Abstract
The hitherto difficult task of reliably estimating populations of wide-ranging megafauna has been enabled by advances in capture–recapture methodology. Here we combine photographic sampling with a Bayesian spatially-explicit capture–recapture (SCR) model to estimate population parameters for the endangered Asian elephant Elephas maximus in the productive floodplain ecosystem of Kaziranga National Park, India. Posterior density estimates of herd-living adult females and sub-adult males and females (herd-adults) was 0.68 elephants/km2 (95% Credible Intervals, CrI = 0.56−0.81) while that of adult males was 0.24 elephants/km2 (95% CrI = 0.18−0.30), with posterior density estimates highlighting spatial heterogeneity in elephant distribution. Estimates of the space-usage parameter suggested that herd-adults ({hat{sigma }}_{HA} = 5.91 km, 95% CrI = 5.18–6.81) moved around considerably more than adult males ({hat{sigma }}_{AM} = 3.64 km, 95% CrI = 3.09–4.34). Based on elephant movement and age–sex composition, we derived the population that contributed individuals sampled in Kaziranga to be 908 herd-adults, 228 adult males and 610 young (density = 0.46 young/km2, SD = 0.06). Our study demonstrates how SCR is suited to estimating geographically open populations, characterising spatial heterogeneity in fine-scale density, and facilitating reliable monitoring to assess population status and dynamics for science and conservation.
Highlights
The hitherto difficult task of reliably estimating populations of wide-ranging megafauna has been enabled by advances in capture–recapture methodology
Our study demonstrates how spatially-explicit capture–recapture (SCR) is suited to estimating geographically open populations, characterising spatial heterogeneity in fine-scale density, and facilitating reliable monitoring to assess population status and dynamics for science and conservation
Spatiotemporal variation in detection probability, and inadequate or unrepresentative spatial sampling are primary factors that lead to biased estimates of population size or density[2], thereby misrepresenting population status and potentially misleading conservation and management decisions
Summary
The hitherto difficult task of reliably estimating populations of wide-ranging megafauna has been enabled by advances in capture–recapture methodology. Unbiased and precise estimation of state variables and associated vital rates transcends applied research, and lays the foundation for the pursuit of several core questions in ecology Consider, for example, those that pertain to understanding the dynamics and regulation of animal populations[7,8]. The large spatial scales that are typically involved in monitoring wide-ranging species pose a constraint that can lead to the collection of data that are inadequate or www.nature.com/scientificreports/. Spatiotemporal variation in detection probability, and inadequate or unrepresentative spatial sampling are primary factors that lead to biased estimates of population size or density[2], thereby misrepresenting population status and potentially misleading conservation and management decisions. Given that elephants worldwide are highly threatened by continuing habitat loss and degradation, staggering spurts in poaching for ivory, and increasing conflict with people[13], reliable monitoring of their populations is a key priority for conservation policy and action
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
