Abstract：
Humans are perceived as predators by many species and may generate landscapes of fear, influencing spatiotemporal activity of wildlife. Additionally, wildlife might seek out human activity when faced with predation risks (human shield hypothesis). We used the anthropause, a decrease in human activity resulting from the COVID-19 pandemic, to test ecology of fear and human shield hypotheses and quantify the effects of bear-viewing ecotourism on grizzly bear (Ursus arctos) activity. We deployed camera traps in the Khutze watershed in Kitasoo Xai\'xais Territory in the absence of humans in 2020 and with experimental treatments of variable human activity when ecotourism resumed in 2021. Daily bear detection rates decreased with more people present and increased with days since people were present. Human activity was also associated with more bear detections at forested sheltered sites and less at exposed sites, likely due to the influence of habitat on bear perception of safety. The number of people negatively influenced adult male detection rates, but we found no influence on female with young detections, providing no evidence that females responded behaviorally to a human shield effect from reduced male activity. We also observed apparent trade-offs of risk avoidance and foraging. When salmon levels were moderate to high, detected bears were more likely to be females with young than adult males on days with more people present. Should managers want to minimize human impacts on bear activity and maintain baseline age-sex class composition at ecotourism sites, multiday closures and daily occupancy limits may be effective. More broadly, this work revealed that antipredator responses can vary with intensity of risk cues, habitat structure, and forage trade-offs and manifest as altered age-sex class composition of individuals using human-influenced areas, highlighting that wildlife avoid people across multiple spatiotemporal scales.
摘要：
人类被许多物种视为捕食者，可能会产生恐惧的景观，影响野生动物的时空活动。此外,当面临捕食风险时，野生动物可能会寻求人类活动(人类盾牌假说)。我们使用了人类更年期，COVID-19大流行导致人类活动减少，测试恐惧和人类盾牌假设的生态学，并量化观察熊的生态旅游对灰熊（Ursusarctos）活动的影响。在2020年没有人类的情况下，我们在KitasooXai\'xais领土的Khutze流域部署了相机陷阱，并在2021年恢复生态旅游时对可变的人类活动进行了实验性处理。每天的熊检出率随着人数的增加而降低，而随着人数的增加而增加。人类活动还与在森林庇护地点检测到更多的熊有关，而在暴露地点检测到的熊更少，可能是由于栖息地对熊安全感的影响。人数对成年男性检出率有负面影响，但是我们没有发现对年轻女性的影响，没有证据表明女性在行为上对男性活动减少的人盾效应做出反应。我们还观察到风险规避和觅食的明显权衡。当鲑鱼含量中等到很高时，在有更多人在场的日子里，被发现的熊更有可能是年轻的雌性比成年雄性。如果管理人员希望最大程度地减少人类对熊活动的影响，并在生态旅游景点保持基线年龄-性别类别组成，多日关闭和每日入住限制可能是有效的。更广泛地说,这项工作表明，反捕食者的反应可以随着风险线索的强度而变化，生境结构,和觅食权衡，并表现为使用受人类影响的地区的个体的年龄-性别组成发生变化，强调野生动物在多个时空尺度上避开人。
