Department of Biology, Dickinson College, Carlisle, PA, USA.
Fort Collins Science Center, U.S. Geological Survey, Fort Collins, CO, USA.
Sci Rep. 2022 Jul 26;12(1):12705. doi: 10.1038/s41598-022-16660-y.
Animal movements reflect temporal and spatial availability of resources as well as when, where, and how individuals access such resources. To test these relationships for a predatory reptile, we quantified the effects of prey abundance on the spatial ecology of invasive brown treesnakes (Boiga irregularis) on Guam. Five months after toxicant-mediated suppression of a brown treesnake population, we simultaneously used visual encounter surveys to generate relative rodent abundance and radiotelemetry of snakes to document movements of surviving snakes. After snake suppression, encounter rates for small mammals increased 22-fold and brown treesnakes had smaller mean daily movement distances (24 ± 13 m/day, [Formula: see text] ± SD) and activity areas (5.47 ± 5 ha) than all previous observations. Additionally, snakes frequenting forest edges, where our small mammal encounters were the highest, had smaller mean daily movement distances and three-dimensional activity volumes compared to those within the forest interior. Collectively, these results suggest that reduced movements by snakes were in part a response to increased prey availability. The impact of prey availability on snake movement may be a management consideration when attempting to control cryptic invasive species using tools that rely on movement of the target species to be effective.
动物的运动反映了资源的时间和空间可利用性，以及个体何时、何地以及如何获取这些资源。为了测试捕食性爬行动物的这些关系，我们量化了猎物丰度对关岛入侵的棕树蛇（Boiga irregularis）空间生态学的影响。在使用毒物抑制棕树蛇种群五个月后，我们同时使用视觉遭遇调查来生成相对啮齿动物的丰度，并使用无线电遥测来记录幸存蛇的运动。在蛇类被抑制后，小型哺乳动物的遭遇率增加了 22 倍，棕树蛇的平均每日移动距离（24 ± 13 m/天，[公式：见正文] ± SD）和活动区域（5.47 ± 5 公顷）比所有以前的观察都小。此外，在我们遇到小型哺乳动物最多的森林边缘活动的蛇，其平均每日移动距离和三维活动体积比在森林内部的蛇要小。总的来说，这些结果表明，蛇类活动减少部分是对猎物增加的一种反应。当试图使用依赖目标物种运动来发挥作用的工具来控制隐匿性入侵物种时，猎物丰度对蛇类运动的影响可能是管理上需要考虑的一个因素。
