Article
Ecology
Brynn A. Mclellan, Eric Howe, Robby R. Marrotte, Joseph M. Northrup
Summary: Reliable estimates of population density are crucial for wildlife management and conservation. Spatially explicit capture-recapture models and information-theoretic model selection criteria are commonly used for density estimation. This study tested the performance of these models and criteria in the presence of realistic levels of density and detectability variation. Simulations of American black bear populations were used to assess the reliability of model selection criteria and the accuracy of density estimates. The study found that unmodeled heterogeneity in density and detectability can lead to biased estimates, but including a good approximating model can yield accurate results.
Article
Ecology
Gates Dupont, J. Andrew Royle, Muhammad Ali Nawaz, Chris Sutherland
Summary: The study proposes using a genetic algorithm to optimize sampling designs and compares the performance of designs based on different model-based criteria, finding that these designs outperform existing recommendations in terms of bias, precision, and accuracy in population size estimation.
Article
Ecology
Brett T. McClintock, Briana Abrahms, Richard B. Chandler, Paul B. Conn, Sarah J. Converse, Robert L. Emmet, Beth Gardner, Nathan J. Hostetter, Devin S. Johnson
Summary: Ecologists and conservation biologists increasingly rely on spatial capture-recapture (SCR) and movement modeling to study animal populations. Historically, SCR has focused on population-level processes, while animal movement modeling has focused on individual behavior. Integrating SCR and animal movement modeling has the potential to scale up from individuals to populations, advancing types of inferences and improving population-level parameter estimations critical for species conservation and management.
Article
Ecology
Murray G. G. Efford
Summary: Some capture-recapture models for population estimation cannot be easily fitted by conventional methods. A new R package is introduced in this study to refine and extend a simulation and inverse prediction method for estimating population density, including models with varying density, trap interference, and other sources of non-independence among detection histories. The method is applied to a trapping study of brushtail possums in New Zealand, and the impact of time-varying interference on population decline is discussed.
METHODS IN ECOLOGY AND EVOLUTION
(2023)
Article
Environmental Sciences
Thomas Connor, Wildlife Division, Emilio Tripp, William T. Bean, B. J. Saxon, Jessica Camarena, Asa Donahue, Daniel Sarna-Wojcicki, Luke Macaulay, William Tripp, Justin Brashares
Summary: Recent developments have extended the use of spatial-capture recapture models to species that are not uniquely identifiable, and have allowed the inclusion of continuous environmental covariates. This paper presents an extension to the unmarked spatial capture recapture (uSCR) modeling framework, allowing the fitting of continuous environmental covariates to animal density. The study found that increasing forb/grass cover has a positive effect on elk density, while increasing tree cover has a negative effect.
Article
Ecology
Beth Gardner, Brett T. McClintock, Sarah J. Converse, Nathan J. Hostetter
Summary: Spatial capture-recapture (SCR) models have been widely used to estimate demographic parameters in ecological studies. However, the existing models often make unrealistic assumptions about animal movement and space use. We developed SCR models that integrate more complex movement processes inferred from telemetry data, and demonstrated their ability to address ecological questions related to animal space use, habitat selection, and behavior.
Article
Ecology
Gates Dupont, Daniel W. Linden, Chris Sutherland
Summary: Understanding how individual-level processes influence patterns in animal populations is a challenge in ecology, with recent focus on integrated modeling driven by ecological theory and data-integration opportunities. However, advancements in this area may be hindered by data requirements for quantifying individual-level processes.
Article
Ecology
Nathan J. Crum, Timothy A. Gowan, Kandethody M. Ramachandran
Summary: Wildlife movement is a crucial process that affects species population biology and community interactions. Recent advancements in spatial capture-recapture modeling and hidden Markov models have improved the estimation and prediction of wildlife movement, especially for untagged and undetected individuals.
