反捕食不能充分解释獐的集群行为(英文)

我在江西鄱阳湖国家自然保护区研究了獐 (Hydropotesinermis)的集群行为并检验了集群是动物反捕食对策的假说。如果这个假说成立 ,我们则可以做三个预测 :(1)集群大小应与植物覆盖度成负相关 ;(2 )集群动物比单独活动的动物有更多的时间取食 ;(3)集群动物与单独活动的动物相比 ,用于警戒的时间较少。结果表明 ,獐的集群在交配季节最大而在产仔季节最小 ,獐在短草期比在高草期倾向于形成较大集群。因此 ,本研究支持了第一个预测。但是 ,集群的獐和单独活动的獐在取食和警戒时间分配上并无差异。因此 ,本研究不支持第二和第三个预测。时间收支 (timebudget)分析显示 ,在非交配季节 ,带幼仔的雌性用于取食的时间较少但走动频繁。在交配季节 ,与单独活动的雌性相比 ,与雄性在一起的雌性用于取食的时间较少 ,而单独活动的雄性却比与雌性在一起的雄性花较多的时间用于观望寻找雌性。鉴于獐集群行为的复杂性 ,本研究认为 ,獐并不只因反捕食而集群 ,其它社会和生态因子在决定獐的集群行为中也很重要。

ANTI-PREDATION DOES NOT FULLY EXPLAIN GROUPING IN THE CHINESE WATER DEER (HYDROPOTES INERMIS)

The grouping behavior of the Chinese water deer (Hydropotes inermis) was studied at Poyang Lake National Nature Reserve, Jiangxi, China. I made three predictions to test the hypothesis that grouping is an anti predatory strategy: (1) group size is negatively related to vegetation cover, (2) animals in groups have more time to feed than solitary animals, and (3) animals spend less time in vigilance when they are in groups than when they are alone. Results showed that group size was largest in the mating season and smallest in the parturition season. Deer tended to form larger groups when they were in short grass areas than in tall grass areas. Hence, the first prediction is supported. However, solitary deer and deer in groups did not differ in time allocated to feeding or vigilance. Therefore, predictions 2 and 3 are not supported. Time budget analysis revealed that females with young allocated less time to feeding, but more time to walking during the non mating season. During the mating season, females grouped with males spent less time feeding than solitary females, and solitary males spent more time looking for females than did males grouped with females during the mating season. In light of the complications found in the grouping behavior of the water deer, the anti predatory hypothesis seems to be insufficient as the only reason for the deer to group. Other socio ecological factors are also important in determining the grouping behavior of this species.