Habitat diversity influences puma (Puma concolor) diet in the Chihuahuan Desert

Habitat heterogeneity and corresponding diversity in potential prey species should increase the diet breadth of generalist predators. Many previous studies describing puma Puma concolor diets in the arid regions of the southwestern United States were focused within largely xeric locations, overlooking the influence of heterogeneity created by riparian forests. Such habitat heterogeneity and corresponding prey diversity could influence prey availability and puma diet composition. We examined seasonal prey composition of pumas occupying areas with different habitat conditions representing riparian areas adjacent to the Rio Grande and xeric Chihuahuan Desert uplands in southern New Mexico. We collected prey composition data from 686 kill sites made by 17 (9 males and 8 females) GPS-collared pumas from 2014 to 2018. Diet composition included 32 different avian, aquatic, small mammal, and ungulate prey species. Prey composition varied, with more ungulate prey consumed by pumas inhabiting the upland desert areas and more aquatic prey consumed in the riparian bosque. Prey composition differed between seasons, with ungulate prey decreasing and aquatic prey increasing during the hot–dry season. Prey composition also varied between puma sex and habitat with females in the desert uplands consuming more small mammals than either males or females in riparian areas. The diverse diets of the pumas inhabiting the heterogeneous landscapes in southern New Mexico provide additional evidence that pumas have broad diets that are strongly influenced by the habitat and prey community that their home range encompasses.

生境异质性与潜在猎物种群的相应多样性，可提升广食性捕食者（generalist predators）的食谱宽度。此前诸多针对美国西南部干旱区域美洲狮（Puma concolor）食谱的研究，多聚焦于极端旱生生境，却忽略了河岸林所构建的生境异质性及其影响。此类生境异质性与对应的猎物多样性，可能会影响猎物可获得性与美洲狮的食谱组成。我们对新墨西哥州南部的美洲狮开展研究，其栖息生境涵盖毗邻格兰德河的河岸区域与奇瓦瓦沙漠（Chihuahuan Desert）旱生高地两类生境条件差异显著的区域，本研究分析了该种群美洲狮的季节性猎物组成。我们于2014年至2018年间，从17只佩戴GPS项圈的美洲狮（9只雄性、8只雌性）的686个猎物捕杀位点收集了猎物组成相关数据。该种群美洲狮的食谱涵盖32个不同类群的猎物，包括鸟类、水生生物、小型哺乳动物与有蹄类动物（ungulate）。猎物组成存在显著分异：栖息于沙漠高地的美洲狮捕食的有蹄类动物占比更高，而河岸林带的美洲狮则捕食更多水生猎物。猎物组成同时存在季节差异：在炎热干旱季节，有蹄类动物的占比下降，水生猎物的占比则随之上升。猎物组成亦因美洲狮的性别与栖息生境而异：相较于河岸区域的雌性美洲狮，沙漠高地的雌性美洲狮捕食的小型哺乳动物占比更高。栖息于新墨西哥州南部异质性生境中的美洲狮拥有多样的食谱，这为美洲狮具备宽泛食谱、且其食谱强烈受活动范围内的生境与猎物群落影响这一结论提供了补充实证依据。