Mumma Matthew A, Holbrook Joseph D, Rayl Nathaniel D, Zieminski Christopher J, Fuller Todd K, Organ John F, Mahoney Shane P, Waits Lisette P
Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, Canada.
Land Resources and Environmental Sciences, Montana State University, Bozeman, USA.
Oecologia. 2017 Dec;185(4):725-735. doi: 10.1007/s00442-017-3971-8. Epub 2017 Oct 16.
Anthropogenic disturbances have altered species' distributions potentially impacting interspecific interactions. Interference competition is when one species denies a competing species access to a resource. One mechanism of interference competition is aggression, which can result in altered space-use of a subordinate species due to the threat of harm, otherwise known as a 'landscape of fear'. Alternatively, subordinates might outcompete dominant species in resource-poor environments via a superior ability to extract resources. Our goal was to evaluate spatial predictions of the 'landscape of fear' hypothesis for a carnivore guild in Newfoundland, Canada, where coyotes recently immigrated. Native Newfoundland carnivores include red foxes, Canada lynx, and black bears. We predicted foxes and lynx would avoid coyotes because of their larger size and similar dietary niches. We used scat-detecting dogs and genetic techniques to locate and identify predator scats. We then built resource selection functions and tested for avoidance by incorporating predicted values of selection for the alternative species into the best supported models of each species. We found multiple negative relationships, but notably did not find avoidance by foxes of areas selected by coyotes. While we did find that lynx avoided coyotes, we also found a reciprocal relationship. The observed patterns suggest spatial partitioning and not coyote avoidance, although avoidance could still be occurring at different spatial or temporal scales. Furthermore, Newfoundland's harsh climate and poor soils may swing the pendulum of interspecific interactions from interference competition to exploitative competition, where subordinates outcompete dominant competitors through a superior ability to extract resources.
人为干扰改变了物种分布，可能影响种间相互作用。干扰竞争是指一个物种阻止竞争物种获取资源。干扰竞争的一种机制是攻击行为，这可能会因伤害威胁导致从属物种的空间利用方式改变，即所谓的“恐惧景观”。另外，在资源匮乏的环境中，从属物种可能凭借更强的资源获取能力胜过优势物种。我们的目标是评估加拿大纽芬兰一个食肉动物群落的“恐惧景观”假说的空间预测，那里最近有郊狼迁入。纽芬兰本土的食肉动物包括赤狐、加拿大猞猁和黑熊。我们预测狐狸和猞猁会避开郊狼，因为郊狼体型更大且食性生态位相似。我们使用粪便探测犬和基因技术来定位和识别捕食者的粪便。然后我们构建资源选择函数，并通过将替代物种的预测选择值纳入每个物种的最佳支持模型中来测试是否存在回避行为。我们发现了多个负相关关系，但值得注意的是，没有发现狐狸会避开郊狼选择的区域。虽然我们确实发现猞猁会避开郊狼，但我们也发现了一种相互关系。观察到的模式表明是空间划分而非郊狼回避，不过回避仍可能在不同的空间或时间尺度上发生。此外，纽芬兰恶劣的气候和贫瘠的土壤可能会使种间相互作用的天平从干扰竞争转向剥削竞争，即从属物种凭借更强的资源获取能力胜过优势竞争者。