METHODS IN ECOLOGY AND EVOLUTION
(2023)
Article
Biodiversity Conservation
Charlotte E. Searle, Josephine Smit, Paolo Strampelli, Lameck Mkuburo, Dennis Ikanda, David W. Macdonald, Andrew J. Loveridge, Amy J. Dickman
Summary: This study compares leopard population densities across different components of a mixed-use landscape in Tanzania. The highest densities were found in the core tourist area of Ruaha National Park and a neighboring community-managed area, with population density strongly correlated with prey abundance. The findings suggest that prey availability is the main driver of leopard density variations in different habitats.
BIOLOGICAL CONSERVATION
(2021)
Article
Ecology
Ian Durbach, David Borchers, Chris Sutherland, Koustubh Sharma
Summary: SCR methods estimate animal density using detector locations and spatial capture histories. Recent research shows that precision can be approximated based on the expected number of detected individuals and recapture events. Optimizing detector placement can increase the number of detected individuals and recaptures, but may not always lead to more precise density estimations.
METHODS IN ECOLOGY AND EVOLUTION
(2021)
Article
Biodiversity Conservation
Dinal J. S. Samarasinghe, Eric D. Wikramanayake, Arjun M. Gopalaswamy, Rukshan Jayewardene, Jehan Kumara, Javana Fernando, Kithsiri Gunawardene, Justine Shanti Alexander, Alexander Braczkowski
Summary: Understanding the population dynamics of large carnivores is crucial for conservation strategies, especially in island environments. The Sri Lankan leopard, the only apex predator in Sri Lanka, has limited research. This study reveals that Wilpattu National Park supports a relatively high density of leopards, making it a critical stronghold for their long-term population viability in the larger landscape.
GLOBAL ECOLOGY AND CONSERVATION
(2022)
Article
Biodiversity Conservation
Carolyn H. Devens, Matt W. Hayward, Thulani Tshabalala, Amy Dickman, Jeannine S. McManus, Bool Smuts, Michael J. Somers
Summary: Leopards play a critical role in maintaining ecosystem health but are vulnerable to habitat degradation and mortality. A study in South Africa's Western Cape province found leopard density to be 0.35-1.18 individuals per 100 square kilometers, with a predicted population size of 102-345 individuals. Providing a baseline population density estimate is crucial for understanding population dynamics and conservation efforts.
Article
Ecology
D. Doran-Myers, A. J. Kenney, C. J. Krebs, C. T. Lamb, A. K. Menzies, D. Murray, E. K. Studd, J. Whittington, S. Boutin
Summary: Unbiased population density estimates are crucial for ecological research and wildlife management, but estimating density accurately can be challenging. This study on Canada lynx highlighted the significant variation in density estimates across methods, despite following method requirements and assumptions. It emphasizes the importance of careful and unbiased sampling design and the need for further research to fully assess the accuracy and limitations of wildlife density estimation methods.
Article
Zoology
Xiaoxing Bian, Xuchang Liang, Byron Weckworth, Dorje Jyal, Vanessa Hull, Le Yang
Summary: Knowledge of population abundance is essential for wildlife management and conservation, especially for rare species such as the snow leopard. This study used camera trapping to estimate the density of snow leopards in a previously unsurveyed area on the Tibetan Plateau, with a result of 1.40 individuals per 100 km(2). The findings provide an important baseline reference for future population trend assessments and conservation measures.
INTEGRATIVE ZOOLOGY
(2023)
Review
Ecology
Murray G. Efford, Matthew R. Schofield
Summary: The article discusses the critical issues of survival rate and recruitment rate in population management, introduces the movement component and related issues in open population spatially explicit capture-recapture models, and provides detailed explanations through simulations and case studies. It shows that the flexible 2-parameter kernels, such as the bivariate t$$ t $$-distribution, are more suitable than the popular bivariate normal distribution, leading to higher estimates of survival; there may be problems in the movement models when dealing with data of different distances, calling for more complete and consistent reporting.
METHODS IN ECOLOGY AND EVOLUTION
(2022)
Review
Biodiversity Conservation
Joseph Drake, Xavier Lambin, Chris Sutherland
Summary: Connectivity plays a vital role in ecology, affecting species survival and ecosystem functioning. It consists of both structural and functional components, and the interaction of these components often better describes ecological processes. Demographically-informed connectivity serves as a general framework for addressing current ecological issues, particularly in the fields of population ecology, conservation biology, and landscape ecology.
