祁连山北坡中段小型哺乳动物群落多样性的垂直分布格局研究

Vertical distribution pattern of small mammal community diversity in the middle section of northern slope of Qilian Mountain,China

采用样线夹日法，对夏季（7～8月份）祁连山北坡中段7个不同海拔梯度（1600～3900m）的小型哺乳动物群落多样性进行了调查研究。共置铗6720夹日，捕获10种254个个体，其中兔形目（Lagomorpha）2种，啮齿目（Rodentia）8种，五趾跳鼠（Allactaga sibirica）的捕获数量最高，占总数的23．27％，与三趾跳鼠（Dipus sagitta）、黑线仓鼠（Cricetulus barabensis）和长尾仓鼠（C．longicaudatus）构成常见种，占总捕获数量的70．20％。物种在不同海拔梯度中呈明显的不均匀分布。相关性分析发现，物种丰富度和多样性在中海拔地带最高，物种丰富度和多样性与海拔呈明显的单蜂关系，但动物捕获率却与海拔高度呈明显的负线性相关关系。物种丰富度和多样性单峰状海拔分布与初级生产力和革本层植物多样性的海拔分布格局一致。

A survey of the elevational distribution of small mammal communities in the middle section of the northern slopes of Mt. Qilian,northwestern China was conducted from July to August 2001. Removal trapping was conducted using standard sampling techniques at 7 sites within an elevation of 1600- 3900m in the study area. A total of 254 samples of 10 rodent species are collected during 6720 trap nights. The mammals are composed of 2 species of lagomorphs and 8 species of rodents. Of the species,Allactaga sibirica （23.27 % ） is most abundant. Next is Dipus sagitta （17.96 % ）,followed by Cricetulus barabensis （ 15.10 % ）and C. longicaudatus （ 13.88 % ）. They are the most commonly trapped species in the region, acenunting for 70.20 % of the total catch. Correlation, regression and graphical analyses show diversity of the mammals along elevational gradient to be unevenly distributed. The results further show humped-shape relationships between species richness and diversity,and elevation;and a transect is noted between diversity peaks and middle elevations. A negative correlation is also noted between relative abundance of the mammals and elevation. Maximum diversity of rodent species occurs at mid-elevations where plant diversity and primary productivity are at maximum.