos, or recordings, of living organisms (e.g. iNaturalist) are increasingly recognized for their importance in monitoring biodiversity. These projects are focussed primarily on recording the occurrence of individual species in space and time. Each photo potentially also contains additional valuable information. Here, we explored the amount and potential value of background information captured in fish photographs as a method to characterise reef habitats. The habitat in the background of fish photographs shared on iNaturalist was analysed for 6 sites across Australia. To measure accuracy of the habitat data captured in the iNaturalist photos, the habitat composition of each site was compared to standardised photo-quadrats from the citizen science project Reef Life Survey (RLS). Across all sites, 70-85% of the fish photographs from iNaturalist contained discernible biotic habitat in the background. Habitat composition as measured from the background of opportunistic fish photographs was similar to those of standardised surveys from RLS. In the face of rapid environmental change, opportunistic photographs collected by recreational divers represent a complementary way to rapidly and cost-effectively collect habitat data at more reefs and more frequently than is generally feasible with standardised scientific surveys.
@article{segar2022urban,
title = {Urban conservation gardening in the decade of restoration},
author = {Segar, Josiane and Callaghan, Corey T and Ladouceur, Emma and Meya, Jasper N and Pereira, Henrique M and Perino, Andrea and Staude, Ingmar R},
journal = {Nature Sustainability},
pages = {1--8},
year = {2022},
publisher = {Nature Publishing Group},
file = {Segar_et_al-2022-Urban conservation gardening in the decade of restoration.pdf},
doi = {10.1038/s41893-022-00882-z}
}
Global commitments and policy interventions for conservation have failed to halt widespread declines in plant biodiversity, highlighting an urgent need to engage novel approaches and actors. Here we propose that urban conservation gardening, namely the cultivation of declining native plant species in public and private green spaces, can be one such approach. We identify policy and complementary social mechanisms to promote conservation gardening and reform the existing horticultural market into an innovative nature-protection instrument. Conservation gardening can be an economically viable and participatory measure that complements traditional approaches to plant conservation.
@article{bowler2022temporal,
title = {Temporal trends in the spatial bias of species occurrence records},
author = {Bowler, Diana E and Callaghan, Corey T and Bhandari, Netra and Henle, Klaus and Benjamin Barth, M and Koppitz, Christian and Klenke, Reinhard and Winter, Marten and Jansen, Florian and Bruelheide, Helge and others},
journal = {Ecography},
pages = {e06219},
year = {2022},
publisher = {Blackwell Publishing Ltd Oxford, UK},
file = {Bowler_et_al-2022-Temporal trends in the spatial bias of species occurrence records.pdf},
doi = {10.1111/ecog.06219}
}
Large-scale biodiversity databases have great potential for quantifying long-term trends of species, but they also bring many methodological challenges. Spatial bias of species occurrence records is well recognized. Yet, the dynamic nature of this spatial bias – how spatial bias has changed over time – has been largely overlooked. We examined the spatial bias of species occurrence records within multiple biodiversity databases in Germany and tested whether spatial bias in relation to land cover or land use (urban and protected areas) has changed over time. We focused our analyses on urban and protected areas as these represent two well-known correlates of sampling bias in biodiversity datasets. We found that the proportion of annual records from urban areas has increased over time while the proportion of annual records within protected areas has not consistently changed. Using simulations, we examined the implications of this changing sampling bias for estimation of long-term trends of species’ distributions. When assessing biodiversity change, our findings suggest that the effects of spatial bias depend on how it affects sampling of the underlying land-use change drivers affecting species. Oversampling of regions undergoing the greatest degree of change, for instance near human settlements, might lead to overestimation of the trends of specialist species. For robust estimation of the long-term trends in species’ distributions, analyses using species occurrence records may need to consider not only spatial bias, but also changes in the spatial bias through time.
@article{bowler2022decision,
title = {Decision-making of citizen scientists when recording species observations},
author = {Bowler, Diana E and Bhandari, Netra and Repke, Lydia and Beuthner, Christoph and Callaghan, Corey T and Eichenberg, David and Henle, Klaus and Klenke, Reinhard and Richter, Anett and Jansen, Florian and others},
journal = {Scientific Reports},
volume = {12},
number = {1},
pages = {1--11},
year = {2022},
publisher = {Nature Publishing Group},
file = {Bowler_et_al-2022-Decision-making of citizen scientists.pdf},
doi = {10.1038/s41598-022-15218-2}
}
Citizen scientists play an increasingly important role in biodiversity monitoring. Most of the data, however, are unstructured—collected by diverse methods that are not documented with the data. Insufficient understanding of the data collection processes presents a major barrier to the use of citizen science data in biodiversity research. We developed a questionnaire to ask citizen scientists about their decision-making before, during and after collecting and reporting species observations, using Germany as a case study. We quantified the greatest sources of variability among respondents and assessed whether motivations and experience related to any aspect of data collection. Our questionnaire was answered by almost 900 people, with varying taxonomic foci and expertise. Respondents were most often motivated by improving species knowledge and supporting conservation, but there were no linkages between motivations and data collection methods. By contrast, variables related to experience and knowledge, such as membership of a natural history society, were linked with a greater propensity to conduct planned searches, during which typically all species were reported. Our findings have implications for how citizen science data are analysed in statistical models; highlight the importance of natural history societies and provide pointers to where citizen science projects might be further developed.
@article{callaghan2021build,
title = {How to build a biodiverse city: environmental determinants of bird diversity within and among 1581 cities},
author = {Callaghan, Corey T and Poore, Alistair GB and Major, Richard E and Cornwell, William K and Wilshire, John H and Lyons, Mitchell B},
journal = {Biodiversity and Conservation},
volume = {30},
number = {1},
pages = {217--234},
year = {2021},
publisher = {Springer Netherlands},
file = {Callaghan_et_al-2021-How to build a biodiverse city.pdf},
doi = {10.1007/s10531-020-02088-1}
}
Cities are novel environments compared with the evolutionary history of the species that reside within them. Collectively, cities and their fauna can be thought of as ecosystems, recognized as playing a critical role in supporting global biodiversity, but they are fundamentally a combination of ‘old species’ surviving or thriving in a new environment. We aimed to understand—at a broad macroecological scale—how biodiversity responds to urban ecosystems both among and within cities. We integrated > 5 million eBird citizen science observations with remotely sensed landcover products throughout 1581 cities within the continental United States. We first investigated the species-area relationship as it pertains to cities and compared the slope of this relationship to randomly sampled polygons (i.e., among cities). Second, we investigated how biodiversity responds to an urbanization gradient at the level of localized bird observations (i.e., within cities). We found strong support for the longstanding species-area relationship: geographically larger cities had greater species richness. Surprisingly, the species-area relationship was stronger (i.e., steeper slope) in cities when compared to the species-area relationship for randomly sampled polygons in the study region. Our findings suggest that diverse and heterogeneous cities play a significant role in supporting biodiversity. But we also found that there is a consistent threshold where the level of urbanization begins to profoundly and negatively affect biodiversity. Critically, urban planning at the city-scale and at a local-scale (e.g., neighborhood) should focus on preserving attributes of water-cover and tree-cover for increased biodiversity to keep as much of the city as possible above this threshold value.
@article{kirchhoff2021rapidly,
title = {Rapidly mapping fire effects on biodiversity at a large-scale using citizen science},
author = {Kirchhoff, Casey and Callaghan, Corey T and Keith, David A and Indiarto, Dony and Taseski, Guy and Ooi, Mark KJ and Le Breton, Tom D and Mesaglio, Thomas and Kingsford, Richard T and Cornwell, William K},
journal = {Science of The Total Environment},
volume = {755},
pages = {142348},
year = {2021},
publisher = {Elsevier},
file = {Kirchoff_et_al-2020-Rapidly mapping fire effects on biodiversity at a large-scale using citizen science.pdf},
doi = {10.1016/j.scitotenv.2020.142348}
}
The unprecedented scale of the 2019–2020 eastern Australian bushfires exemplifies the challenges that scientists and conservation biologists face monitoring the effects on biodiversity in the aftermath of large-scale environmental disturbances. After a large-scale disturbance, conservation policy and management actions need to be both timely and informed by data. By working with the public, often widely spread out over such disturbed areas, citizen science offers a unique opportunity to collect data on biodiversity responses at the appropriate scale. We detail a citizen science project, hosted through iNaturalist, launched shortly after the 2019–2020 bushfire season in eastern Australia. It rapidly (1) provided accurate data on fire severity, relevant to future recovery; and (2) delivered data on a wide range (mosses to mammals) of biodiversity responses at a scale that matched the geographic extent of these fires.
@article{callaghan2021validation,
title = {Validation of a globally-applicable method to measure urban tolerance of birds using citizen science data},
author = {Callaghan, Corey T and Sayol, Ferran and Benedetti, Yanina and Morelli, Federico and Sol, Daniel},
journal = {Ecological Indicators},
volume = {120},
pages = {106905},
year = {2021},
publisher = {Elsevier},
file = {Callaghan_et_al-2021-Validation of a globally-applicable method to measure urban tolerance of birds using citizen science data.pdf},
doi = {10.1016/j.ecolind.2020.106905}
}
Understanding species-specific responses to urbanization is essential to mitigate and preserve biodiversity in the face of increasing urbanization, but a major challenge is how to estimate urban tolerances for a wide array of species applicable over disparate regions. A promising approach is to assess urban tolerance by integrating geo-referenced information on species detections from citizen science data with estimations of urbanization intensity based on remotely-sensed night-time lights. While such citizen science urbanness scores (CSUS) are cost-effective, intuitive, and easily-repeatable anywhere in the world, whether the scores accurately describe urban tolerance still awaits empirical verification. By analysing >900 bird species worldwide, we find that CSUS correlates well with a standard measure of urban tolerance based on changes in abundance between urbanized and non-urbanized nearby habitats. Our analyses show that there is substantial variability in the relationship between these two metrics, but nevertheless highlights the potential for the CSUS approach in the future. Future improvements to the index, including incorporating rare species, and understanding the influence of intra-specific variability in response to urbanization, will be necessary to maximize the broad utility of the approach.
@article{callaghan2021continental,
title = {A continental assessment of diurnality in frog calling behaviour},
author = {Callaghan, Corey T and Rowley, Jodi JL},
journal = {Austral Ecology},
volume = {46},
number = {1},
pages = {65--71},
year = {2021},
file = {Callaghan_and_Rowley-2020-A continental assessment of diurnality in frog calling behaviour.pdf},
doi = {10.1111/aec.12959}
}
Acoustic signalling is evolutionarily important, influencing sexual selection and serving as a premating isolation mechanism. There is a strong evolutionary basis for acoustic signalling to occur nocturnally across many terrestrial vertebrate groups including mammals, reptiles and amphibians. Within some of these groups, there is a general assumption that ‘most taxa are nocturnal’ in their acoustic signalling, and this is a particularly strongly held view for most frogs. Here we challenge this well-accepted notion by quantifying diurnal calling behaviour in Australian frogs, leveraging a continental-wide citizen science dataset. Of 196 species present in the citizen science dataset, 140 (71%) were recorded at least once during the day. Of the most commonly observed species (i.e. species with at least 150 calls recorded in the database), there were surprisingly high rates of diurnal calling: 14 species had >25% of their calls recorded during the day. We also found that the relative rate of diurnal calling in frogs showed a strong phylogenetic signal, suggesting that the plasticity in calling behaviour as it relates to time of the day is strongly evolutionarily conserved. Our results highlight a suite of ecological and evolutionary questions that are worthy of further investigation.
