Comparison of Two Methods for Detecting Atlantic Salt Marsh Mink

Abstract

ABSTRACTThe Atlantic salt marsh mink (ASMM; Neovison vison lutensis) has a limited distribution in Florida and may be vulnerable to extirpation through habitat loss or degradation. To evaluate ASMM population status, survey methods are needed that are effective and practical in salt marsh habitat where mink are difficult to detect. In 2013–2014, we compared the effectiveness of 2 survey methods, spotlight surveys and floating camera traps, to estimate site occupancy and detectability of ASMM in northeast Florida. Using spotlight surveys, we sampled 148, 1‐km2 units over 3 months and detected ASMM in 9% of the sampled units. With floating camera traps, we sampled 42, 1‐km2 units over 10 months and detected ASMM in 36% of sampled units. Floating cameras traps were a more effective survey method for ASMM, resulting in higher estimated site occupancy (Ψ = 0.36) and detection probability (P = 0.46) when compared to spotlight surveys (Ψ = 0.15, P = 0.24). Spotlight surveys for ASMM were effective only at peak high tide when water levels rise to the height of the marsh grass and many individuals take cover on floating vegetation. We conducted all spotlight surveys during times of peak high tide, but tide height varied by location across the study area and likely affected detection rates. As a result, we detected ASMM only during spotlight surveys in the northern part of our study area, where mean tide height was 1.97 m compared with 1.46 m in the southern part of the study area. Therefore, we recommend floating camera traps for future surveys of ASMM to estimate site occupancy. © 2021 The Wildlife Society.