Modeling community occupancy from line transect data: a case study with large mammals in post-war Angola

Human disturbance can have a profound effect on the occurrence and distribution of wildlife. Such disturbance often extends into protected areas (PAs), particularly in countries that have undergone civil strife and lack the institutional capacity to effectively mitigate anthropogenic threats. We demonstrate the first application of a multi-species hierarchical occupancy model to spatially correlated detections from vehicle-based spoor transects, estimating species richness and species-specific drivers of occurrence of a large mammal community comprising five large carnivores [cheetah (Acinonyx jubatus), leopard (Panthera pardus), lion (Panthera leo), spotted hyena (Crocuta crocuta), and wild dog (Lycaon pictus)] and six large herbivores [buffalo (Syncerus caffer), eland (Taurotragus oryx), elephant (Loxodonta africana), giraffe (Giraffa giraffa), roan (Hippotragus equinus), and sable (Hippotragus niger)] in Luengue-Luiana and Mavinga National Parks, Angola. This area is the largest contiguous national park complex within a single African country and part of the largest transfrontier conservation area in the world, and is still recovering from the effects of civil war. In this post-war landscape, the most substantive drivers of community-level occupancy were anthropogenic, with occupancy associated with lower frequency of human sign, proximity to adjacent national park, and distance away from human settlement. In contrast, ecological variables (precipitation, vegetation cover, seasonal water availability) had less explanatory value. Our results highlight the deleterious effects of human incursion into PAs on the richness and distribution of large mammal species, underscoring the need for intensive mitigation of anthropogenic threats (e.g. poaching, bushmeat hunting) to maintain species of high conservation value in areas impacted by war.