@article{callaghan2021three,
title = {Three frontiers for the future of biodiversity research using citizen science data},
author = {Callaghan, Corey T and Poore, Alistair GB and Mesaglio, Thomas and Moles, Angela T and Nakagawa, Shinichi and Roberts, Christopher and Rowley, Jodi JL and Verg{\'e}s, Adriana and Wilshire, John H and Cornwell, William K},
journal = {BioScience},
volume = {71},
number = {1},
pages = {55--63},
year = {2021},
publisher = {Oxford University Press},
file = {Callaghan_et_al-2021-Three frontiers for the future of biodiversity research using citizen science data.pdf},
doi = {10.1093/biosci/biaa131}
}
Citizen science is fundamentally shifting the future of biodiversity research. But although citizen science observations are contributing an increasingly large proportion of biodiversity data, they only feature in a relatively small percentage of research papers on biodiversity. We provide our perspective on three frontiers of citizen science research, areas that we feel to date have had minimal scientific exploration but that we believe deserve greater attention as they present substantial opportunities for the future of biodiversity research: sampling the undersampled, capitalizing on citizen science’s unique ability to sample poorly sampled taxa and regions of the world, reducing taxonomic and spatial biases in global biodiversity data sets; estimating abundance and density in space and time, develop techniques to derive taxon-specific densities from presence or absence and presence-only data; and capitalizing on secondary data collection, moving beyond data on the occurrence of single species and gain further understanding of ecological interactions among species or habitats. The contribution of citizen science to understanding the important biodiversity questions of our time should be more fully realized.
@article{callaghan2021conservation,
title = {Conservation birding: A quantitative conceptual framework for prioritizing citizen science observations},
author = {Callaghan, Corey T and Watson, James EM and Lyons, Mitchell B and Cornwell, William K and Fuller, Richard A},
journal = {Biological Conservation},
volume = {253},
pages = {108912},
year = {2021},
publisher = {Elsevier},
file = {Callaghan_et_al-2021-Conservation birding - a quantitative conceptual framework for prioritizing citizen science observations.pdf},
doi = {10.1016/j.biocon.2020.108912}
}
Despite impressive growth in global biodiversity data, knowledge about the occurrence of species in many parts of the world remains incomplete because of major gaps in the underlying data. This can lead to ill-informed conservation decisions. The collective effort of citizen scientists can generate a great deal of data quickly, but how might we prioritize the powerful — but finite — effort? We argue that instead of simply filling empty spots on the map based solely on where biodiversity information is incomplete, near-term threats to the integrity or persistence of biodiversity assemblages could also be incorporated to prioritize citizen science sampling. Here we develop a quantitative framework illustrating how citizen science sampling and initiatives can be prioritized when simultaneously considering both the completeness of biodiversity sampling and the risk of habitat conversion. We illustrate this framework for birds using global citizen science data from the eBird platform and a global model of the risk of habitat conversion. We find that regions in Africa and southeast Asia would rank as the highest priorities for new and expanded citizen science initiatives. Our framework provides a mechanism to quantify where new biodiversity data are most urgently needed, ultimately helping to improve environmental decision-making. We anticipate this framework can be used in the future at a suite of relevant planning scales, ranging from local to regional to global.
@article{callaghan2021urban,
title = {Urban tolerance of birds changes throughout the full annual cycle},
author = {Callaghan, Corey T and Cornwell, William K and Poore, Alistair GB and Benedetti, Yanina and Morelli, Federico},
journal = {Journal of Biogeography},
volume = {48},
number = {6},
pages = {1503--1517},
year = {2021},
file = {Callaghan_et_al-2021-Urban tolerance of birds changes throughout the full annual cycle.pdf},
doi = {10.1111/jbi.14093}
}
Aim As urban areas continue to expand, it is increasingly important to quantify species-specific responses to urban environments, and how these change across the full annual cycle. Our objective was to quantify urban tolerance for North American birds across the time. We tested (a) whether intra-annual variability of urban tolerance differed between migrants and residents and (b) whether intra-annual variability of urban tolerance was phylogenetically conserved. We then assessed how the relationship between ecological and life history traits and urban tolerance differed both across the year and between migrants and residents. Location North America. Taxon Birds. Methods We integrated a large citizen science dataset of observations for 237 bird species, remotely sensed VIIRS night-time lights data, and trait data on each species. We estimate, for each species and each month of the year, a continuous measure of urban tolerance (i.e. the median of their distribution of observations across an urbanization gradient). We then use phylogenetic linear models to assess the relationship between this measure of urban tolerance and various life history and ecological traits. Results There was a distinct drop in the overall urban tolerance scores corresponding with the breeding period; this pattern was more pronounced for migrants compared to residents. Migrants also had greater intra-annual variability than resident species. We also found that the strength of the relationships between ecological and life history traits and urban tolerance was highly seasonal for most traits considered, and some divergent patterns were noted between migrants and residents. Main conclusions The urban tolerance of birds greatly changed throughout the annual cycle, with different patterns for migrants and residents. Compared to residents, migrants showed more intra-annual variability of urban tolerance with a drop in the average urban tolerance score during the breeding season. Together, our results suggest that urban tolerance is a function of both species and season, and they highlight the importance of considering the dynamic nature of birds’ use of urban ecosystems throughout the full annual cycle.
@article{mesaglio2021overview,
title = {An overview of the history, current contributions and future outlook of iNaturalist in Australia},
author = {Mesaglio, Thomas and Callaghan, Corey T},
journal = {Wildlife Research},
volume = {48},
number = {4},
pages = {289--303},
year = {2021},
publisher = {CSIRO PUBLISHING},
file = {Mesaglio_and_Callaghan-2021-Overview of iNaturalist in Australia.pdf},
doi = {10.1071/WR20154}
}
Citizen science initiatives and the data they produce are increasingly common in ecology, conservation and biodiversity monitoring. Although the quality of citizen science data has historically been questioned, biases can be detected and corrected for, allowing these data to become comparable in quality to professionally collected data. Consequently, citizen science is increasingly being integrated with professional science, allowing the collection of data at unprecedented spatial and temporal scales. iNaturalist is one of the most popular biodiversity citizen science platforms globally, with more than 1.4 million users having contributed over 54 million observations. Australia is the top contributing nation in the southern hemisphere, and in the top four contributing nations globally, with over 1.6 million observations of over 36 000 identified species contributed by almost 27 000 users. Despite the platform’s success, there are few holistic syntheses of contributions to iNaturalist, especially for Australia. Here, we outline the history of iNaturalist from an Australian perspective, and summarise, taxonomically, temporally and spatially, Australian biodiversity data contributed to the platform. We conclude by discussing important future directions to maximise the usefulness of these data for ecological research, conservation and policy.
@article{laitly2021color,
title = {Is color data from citizen science photographs reliable for biodiversity research?},
author = {Laitly, Alexandra and Callaghan, Corey T and Delhey, Kaspar and Cornwell, William K},
journal = {Ecology and evolution},
volume = {11},
number = {9},
pages = {4071--4083},
year = {2021},
file = {Laitly_et_al-2021-Colour data from citizen science photographs.pdf},
doi = {10.1002/ece3.7307}
}
Color research continuously demands better methods and larger sample sizes. Citizen science (CS) projects are producing an ever-growing geo- and time-referenced set of photographs of organisms. These datasets have the potential to make a huge contribution to color research, but the reliability of these data need to be tested before widespread implementation. We compared the difference between color extracted from CS photographs with that of color extracted from controlled lighting conditions (i.e., the current gold standard in spectrometry) for both birds and plants. First, we tested the ability of CS photographs to quantify interspecific variability by assessing > 9,000 CS photographs of 537 Australian bird species with controlled museum spectrometry data. Second, we tested the ability of CS photographs to quantify intraspecific variability by measuring petal color data for two plant species using seven methods/sources with varying levels of control. For interspecific questions, we found that by averaging out variability through a large sample size, CS photographs capture a large proportion of across species variation in plumage color within the visual part of the spectrum (R2 = 0.68–0.71 for RGB space and 0.72–0.77 for CIE-LAB space). Between 12 and 14 photographs per species are necessary to achieve this averaging effect for interspecific studies. Unsurprisingly, the CS photographs taken with commercial cameras failed to capture information in the UV part of the spectrum. For intraspecific questions, decreasing levels of control increase the color variation but averaging larger sample sizes can partially mitigate this, aside from particular issues related to saturation and irregularities in light capture. CS photographs offer a very large sample size across space and time which offers statistical power for many color research questions. This study shows that CS photographs contain data that lines up closely with controlled measurements within the visual spectrum if the sample size is large enough, highlighting the potential of CS photographs for both interspecific and intraspecific ecological or biological questions. With regard to analyzing color in CS photographs, we suggest, as a starting point, to measure multiple random points within the ROI of each photograph for both patterned and unpatterned patches and approach the recommended sample size of 12–14 photographs per species for interspecific studies. Overall, this study provides groundwork in analyzing the reliability of a novel method, which can propel the field of studying color forward.
@article{callaghan2021urbanization,
title = {Urbanization negatively impacts frog diversity at continental, regional, and local scales},
author = {Callaghan, Corey T and Liu, Gracie and Mitchell, Brittany A and Poore, Alistair GB and Rowley, Jodi JL},
journal = {Basic and Applied Ecology},
volume = {54},
pages = {64--74},
year = {2021},
publisher = {Urban \& Fischer},
file = {Callaghan_et_al-2021-Urbanization negatively impacts frog diversity at continental, regional, and local scales.pdf},
doi = {10.1016/j.baae.2021.04.003}
}
Urban environments are novel ecosystems, with increased chemical, sound, and light pollution differentially impacting many animals. Understanding the impacts of urban environments on biodiversity is the first step to understanding how to best mitigate biodiversity losses in an increasingly urbanizing world. Analyses with broad geographic and taxonomic coverage can offer critical context for informing urban biodiversity conservation. But such studies are currently lacking, especially for under-studied, but likely highly impacted, taxa such as frogs. Our objective was to document frog diversity in relation to urban environments at continental, regional, and local scales. We used FrogID data, an opportunistic citizen science dataset generated by volunteers recording calling frogs using a smartphone and validated by experts throughout continental Australia, to calculate species richness, Shannon diversity, and phylogenetic diversity of frogs in urban and non-urban areas, as well as along a continuous urbanization gradient. The overall species richness of frogs was, on average, 57% less in urban than non-urban areas across six ecoregions. Further, we found significantly lower frog diversity in urban environments compared with non-urban environments across the country, with an average reduction of 59% species richness, 86% Shannon diversity, and 72% phylogenetic diversity. We also found evidence for a steady decrease in frog diversity along an urbanization gradient, with no obvious thresholds. Our results highlight the negative impacts of urbanization, at a continental scale, on frog diversity, and clearly highlight the necessity to consider frog diversity in future urban land development decisions.
