Evaluating elements of artificial cover object design for terrestrial salamander monitoring

Abstract

Abstract Declines in amphibian populations have led to greater research and monitoring of species of interest, including terrestrial salamanders. Several methods have been used to study salamanders, including artificial cover objects (ACOs). Artificial cover objects are easy to install and use, limit destruction to habitats, are easily reproducible both across and within studies, and can reduce variability between observers and sites by not relying on observer search time or effort, or on natural cover. However, different ACO designs and spacing may yield different capture rates, and thus different estimates of population densities. We examined the influence of ACO wood type, size, shape, and spacing arrays on the number of individually marked red‐backed salamanders (Plethodon cinereus) captured under ACOs. White pine (Pinus strobus) ACOs yielded the most (average of 14 across 3 replicates) individuals, while white ash (Fraxinus americana) ACOs had the least (average of 7 across 3 replicates). Larger ACOs had similar capture rates compared to equal sampled areas of smaller ACOs, but a single smaller ACO tended to have fewer individual salamander captures than a single large ACO. Our results suggested that high‐density ACO spacing arrays may increase capture probability but reduce the area uniquely sampled by each ACO. In contrast, low‐density ACO arrays may produce population estimates more comparable to other arrays. Future studies should consider monitoring goals and available sampling effort when choosing a spacing array. As ACO study design impacts salamander capture rates, a clear understanding of the effects of each element of ACO design is important when drawing inferences or making comparisons among studies.

Keywords

• artificial cover objects
• coverboard
• indicator species
• monitoring
• salamanders