Article
Biodiversity Conservation
R. Pal, C. Sutherland, Q. Qureshi, S. Sathyakumar
Summary: This study examines the spatial distribution of snow leopards in the Gangotri landscape, finding a positive association between snow leopard density and elevation and slope, with higher density in protected areas. The study suggests regulating human activities and managing non-protected areas to ensure functional connectivity and revive prey base. Overall, the study provides a framework for quantifying abundance, distribution, and connectivity in a multiuse landscape, with broad applicability for strategic planning.
ANIMAL CONSERVATION
(2022)
Article
Biodiversity Conservation
Alexej P. K. Siren, Chris S. Sutherland, Ambarish V. Karmalkar, Matthew J. Duveneck, Toni Lyn Morelli
Summary: Identifying the mechanisms influencing species' distributions is crucial for accurate climate change forecasts. This study compared current and future distributions of mammalian carnivores and competitors in the northeastern US using causal and correlational models. The results demonstrate that a causal framework can generate more accurate predictions of species distributions and help understand range limits and species' response to climate change.
DIVERSITY AND DISTRIBUTIONS
(2022)
Article
Ecology
Goncalo Curveira-Santos, Laura Gigliotti, Andre P. Silva, Chris Sutherland, Stefan Foord, Margarida Santos-Reis, Lourens H. Swanepoel
Summary: The study revisited existing theories on intraguild killing among African carnivores using online photographs, revealing a wider range of species and interactions than previously thought. It suggests that the current IGK theory underestimates the alternative competition pathways and the role of predatory and incidental killing, highlighting the potential for IGK-mediated cascades in species-rich assemblages and community-wide suppressive effects of large carnivores.
Article
Biology
Joshua P. Twining, Chris Sutherland, Neil Reid, David G. Tosh
Summary: The recovery of native predators can have significant implications for species interactions, and this study shows that these interactions are mediated by habitat. The expansion of the native pine marten was not influenced by human habitat modification, but its effect on the red squirrel was dependent on habitat type. These findings highlight the importance of habitat in shaping the interactions between predators and prey.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2022)
Article
Ecology
Logan Luevano, Chris Sutherland, Stephanie J. Gonzalez, Raisa Hernandez-Pacheco
Summary: Early-life adversity, such as major hurricanes and density changes, can affect the reproductive potential of rhesus macaque females. However, long-lived populations can adapt to adverse conditions and optimize their reproductive schedules. Females that experience major hurricanes exhibit delayed reproductive debut but maintain reproductive pace and higher fertility during prime reproductive ages. Increasing density at birth is associated with decreased fertility and reproductive pace, except at intermediate densities. Our study suggests that hurricanes predict a delay-overhand pattern in fertility, while density has a complex relationship with reproduction, indicating that females experiencing regulated population density can optimize reproductive schedules.
ECOLOGY AND EVOLUTION
(2022)
Article
Ecology
Benjamin J. Padilla, Chris Sutherland
Summary: This research explores patterns of avian diversity and abundance in heterogenous landscapes using multiple dimensional gradients of human-mediated modification. The results show that avian richness is highest in more heterogeneous regions of the landscape, and individual species exhibit varying responses. This study provides valuable insight for conservation and management in human-dominated landscapes.
Article
Ecology
Joseph Drake, Xavier Lambin, Chris Sutherland
Summary: Connectivity is a fundamental concept that links dispersal to the dynamics and persistence of spatially structured populations. While traditional measures of connectivity assume it to be static, it is actually dynamic and related to the spatial distribution of individuals and populations. Using occupancy data from water voles, we found that considering the dynamic nature of connectivity improves the recovery of population dynamics and has implications for metapopulation capacity predictions.