@article{liu2021species,
title = {Species' traits drive amphibian tolerance to anthropogenic habitat modification},
author = {Liu, Gracie and Rowley, Jodi JL and Kingsford, Richard T and Callaghan, Corey T},
journal = {Global Change Biology},
volume = {27},
number = {13},
pages = {3120--3132},
year = {2021},
file = {Liu_et_al_2021-Species traits drive amphibian tolerance to anthropogenic habitat modification.pdf},
doi = {10.1111/gcb.15623}
}
Anthropogenic habitat modification is accelerating, threatening the world’s biodiversity. Understanding species’ responses to anthropogenic modification is vital for halting species’ declines. However, this information is lacking for globally threatened amphibians, informed primarily by small community-level studies. We integrated >126,000 verified citizen science observations of frogs, with a global continuous measure of anthropogenic habitat modification for a continental scale analysis of the effects of habitat modification on frogs. We derived a modification tolerance index—accounting for anthropogenic stressors such as human habitation, agriculture, transport and energy production—for 87 species (36% of all Australian frog species). We used this index to quantify and rank each species’ tolerance of anthropogenic habitat modification, then compiled traits of all the frog species and assessed how well these equipped species to tolerate modified habitats. Most of Australia’s frog species examined were adversely affected by habitat modification. Habitat specialists and species with large geographic range sizes were the least tolerant of habitat modification. Call dominant frequency, body size, clutch type and calling position (i.e. from vegetation) were also related to tolerance of habitat modification. There is an urgent need for improved consideration of anthropogenic impacts and improved conservation measures to ensure the long-term persistence of frog populations, particularly focused on specialists and species identified as intolerant of modified habitats.
@article{callaghan2021global,
title = {Global abundance estimates for 9,700 bird species},
author = {Callaghan, Corey T and Nakagawa, Shinichi and Cornwell, William K},
journal = {Proceedings of the National Academy of Sciences},
volume = {118},
number = {21},
pages = {e2023170118},
year = {2021},
publisher = {National Academy of Sciences},
file = {Callaghan_et_al-2021-Global abundance estimates for 9700 bird species.pdf},
doi = {10.1073/pnas.2023170118}
}
Quantifying the abundance of species is essential to ecology, evolution, and conservation. The distribution of species abundances is fundamental to numerous longstanding questions in ecology, yet the empirical pattern at the global scale remains unresolved, with a few species’ abundance well known but most poorly characterized. In large part because of heterogeneous data, few methods exist that can scale up to all species across the globe. Here, we integrate data from a suite of well-studied species with a global dataset of bird occurrences throughout the world—for 9,700 species (∼92% of all extant species)—and use missing data theory to estimate species-specific abundances with associated uncertainty. We find strong evidence that the distribution of species abundances is log left skewed: there are many rare species and comparatively few common species. By aggregating the species-level estimates, we find that there are ∼50 billion individual birds in the world at present. The global-scale abundance estimates that we provide will allow for a line of inquiry into the structure of abundance across biogeographic realms and feeding guilds as well as the consequences of life history (e.g., body size, range size) on population dynamics. Importantly, our method is repeatable and scalable: as data quantity and quality increase, our accuracy in tracking temporal changes in global biodiversity will increase. Moreover, we provide the methodological blueprint for quantifying species-specific abundance, along with uncertainty, for any organism in the world.
@article{callaghan2021thermal,
title = {Thermal flexibility and a generalist life history promote urban affinity in butterflies},
author = {Callaghan, Corey T and Bowler, Diana E and Pereira, Henrique M},
journal = {Global Change Biology},
volume = {27},
number = {15},
pages = {3532--3546},
year = {2021},
file = {Callaghan_et_al-2021-Thermal flexibility and a generalist life history promote urban tolerance in butterflies.pdf},
doi = {10.1111/gcb.15670}
}
Urban expansion poses a serious threat to biodiversity. Given that the expected area of urban land cover is predicted to increase by 2–3 million km2 by 2050, urban environments are one of the most widespread human-dominated land-uses affecting biodiversity. Responses to urbanization differ greatly among species. Some species are unable to tolerate urban environments (i.e., urban avoiders), others are able to adapt and use areas with moderate levels of urbanization (i.e., urban adapters), and yet others are able to colonize and even thrive in urban environments (i.e., urban exploiters). Quantifying species-specific responses to urbanization remains an important goal, but our current understanding of urban tolerance is heavily biased toward traditionally well-studied taxa (e.g., mammals and birds). We integrated a continuous measure of urbanization—night-time lights—with over 900,000 species’ observations from the Global Biodiversity Information Facility to derive a comprehensive analysis of species-specific (N = 158 species) responses of butterflies to urbanization across Europe. The majority of butterfly species included in our analysis avoided urban areas, regardless of whether species’ urban affinities were quantified as a mean score of urban affinity across all occurrences (79%) or as a species’ response curve to the whole urbanization gradient (55%). We then used species-specific responses to urbanization to assess which life history strategies promote urban affinity in butterflies. These trait-based analyses found strong evidence that the average number of flight months, likely associated with thermal niche breath, and number of adult food types were positively associated with urban affinity, while hostplant specialism was negatively associated with urban affinity. Overall, our results demonstrate that specialist butterflies, both in terms of thermal and diet preferences, are most at risk from increasing urbanization, and should thus be considered in urban planning and prioritized for conservation.
@article{ferretto2021naturally,
title = {Naturally-detached fragments of the endangered seagrass Posidonia australis collected by citizen scientists can be used to successfully restore fragmented meadows},
author = {Ferretto, Giulia and Glasby, Tim M and Poore, Alistair GB and Callaghan, Corey T and Housefield, Graham P and Langley, Madelaine and Sinclair, Elizabeth A and Statton, John and Kendrick, Gary A and Verg{\'e}s, Adriana},
journal = {Biological Conservation},
volume = {262},
pages = {109308},
year = {2021},
publisher = {Elsevier},
file = {Ferretto_et_al-2021-Restoration of seagrass.pdf},
doi = {10.1016/j.biocon.2021.109308}
}
Posidonia australis is a slow-growing seagrass that forms extensive meadows in sheltered coastal locations which are often popular areas for recreational boating. Traditional block-and-chain boat moorings can directly impact P. australis meadows, with the action of heavy chains eroding the seafloor and creating bare sand scars that fragment meadows. The installation of new environmentally friendly moorings (EFMs) can reduce damage to seagrasses, but natural re-establishment by P. australis to scars can be very slow. Given the endangered status of this species in New South Wales, Australia, we developed an innovative restoration procedure to re-establish P. australis transplants within old scars without damaging existing meadows. Naturally-detached rhizome fragments were collected from the shore by citizen-scientists, stored within aquaculture tanks and then planted underwater. We planted a total of 863 fragments into six mooring scars at three different times. Survival of fragments after one year was significantly greater for those planted in June (54%) than in January (31%). The planting techniques (with or without natural fibre mats to stabilize sediments) and environmental conditions (surrounding habitat, depth and presence of the EFM) did not influence survival. Many surviving fragments (36.3%) had produced new shoots during the year. Our results show that naturally-detached seagrass fragments can be used to effectively restore P. australis meadows. This is an important new approach for supplying propagules for restoration without damaging remaining populations of an endangered seagrass, and presents a compelling management approach that engages local communities and enhances conservation efforts.
@article{callaghan2021large,
title = {Large-bodied birds are over-represented in unstructured citizen science data},
author = {Callaghan, Corey T and Poore, Alistair GB and Hofmann, Max and Roberts, Christopher J and Pereira, Henrique M},
journal = {Scientific Reports},
volume = {11},
number = {1},
pages = {1--11},
year = {2021},
publisher = {Nature Publishing Group},
file = {Callaghan_et_al-2021-Large-bodied birds are over-represented in unstructured citizen science data.pdf},
doi = {10.1038/s41598-021-98584-7}
}
Citizen science platforms are quickly accumulating hundreds of millions of biodiversity observations around the world annually. Quantifying and correcting for the biases in citizen science datasets remains an important first step before these data are used to address ecological questions and monitor biodiversity. One source of potential bias among datasets is the difference between those citizen science programs that have unstructured protocols and those that have semi-structured or structured protocols for submitting observations. To quantify biases in an unstructured citizen science platform, we contrasted bird observations from the unstructured iNaturalist platform with that from a semi-structured citizen science platform—eBird—for the continental United States. We tested whether four traits of species (body size, commonness, flock size, and color) predicted if a species was under- or over-represented in the unstructured dataset compared with the semi-structured dataset. We found strong evidence that large-bodied birds were over-represented in the unstructured citizen science dataset; moderate evidence that common species were over-represented in the unstructured dataset; strong evidence that species in large groups were over-represented; and no evidence that colorful species were over-represented in unstructured citizen science data. Our results suggest that biases exist in unstructured citizen science data when compared with semi-structured data, likely as a result of the detectability of a species and the inherent recording process. Importantly, in programs like iNaturalist the detectability process is two-fold—first, an individual organism needs to be detected, and second, it needs to be photographed, which is likely easier for many large-bodied species. Our results indicate that caution is warranted when using unstructured citizen science data in ecological modelling, and highlight body size as a fundamental trait that can be used as a covariate for modelling opportunistic species occurrence records, representing the detectability or identifiability in unstructured citizen science datasets. Future research in this space should continue to focus on quantifying and documenting biases in citizen science data, and expand our research by including structured citizen science data to understand how biases differ among unstructured, semi-structured, and structured citizen science platforms.
@article{gorta2021avifaunal,
title = {Avifaunal use of an artificial waterpoint in the Strzelecki Desert during an extended dry period},
author = {Gorta, Simon BZ and Pedler, Reece D and Kingsford, Richard T and Callaghan, Corey T},
journal = {Emu-Austral Ornithology},
volume = {121},
number = {4},
pages = {354--359},
year = {2021},
publisher = {Taylor \& Francis},
file = {Gorta_et_al-2021-Avifaunal use of an artificial waterpoint in the Strzelecki Desert.pdf},
doi = {10.1080/01584197.2021.1966311}
}
Dryland ecosystems have limited and patchily distributed water – a vital resource for species in these landscapes. Degradation of these ecosystems is increasing due to climate change and understanding species’ responses to this drying is critical for effective ecosystem management. During an extended dry period, we surveyed drinking visits of an avian community at an artificial waterpoint in semi-arid Australia. Opportunistically, a small rainfall event punctuated the survey, enabling comparisons of avian visitations, before and after the event, as a proxy for increased water availability in the landscape. Visitations of drinking birds to the waterpoint before the rainfall event (17 species) were significantly higher than after (3 species). Permanent waterpoints, such as the single site surveyed in this study, can sustain avifauna during extended dry periods in drylands, affecting spatio-temporal and potentially functional avian community dynamics. Periodic reliance of dryland birds on permanent water may increase with prolonged droughts under climate change, and this reliance must be considered alongside the negative ecological consequences of permanent waterpoints in the management of these ecosystems.
@article{callaghan2020birds,
title = {Birds are valuable: the case of vagrants},
author = {Callaghan, Corey T and Benson, Ian and Major, Richard E and Martin, John M and Longden, Thomas and Kingsford, Richard T},
journal = {Journal of Ecotourism},
volume = {19},
number = {1},
pages = {82--92},
year = {2020},
publisher = {Routledge},
file = {Callaghan_et_al-2020-Birds are valuable.pdf},
doi = {10.1080/14724049.2019.1614010}
}
Biodiversity values need to be appropriately quantified and thence incorporated in future land development decisions. We assessed the economic and conservation-fundraising potential of vagrant Aleutian Terns in New South Wales, Australia. We found that an estimated 375–581 birdwatchers travelled far (580 ± 522 km [mean ± SD]) and reacted quickly (22% of visits were within the first week and 47% within the first two weeks) to see Aleutian Terns in an area where they had never been seen. We estimated that the total expenditure of these birdwatchers ranged from ∼ 199,000–363,000 AUD and we further estimated that birdwatchers would have been cumulatively willing to donate upwards of $30,000 AUD to a non-governmental conservation organisation in order to have viewed the terns. These results suggest that birdwatchers highly value vagrant birdwatching and conservation campaign potential should be explored in future long-staying vagrant bird occurrences.
