Abstract:
Compound effects of anthropogenic disturbances on wildlife emerge through a complex network of direct responses and species interactions. Land-use changes driven by energy and forestry industries are known to disrupt predator-prey dynamics in boreal ecosystems, yet how these disturbance effects propagate across mammal communities remains uncertain. Using structural equation modeling, we tested disturbance-mediated pathways governing the spatial structure of multipredator multiprey boreal mammal networks across a landscape-scale disturbance gradient within Canada\'s Athabasca oil sands region. Linear disturbances had pervasive direct effects, increasing site use for all focal species, except black bears and threatened caribou, in at least one landscape. Conversely, block (polygonal) disturbance effects were negative but less common. Indirect disturbance effects were widespread and mediated by caribou avoidance of wolves, tracking of primary prey by subordinate predators, and intraguild dependencies among predators and large prey. Context-dependent responses to linear disturbances were most common among prey and within the landscape with intermediate disturbance. Our research suggests that industrial disturbances directly affect a suite of boreal mammals by altering forage availability and movement, leading to indirect effects across a range of interacting predators and prey, including the keystone snowshoe hare. The complexity of network-level direct and indirect disturbance effects reinforces calls for increased investment in addressing habitat degradation as the root cause of threatened species declines and broader ecosystem change.
摘要:
人为干扰对野生动植物的复合影响是通过直接响应和物种相互作用的复杂网络出现的。众所周知,由能源和林业产业驱动的土地利用变化会破坏北方生态系统中的捕食者-猎物动态,然而,这些干扰效应如何在哺乳动物群落中传播仍不确定。使用结构方程模型,我们测试了在加拿大阿萨巴斯卡油砂地区的景观尺度扰动梯度上控制多捕食者多猎物北方哺乳动物网络空间结构的扰动介导途径。线性干扰具有普遍的直接影响,增加所有焦点物种的场地使用,除了黑熊和濒临灭绝的驯鹿,在至少一个景观中。相反,块(多边形)干扰效应是负面的,但不太常见。间接干扰效应广泛存在,并由驯鹿避开狼介导,下属捕食者跟踪主要猎物,以及捕食者和大型猎物之间的内部依赖关系。对线性干扰的上下文相关响应在猎物和具有中等干扰的景观中最为常见。我们的研究表明,工业干扰通过改变饲料的可用性和运动直接影响一套北方哺乳动物,导致一系列相互作用的捕食者和猎物的间接影响,包括梯形雪鞋野兔.网络级直接和间接干扰效应的复杂性加强了对解决生境退化的投资,因为受威胁物种减少和更广泛的生态系统变化的根本原因。