JOURNAL OF ANIMAL ECOLOGY
(2022)
Article
Zoology
Patricia Levasseur, Michael T. Jones, Barbara Brennessel, Robert Prescott, Mark Faherty, Chris Sutherland
Summary: The status, size, and density of Diamondback Terrapin populations along the Atlantic coast have been reported as unknown or declining. Using spatial capture-recapture (SCR) methods, the study presents the first application of SCR to analyze Diamondback Terrapins in two known activity areas in Massachusetts. The results show that detection of terrapins is influenced by survey effort, day of the season, tide cycle, time of tide, survey time relative to the tide, cloud cover, and windspeed. The study also found significant differences in density and space use between the two sites, as well as a female-biased sex ratio. This study demonstrates the usefulness of SCR methods in estimating population size and density, while providing insights into space use and detection in Diamondback Terrapins.
JOURNAL OF HERPETOLOGY
(2022)
Article
Ecology
Goncalo Curveira-Santos, Laura Gigliotti, Chris Sutherland, Daniela Rato, Margarida Santos-Reis, Lourens H. Swanepoel
Summary: Carnivore intraguild dynamics are influenced by the complex interplay between environmental affinities and interspecific interactions. The management and conservation paradigms in South Africa have significantly altered the structure of local carnivore assemblages. Our study reveals that carnivores are generally distributed independently across space but existing spatial dependencies are context-specific. Furthermore, temporal overlap patterns mostly depend on species' endogenous clock rather than the local context.
ECOLOGY AND EVOLUTION
(2022)
Article
Biodiversity Conservation
Darragh Hare, Hueseyin Ambarli, Amy J. Dickman, Egil Droge, Mohammad S. Farhidinia, Paul J. Johnson, Munib Khanyari, Rose Mandisodza-Chikerema, Robert A. Montgomery, Chris Sutherland, Hugh Webster, Matthew Wijers
Summary: Trophy hunting is a highly controversial topic in wildlife conservation, with divergent views on its effectiveness and impact. The use of a blanket term for trophy hunting overlooks the variations in hunting practices and reasons behind trophy collection. It is crucial for stakeholders to communicate clearly and specify their stance on different hunting activities.
BIODIVERSITY AND CONSERVATION
(2023)
Article
Biodiversity Conservation
Alexej Siren, Marketa Zimova, Chris S. Sutherland, John T. Finn, Jillian R. Kilborn, Rachel M. Cliche, Leighlan S. Prout, L. Scott Mills, Toni Lyn Morelli
Summary: This study focuses on the influence of resource availability on snowshoe hare populations along their trailing range edge. The results show that variability in resource availability affects population density and fluctuations, as well as survival rates. Hares living in resource-limited environments have lower population density but higher survival rates and lower parasite loads compared to populations in resource-rich environments.
Article
Ecology
Brandon P. Hedrick, Alba Estrada, Chris Sutherland, A. Marcia Barbosa
Summary: The acceleration of climate change is affecting the distributions of many species, particularly amphibians. Understanding the impact of climate change on their distributions is crucial for the overall health of ecosystems.
ECOLOGY AND EVOLUTION
(2023)
Article
Environmental Sciences
Carl Chalmers, Paul Fergus, Serge Wich, Steven. N. N. Longmore, Naomi Davies Walsh, Philip. A. A. Stephens, Chris Sutherland, Naomi Matthews, Jens Mudde, Amira Nuseibeh
Summary: Birds are crucial for monitoring biodiversity and habitat health, and they play a vital role in ecosystem management. Declining bird populations can lead to reduced ecosystem services such as seed dispersal, pollination, and pest control. While monitoring birds is important for ecologists, it is often time-consuming, expensive, and challenging to manage. This paper proposes using deep learning to overcome the challenges and automate bird monitoring in camera trap data.
Article
Biology
Chris Sutherland, Darragh Hare, Paul J. Johnson, Daniel W. Linden, Robert A. Montgomery, Egil Droge
Summary: The debates surrounding model selection paradigms are important, especially in the absence of a consensus. This study highlights the need for a better understanding of existing approaches, specifically among end-users of statistics and model selection tools. The researchers focus on the Akaike information criterion (AIC) in ecological literature and address common misunderstandings related to 'pretending' variables and the interpretation of p-values in relation to AIC. By complementing technical literature with simulations, the study aims to improve statistical practices and the interpretation and reporting of models selected using AIC.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2023)