@article{callaghan2020greenspace,
title = {The Greenspace Bird Calculator: a citizen-driven tool for monitoring avian biodiversity in urban greenspaces},
author = {Callaghan, Corey T and Wilshire, John H and Martin, John M and Major, Richard E and Lyons, Mitchell B and Kingsford, Richard T},
journal = {Australian Zoologist},
volume = {40},
number = {3},
pages = {468--476},
year = {2020},
publisher = {Royal Zoological Society of New South Wales},
file = {Callaghan_et_al-2020-Greenspace Bird Calculator.pdf},
doi = {10.7882/AZ.2019.009}
}
Urbanisation is altering local flora and fauna, but urban greenspaces can provide refugia for a variety of taxa. However, we often lack basic biodiversity information (e.g., species richness) for these urban greenspaces. Citizen science projects are continuously improving our understanding of ecology at broad temporal and spatial scales. But, many conservation-relevant decisions are idiosyncratic and made at small management scales (e.g., local government). Given a general bias of citizen science data towards areas with large human populations, citizen scientists are best placed to contribute to improving our understanding of the biodiversity within cities and urban greenspaces. We introduce the Greenspace Bird Calculator: a web-app aimed at enhancing our collective knowledge of bird diversity in urban greenspaces. Users of the web-app could be land managers seeking to understand the bird diversity in the greenspaces they manage. It is built in a reproducible workflow, allowing anyone to delineate a greenspace and submit it to the web-app administrator, receiving an output comprising the greenspace’s total bird diversity. The Greenspace Bird Calculator web-app provides an automated tool to utilise existing eBird citizen science data to calculate species richness for urban greenspaces globally. Critically, the GBC web-app statistically assesses available data that otherwise would be unlikely to be considered by decision-makers. This web-app is an example of the evolution of citizen science, whereby the data collected has been analysed to allow accessible interpretation and inclusion into urban greenspace management and planning.
@article{callaghan2020avian,
title = {Avian trait specialization is negatively associated with urban tolerance},
author = {Callaghan, Corey T and Benedetti, Yanina and Wilshire, John H and Morelli, Federico},
journal = {Oikos},
volume = {129},
number = {10},
pages = {1541--1551},
year = {2020},
publisher = {Blackwell Publishing Ltd Oxford, UK},
file = {Callaghan_et_al-2020-Avian trait specialization is negatively associated with urban tolerance.pdf},
doi = {10.1111/oik.07356}
}
Generalist species – with their wide niche breadths – are often associated with urban environments, while specialist species are likely to be most at-risk of increasing urbanization processes. But studies which quantify the relationship between trait specialization (i.e. niche breadth) and urban tolerance are generally methodologically limited, with repeatable robust methods to easily quantify this relationship among different regions and time scales often lacking. Our objective was to use novel methods to quantify the relationship between trait specialization and urban tolerance over a broad spatial scale. We used 2 million citizen science observations and spatially intersected these with remotely-sensed VIIRS night-time light values and a novel continuous measure of a species’ trait specialization for 256 European bird species. We found a negative relationship between avian urban tolerance and an overall specialization index. Nesting site niche breadth was especially negatively associated with higher urban tolerance scores. Our results highlight that species with a high degree of trait specialization likely have a lower capacity to persist in urban ecosystems, and hence, could be most at-risk in novel urban ecosystems. We suggest that trait specialization can be used as a proxy for the degree of risk posed by urban environments to a given species.
@article{callaghan2020continental,
title = {A continental measure of urbanness predicts avian response to local urbanization},
author = {Callaghan, Corey T and Major, Richard E and Cornwell, William K and Poore, Alistair GB and Wilshire, John H and Lyons, Mitchell B},
journal = {Ecography},
volume = {43},
number = {4},
pages = {528--538},
year = {2020},
publisher = {Blackwell Publishing Ltd Oxford, UK},
file = {Callaghan_et_al-2020-A continental measure of urbanness.pdf},
doi = {10.1111/ecog.04863}
}
Understanding species-specific relationships with their environment is essential for ecology, biogeography and conservation biology. Moreover, understanding how these relationships change with spatial scale is critical to mitigating potential threats to biodiversity. But methods which measure inter-specific variation in response to environmental parameters that are also generalizable across multiple spatial scales are scarce. We used broad-scale avian citizen science data, over continental Australia, integrated with remotely-sensed products, to produce a measure of urban-tolerance for a given species at a continental-scale. We then compared these urban-tolerances to modelled responses to urbanization at a local-scale, based on systematic sampling within four small cities. For 49 species which had sufficient data for modelling, we found a significant relationship (R2 = 0.51) between continental-scale urbanness and local-scale urbanness. We also found that relatively few citizen science observations ( 250) are necessary for reliable estimates of continental-scale species-specific urban scores to predict local-scale response to urbanization. Our approach demonstrates the applicability of broad-scale citizen science data, contrasting both the spatial grain and extent of standard point-count surveys generally only conducted at small spatial scales. Continental-scale responses in Australia are representative of small-scale responses to urbanization among four small cities in Australia, suggesting that our method of producing species-specific urban scores is robust and may be generalized to other locations lacking appropriate data.
@article{callaghan2020citizen,
title = {Citizen science data accurately predicts expert-derived species richness at a continental scale when sampling thresholds are met},
author = {Callaghan, Corey T and Roberts, J Dale and Poore, Alistair GB and Alford, Ross A and Cogger, Hal and Rowley, Jodi JL},
journal = {Biodiversity and Conservation},
volume = {29},
number = {4},
pages = {1323--1337},
year = {2020},
publisher = {Springer Netherlands},
file = {Callaghan_et_al-2020-Citizen science data accurately predicts expert-derived species richness.pdf},
doi = {10.1007/s10531-020-01937-3}
}
Understanding species richness patterns in time and space is critical for conservation management and ecological analyses. But estimates of species richness for a given place are often imprecise and incomplete, even when derived from expert-validated range maps. The current uptake of citizen science in natural resource management, conservation, and ecology offers great potential for extensive data to define species occurrence and richness patterns in the future. Yet, studies are needed to validate these richness patterns and ensure these data are fit-for-purpose. We compared data from a continental-scale citizen science project—FrogID—with expert-derived range maps to assess how well the former predicts species richness patterns in space. We then investigated how many citizen science submissions are necessary to fully sample the underlying frog community. There was a strong positive association between citizen science species richness estimates and estimates derived from an expert-derived map of frog distributions. An average of 153 citizen science submissions were necessary to fully-sample frog richness based on the expert-derived frog richness. Sampling effort in the citizen science project was negatively correlated with the remoteness of an area: less remote areas were more likely to have a greater number of citizen science submissions and be fully sampled. This suggests that scientists will likely need to rely on professionals for data collection in remote regions. We conclude that a citizen science project that has been running for 18 months, can accurately predict frog species richness at a continental scale compared with an expert-derived map based on 240 years of data accumulation. At large-scales, biodiversity data derived from citizen science projects will likely play a prominent role in the future of biodiversity and conservation.
@article{mitchell2020continental,
title = {Continental-scale citizen science data reveal no changes in acoustic responses of a widespread tree frog to an urbanisation gradient},
author = {Mitchell, Brittany A and Callaghan, Corey T and Rowley, Jodi JL},
journal = {Journal of Urban Ecology},
volume = {6},
number = {1},
pages = {juaa002},
year = {2020},
publisher = {Oxford University Press},
file = {Mitchell_et_al-2020-No changes in acoustic responses of a widespread tree frog to an urbanisation gradient.pdf},
doi = {10.1093/jue/juaa002}
}
One of the major drivers of global biodiversity declines is habitat loss and modification, often associated with anthropogenic environments. To mitigate biodiversity declines, a comprehensive understanding of how species respond to novel anthropogenic environments is required. Compared to natural habitats, human-modified environments often have increased noise and light pollution, potentially affecting acoustically communicating species, such as frogs. These areas may force animals to modulate or alter their calls to communicate with potential mates, as they compete with anthropogenic noise. Using large-scale citizen science data, coupled with remotely sensed data, we examined how the advertisement calls of the Australian red tree frog (Litoria rubella) varied in response to a gradient consistent with anthropogenic disturbance. After measuring a suite of acoustic properties of L.rubella across its range, we discovered that their advertisement calls showed no response to a disturbance urbanisation gradient. The advertisement calls of the species were highly variable, both at continental and local scales. Our results indicate that acoustic communication in male L.rubella may not be impeded in human-modified habitats as (1) they are a loud species typically heard over background noise and multi-species choruses and (2) their calls are highly variable—potentially serving as a buffer to any acoustic disturbances. Overall, our results provide evidence that some frog species may be acoustically urban tolerant and provide a greater understanding of the responses frogs exhibit to human-mediated environmental change.
@article{rowley2020frogid,
title = {The FrogID dataset: expert-validated occurrence records of Australia’s frogs collected by citizen scientists},
author = {Rowley, Jodi JL and Callaghan, Corey T},
journal = {ZooKeys},
volume = {912},
pages = {139},
year = {2020},
publisher = {Pensoft Publishers},
file = {Rowley_and_Callaghan-2020-FrogID dataset paper.pdf},
doi = {10.3897/zookeys.912.38253}
}
This dataset represents expert-validated occurrence records of calling frogs across Australia collected via the national citizen science project FrogID (http://www.frogid.net.au). FrogID relies on participants recording calling frogs using smartphone technology, after which point the frogs are identified by expert validators, resulting in a database of georeferenced frog species records. This dataset represents one full year of the project (10 November 2017–9 November 2018), including 54,864 records of 172 species, 71% of the known frog species in Australia. This is the first instalment of the dataset, and we anticipate providing updated datasets on an annual basis.
@article{justyn2020birds,
title = {Birds rarely hybridize: A citizen science approach to estimating rates of hybridization in the wild},
author = {Justyn, Nicholas M and Callaghan, Corey T and Hill, Geoffrey E},
journal = {Evolution},
volume = {74},
number = {6},
pages = {1216--1223},
year = {2020},
file = {Justyn_et_al-2020-Birds rarely hybridize.pdf},
doi = {10.1111/evo.13943}
}
The rate of hybridization among taxa is a central consideration in any discussion of speciation, but rates of hybridization are difficult to estimate in most wild populations of animals. We used a successful citizen science dataset, eBird, to estimate the rates of hybridization for wild birds in the United States. We calculated the frequency at which hybrid individuals belonging to different species, families, and orders of birds were observed. Between 1 January 2010 and 31 December 2018, a total of 334,770,194 species records were reported to eBird within the United States. Of this total, 212,875 or 0.064% were reported as hybrids. This estimate is higher than the rate of hybridization (0.00167%) reported by Mayr based on impressions from a career studying museum specimens. However, if the 10 most influential hybrid species are removed from the eBird dataset, the rate of hybridization decreases substantially to about 0.009%. We conclude that the rate of hybridization for individuals in most bird species is extremely low, even though the potential for birds to produce fertile offspring through hybrid crosses is high. These findings indicate that there is strong prezygotic selection working in most avian species.
