人为干扰下荒漠啮齿动物群落格局——变动趋势与敏感性反应

Fluctuations and patterns of desert rodent communities under human disturbance: the fluctuating tendency and the sensitive response of their population

2002～2004年,在阿拉善荒漠区的典型地区,选择了4种不同干扰条件的样地,分别为开垦区、轮牧区、过牧区和禁牧区,在两种尺度上研究啮齿动物群落的变动趋势及其种群的敏感性反应,在每种干扰条件的地段设计了标志流放区,面积为0.95hm2,采用标志重捕法,每月连捕4d,同时在4种不同干扰条件的地区选择了4条线路取样,每条线路面积约10 km2,采用铗日法调查,分别在4、7、10月份取样.用不同干扰条件下每个群落组成种的捕获量构成变量矩阵,应用PCA（主成分分析）方法分析群落中种群对不同干扰条件的敏感性反应.结果表明,3个年度中在两个观察尺度上,啮齿动物群落的格局在4种不同的干扰条件下表现出不同特征,各个群落的组成种类和主要种类的数量均有较大差异,特别是在开垦区和过牧区两种干扰条件下啮齿动物群落的组成种类及主要种类的数量均有较大的改变.同时PCA分析结果表明,在3个年度的两种观察尺度上,啮齿动物群落中的主要种群在4种不同干扰条件下的敏感性反应具有明显的差别.在开垦区黑线仓鼠的敏感性反应最强,在禁牧区的反应也较明显;在轮牧区各鼠种的敏感性反应差别不明显,而在过牧区三趾跳鼠和小毛足鼠的反应最强.

The four kinds of sites under different kinds of human disturbance were selected in the typical region of the Alashan Desert of Inner Mongolia from April to October 2002, from April 2003 to October 2003, and from April 2004 to October 2004, i.e. a farmland area, a rotational-grazing area, a over-grazing area and a prohibited-grazing area. The fluctuating tendency of rodent communities and the sensitive response of their populations were studied by using mark-recapture and trap-day methods. The four kinds of mark-recapture samples and of line samples were taken in different human disturbance areas. The area of the mark-recapturing sample was 0.96 hm^2 and that of the line sample was 10 km^2 . The samples were collected every month in the mark-recapturing sites for 4 consecutive days and in line sites in April, July, and October every year. The variable matrix was composed of the numbers of captured rodents of the rodent communities. The sensitive response of the populations of the communities was analyzed with Principal Component Analysis （ PCA）. The results showed that there were different types of rodent communities under different kinds of human disturbance on two scales in three years. In each scale, there were large differences in both the number of species and number of main population in the rodent communities under different kinds of human disturbance on the farmland area and over-grazing area especially. The results of PCA showed that the sensitive response of the populations of the communities was significantly different under different kinds of human disturbance on the two scales in the three years. Cricetulus barabensis was the most sensitive on the farmland area, there were no differences in sensitive response of the various rodents on the rotational-grazing area, and Dipus sagitta and Phodopus roborovskii were the most sensitive on the over-grazing area.