古尔班通古特沙漠植物分布的中域特征

探讨物种丰富度格局的中域特征是宏观生态学和保护生物学研究的热点问题,本文以具有代表性的温带沙漠-古尔班通古特沙漠南部为研究区域,结合调查实测的植物物种丰富度数据及样地间等距插值数据,分析了该区物种多样性分别沿纬向方向和经向方向上分布特点,探讨沙漠植物丰富度和密度格局的中域特征。结果显示,植物物种丰富度和密度格局在纬向和经向方向上形成不同的分布格局,中域特征不明显。在纬向方向上,呈现右半边驼形峰的格局模式,随着纬度的增加,物种丰富度和密度格局呈下降趋势;在经向方向上,分布格局呈现单调递增的趋势,但是趋势不明显。综合研究出现此现象的原因,认为本研究区尺度较小,纬向跨度为1.5°,经向跨度为4.5°,物种多样性受边界生境强烈影响。在纬向方向上,物种多样性受到绿洲小气候的影响,靠近绿洲地区的物种多样性较远离绿洲边缘的区域丰富度高;而在经向方向上,由西向东海拔逐渐增高,在降水随之增加影响下形成了物种多样性单向梯度变化,未能形成单峰的中域格局。由此可知,古尔班通古特沙漠研究区过小,植物多样性的中域特性不明显,在干旱区中域特征同样表现在大尺度上。

The Mid-domain Effect of Plants Distribution in Gurbantonggut Desert,China

Understand the pattern of species richness has been the key problem of the research of macroscopic ecology and conservation biology,the mid-domain theory is an important progress in the research of this field. In this paper,we take the typical temperate desert-the southern of Gurbantonggut desert as our study area.Using the measured data of 71 sample species richness,together with 40 groups of data with interpolation by equidistant among samples,we summarize the distribution characteristics of species diversity,respectively along the latitude and longitude direction to explore the mid-domain features of desert plants richness and density pattern and found Mid-domain feature of plant diversity in Gurbantonggut desert is not obvious. The results show that the pattern of species richness and density in latitude and longitude direction into different forms. In latitude direction,presenting the right half of camel peak shape,With the increase of latitude,species richness and density is on the decline. In the longitude direction,distribution pattern present the monotone increasing trend,but the trend is not obvious. Then we further analyze the reasons for this phenomenon,study area across the range is 1.5 ~ in latitude and the range is 4.5 ~ in longitude,belong to small scale,affected by environment and habitat,distribution of species diversity does not show the gradient change. In the weft direction ,species diversity under the influence of the oasis micro-climate, species richness has higher abundance near the oasis than relatively far away from the edge of the oasis area,In the meridional direction,desert altitude increased gradually from west to east,the precipitation under the altitude is the direct cause to formate this pattern, failed to form a mid-domain pattern with unimodal.In conclusion,the study area of Gurbantonggut desert is too small,the mid-domain feature of plant diversity is not obvious,so the Mid-domain effect in arid areas have also performed on a large scale.