Evaluation of the AHDriFT Camera Trap System to Survey for Small Mammals and Herpetofauna

Abstract

AbstractTraditional surveys for small mammals and herpetofauna require intensive field effort because these taxa are often difficult to detect. Dynamic environmental conditions and dense vegetative cover, both of which are attributes of biodiverse wet meadow ecosystems, further hamper field surveys. Camera traps may be a solution, but commonly used passive infrared game cameras face difficulties photographing herpetofauna and small mammals. The adapted-Hunt drift fence technique (AHDriFT) is a camera trap and drift fence system designed to overcome traditional limitations, but has not been extensively evaluated. We deployed 15 Y-shaped AHDriFT arrays (three cameras per array) in northern Ohio wet meadows from March 10 to October 5, 2019. Equipment for each array cost approximately US$1,570. Construction and deployment of each array took approximately 3 h, with field servicing requiring 15 min per array. Arrays proved durable under wind, ice, snow, flooding, and heat. Processing 2 wk of images of 45 cameras averaged about 13 person-hours. We obtained 9,018 unique-capture events of 41 vertebrate species comprised of 5 amphibians, 13 reptiles (11 snakes), 16 mammals, and 7 birds. We imaged differing animal size classes ranging from invertebrates to weasels. We assessed detection efficacy by using expected biodiversity baselines. We determined snake communities from 3 y of traditional surveys and possible small mammal and amphibian biodiversity from prior observations and species ranges and habitat requirements. We cumulatively detected all amphibians and 92% of snakes and small mammals that we expected to be present. We also imaged four mammal and two snake species where they were not previously observed. However, capture consistency was variable by taxa and species, and low-mobility species or species in low densities may not be detected. In its current design, AHDriFT proved to be effective for terrestrial vertebrate biodiversity surveying.