Estimating forest antelope population densities using distance sampling with camera traps

Rajan Amin,David Olson,Andrew Fowler,Hannah Klair,Tom Bruce,Tim Wacher,Constant Ndjassi

doi:10.1017/s0030605320001209

Abstract

AbstractTraditional transect survey methods for forest antelopes often underestimate density for common species and do not provide sufficient data for rarer species. The use of camera trapping as a survey tool for medium and large terrestrial mammals has become increasingly common, especially in forest habitats. Here, we applied the distance sampling method to images generated from camera-trap surveys in Dja Faunal Reserve, Cameroon, and used an estimate of the proportion of time animals are active to correct for negative bias in the density estimates from the 24-hour camera-trap survey datasets. We also used multiple covariate distance sampling with body weight as a covariate to estimate detection probabilities and densities of rarer species. These methods provide an effective tool for monitoring the status of individual species or a community of forest antelope species, information urgently needed for conservation planning and action.

Highlights

Antelopes and other artiodactyl species constitute a significant component of forest and woodland ecosystems both in terms of biomass (White, ) and ecological services (Feer, )
We demonstrate its use for monitoring the status of threatened forest antelopes in the Dja Faunal Reserve, southern Cameroon
We have shown that camera-trap distance sampling can be an effective method for monitoring the densities and population status of a community of forest antelopes, information urgently needed for conservation planning and action

Summary

Introduction

Antelopes and other artiodactyl species constitute a significant component of forest and woodland ecosystems both in terms of biomass (White, ) and ecological services (Feer, ). Many species are increasingly threatened by habitat loss and hunting for bushmeat (East, ). Forest antelopes are primary targets for the trade in bushmeat (Wilkie & Carpenter, ; Fa et al, ) and have undergone major local and regional declines as a result (e.g. van Vliet et al, ). Monitoring the status of forest antelopes is a critical conservation need. Forest antelopes are difficult to monitor using traditional methods based on direct sightings or signs as many species are solitary, nocturnal, shy, spend long periods.

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Results

Conclusion