背景:人为线性特征改变了物种的行为和选择模式,它必须适应这些不断增长的景观特征。道路是一个经过充分研究的线性特征,它改变了生存状态,运动,和动物的分布。人们不太了解围栏对野生动物的影响,尽管它们在整个景观中比道路更普遍。当在运输走廊沿线的道路上发现围栏时,人们对潜在的间接影响的了解甚至更少。
方法:我们评估了围栏和道路的空间配置如何影响阿尔伯塔省南部草原上部分迁徙的叉角叉角种群(Antilocapraamericana)的运动(穿越效应)和分布(邻近效应),加拿大。我们在步长选择函数框架内使用来自55个领角叉角牛的数据来评估4个线性特征的影响:(1)牧场围栏,(2)道路没有围栏,(3)一侧围成的道路,以及(4)在迁徙和居留动物的选择模式上两侧围起来的道路。我们检查了是否沿着运动路径(即,交叉效应)受到试图交叉的线性特征动物的类型的影响,这些特征是否影响叉角的分布(即,邻近效应)在整个景观中。
结果:两种运动策略的交叉效应的顶级模型包含所有4个线性特征和土地覆盖。所有线性特征的回归系数均为负,这表明个体不太可能选择跨越线性特征的步骤。对于邻近效应,移民动物避开了所有线性特征,除了两边围起来的道路,他们选择了更接近此功能的区域。居民动物,另一方面,被发现靠近牧场围栏,但远离没有围栏的道路。
结论:我们的结果表明,围栏和道路都在空间和行为上间接影响着叉角叉角的资源利用,无论每个线性特征是单独找到还是串联找到。修改现有围栏和道路以考虑对这些不同线性特征的响应可以促进更成功的穿越机会和/或分布变化。允许叉角在景观中自由移动将保持功能连通性,以确保这种特有有蹄类动物的种群持久性。
BACKGROUND: Anthropogenic linear features change the behavior and selection patterns of species, which must adapt to these ever-increasing features on the landscape. Roads are a well-studied linear feature that alter the survival, movement, and distribution of animals. Less understood are the effects of fences on wildlife, though they tend to be more ubiquitous across the landscape than roads. Even less understood are potential indirect effects when fences are found in tandem with roads along transportation corridors.
METHODS: We assessed how the spatial configuration of fences and roads effect the movement (crossing effect) and distribution (proximity effect) of a partially migratory pronghorn population (Antilocapra americana) on the grasslands of southern Alberta, Canada. We used data from 55 collared pronghorn within a step-selection function framework to assess the influence of 4 linear features: (1) pasture fences, (2) roads not fenced, (3) roads fenced on one side, and (4) roads fenced on both sides on the selection pattern of migratory and resident animals. We examined whether steps along a movement pathway (i.e., crossing effect) were influenced by the type of linear feature animals attempted to cross and, whether these features affected the distribution of pronghorn (i.e., proximity effect) across the landscape.
RESULTS: The top model for crossing effect for both movement tactics contained all 4 linear features and land cover. Regression coefficients were negative for all linear features, indicating that individuals were less likely to chose steps that crossed linear features. For the proximity effect, migrant animals avoided all linear features except roads fenced on both sides, where they selected areas closer to this feature. Resident animals, on the other hand, were found closer to pasture fences but further from roads without fences.
CONCLUSIONS: Our results indicate that both fences and roads are indirectly affecting pronghorn resource use spatially and behaviorally, whether each linear feature is found separately or in tandem. Modifying existing fences and roads to account for responses to these distinct linear features could facilitate more successful crossing opportunities and/or shifts in distribution. Allowing pronghorn to freely move across the landscape will maintain functional connectivity to ensure population persistence of this endemic ungulate.