Population size, density, and ranging behaviour in a key leopard population in the Western Cape, South Africa

Globally, leopards are the most widespread large felid. However, mounting anthropogenic threats are rapidly reducing viable leopard populations and their range. Despite the clear pressures facing this species, there is a dearth of robust and reliable population and density estimates for leopards across their range, which is particularly important in landscapes that consist of protected and non-protected areas. We conducted a camera trapping survey between 2017 and 2018 in the Western Cape, South Africa to estimate the occupancy, density, and population size of a leopard population. Leopards were recorded at 95% of camera trapping sites, which resulted in a high occupancy that showed no significant variation between seasons, habitat types, or along an altitudinal gradient. Our results indicated a low leopard density in the study area, with an estimated 1.53 leopards/100 km2 in summer and 1.62 leopards/100 km2 in winter. Mean leopard population size was therefore estimated at 107 and 113 individuals in the winter and summer respectively. Leopard activity centres for female ranges were centred in the core study area and could be predicted with good certainty, while males appeared to move out of the study area during winter which resulted in a higher uncertainty in locations of activity centres. Interestingly, livestock depredation events in the surrounding farmlands were significantly higher in winter, which coincides with male leopards moving outside the core protected area into the surrounding farmlands. To reduce livestock losses and retaliatory leopard killings, we suggest that human-carnivore conflict mitigation measures be intensely monitored during the winter months in the study area. We also suggest that future leopard conservation efforts should focus on privately-owned land as these non-protected areas contain the majority of the remaining suitable leopard habitat and may provide important dispersal corridors and buffer zones on which the long-term sustainability of leopard populations depends.

全球范围内，豹子是分布最广的大型猫科动物。然而，日益严峻的人为威胁正迅速减少豹子的有效种群及其分布范围。尽管该物种面临着明显的压力，但在其分布范围内，对于豹子的种群和密度估计仍缺乏可靠且坚实的数据，这在由保护区和非保护区组成的景观中尤为重要。我们于2017年至2018年在南非的开普西部进行了一次相机捕捉调查，以估算该地区豹子的栖息度、密度和种群规模。豹子在95%的相机捕捉点被记录，这导致了高栖息度，且在季节、生境类型或海拔梯度上均未显示出显著差异。我们的研究结果指出，研究区域内的豹子密度较低，夏季估计为每平方公里1.53只，冬季为每平方公里1.62只。因此，平均豹子种群规模在冬季和夏季分别估计为107和113只。雌豹的活动中心位于核心研究区域，并且可以高度预测，而雄豹似乎在冬季会离开研究区域，这导致了活动中心位置的更大不确定性。有趣的是，周边农田的牲畜侵害事件在冬季显著增加，这与雄豹移动至核心保护区外围的农田相吻合。为了减少牲畜损失和报复性豹子猎杀，我们建议在研究区域冬季月份加强对人兽冲突缓解措施的监测。我们还建议未来的豹子保护工作应聚焦于私有土地，因为这些非保护区包含着剩余大部分适宜豹子的栖息地，并且可能为豹子种群的长期可持续性提供重要的扩散走廊和缓冲区。