The effects of aridity on land use, biodiversity and dietary breadth in leopards

Abstract

Global distributions of most terrestrial large mammals have been dramatically reduced through the loss and fragmentation of natural habitat. These impacts are likely to be intensified by the effects of global climate change. Here we use two free roaming leopard (Panthera pardus) populations to explore the intersecting influences of climatic conditions and land use on the feeding ecology of a large carnivore. We predicted that greater aridity would influence land use, and that this would in turn influence species richness and consequently leopard diet. We compared diet, mammal species richness and land use patterns in two topographically similar regions of south-western South Africa, the Boland, a mesic temperate region and the Little Karoo, a semi-arid region located approximately 200 km to the east. The Boland has retained only ∼33% of natural land at low elevations, compared to over 90% in the Little Karoo. Extensive camera trap surveys in both regions revealed far lower mammal species richness in the Boland (22 species) than the Little Karoo (51 species). Leopard diet differed significantly between the two regions; leopards in the Boland fed on fewer (n = 15), smaller prey species (ranging from 3–25 kg) associated specifically with mountain habitat. By contrast, leopards in the Little Karoo had a broader prey range (n = 21), and were able to access larger prey (up to 138 kg). These results suggest that aridity has a significant influence on anthropogenic land use patterns, and that these changes are reflected both in the richness of the mammal community, and the diet of a large carnivore. However, the less intensive land use in the Little Karoo also increased the potential for conflict between leopards and people. Increased aridity as a result of global climate change may thus present opportunities to enhance the conservation status of free-roaming carnivores, but may also increase the potential for human-wildlife conflict as carnivores recolonize previously transformed areas.