Supplementation of seasonal natural resources with year-round anthropogenic resources by coyotes in natural fragments within a high-density urban area

Coyotes (Canis latrans) in urban landscapes provide important food web functions and ecological services but can also trigger human-wildlife conflict when their diet includes anthropogenic resources or domestic pets. As adaptable omnivores, coyotes adjust their diet to their environment, routinely switching among food items to accommodate spatial and seasonal differences in availability. To evaluate coyotes’ potential impacts within the food web of urban Long Beach, California where human-wildlife conflict involving coyotes may occur, we analyzed 115 scat samples collected once every two weeks from two open space fragments inside the urban matrix. We hypothesized that differences in scat composition would correlate with seasonal and site differences, with greater use of anthropogenic resources during the dry season supplementing lower prey availability, and greater consumption of wild mammal prey during the wet season when rabbits and small mammals reproduce. We found coyote diet was predominately composed of natural prey and vegetation year-round. Mammals made up more of the coyote diet in the wet season than the dry, while arthropods and vegetation occurred more in dry season scats. Coyotes relied on rabbits as their main prey year-round across all sites. Domestic cats (Felis catus) were the third most common individual prey species found in coyote scats; we did not find evidence of domestic dog (Canis lupus familiaris) consumption. The overall frequency of mammalian remains did not differ across sites but did differ across sites for other prey types. While there is a potential for human-wildlife conflict in coyote’s consumption of feral or domestic cats, coyotes may also be providing an ecological service by reducing cats in natural habitat fragments.

栖息于城市景观中的郊狼（Canis latrans）不仅发挥着重要的食物网功能与生态服务价值，当其食谱包含人为源食物或家养宠物时，也可能引发人与野生动物的冲突。作为适应性极强的杂食动物，郊狼会根据所处环境调整取食策略，通过常规切换食物类群以应对食物可获得性的空间与季节差异。为评估郊狼在加州长滩市城市食物网中的潜在影响——该区域曾出现涉及郊狼的人兽冲突——我们对采自城市基质内两处开放空间斑块、每两周采集一次的115份粪便样本进行了分析。我们提出如下研究假说：粪便组成差异与季节和采样位点差异存在相关性，即旱季猎物可获得性较低时，郊狼会更多利用人为源食物作为补充；而雨季兔类与小型哺乳动物进入繁殖期，郊狼对野生哺乳类猎物的取食比例会更高。研究结果显示，全年郊狼的食谱主要由自然猎物与植物类群构成。相较于旱季，雨季时哺乳类在郊狼食谱中的占比更高，而节肢动物与植物在旱季粪便样本中的占比更为突出。所有采样位点中，兔类均为郊狼全年的核心猎物。家猫（Felis catus）是郊狼粪便中检出的第三大常见单一猎物物种；本研究未发现郊狼取食家犬（Canis lupus familiaris）的相关证据。哺乳类残骸的总体出现频率在不同采样位点间无显著差异，但其他类群猎物的出现频率则存在位点间差异。尽管郊狼取食野生或家猫存在引发人兽冲突的潜在风险，但它们也可通过在自然生境斑块中抑制猫类种群，发挥正向生态服务功能。