大兴安岭沟谷冻土湿地植物群落分类、物种多样性和物种分布梯度

应用双向指示种分析法（TWINSPAN）和除趋势对应分析法（DCA），对大兴安岭不同纬度的12个沟谷的冻土湿地植物群落之间的物种多样性和物种分布的环境梯度变化进行了分析．结果表明：研究区12个沟谷冻土湿地样地可划分为4个群丛组，分别位于不同的纬度范围；TWINSPAN的分类结果很好地反映了研究区沟谷冻土湿地植物群丛组的分布与纬度的关系，并在DCA二维排序图上得到了较好的验证．随着纬度的减小以及年均气温、年均降水量、1月平均气温和干燥度的增加，群落的物种多样性逐渐增大．研究区沟谷冻土湿地植物群落的灌木层和草本层的优势种和共优种多为适应湿地环境的沼生和湿生植物，随着纬度的减小，喜冷湿环境的沼生和湿生植物种类逐渐减少，甚至消失，而耐旱的中生植物的比重则逐渐加大.

Classification, species diversity, and species distribution gradient of permafrost wetland plant communities in Great Xing'an Mountains valleys of Northeast China

By using two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA), this paper analyzed the environmental gradients of the species diversity and distribution of permafrost wetland plant communities in 12 valleys at different latitudes of the Great Xing’an Mountains. The plant communities in the 12 valleys could be classified into four plant associations, based on the latitudes. The classification results of TWINSPAN reflected well the relationships between the distribution of the plant associations and the latitudes, and these relationships were better validated by DCA ordination. The species diversity increased with decreasing latitude and increasing mean annual temperature, mean annual precipitation, mean temperature in January, and aridity. The dominant and co-dominant species in shrub and herb layers were mostly helophytes and hygrophytes. With decreasing latitude, the helophytes and hygrophytes decreased or disappeared, while mesophytes increased.