Foraging animals choose habitats based on characteristics that often cannot be satisfied simultaneously, such as easy mobility, abundant or high-quality foods, and safety from predators. Invasive plants may alter habitat structure and provide novel foods; thus, measuring how animals forage in invaded landscapes offers insights into these new ecological relationships. We examined the movements of Great Basin pocket mice (Perognathus parvus) in sage-steppe habitats invaded by cheatgreass (Bromus tectorum) in southcentral British Columbia, Canada. The pathway tortuosity (fractal D) of pocket mice increased with vegetative cover and population density and decreased with open habitat, but these variables explained little of the variation in tortuosity. The fractal dimension of movement pathways of pocket mice was consistent over spatial scales ranging from 0.5 m to two-thirds of the home range size, unlike in other species where fractal dimensions are not consistent over multiple spatial scales. Collectively, our results indicate that foraging movements of pocket mice were not affected by the low densities of cheatgrass in this system.

中文翻译：

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什么因素预测了大盆地袋鼠在灌木草原栖息地被草履虫入侵的路径曲折性？

觅食动物根据通常无法同时满足的特征选择栖息地，例如容易移动、丰富或优质的食物以及免受捕食者的侵害。入侵植物可能会改变栖息地结构并提供新的食物；因此，测量动物如何在入侵的景观中觅食可以深入了解这些新的生态关系。我们研究了加拿大不列颠哥伦比亚省中南部鼠尾草（Bromus tectorum）侵入鼠尾草栖息地的大盆地袋鼠（Perognathus parvus）的活动。袋鼠的通路曲折度（分形 D）随着植被覆盖度和种群密度的增加而增加，随着栖息地的开放而减少，但这些变量几乎不能解释曲折度的变化。袋鼠运动路径的分形维数在 0.5 m 到三分之二的家庭范围大小的空间尺度上是一致的，这与分形维数在多个空间尺度上不一致的其他物种不同。总的来说，我们的结果表明袋鼠的觅食运动不受该系统中低密度草的影响。