@article{morelli2020ecological,
title = {Ecological specialization and population trends in European breeding birds},
author = {Morelli, Federico and Benedetti, Yanina and Callaghan, Corey T},
journal = {Global Ecology and Conservation},
volume = {22},
pages = {e00996},
year = {2020},
publisher = {Elsevier},
file = {Benedetti_et_al-2022-Distribution and protection of avian specialization in Europe.pdf},
doi = {10.1016/j.gecco.2020.e00996}
}
Successful conservation strategies depend on the correct identification of animal species and populations at a higher risk of extinction. But not all species are equally sensitive to environmental changes. Specialist species are often considered more prone to extinction than generalist species. However, even considering the importance of the link between specialization and population trends of species (a potential proxy for extinction risk), only a few studies have provided evidence supporting this relationship. Here, we tested whether the population trend of breeding birds in Europe is linked to a specific category of species’ specialization, using continuous measures of avian specialization based on a trait-approach. We focused on five different indices of avian specialization: diet, foraging behavior, foraging substrate, habitat selection, and nesting site selection. We calculated the mean value and the standard deviation of the population trend for 139 bird species. Then, we tested for the presence of a phylogenetic signal in bird population trends, in order to investigate if the tendency for related species to resemble each other, often demonstrated regarding phenotypes, is present also for the species’ trends in Europe. We found evidence that bird species with negative trends were characterized by higher ecological specialization than species with positive trends. Specifically, population trends were negatively associated with nesting site specialization. We highlight that the species’ degree of specialization can be used as a proxy for that species’ ability to adapt and persist to environmental changes. Finally, the lack of a phylogenetic signal in either the mean value or standard deviation of the bird population trend suggests that the current status of a species is not strongly associated with the degree of phylogenetic relatedness.
@article{francis2020quantifying,
title = {Quantifying bird diversity at three sites of differing herbivore presence},
author = {Francis, Roxane J and Brandis, Kate J and Kingsford, Richard T and Callaghan, Corey T},
journal = {Journal of Ornithology},
volume = {161},
number = {4},
pages = {1117--1127},
year = {2020},
publisher = {Springer Berlin Heidelberg},
file = {Francis_et_al-2020-Quantifying bird diversity at differing herbivore levels.pdf},
doi = {10.1007/s10336-020-01804-6}
}
Large herbivores directly and indirectly influence ecosystem function, positively and negatively affecting diversity of plants and animals, including birds. Such cascading effects are clearly important, particularly given ongoing global declines in large herbivores and many avian communities. We examined relationships between bird diversity (species richness and Shannon-Weiner Index, at a species and functional group level) at three similarly vegetated and flooded sites in northern Botswana. We explored the role that herbivore presence plays in ecosystem functioning considering bird species richness was significantly higher at the site of intermediate presence, followed by the high presence site. At a functional group level, the site of highest presence consistently had the greatest functional group richness. Also, at a functional group level we identified higher species richness and diversity in the two sites where herbivores were present at high levels. This was particularly pronounced for the avian aquatic carnivore, terrestrial herbivore, and aerial invertivore functional groupings. Large herbivores probably increased habitat complexity through their browsing and grazing, altering habitat structure, alongside other benefits such as faeces deposition and mutualistic relationships, creating more niches for avian communities. Fencing out large herbivores to reduce their grazing and browsing may therefore reduce bird diversity, and correspondingly, allowing large herbivores to increase in abundance through protected areas may indirectly increase bird diversity, acknowledging over abundance may be detrimental.
@article{callaghan2020capitalizing,
title = {Capitalizing on opportunistic citizen science data to monitor urban biodiversity: A multi-taxa framework},
author = {Callaghan, Corey T and Ozeroff, Ian and Hitchcock, Colleen and Chandler, Mark},
journal = {Biological conservation},
volume = {251},
pages = {108753},
year = {2020},
publisher = {Elsevier},
file = {Callaghan_et_al-2020-Capatilizing on opportunistic citizen science data.pdf},
doi = {10.1016/j.biocon.2020.108753}
}
Monitoring urban biodiversity is increasingly important, given the increasing anthropogenic pressures on biodiversity in urban areas. While the cost of broad-scale monitoring by professionals may be prohibitive, citizen science (also referred to as community science) will likely play an important role in understanding biodiversity responses to urbanization into the future. Here, we present a framework that relies on broad-scale citizen science data –– collected through iNaturalist –– to quantify (1) species-specific responses to urbanization on a continuous scale, capitalizing on globally-available VIIRS night-time lights data; and (2) community-level measures of the urbanness of a given biological community that can be aggregated to any spatial unit relevant for policy-decisions. We demonstrate the potential utility of this framework in the Boston metropolitan region, using >1000 species aggregated across 87 towns throughout the region. Of the most common species, our species-specific urbanness measures highlighted the expected difference between native and non-native species. Further, our biological community-level urbanness measures –– aggregated by towns –– negatively correlated with enhanced vegetation indices within a town and positively correlated with the area of impervious surface within a town. We conclude by demonstrating how towns can be ‘ranked’ promoting a framework where towns can be compared based on whether they over- or under-perform in the urbanness of their community relative to other towns. Ultimately, biodiversity conservation in urban environments will best succeed with robust, repeatable, and interpretable measures of biodiversity responses to urbanization, and involving the broader public in the derivation and tracking of these responses will likely result in increased bioliteracy and conservation awareness.
@article{rowley2020widespread,
title = {Widespread short-term persistence of frog species after the 2019--2020 bushfires in eastern Australia revealed by citizen science},
author = {Rowley, Jodi JL and Callaghan, Corey T and Cornwell, William K},
journal = {Conservation Science and Practice},
volume = {2},
number = {11},
pages = {e287},
year = {2020},
publisher = {John Wiley \& Sons, Ltd Chichester, UK},
file = {Rowley_et_al-2020-Widespread short-term persistence of frogs after bushfires.pdf},
doi = {10.1111/csp2.287}
}
Fires change ecosystem composition and influence species extinction risk, yet information on the impact of fire on biodiversity is scant. The bushfires in southeastern Australia during the summer of 2019/20 were unprecedented in their extent and intensity, and postfire management decisions have been hindered by a lack of knowledge of the impact of fires on biodiversity. We examine the short-term persistence of frog species across southeastern Australia after these fires using records of calling frogs from the national citizen science project FrogID. We demonstrate widespread short-term persistence of frog species. Sixty-six frog species were detected in the firegrounds before the fire, and within 125 days postfire, 45 of these were detected. All 33 frog species with more than five records that were detected in the months of December–March prefire were detected postfire. While the short-term postfire persistence of so many frog species is a positive result, the population-level and longer-term consequences of the fires remain unknown, as does the ability of frogs to persist with the changing fire regimes predicted as a consequence of global climate change. We illustrate the value of citizen science in collecting large-scale and rapid observations in response to increasing anthropogenically-driven ecological events.
@article{weaver2020anuran,
title = {Anuran accents: Continental-scale citizen science data reveal spatial and temporal patterns of call variability},
author = {Weaver, Savannah J and Callaghan, Corey T and Rowley, Jodi JL},
journal = {Ecology and Evolution},
volume = {10},
number = {21},
pages = {12115--12128},
year = {2020},
file = {Weaver_et_al-2020-Anuran accents.pdf},
doi = {10.1002/ece3.6833}
}
Many animals rely on vocal communication for mating advertisement, territorial displays, and warning calls. Advertisement calls are species-specific, serve as a premating isolation mechanism, and reinforce species boundaries. Nevertheless, there is a great deal of interspecific variability of advertisement calls. Quantifying the variability of calls among individuals within a species and across species is critical to understand call evolution and species boundaries, and may build a foundation for further research in animal communication. However, collecting a large volume of advertisement call recordings across a large geographic area has traditionally posed a logistical barrier. We used data from the continental-scale citizen science project FrogID to investigate the spatial and temporal patterns of call characteristics in six Australian frog species. We found intraspecific call variability in both call duration and peak frequency across species. Using resampling methods, we show that variability in call duration and peak frequency was related to the number of individuals recorded, the geographic area encompassed by those individuals, and the intra-annual time difference between those recordings. We conclude that in order to accurately understand frog advertisement call variation, or “anuran accents,” the number of individuals in a sample must be numerous (N ≥ 20), encompass a large geographic area relative to a species’ range, and be collected throughout a species’ calling season.
@article{lyons2019monitoring,
title = {Monitoring large and complex wildlife aggregations with drones},
author = {Lyons, Mitchell B and Brandis, Kate J and Murray, Nicholas J and Wilshire, John H and McCann, Justin A and Kingsford, Richard T and Callaghan, Corey T},
journal = {Methods in Ecology and Evolution},
volume = {10},
number = {7},
pages = {1024--1035},
year = {2019},
file = {Lyons_et_al-2019-Monitoring large wildlife aggregations with drones.pdf},
doi = {10.1111/2041-210X.13194}
}
1.Recent advances in drone technology have rapidly led to their use for monitoring and managing wildlife populations but a broad and generalised framework for their application to complex wildlife aggregations is still lacking. 2. We present a generalised semi-automated approach where machine learning can map targets of interest in drone imagery, supported by predictive modelling for estimating wildlife aggregation populations. We demonstrated this application on four large spatially complex breeding waterbird colonies on floodplains, ranging from c. 20,000 to c. 250,000 birds, providing estimates of bird nests. 3. Our mapping and modelling approach was applicable to all four colonies, without any modification, effectively dealing with variation in nest size, shape, colour and density and considerable background variation (vegetation, water, sand, soil, etc.). Our semi-automated approach was between three and eight times faster than manually counting nests from imagery at the same level of accuracy. 4. This approach is a significant improvement for monitoring large and complex aggregations of wildlife, offering an innovative solution where ground counts are costly, difficult or not possible. Our framework requires minimal technical ability, is open-source (Google Earth Engine and R), and easy to apply to other surveys.
@article{callaghan2019generalists,
title = {Generalists are the most urban-tolerant of birds: a phylogenetically controlled analysis of ecological and life history traits using a novel continuous measure of bird responses to urbanization},
author = {Callaghan, Corey T and Major, Richard E and Wilshire, John H and Martin, John M and Kingsford, Richard T and Cornwell, William K},
journal = {Oikos},
volume = {128},
number = {6},
pages = {845--858},
year = {2019},
publisher = {Blackwell Publishing Ltd Oxford, UK},
file = {Callaghan_et_al-2019-Generalists are the most urban-tolerant of birds.pdf},
doi = {10.1111/oik.06158}
}
Identifying which ecological and life history traits influence a species’ tolerance to urbanization is critical to understanding the trajectory of biodiversity in an increasingly urbanizing world. There is evidence for a wide array of contrasting patterns for single trait associations with urbanization. In a continental-scale analysis, incorporating 477 species and >5 000 000 bird observations, we developed a novel and scalable methodology that evaluated the ecological and life history traits which most influence a species’ adaptability to persist in urban environments. Specifically, we assigned species-specific scores based on continuous measures of response to urbanization, using VIIRS night-time light values (i.e. radiance) as a proxy for urbanization. We identified generalized, phylogenetically controlled patterns: bird species which are generalists (i.e. large niche breadth), with large clutch size, and large residual brain size are among the most urban-tolerant bird species. Conversely, specialized feeding strategies (i.e. insectivores and granivores) were negatively associated with urbanization. Enhancement and persistence of avian biodiversity in urban environments probably relies on protecting, maintaining and restoring diverse habitats serving a range of life history strategies.
