摘要
2004年10月2～7日在内蒙古东乌珠穆沁旗额和宝力格苏木鼠害草场采用鼠洞口数量作为布氏田鼠（Lasiopodomys brandtii）秋季集群大小的指标，分析了大鸳（Buteo hemilasius）对不同大小布氏田鼠集群的捕食选择偏好。统计了实验样地内可以观察到的大萑蹲守布氏田鼠洞群鼠洞口数量，以及样地内大鹭没有蹲守的布氏田鼠洞群的鼠洞口数量。运用非参数Mann—WhitneyU检验进行分析，大鹭没有蹲守的布氏田鼠洞群的洞口数量秩和统计量为1753．5，而大鸳蹲守的布氏田鼠洞群的洞口数量总秩和为1406．5，统计量u值为213．5，校正之后的z值为-4．76426，这表明，两组差异达到极显著水平（P=0．000002），大驾蹲守次数（B）与田鼠洞群洞口数量（Ⅳ）呈显著的正相关关系，相关式为B=-0．7332＋0．04436N（r=0．59265，P〈0．05）。结果表明，大骛优先选择集群数量高的布氏田鼠集群，该结果可以解释布氏田鼠在秋季出现的分群行为。由于捕食风险的存在，布氏田鼠借助秋季的分群行为以降低冬季集群大小和被捕食风险，从而避免成为捕食性天敌首要攻击的目标，该结果从捕食风险角度支持了鼠类最优集群理论。
Group sizes of Brandt＇s vole （Lasiopodomys brandtii） overwintering colonies could affect colonies＇ predation risks. Using the number of Brandt＇s vole colony as an indicator of family group size, we studied how group sizes of Brandt＇s voles affect the predation preference of upland buzzard （Buteo hemilasius） in Xilinguole typical steppe, Inner Mongolia, from October 2 to 7, 2004. We recorded the different colonies of Brandt＇s voles within sampling area. All colonies are dived into two groups by whether they were visited by upland buzzard or not. But we don＇t distinguish the upland buzzard visiting times on the Brandt＇s vole. Then the Mann-Whitney U of nonparametfic was used to analyze the data. The results show that the rank sum of the groups without upland buzzard＇s visiting is 1 753.5, while which of the groups that have been visited by upland buzzard is 1 406.5 （U value = 213.5, Adjusted Z Value = - 4.764 26）. This suggests that the differences between the two groups is significant （P = 0.000 002）. The correlation between times of upland buzzard visited （B） and group size of the Brandt＇s vole （N） were as follow： B = - 0.733 2 ＋ 0.044 36 N （r = 0.592 65, P 〈 0.05）.The result shows that upland buzzards significantly prefers to high number of group sizes of vole＇s colonies. This finding indicates that the colonies with larger size result into a higher predator risk, which explains why Brandt＇s vole dispersal happened during fall, In order to avoid predation risk Brandt＇s vole colonies choose to reduce their group sizes through dispersal. Such result also supports the optimum group size theory of small mammals.
出处
《动物学杂志》
CAS
CSCD
北大核心
2015年第5期795-800,共6页
Chinese Journal of Zoology
基金
中国科学院战略生物资源科技支撑体系运行专项(野生)动物实验平台运行补助经费项目
公益性行业(农业)科研专项经费项目(No.201203041)
关键词
布氏田鼠
大■
捕食风险
集群数量
Brandt＇s vole Lasiopodomys brandtii
Upland buzzard Buteo hemilasius
Predator risk
Group size
