地表覆盖物对高原鼠兔栖息地利用的影响

对地表覆盖物对高原鼠兔栖息地利用的作用进行了研究, 地表覆盖物增加后, 高原鼠兔能依据其程度及毗邻生境状况, 或减少地面活动增加对洞道系统的利用; 或转移到较安全区域; 同时摄食行为也发生变化, 显著增加用于防御的时间, 且取食区域几乎集中于洞口附近。研究表明, 高原鼠兔视地表覆盖物为一种捕食风险源, 并对此具有一定的评估能力, 其行为反应实质上是通过对食物获取与风险大小的权衡而做出的一种行为决策。间接捕食风险是高原鼠兔在选择和利用栖息地时所必须考虑的权衡因子, 也是一个重要的摄食代价。

INFLUENCE OF COVER ON HABITAT UTILIZATION OF PLATEAU PIKA(OCHOTONA CURZONIAE)

The influence of cover on habitat utilization of plateau pikas (Ochotona curzoniae) were studied. The work was carried out at the bird-island area of Qinghai province, the People's Republic of China from May to August1994. The cover was manipulated by placement of small boards in the area where the pika inhabited in. Habitat utilization was responsive to change in the cover treatments. The pika either increased burrow utilization and decreased microhabitat utilization, or shifted into a safe microhabitat that was not treated with the boards. On the other hand, foraging behaviors were also affected by the treatments. The time spent on feeding was significantly decreased, however, the time spent on vigilance was significantly increased. In addition, feeding rang was shrunk by feeding close to the hole of the burrow as possible. These results suggest that the cover is not a refuge, but only a source of indirect predation risk for the pika. The pika possenses the ability to assess the risk of be preyed upon. The behavioral change in habitat utilization in fact .is a behavioral decision made b y the pika based on trade off energy gain against risk of predation. Predation risk is not only an important factor that they decide where to feed, but also an important foraging cost.