@article{rowley2019frogid,
title = {FrogID: Citizen scientists provide validated biodiversity data on frogs of Australia},
author = {Rowley, Jodi JL and Callaghan, Corey T and Cutajar, Timothy and Portway, Christopher and Potter, Kathy and Mahony, Stephen and Trembath, Dane F and Flemons, Paul and Woods, Adam},
journal = {Herpetological Conservation and Biology},
volume = {14},
number = {1},
pages = {155--170},
year = {2019},
file = {Rowley_et_al-2019-FrogID.pdf},
doi = {}
}
@article{callaghan2019using,
title = {Using citizen science data to define and track restoration targets in urban areas},
author = {Callaghan, Corey T and Major, Richard E and Lyons, Mitchell B and Martin, John M and Wilshire, John H and Kingsford, Richard T and Cornwell, William K},
journal = {Journal of Applied Ecology},
volume = {56},
number = {8},
pages = {1998--2006},
year = {2019},
file = {Callaghan_et_al-2019-Using citizen science data to define and track restoration targets.pdf},
doi = {10.1111/1365-2664.13421}
}
1. Habitat fragmentation and land degradation, directly and indirectly caused by urbanization, are drastically altering the world’s ecosystems and are therefore driving an imperative for ecological restoration within the world’s cities. Current methods for the implementation and monitoring of restoration are limited. Restoration ecology needs cost-effective and repeatable tools for tracking changes at global scales, but with local relevance. 2. We propose the Urban Greenspace Integrity Index—a locally relevant measure of an urban greenspace’s response to urbanization, derived from widely accessible citizen science data. Unlike classical measurements of biodiversity (e.g. species richness, species diversity), this index measures species-specific responses to continuous measures of urbanization. 3. Increases in this index are evidence of a successful urban restoration project; that is, restoration results in a community shift that favours urban-sensitive species. Importantly, data for this index are easily and efficiently collected by citizen scientists, providing long-term repeatable data. This urban index, calculated from greenspace surveys, correlates with and complements traditional biodiversity metrics. 4. Synthesis and applications. Policymakers and practitioners can use the index—a measure of the urbanness of the local bird community—to define and track restoration of urban ecosystems, effectively measuring changes in biodiversity in response to urbanization: measuring whether the urbanness of the bird community changes through time. Importantly, this index can be calculated using citizen science data, providing a potentially long-term monitoring effort of restoration projects.
@article{gorta2019pelagic,
title = {Pelagic citizen science data reveal declines of seabirds off south-eastern Australia},
author = {Gorta, Simon BZ and Smith, James A and Everett, Jason D and Kingsford, Richard T and Cornwell, William K and Suthers, Iain M and Epstein, Hal and McGovern, Roger and McLachlan, Greg and Roderick, Mick and others},
journal = {Biological Conservation},
volume = {235},
pages = {226--235},
year = {2019},
publisher = {Elsevier},
file = {Gorta_et_al-2019-Seabird declines in SE Australia.pdf},
doi = {10.1016/j.biocon.2019.05.007}
}
Many seabird communities are declining around the world, a trend frequently linked to climate change and human impacts on habitat and prey. Time series observations of seabirds away from breeding colonies are generally rare, which limits our understanding of long-term changes for conservation actions. We analysed a dedicated citizen science dataset of pelagic seabird abundance (86 species – 30 used for modelling analysis - from 385 trips) from two locations over 17 years (2000–2016) and a third for seven years, over the continental shelf and slope of south-eastern Australia. To estimate temporal trends and environmental drivers, we used generalised additive modelling and species archetype modelling for groups. Almost half (43%) of the most abundant seabird species declined in our study area over the 17 years. The declines may be associated with human-induced ecosystem change and represent poleward shifts in distribution out of our study area, changes in population abundance, or both. Winter-dominant groups, primarily species rarely frequenting warmer water, were often negatively associated with SSTanom, while summer-dominant groups, composed of species more tolerant of temperate and tropical environments, were generally positively associated with SSTanom. Widespread local declines in seabird populations are of increasing concern. Understanding the extent to which these observed declines represent real declines in abundance, or range shifts, should be a priority. Changing sea temperatures are probably contributing to both. These results from the coast of south-eastern Australia need to be placed in the context of the highly mobile study organisms and the vast spatial scale of the ocean. Long-term citizen science observations, from an array of locations around the world, promise to provide valuable insights into seabird ecology, playing a key part in seabird conservation.
@article{callaghan2019heterogeneous,
title = {Heterogeneous urban green areas are bird diversity hotspots: insights using continental-scale citizen science data},
author = {Callaghan, Corey T and Bino, Gilad and Major, Richard E and Martin, John M and Lyons, Mitchell B and Kingsford, Richard T},
journal = {Landscape Ecology},
volume = {34},
number = {6},
pages = {1231--1246},
year = {2019},
publisher = {Springer Netherlands},
file = {Callaghan_et_al-2019-Heterogeneous urban green areas are bird diversity hotspots.pdf},
doi = {10.1007/s10980-019-00851-6}
}
Context Urbanization fragments and destroys natural landscapes, generally decreasing bird diversity. While in some cases bird diversity continuously decreases in response to urbanization, in others a non-linear response is evident, with peak bird diversity observed at intermediate levels of urbanization. But many studies previously investigating this pattern are spatially or temporally constrained. Objectives In this study, we analyzed the impacts of urbanization on bird diversity, stratified to native and exotic species. We specifically investigated the differences in bird diversity between natural and urban green areas. Methods We used eBird citizen science data (> 4,000,000 bird-survey lists) and remotely-sensed landcover data, throughout the contiguous United States of America. Results We found a non-linear response to urbanization for both species richness and Shannon diversity. There was distinctly greater bird richness and Shannon diversity in urban green areas compared to natural green areas. Our observed response is likely explained by an increase in habitat heterogeneity of urban green areas compared with natural green areas. Conclusions Our work highlights the importance of diverse urban green areas for supporting bird diversity in urban areas. We recommend that urban planning should focus on maintaining high habitat heterogeneity in urban green areas to promote greater bird diversity.
@article{callaghan2019improving,
title = {Improving big citizen science data: Moving beyond haphazard sampling},
author = {Callaghan, Corey T and Rowley, Jodi JL and Cornwell, William K and Poore, Alistair GB and Major, Richard E},
journal = {PLoS biology},
volume = {17},
number = {6},
pages = {e3000357},
year = {2019},
publisher = {Public Library of Science San Francisco, CA USA},
file = {Callaghan_et_al-2019-Improving big citizen science data.pdf},
doi = {10.1371/journal.pbio.3000357}
}
Citizen science is mainstream: millions of people contribute data to a growing array of citizen science projects annually, forming massive datasets that will drive research for years to come. Many citizen science projects implement a “leaderboard” framework, ranking the contributions based on number of records or species, encouraging further participation. But is every data point equally “valuable?” Citizen scientists collect data with distinct spatial and temporal biases, leading to unfortunate gaps and redundancies, which create statistical and informational problems for downstream analyses. Up to this point, the haphazard structure of the data has been seen as an unfortunate but unchangeable aspect of citizen science data. However, we argue here that this issue can actually be addressed: we provide a very simple, tractable framework that could be adapted by broadscale citizen science projects to allow citizen scientists to optimize the marginal value of their efforts, increasing the overall collective knowledge.
@article{callaghan2019optimizing,
title = {Optimizing future biodiversity sampling by citizen scientists},
author = {Callaghan, Corey T and Poore, Alistair GB and Major, Richard E and Rowley, Jodi JL and Cornwell, William K},
journal = {Proceedings of the Royal Society B},
volume = {286},
number = {1912},
pages = {20191487},
year = {2019},
publisher = {The Royal Society},
file = {Callaghan_et_al-2019-Optimizing biodiversity sampling by citizen scientists.pdf},
doi = {10.1098/rspb.2019.1487}
}
We are currently in the midst of Earth’s sixth extinction event, and measuring biodiversity trends in space and time is essential for prioritizing limited resources for conservation. At the same time, the scope of the necessary biodiversity monitoring is overwhelming funding for professional scientific monitoring. In response, scientists are increasingly using citizen science data to monitor biodiversity. But citizen science data are ‘noisy’, with redundancies and gaps arising from unstructured human behaviours in space and time. We ask whether the information content of these data can be maximized for the express purpose of trend estimation. We develop and execute a novel framework which assigns every citizen science sampling event a marginal value, derived from the importance of an observation to our understanding of overall population trends. We then make this framework predictive, estimating the expected marginal value of future biodiversity observations. We find that past observations are useful in forecasting where high-value observations will occur in the future. Interestingly, we find high value in both ‘hotspots’, which are frequently sampled locations, and ‘coldspots’, which are areas far from recent sampling, suggesting that an optimal sampling regime balances ‘hotspot’ sampling with a spread across the landscape.
@article{alabai2019first,
title = {First record of Solomons Nightjar Eurostopodus nigripennis for Malaita, with a description of its nest site},
author = {Alabai, Maasafi and Esau, Tommy and Kekeubata, Esau and Waneagea, Jackson and MacLaren, David and Major, Richard E and Callaghan, Corey T},
journal = {Bulletin of the British Ornithologists’ Club},
volume = {139},
number = {4},
pages = {325--327},
year = {2019},
publisher = {British Ornithologists' Club},
file = {Alabai_et_al-2019-Solomons Nightjar record.pdf},
doi = {10.25226/bboc.v139i4.2019.a4}
}
Solomons Nightjar Eurostopodus nigripennis, listed as Vulnerable by BirdLife International, has previously been recorded only from the north and central Solomon Islands. Even within the species’ known range there are few records, limiting knowledge of its ecology. We provide photographic evidence of a Solomons Nightjar nest in a streambed on the island of Malaita at an altitude of c.270 m—the first record on this large island. This observation, combined with traditional local knowledge, suggests that the species may have a wider range of nesting habitat than previously documented, and that further surveys in collaboration with local tribespeople could be important for conservation efforts.
@article{callaghan2019collaborative,
title = {A collaborative bird survey of East Kwaio, Malaita, Solomon Islands},
author = {Callaghan, Corey T and Kekeubata, Esau and Waneagea, Jackson and Alabai, Maasafi and Esau, Tommy and MacLaren, David and Major, Richard E},
journal = {Check List},
volume = {15},
pages = {1119},
year = {2019},
publisher = {Pensoft Publishers},
file = {Callaghan_et_al-2019-Survey of Malaita avifauna.pdf},
doi = {10.15560/15.6.1119}
}
We surveyed the birds of East Kwaio, Malaita, Solomon Islands from 20 October to 2 November 2018. We conducted 66 point counts and recorded or observed 58 species of resident landbirds, including 23 of the 24 passerine species known from the island of Malaita and 15 waterbird species. We collected some form of samples (e.g., whole specimens and/or blood samples) from 61 individuals of 17 species, including representatives of the four species-level endemics: Malaita Fantail Rhipidura malaitae (Mayr, 1931), Malaita Dwarf-Kingfisher Ceyx malaitae (Mayr, 1935), Malaita White-eye Zosterops stresemanni (Mayr, 1931), and Red-bellied Myzomela Myzomela malaitae (Mayr, 1931). We demonstrate the considerable potential for conservation of the Malaitan avifauna on traditional lands in the mountains of East Kwaio. The extensive knowledge of the local people was a key factor in the success of the expedition. To facilitate ongoing conservation efforts, we documented the local Kwaio names of the birds we encountered.
