不同干扰下阿拉善荒漠啮齿动物群落格局的变动特征

Research on the rodent community patterns variation features under different disturbances in Alashan Desert.

干扰广泛被认为是影响物种多样性变化的最主要的因素。近年来,物种多样性对干扰的响应是生态学家关注和研究的热点问题之一。2002—2011年,在内蒙古阿拉善荒漠区对人为不同利用(干扰)方式形成的禁牧、轮牧、过牧和开垦4种不同区域中,通过对啮齿动物群落的物种数、物种总捕获率、Shannon-Wiener多样性指数和Pielou均匀性指数等4个变量的时间序列资料的比较,分析了这些变量的年间变动特点及在不同干扰条件下的变动规律,并对不同干扰区各变量的趋势进行分析,探讨啮齿动物群落对不同干扰过程的响应。结果表明:4个变量的最高值均出现在受中等干扰的轮牧区中,物种总捕获率2003年出现了各区的第1个高峰,总捕获率分别为过牧区10.75%、轮牧区19.60%、禁牧区11.20%、开垦区10.55%;2008年出现第2个高峰,4个区物种总捕获率均达到了各区的最高峰,捕获率分别为过牧区29.60%、轮牧区34.15%、禁牧区14.20%、开垦区27.10%。过牧区与轮牧区群落物种总捕获率、Shannon-Wiener指数和Pielou均匀性指数显著相关(p<0.05),变动规律相似。过牧区与轮牧区、禁牧区与过牧区、轮牧区与禁牧区之间的物种总捕获率呈极显著正相关(p<0.01)。过牧区与轮牧区相似度较高(I=0.856 8);过牧区Shannon-Wiener指数表现为有显著的下降趋势(Y=-0.142 lnt+1.487,F=6.320,p<0.05),表明随着过牧时间的积累,对生境的干扰逐步加重,啮齿动物群落的多样性会逐渐降低。

Interference widely considered to be the main factors of affecting species diversity changes. In recent years, the response of the species diversity for the interference is an one of the hot issues of ecologist concern and research.In a long-term study research data were examined on desert rodent communities in Alashan desert （Inner Mongolia, China） to indicate interference processes. The study was conducted between 2002 and 2011, all data were determined in four conditions：a） forbidden grazing area, b） rotational grazing area, c） over grazing area, and d） farmland area. The parameters species total capture rate, species number, Shannon Wiener index and Pielou index were analyzed to distinguish changes within years and regular changing patterns. We found that the highest values of all the four parameters were recorded in rotational grazing areas. The first peak of species total capture rate was appeared in 2003 in each area, total capture rate of over grazing area was 10.75%, total capture rate of rotational grazing area was 19.60%, total capture rate of forbidden grazing area was 11.20%, total capture rate of farmland area was 10.55%;the second peak was appeared in 2008, species total capture rate had reached the peak of four area, capture rate of over grazing area was 29.60%, capture rate of rotational grazing area was 34.15%, forbidden grazing area and farmland area were 14.20%and 27.10%respectively. Species total capture rate, Shannon-Wiener index and Pielou index were positively correlated （P〈0.05） between rotational grazing area and over grazing area, and featured similar changing rule.Further correlations （P〈0.01） of the species total capture rate were found between over grazing area and rotational grazing area, forbidden grazing area and over grazing area, rotational grazing and forbidden grazing area. Over grazing area and rotational grazing area similarity is higher than others （I=0.856 8）. Finally, the Shannon-Weiner index was characterized by a significant downward trend in overgrazing areas （regression equation： Y= -0.142 lnt ＋1.487, F=6.320, P〈0.05）, suggesting that an increase of overgrazing negatively affects habitats gradually which will reduce diversity of rodent communities.