Enhancing wild-felid conservation by resolving biases in population-density estimation and evaluating human perceptions of felids

Abstract

Big cat populations are threatened worldwide by poaching for illegal trade of their body parts, habitat loss and degradation, and negative interactions with humans. Ensuring healthy populations in the wild and peaceful coexistence with humans has become a cornerstone of wild felid conservation. Towards this end, knowledge of population abundances is a prerequisite for the judicious implementation of management strategies. Camera trapping is now the standard and globally ubiquitous method of population estimation of big cats. However, estimates from camera-trap studies are often biased by opportunistic sampling that deploys traps where they are most easily placed and will catch most animals, often on trails. This non-random sampling with respect to habitat tends to produce a male bias in captures, due to male-avoidance behaviours by the smaller females and their cubs. Resulting biases in population estimation often undermine the resources, time and effort involved in the camera-trap studies. This thesis aims to resolve biases in density estimates of big cats derived from camera trap studies by evaluation of alternative deployment protocols for unbiased camera trapping, and to evaluate social perceptions of wild felids in Bhutan as a first step towards enhancing positive interactions of human with wild felids. Chapter 2 evaluates bias in conventional camera trapping by comparing density estimates of individually identifiable big cats between trail-based and random deployments across 400 km2 of montane forest in Bhutan. Three camera traps were deployed in each of 100 2x2-km grid cells: one pair on a trail, and one in the exact centre of the cell (making it random with respect to habitat). Each deployment caught some individuals not caught in the other, with the trail deployment catching males of most species much more frequently than females. The random deployment tended to catch fewer total individuals but more females, leading to higher total density estimates and wider confidence intervals. Given the potential for the trail-based deployment to produce precisely wrong estimates from its larger sample and male bias, and the logistical difficulties inherent to random deployment combined with its risk of catching too few individuals for estimation, the overall recommendation is for a mixed deployment. Chapter 3 compares population density estimates between Spatially Explicit Capture-Recapture (SECR) models and Random Encounter Models (REM) for individually identifiable spotted cats, and assesses the density of Asiatic golden cats, which are not individually identifiable, with REM for different combination of random and trail-based deployments. It applies REM field protocols and analytical methods and compares them with the most robust density estimates derived from SECR in chapter 2. The chapter evaluates the sensitivity of REM density estimates to the accuracy of REM input parameter measurements. It compares the precision in density estimates from REM and SECR by computing their coefficients of variation. The chapter further evaluates the influence on REM density estimates of adding in trail cameras, comparing outcomes with the density estimates from the random-only deployment of camera traps. It includes the first assessment of the density estimates for the region of one unmarked felid (Asiatic golden cat), six unmarked prey species and two unmarked sympatric carnivores using REM. Chapter 4 evaluates the movement paths taken by common leopard, Asiatic golden cat, dhole, and leopard cat, obtained by GPS tracking, with reference to their use of habitat within the camera-trapping grid. The chapter computes separate home ranges for all the individuals to enumerate differences in home ranges between sexes and different geographical locations. It further quantifies the resource selection functions of all the carnivores. The analyses reveal a contrast in home range and resource selection by carnivores between the Southern and Northern habitats of Bhutan. Larger felids tend to select resources nearer to human settlement compared to the smaller felids. Chapter 5 evaluates the knowledge, attitudes, and practices of local communities in our study area with respect to conservation of wild felids and dhole. The chapter quantifies knowledge of wild felids, and the perceived importance of wild-felid conservation, for four communities at the edges of two national parks in Bhutan. It explores social factors contributing to positive or negative human-felid interactions, and human behaviours influencing the social acceptance of wild felids. The chapter adds to knowledge of human-felid interaction by the key informants (local leaders, government officials, and NGO personnel) in our study area and their recommendation for felid conservation. It finds that government incentives influence the social acceptance of wild carnivores by local communities, without improving positive attitudes towards them. Chapter 6 synthesizes the key conclusions drawn from each preceding chapters, emphasizing the significance of employing camera traps at both trail and random locations for robust density estimation. We found out that the unmarked method for density estimation can serve as a viable alternative in scenarios where identifying individuals within a population is challenging. Additionally, our findings indicate varying movement patterns among montane wild carnivores in Bhutan across different habitat types, impacting their resource selection behaviours. Furthermore, we observed social acceptance of communities for the conservation of wild carnivores is positively affected by government initiatives and incentives.

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Identifiers

ORCID for Lungten Dorji: orcid.org/0000-0003-1035-8439

ORCID for Patrick Doncaster: orcid.org/0000-0001-9406-0693

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