@article{callaghan2018travelling,
title = {Travelling birds generate eco-travellers: The economic potential of vagrant birdwatching},
author = {Callaghan, Corey T and Slater, Michael and Major, Richard E and Morrison, Mark and Martin, John M and Kingsford, Richard T},
journal = {Human Dimensions of Wildlife},
volume = {23},
number = {1},
pages = {71--82},
year = {2018},
publisher = {Routledge},
file = {Callaghan_et_al-2018-Travelling birds generate eco travellers.pdf},
doi = {10.1080/10871209.2017.1392654}
}
Avitourism is one of the faster growing subsectors of ecotourism, recognized for its economic value. Much of our current understanding of the economic value of avitourism revolves around bird festivals, migration events, or well-known birdwatching sites. Birdwatchers are a diverse group, some of whom competitively seek vagrant birds (i.e., birds outside their normal geographic range). The economic value from these unpredictable and transient birdwatching events remains poorly known. Using the travel cost method in a readily-quantifiable environment, we estimated that a vagrant Black-backed Oriole in Pennsylvania, United States of America, stimulated travel activity valued at about 223,000 USD or about 3,000 per day over 67 days. Some birdwatchers value rare birds, contributing significant time and financial resources to their viewing. Identifying such significant real economic value from avitourism can help to evaluate competing costs in debate over human land-use scenarios.
@article{callaghan2018unnatural,
title = {Unnatural history: is a paradigm shift of natural history in 21st century ornithology needed?},
author = {Callaghan, Corey T and Martin, John M and Kingsford, Richard T and Brooks, Daniel M},
volume = {160},
number = {2},
pages = {475--480},
year = {2018},
file = {Callaghan_et_al-2018-Unnatural history.pdf},
doi = {10.1111/ibi.12555}
}
Natural history, across disciplines, is essential for the continuation of science, especially as we attempt to identify the myriad of threats that biodiversity faces in this rapidly changing world. Recording the natural history of birds is perhaps the most prominent, widespread and long-standing pursuit of this activity. Yet, there is a distinct decrease in publishing of natural history in the ornithological sciences. Concomitantly, the natural history information being published is often in small and regional journals, less accessible by the global ornithological community. We argue that historical natural history needs a modern reinvigoration, and should focus on placing natural history observations in the context of an anthropogenically altered world – ‘unnatural history’. This includes, but is not limited to, behavioural adaptations, novel diet choices, hybridization and novel adaptations to urbanization. Here, we elaborate on natural history’s place in modern ornithology, how this relates to citizen science and the potential cost of ignoring it. Ultimately, increased accessibility of natural history observations, encouragement of amateur ornithologists’ participation in professional societies (and vice versa) and targeted citizen science projects are potential mechanisms by which to reinvigorate natural history in 21st century ornithology.
@article{callaghan2018avian,
title = {Avian monitoring--comparing structured and unstructured citizen science},
author = {Callaghan, Corey T and Martin, John M and Major, Richard E and Kingsford, Richard T},
journal = {Wildlife Research},
volume = {45},
number = {2},
pages = {176--184},
year = {2018},
publisher = {CSIRO PUBLISHING},
file = {Callaghan_et_al-2018-Avian monitoring - comparing structured and unstructured citizen science data.pdf},
doi = {10.1071/WR17141}
}
Context. Citizen science is increasingly used to collect biodiversity data to inform conservation management, but its validity within urban greenspaces remains largely unresolved. Aims. To assess the validity of eBird data for generating biodiversity estimates within an urban greenspace. Methods. We compared data from structured avian surveys with eBird data at an urban greenspace in Sydney during 2012–16, using species richness and Shannon diversity indices. We also compared community composition, using non-metric multidimensional scaling (NMDS) and dissimilarities using non-parametric MANOVA. Key results. Structured surveys had a lower overall species richness (80 versus 116) and Shannon diversity (3.64 versus 3.94) than eBird data, but we found no significant differences when using years as replicates. After standardising the richness and diversity indices by time spent surveying in a given year, structured surveys produced significantly higher biodiversity estimates. Further, when grouped into species occupying different broad habitats, there were no significant differences in waterbird or landbird species richness, or in Shannon diversity between data sources. Conclusions. The most likely explanation for the larger magnitudes of the biodiversity indices from the eBird data is the increase in effort manifested in the number of observers, time spent surveying and spatial coverage. This resulted in increased detection of uncommon species, which in turn accounted for a significant difference (R2 = 0.21, P = 0.015) in overall community composition measured by the two methods.
@article{lyons2018bird,
title = {Bird interactions with drones, from individuals to large colonies},
author = {Lyons, Mitchell and Brandis, Kate and Callaghan, Corey and McCann, Justin and Mills, Charlotte and Ryall, Sharon and Kingsford, Richard},
journal = {Australian Field Ornithology},
volume = {35},
pages = {51--56},
year = {2018},
publisher = {Birdlife Australia},
file = {Lyons_et_al-2018-Bird interactions with drones.pdf},
doi = {}
}
Drones are rapidly becoming a key part of the toolkit for a range of scientific disciplines, as well as a range of management and commercial applications. This presents challenges in the context of how drone use might impact on nearby wildlife, especially birds as they might share the airspace. This paper presents observations (from 97 flight hours) and offers preliminary guidance for drone-monitoring exercises and future research to develop guidelines for safe and effective monitoring with drones. Our study sites spanned a range of arid, semi-arid, dunefield, floodplain, wetland, woodland, forest, coastal heath and urban environments in south-eastern and central Australia. They included a nesting colony of >200 000 Straw-necked Ibis Threskiornis spinicollis, the largest drone-based bird-monitoring exercise to date. We particularly focused on behavioural changes towards drones during the breeding season, interactions with raptors, and effects on birds nesting in large colonies—three areas yet to be explored in published literature. Some aggressive behaviour was encountered from solitary breeding birds, but several large breeding bird colonies were surveyed without such issues. With multi-rotor drones, we observed no incidents that posed a threat to birds, but one raptor attacked and took down a fixed-wing drone. In addition to providing observations of interactions with specific bird species, we detail our procedures for flight planning, safe flying and avoidance of birds, and highlight the need for more research into bird– drone interactions, most notably with respect to territorial breeding birds, safety around large raptors, and the effects of drones on the behaviour of birds in large breeding colonies.
@article{callaghan2018effects,
title = {The effects of local and landscape habitat attributes on bird diversity in urban greenspaces},
author = {Callaghan, Corey T and Major, Richard E and Lyons, Mitchell B and Martin, John M and Kingsford, Richard T},
journal = {Ecosphere},
volume = {9},
number = {7},
pages = {e02347},
year = {2018},
file = {Callaghan_et_al-2018-Effects of habitat attributes on bird diversity in urban greenspaces.pdf},
doi = {10.1002/ecs2.2347}
}
Contrasting trajectories of biodiversity loss and urban expansion make it imperative to understand biodiversity persistence in cities. Size-, local-, and landscape-level habitat factors of greenspaces in cities may be critical for future design and management of urban greenspaces in conserving bird biodiversity. Most current understanding of bird communities in cities has come from disparate analyses of single cities, over relatively short time periods, producing limited understanding of processes and characteristics of bird patterns for improved biodiversity management of the world’s cities. We analyzed bird biodiversity in 112 urban greenspaces from 51 cities across eight countries, using eBird, a broadscale citizen science project. Species richness and Shannon diversity were used as response variables, while percent tree cover, percent water cover, and vegetation index were used as habitat predictor variables at both a landscape (5 and 25 km radius) and local-scale level (specific to an individual greenspace) in the modeling process, retrieved using Google Earth Engine. Area of a greenspace was the most important predictor of bird biodiversity, underlining the critical importance of habitat area as the most important factor for increasing bird biodiversity and mitigating loss from urbanization. Surprisingly, distance from the city center and distance from the coast were not significantly related to bird biodiversity. Landscape-scale habitat predictors were less related to bird biodiversity than local-scale habitat predictors. Ultimately, bird biodiversity loss could be mitigated by protecting and developing large greenspaces with varied habitat in the world’s cities.
@article{callaghan2018comment,
title = {A comment on the limitations of UAVS in wildlife research--the example of colonial nesting waterbirds},
author = {Callaghan, Corey T and Brandis, Kate J and Lyons, Mitchell B and Ryall, Sharon and Kingsford, Richard T},
journal = {Journal of Avian Biology},
volume = {49},
number = {9},
pages = {e01825},
year = {2018},
publisher = {Blackwell Publishing Ltd Oxford, UK},
file = {Callaghan_et_al-2018-A comment on the limitations of UAVs.pdf},
doi = {10.1111/jav.01825}
}
@article{callaghan2017shadow,
title = {'Shadow-boxing' by a Northern Mockingbird (Mimus polyglottos)},
author = {Callaghan, Corey T.},
journal = {Florida Field Naturalist},
volume = {5},
number = {1},
pages = {21--23},
year = {2017},
publisher = {Florida Ornithological Society},
file = {Callaghan-2017-Northern Mockingbird Shadow-boxing.pdf},
doi = {}
}
@article{callaghan2017probable,
title = {A probable Australian White Ibis' Threskiornis moluccus'x Straw-necked Ibis' T. spinicollis' hybrid},
author = {Callaghan, Corey T and Ryall, Sharon and Kingsford, Richard T},
journal = {Australian Field Ornithology},
volume = {34},
pages = {47--48},
year = {2017},
file = {Callaghan_et_al-2017-Australian White Ibis and Straw-necked Ibis hybrid.pdf},
doi = {}
}
We observed a probable juvenile Australian White Ibis Threskiornis moluccus × Straw-necked Ibis T. spinicollis hybrid on the Lachlan River catchment, New South Wales, in November 2016. Photographs, combined with observations, demonstrate phenotypic characteristics of both these ibis species. The bird had a pattern on the wing similar to the Australian White Ibis but coloration on the body similar to the Straw-necked Ibis. To our knowledge, this is only the second report of a probable hybrid between these two species in the wild, and the first report documented with photographs.
@article{callaghan2017assessing,
title = {Assessing the reliability of avian biodiversity measures of urban greenspaces using eBird citizen science data},
author = {Callaghan, Corey and Lyons, Mitchell and Martin, John and Major, Richard and Kingsford, Richard},
journal = {Avian Conservation and Ecology},
volume = {12},
number = {2},
year = {2017},
publisher = {The Resilience Alliance},
file = {Callaghan_et_al-2017-Assessing reliability of eBird data in urban greenspaces.pdf},
doi = {10.5751/ACE-01104-120212}
}
Urban greenspaces are important areas for biodiversity, serving multiple uses, sometimes including conservation and biodiversity management. Citizen science provides a cheap and potentially effective method of assisting biodiversity management in urban greenspaces. Despite this potential, the minimum amount of citizen science data required to adequately represent a community is largely untested. We used eBird data to test the minimum sampling effort required to be confident in results for three biological metrics, species richness, Shannon diversity, and community composition (Bray-Curtis similarity). For our data, from 30 urban greenspaces in North America, for a 90% threshold level, a minimum mean number of 210, 33, and 58 checklists were necessary for species richness, Shannon diversity, and community composition, respectively. However, when we eliminated those species that were present in fewer than 5% of checklists at a given site, there was a marked decrease in mean minimum number of checklists required (17, 9, and 52, respectively). Depending on the ecological questions of interest, eBird data may be a potentially reliable data source in urban greenspaces. We provide a validation methodology using eBird data, with its associated code in the R statistical environment, to provide confidence for land managers and community groups managing urban greenspaces.
