Abstract
AbstractReliably estimating population parameters for highly secretive or rare animals is challenging. We report on the status of the two largest remaining populations of the Critically Endangered Bermuda skink Plestiodon longirostris, using a robust design capture–mark–recapture analysis. Skinks were tagged with passive integrated transponders on two islands and captured on 15 sampling occasions per year over 3 years. The models provided precise estimates of abundance, capture and survival probabilities and temporary emigration. We estimated skink abundance to be 547 ± SE 63.5 on Southampton Island and 277 ± SE 28.4 on Castle Island. The populations do not appear to be stable and fluctuated at both sites over the 3-year period. Although the populations on these two islands appear viable, the Bermuda skink faces population fluctuations and remains threatened by increasing anthropogenic activities, invasive species and habitat loss. We recommend these two populations for continued monitoring and conservation efforts.
Highlights
Many threatened species are cryptic, elusive and challenging to survey
Estimates of annual capture probability derived using the model Mth were slightly higher on Southampton Island compared to Castle Island
Annual survival of skinks was higher on Southampton Island (w = . ± SE . ) than on Castle Island (w = . ± SE . )
Summary
Many threatened species are cryptic, elusive and challenging to survey. The development of efficient survey methods to detect them is vitally important for conservation management. A wide variety of methods have been used in monitoring studies, including capture– mark–recapture techniques to estimate abundance and MARK E. OUTERBRIDGE Government of Bermuda, Department of Environment and Natural Resources, Flatt’s Village, Bermuda. GERARDO GARCIA ( orcid.org/0000-0002-3007-8998) Chester Zoo, Cedar House, Chester, UK.
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