Examining the spatial occurrence of carnivores across a gradient of anthropogenic pressure in southern Tanzania, with a focus on the Ruaha landscape and adjacent areas

Tanzania’s Ruaha landscape harbours some of the most important carnivore population strongholds in East Africa. However, ongoing human-induced changes of natural habitat expose these carnivore populations to increased anthropogenic pressure, even within protected areas. Such habitat changes can disrupt carnivore distribution and species interactions, which can be detrimental for species conservation. Yet, there is limited understanding about how anthropogenic-related variables influence carnivore occurrence and interspecific interactions in this landscape, which hinders the development of strategies to conserve carnivores. In this thesis, I examined the spatial occurrence of carnivores across the gradient of anthropogenic pressure in the Ruaha landscape and adjacent areas. In the first data chapters I investigated how landscape and human-related variables influenced carnivore site occupancy and interspecific interactions in the Ruaha National Park (RNP), surrounding wildlife management area, and village lands through extensive camera-trapping data. I found a consistent and steady decline in carnivore detections with increasing distance from RNP, especially closer to human households. Large carnivores, specifically, were not detected anywhere in the village lands. There was a notable variation on the influence of anthropogenic and landscape variables to carnivore site use: large carnivores were influenced by prey biomass and anthropogenic variables, whereas mesocarnivores were largely influenced by distance to the Great Ruaha River. In addition, mesocarnivore detections were correlated with those of top-order carnivores. Furthermore, increased probability for interspecific interactions between mesocarnivores was influenced by proximity to households. Overall, I identified that the village lands were likely acting as a hard edge that limited carnivore distribution outside RNP. On my last data chapter, I investigated the determinants of carnivore habitat suitability beyond Ruaha, and generated a predictive map of highly suitable carnivore habitats for the human gradient between the Ruaha and Selous landscapes, using the lion (Panthera leo) as a key-species. Highly suitable habitats were associated with low human population density (<10 people/km2) and rainfall, and over 75% of these habitats were limited to protected areas, with the remainder patchily distributed across village lands. The results suggested limited potential for landscape connectivity between Ruaha and Selous. Overall, this thesis provides a rigorous assessment of the first comprehensive baseline data of carnivore spatial occurrence within a gradient of anthropogenic pressure in this landscape. The framework presented here can be used to help informing carnivore conservation planning in Ruaha, with applications elsewhere where carnivores and humans overlap.