@article{callaghan2017history,
title = {History, current distribution, and status of the Egyptian Goose (Alopochen aegyptiaca) in the contiguous United States},
author = {Callaghan, Corey T and Brooks, Daniel M},
journal = {The Southwestern Naturalist},
volume = {62},
number = {4},
pages = {296--300},
year = {2017},
publisher = {Southwestern Association of Naturalists},
file = {Callaghan_and_Brooks-2017-Egyptian Goose history, distribution, status.pdf},
doi = {}
}
We summarize the history, current distribution, and status of Egyptian geese (Alopochen aegyptiaca) in the contiguous United States, using published records and the eBird database of bird observations. The area of occupancy for the Egyptian goose has increased throughout the contiguous United States. The species has three populations that appear to be strongholds throughout the United States: Florida, California, and Texas. The potential ecological and economic consequences of an apparent increase in the United States warrant further research on a number of aspects of Egyptian goose biology.
@article{callaghan2016diet,
title = {Diet and selectivity of Porphyrio porphyrio (Purple Swamphen) in Florida},
author = {Callaghan, Corey T and Gawlik, Dale E},
journal = {Southeastern Naturalist},
volume = {15},
number = {sp8},
pages = {1--14},
year = {2016},
publisher = {Eagle Hill Institute},
file = {Callaghan_and_Gawlik-2016-Purple Swamphen diet.pdf},
doi = {10.1656/058.015.sp801}
}
We tested whether Porphyrio porphyrio (Purple Swamphen) in South Florida selected particular types of food and whether their diets differed among 3 geographically separate wetlands (northern Everglades, a stormwater treatment marsh, and Lake Okeechobee littoral zone). We found that the Purple Swamphens we collected from the treatment marsh were larger than those from the other sites. The primary food item of the Purple Swamphen at all 3 sites was Eleocharis cellulosa (Gulf-coast Spikerush), comprising 79%, 72%, and 49% mean dry weight of total gut contents for the northern Everglades, littoral zone, and treatment marsh, respectively. Accounting for availability, Purple Swamphens were strongly selective for Gulf-coast Spikerush, which is a common plant in the southeastern US. The availability of this plant is not likely to be a factor limiting the spread of this bird northward.
@article{chastant2016morphometric,
title = {Morphometric variation during chick development in interior double-crested Cormorants (Phalacrocorax auritus)},
author = {Chastant, Jennifer E and Callaghan, Corey T and King, D Tommy},
journal = {Waterbirds},
volume = {39},
number = {3},
pages = {260--267},
year = {2016},
publisher = {The Waterbird Society},
file = {Chastant_et_al-2016-Double-crested Cormorant morphometrics.pdf},
doi = {10.1675/063.039.0305}
}
In numerous avian species, egg size is correlated to female body condition, hatchling size and nestling growth. Recent demography studies of Interior Double-crested Cormorants (Phalacrocorax auritus) suggest a migratory divide across the Great Lakes; western populations winter in the Gulf of Mexico region of the southeastern United States (Alabama, Arkansas, Louisiana, and Mississippi) with extensive catfish (Ictalurus punctatus) aquaculture, and eastern populations winter in Florida, where catfish aquaculture is not pervasive. If Double-crested Cormorants have improved their overall body condition through catfish exploitation, then egg and chick sizes should also be affected. Three breeding areas in Ontario (east, central, and west) were selected for empirical measures of size variation. During the breeding seasons of 2006 and 2007, egg, naked young, fledgling, and adult morphometric data were collected. Eggs in eastern areas (volume = 465.8 ± 3.9 cm³) were on average larger than eggs in central (volume = 458.1 ± 3.5 cm³) and western (volume = 451.7 ± 3.5 cm³) areas. However, chicks in eastern areas (culmen = 54.9 ± 0.6 mm) were smaller than chicks in central (culmen = 57.6 ± 0.4 mm) and western (culmen = 59.3 ± 0.3 mm) areas, not only at hatching, but throughout development and fledging. A comprehensive Double-crested Cormorant morphometric gradient that may suggest a potential reproductive advantage for birds exploiting aquaculture facilities is presented.
@article{callaghan2016pacific,
title = {Pacific Golden-Plover (Pluvialis fulva) in Florida: a First State Record},
author = {Callaghan, Corey T.},
journal = {Florida Field Naturalist},
volume = {44},
number = {4},
pages = {169--174},
year = {2016},
file = {Callaghan-2016-Pacific Golden Plover.pdf},
doi = {}
}
On 9 April 2016, while birding in western Palm Beach County, I noted an odd shorebird that I was not immediately familiar with. The overall size and coloration quickly led me to the conclusion that it was one of the golden-plovers (Pluvialis dominica/fulva/apricaria.). Given a viewing period of < 5 min, significant heat shimmer, and long viewing distance, I concluded that it was an odd-looking American Golden Plover (Pluvialis dominica). On 10 April 2016, Kenny Miller and Brian Fedak re-located the golden-plover and obtained photos sufficient to identify it as Pacific Golden-Plover (Pluvialis fulva) (Fig. 1). The bird persisted until at least 24 April 2016. This observation represents the first record of this species in Florida. Here I describe observations of the bird, discuss identification, and review the species’ status in North America.
@article{callaghan2016ecology,
title = {Ecology, Behavior, and Reproduction of Invasive Egyptian Geese (Alopochen aegyptiaca) in Texas},
author = {Callaghan, Corey T. and Brooks, Daniel M.},
journal = {Bulletin of the Texas Ornithological Society},
volume = {49},
number = {1-2},
pages = {37--45},
year = {2016},
publisher = {Texas Ornithological Society},
file = {Callaghan_and_Brooks-2016-Egytian Goose Life History.pdf},
doi = {}
}
@article{callaghan2015efficacy,
title = {Efficacy of eBird data as an aid in conservation planning and monitoring},
author = {Callaghan, Corey T and Gawlik, Dale E},
journal = {Journal of Field Ornithology},
volume = {86},
number = {4},
pages = {298--304},
year = {2015},
file = {Callaghan_and_Gawlik-2015-Efficacy of ebird data.pdf},
doi = {10.1111/jofo.12121}
}
One of the world’s largest citizen science projects is eBird, a database that has been used primarily to address questions of bird distributions and abundance over large spatial scales. However, addressing finer-scale questions is also possible, depending on survey coverage and whether assumptions and limitations are matched to the scale of inferences. Our objective was to determine if the eBird database could be used to develop estimates of bird abundance and diversity comparable to those from standardized shorebird surveys. We compared a year of standardized shorebird surveys by trained observers at Snook Islands Natural Area located in Palm Beach County, Florida, to a year of eBird observations from the same site. Total species richness derived from eBird (25 species) was higher than that from standardized surveys (20 species). Similarly, we found the Shannon diversity index calculated from eBird was higher (2.81) than the same index calculated from standardized surveys (2.21; P < 0.001). The higher diversity and species richness may reflect the greater effort of eBird participants (35,289 person-hours) compared to our standard surveys (2126 person-hours). We found only a slight difference in parameter estimates between data obtained from eBird and from standardized surveys. Potential use and value of eBird as a tool for land managers and conservationists may be greater than currently realized, but studies conducted in a wider range of ecosystems and locations are needed to develop generalizations.
@inproceedings{callaghan2020using,
title = {Using citizen science to study exotic birds},
author = {Callaghan, Corey T and Brooks, Daniel M},
booktitle = {Invasive Birds: Global Trends and Impacts},
publisher = {CAB International},
pages = {362--367},
year = {2020},
file = {BOOK_Invasive_birds_citizen_science.pdf},
doi = {10.1079/9781789242065.0363}
}
This chapter describes the current usage of citizen science to increase the current knowledge of exotic and invasive bird populations. Citizen science projects aimed at studying and tracking exotic birds are divided into two categories: those that are part of a broad-scale biodiversity collection scheme, and those that are species focused. Some of the current literature that integrates citizen science data and the effects, management and implications of introduced birds are summarized, and select examples that highlight the potential of citizen science aimed at gathering various types of information about exotic birds are included. A vision for the future of citizen science aimed at studying exotic birds is also discussed.
@inproceedings{pranty2020grey,
title = {Grey-headed Swamphen (Porphyrio poliocephalus Latham, 1801).},
author = {Pranty, B and Callaghan, CT},
booktitle = {Invasive Birds: Global Trends and Impacts},
pages = {243--247},
year = {2020},
publisher = {CAB International},
file = {BOOK_Invasive_birds_Gray-headed_Swamphen.pdf},
doi = {10.1079/9781789242065.0243}
}
This chapter describes the common terminologies, taxonomy, morphology, geographical distribution, physiology, diet, behaviour, reproduction, habitats, ecology, invasion pathways, environmental impact, control and human use of the grey-headed swamphen (Porphyrio poliocephalus).
@inproceedings{huysentruyt202028,
title = {Egyptian Goose (Alopochen aegyptiaca Linnaeus, 1766)},
author = {Huysentruyt, Frank and Callaghan, Corey T and Strubbe, Diederik and Winston, Katherine and Adriaens, Tim and Brooks, Daniel M},
pages = {206--212},
year = {2020},
publisher = {CAB International},
booktitle = {Invasive Birds: Global Trends and Impacts},
file = {BOOK_Invasive_birds_Egyptian_Goose.pdf},
doi = {10.1079/9781789242065.0206}
}
This chapter describes the terminology, nomenclature, morphology, geographical distribution, diet, physiology, reproduction, behaviour, ecology, habitats, invasion patterns, environmental impact, control and human use of the Egyptian goose (Alopochen aegyptiacus).
@inproceedings{callaghan2017gray,
title = {Gray-headed Swamphen (Porphyrio poliocephalus)},
author = {Callaghan, C. T. and Pranty, Bill and Pyle, Peter and Patten, Michael A.},
booktitle = {Birds of the World (P. G. Rodewald and S. M. Billerman, Ed.)},
year = {2017},
publisher = {Ithaca: Cornell Lab of Ornithology},
doi = {10.2173/bow.purswa3.01}
}
@inproceedings{callaghan2017egyptian,
title = {Egyptian Goose (Alopochen aegyptiaca)},
author = {Callaghan, C. T. and Brooks, Daniel M. and Pyle, Peter},
booktitle = {Birds of the World (S. M. Billerman, Ed.)},
year = {2017},
publisher = {Ithaca: Cornell Lab of Ornithology},
doi = {10.2173/bow.egygoo.01}
}
Dr. Corey T. Callaghan
Assistant Professor
Wildlife Ecology and Conservation
University of Florida
University of Florida
Fort Lauderdale Research and Education Center
3205 College Avenue
Davie, FL 33314-7799
© 2025 Global ecology research group @ UF