Data from: Leopard distribution and abundance is unaffected by interference competition with lions

Competition can have profound impacts on the structure and function of ecological communities. Despite this, the population-level effects of intraguild competition on large carnivores remain largely unknown, due to a paucity of long-term studies that focus simultaneously on competing species. Here, we comprehensively examine competitive interactions, including their demographic consequences, between 2 top predators, lions Panthera leo and leopards P. pardus. We tested the hypothesis that lions, as the dominant competitor, limit the distribution and abundance of leopards, using dietary, spatial, and life-history data collected concurrently on the 2 species. Dietary overlap between lions and leopards was limited, with lions targeting large- to very large-sized prey and leopards small- to medium-sized prey. Leopards did not actively avoid lions, either predictively or reactively, except in riparian woodland where the likelihood of encountering lions was highest. Lions accounted for more than 20% of leopard mortality, but this appeared to be compensatory. Observed and modeled population growth was similar between the 2 species, with both exhibiting net emigration. Our findings suggest that lions do not suppress leopard populations or limit their distribution, at least in our study area. Adequate availability of suitably-sized prey apparently enabled resource partitioning between lions and leopards, facilitating their coexistence. The potential for competition increases in areas devoid of large prey and should be considered in recovery efforts for the 2 species. Our study provides novel empirical evidence that intraguild competition does not always have population-level consequences for subordinates, even if they suffer from strong inference competition with dominant competitors.

种间竞争可对生态群落的结构与功能产生深远影响。尽管如此，由于同时针对竞争物种的长期研究较为匮乏，同功能群竞争（intraguild competition）对大型食肉动物的种群级效应在很大程度上仍未明确。本研究针对两种顶级捕食者——狮子（Panthera leo）与豹（Panthera pardus，简称P. pardus）——之间的竞争互动（包括其种群统计学效应）展开全面分析。研究人员基于同时采集的两种物种的食性、空间分布与生活史数据，验证了“作为优势竞争者的狮子会限制豹的分布与种群数量”这一假说。狮子与豹的食性重叠度较低：狮子偏好大型至超大型猎物，而豹则以小型至中型猎物为主要食物来源。除在狮子遭遇概率最高的河岸林地生境外，豹并未主动通过预测性或反应性行为躲避狮子。狮子导致的豹死亡占比超过20%，但该死亡模式似乎属于补偿性死亡。两种物种的观测种群增长与模拟种群增长趋势一致，均呈现净迁出状态。本研究结果表明，至少在本研究区域内，狮子并未抑制豹的种群规模或限制其分布范围。充足的适宜体型猎物资源显然促成了狮子与豹之间的资源分化，进而推动二者实现共存。在缺乏大型猎物的区域，种间竞争的潜在风险会升高，这一因素应被纳入两种物种的种群恢复工作中。本研究提供了全新的实证证据：即便从属竞争者会与优势竞争者发生强烈的干扰竞争（interference competition），同功能群竞争也并非总会对其种群产生显著影响。