安西荒漠植物群落和优势种的分布与环境的关系

ENVIRONMENTAL RELATIONS WITH DESERT PLANT COMMUNITIES AND DISTRIBUTION OF DOMINANTS IN ANXI 

应用排序（ＤＣＡ）和回归分析方法对安西砾石戈壁荒漠植物群落及优势种的分布与环境的关系进行了研究。结果表明，该区群落的盖度（Ｃ）和密度（Ｄ）均与年降水量（Ｒ）有密切关系，而群落的种类丰富度（Ｎ）则与土壤含盐量（Ｓ）相关，其回归关系式为：Ｃ＝０．０５１９６８１６３ｅ０．０４０７８６８２１Ｒ（Ｒ＝０．９５，Ｐ＜０．０１），Ｄ＝０．２７１４７９１３ｅ０．０５２７４１８２９Ｒ（Ｒ＝０．９６，Ｐ＜０．０１），Ｎ＝１３．７７４８－６．４７７３０３ｌｇ１０００Ｓ（Ｒ＝０．８３，Ｐ＜０．０１）。即：年降水量是决定戈壁荒漠植物群落盖度和密度的主要因素，土壤含盐量则与群落种类丰富度的关系尤为突出。优势种的抗旱性顺序是：红砂（Ｒｅａｕｍｕｒｉａｓｏｎｇｏｒｉｃａ（（Ｐａｌ．）Ｍａｘｉｍ．）＞泡泡刺（ＮｉｔｒａｒｉａｓｐｈａｅｒｏｃａｒｐａＭａｘｉｍ．）＞黑柴（ＳｙｍｐｅｇｍａｒｅｇｅｌｉＢｇｅ．）＞珍珠（ＳａｌｓｏｌａｐａｓｅｒｉｎａＢｇｅ．）＞膜果麻黄（ＥｐｈｅｄｒａｐｒｚｅｗａｌｓｋｉＳｔａｐｆ．）。

The ordination (DCA) and the regression analysis methods were used to study the relations between the Gobi desert plant communities as well as the distribution of the dominants and the environment in Anxi. The results indicated that the coverage( C ) and density( D ) of the plant communities have a close relation to the annual precipitation( R ), but the species richness( N ) of the plant communities has a relation to the salt content( S ) in the soil. Their regression equations are as follows: C=0.051968163e 0.040786821R (R=0.95,P<0.01),D=0.27147913e 0.052741829R ( R=0.96 ,P<0.01),N=13.7748-6.477303l g1000 S (R=0.83,P< 0.01). That is to say, the annual precipitation was a main factor deciding the coverage and density of Gobi desert plant communities, but the relationships between the salt content in the soil and the species richness of these plant communities were very outstanding. The resistibility to arid of the main dominants: Reaumuria soongorica (Pall.) Maxim.> Nitraria sphaerocarpa Maxim .>Sympegma regelli Bge. > Salsola passerina Bge. > Ephedra przewalskii Stapf., but the resistibility to salt of the main dominants was found in the order as follows: Salsola passerina > Reaumuria soongorica> Sympegma regelli > Nitraria sphaerocarpa > Ephedra przewalskii.