Data from: Ungulate predation and ecological roles of wolves and coyotes in eastern North America

Understanding the ecological roles of species that influence ecosystem processes is a central goal of ecology and conservation biology. Eastern coyotes (Canis latrans) have ascended to the role of apex predator across much of eastern North America since the extirpation of wolves (Canis spp.) and there has been considerable confusion regarding their ability to prey on ungulates and their ecological niche relative to wolves. Eastern wolves (C. lycaon) are thought to have been the historical top predator in eastern deciduous forests and have previously been characterized as deer specialists that are inefficient predators of moose because of their smaller size relative to gray wolves (C. lupus). We investigated intrinsic and extrinsic influences on per capita kill rates of white-tailed deer (Odocoileus virginianus) and moose (Alces alces) during winter by sympatric packs of eastern coyotes, eastern wolves, and admixed canids in Ontario, Canada to clarify the predatory ability and ecological roles of the different canid top predators of eastern North America. Eastern coyote ancestry within packs negatively influenced per capita total ungulate (deer and moose combined) and moose kill rates. Furthermore, canids in packs dominated by eastern coyote ancestry consumed significantly less ungulate biomass and more anthropogenic food than packs dominated by wolf ancestry. Similar to gray wolves in previous studies, eastern wolves preyed on deer where they were available. However, in areas were deer were scarce, eastern wolves killed moose at rates similar to those previously documented for gray wolves at comparable moose densities across North America. Eastern coyotes are effective deer predators, but their dietary flexibility and low kill rates on moose suggest they have not replaced the ecological role of wolves in eastern North America.

阐明调控生态系统过程的物种的生态功能，是生态学与保护生物学的核心研究目标之一。自灰狼属（Canis spp.）物种在北美东部大部分区域绝迹后，东部郊狼（Eastern coyote, Canis latrans）已跃升为当地的顶级捕食者，但学界此前对其捕食有蹄类动物（ungulates）的能力，以及其相对于灰狼的生态位存在诸多认知分歧与困惑。东部狼（Eastern wolf, C. lycaon）曾被认为是北美东部落叶林的历史顶级捕食者，此前学界将其归类为鹿类专食者，且因其体型小于灰狼（Gray wolf, C. lupus），被认为是捕食驼鹿效率低下的物种。本研究于加拿大安大略省开展，针对冬季时段东部郊狼、东部狼以及混血犬科动物的同域种群，探究其单位个体猎食率的内在与外在影响因素，研究对象为白尾鹿（White-tailed deer, Odocoileus virginianus）与驼鹿（Moose, Alces alces），旨在厘清北美东部不同犬科顶级捕食者的捕食能力与生态功能。种群内的东部郊狼血统占比对单位个体总有蹄类（鹿与驼鹿合计）猎食率以及驼鹿猎食率均产生负向影响。此外，以东郊狼血统为主的种群，其犬科动物的有蹄类生物量摄入量显著低于以狼血统为主的种群，而人为源食物的摄入量则更高。与此前研究中的灰狼行为一致，东部狼在鹿类可获取的区域会捕食鹿类。然而，在鹿类稀缺的区域，东部狼的驼鹿猎食率与此前北美地区在相似驼鹿密度下记录的灰狼猎食率相当。东部郊狼是高效的鹿类捕食者，但其食性可塑性以及较低的驼鹿猎食率表明，它们并未取代北美东部灰狼的生态功能。