Severe environmental conditions create severe conflicts? A novel ecological pathway to extreme coyote attacks on humans

1) Identifying the circumstances and causes of carnivore attacks on humans
is important for prevention of future incidents as well as employing
effective wildlife management strategies. Cape Breton Highlands National
Park (CBHNP) in Nova Scotia has experienced multiple attacks by coyotes
(Canis latrans) on humans, including a fatal attack on an adult in 2009.
2) Here we use a combination of data on space use and diet collected from
2011–2013 to reveal that limited resources and a reliance on a large
ungulate (moose, Alces americanus) as the mechanism leading to aggression
by coyotes in CBHNP. 3) Resident coyotes exhibited large home range sizes
(mean=77.5 km2) indicative of limited resources and spatiotemporal
avoidance of human activity. Carbon (d13C) and nitrogen (d15N) isotope
values of sub-sampled coyote whiskers (n=32), which provide a longitudinal
record of diet over the months before collection, revealed little intra-
and inter-individual variation with nearly all individuals specializing on
moose, a pattern that agrees with indices of natural resource
availability. Specifically, stable isotope mixing models show that moose
was the most important prey for most coyotes (25/32), representing between
41% and 78% of dietary inputs. Only four coyotes exhibited use of
anthropogenic resources (food), and only one of seven coyotes involved in
attacks on people had been consuming human foods before the attacks. 4)
Synthesis and Applications: We have described a unique ecological system
in which a generalist carnivore has expanded its niche to specialize on a
large prey species, with the unfortunate consequence of also expanding
pathways to conflicts with people. Our results suggest extreme unprovoked
predatory attacks by coyotes on people are likely to be quite rare and
associated with unique ecological characteristics. Extreme management
actions such as bounties are unnecessary, but managers may need to employ
hazing or lethal removal earlier in the conflict process than under normal
circumstances. Also, users of these areas should be made aware of the
risks coyotes pose and encouraged to take precautions.

1) 明确食肉动物袭击人类的情境与原因，对于预防未来事件及实施有效的野生动物管理策略至关重要。新斯科舍省的布雷顿角高地国家公园（Cape Breton Highlands National Park，CBHNP）曾发生多起郊狼（Canis latrans）袭击人类事件，其中包括2009年一起导致成年人死亡的致命袭击。
2) 本研究结合2011-2013年收集的空间利用与食性数据，揭示了资源有限及依赖大型有蹄类动物（驼鹿，Alces americanus）是CBHNP郊狼表现出攻击性的机制。
3) 定居郊狼的家域范围较大（均值=77.5平方公里），这表明资源有限且它们在时空上规避人类活动。对32份郊狼胡须子样本的碳（δ¹³C）和氮（δ¹⁵N）同位素值分析显示，个体内及个体间差异极小，几乎所有个体都以驼鹿为主要食物来源——这一模式与自然资源可获得性指数一致；胡须样本可提供其被采集前数月的食性纵向记录。具体而言，稳定同位素混合模型表明，驼鹿是大多数郊狼（32只中的25只）最重要的猎物，占其饮食输入的41%至78%。仅有4只郊狼使用了人为资源（食物），且在参与袭人事件的7只郊狼中，仅有1只在袭击前食用过人类食物。
4) 综合与应用：本研究描述了一个独特的生态系统——在该系统中，一种泛化型食肉动物拓展了其生态位，转而专门以大型猎物为食，不幸的是，这也增加了其与人类发生冲突的途径。研究结果表明，郊狼对人类发起的极端无端捕食性袭击可能相当罕见，且与独特的生态特征相关。无需采取诸如悬赏猎杀等极端管理措施，但管理者可能需要在冲突过程中比正常情况下更早采用驱避或选择性清除手段。此外，应让这些区域的使用者意识到郊狼带来的风险，并鼓励他们采取预防措施。