不同海拔梯度灌丛草甸群落多样性的分布特征--以五台山亚高山-高山带南坡为例

针对五台山亚高山-高山带南坡灌丛草甸群落多样性沿海拔的分布方式进行研究,对研究地海拔2200-3000m植物群落进行野外调查,分析了灌丛草甸群落盖度、α多样性和β多样性对海拔梯度的响应。结果表明,样地内共调查物种19科44属52种,区系成分具有明显温带属性,兼有北极-高山分布类型。从低海拔到高海拔植被依次分布有金露梅(Potentilla fruticosa)灌丛草甸群落(2201-2700 m)、鬼箭锦鸡儿(Caragana jubata)灌丛草甸群落(2700-2800 m)、高山嵩草(Kobresia pygmaea)草甸群落(2800-3011 m),灌-草结构群落主要分布在2200-2800 m。在海拔梯度上,植物群落草本层盖度总体上大于灌木层,均值分别为75.78%和41.64%,草本层盖度和群落总盖度呈先上升后下降的变化趋势,而灌木层呈相反变化趋势,且波动较大。随着海拔的升高,Patrick指数、Shannon-Wiener指数、Simpson指数和Pielou指数均呈显著下降的分布格局。Cody指数在2201-2296 m和2800-2903 m之间达到峰值,而Sorensen指数出现最小值,表明在2201-2296 m和2800-2903 m海拔范围内β多样性最大,是物种更替速率较快的过渡地带。在整个海拔范围内,灌丛草甸群落主要分布在2200-2800 m之间,海拔变化对灌丛草甸群落多样性差异产生重要的影响。研究结果有助于认识该地区灌丛草甸群落组成及其多样性格局,也将为灌丛草甸资源的生态保护和管理提供参考。

The Distribution Characteristics of Shrub-meadow Community Diversity at Different Elevations:A Case Study of the Southern Slope of Subalpine-alpine Zone in Wutai Mountain

In order to explore the responses of shrub-meadow community cover,αdiversity andβdiversity to elevation gradients,we surveyed the plant characteristics of the shrub-meadow community along the altitude of 2200 to 3000 m on southern slope of subalpine-alpine zone in Wutai Mountain.The result showed that there were 52 species in 48 genera and 27 families.The distribution patterns of these plants were temperate clearly and also contained Arctic-Alpine type.At altitude gradient,the vegetation on southern slope can be recognized as Potentilla fruticosa shrub-meadow community(2201-2700 m),Caragana jubata shrub-meadow community(2700-2800 m)and Kobresia pygmaea meadow community(2800-3011 m),and the shrub-grass types were distributed from 2200 to 2800 m.In general,the coverage of herb layers was higher than shrub layers,and the mean value were 75.78%and 41.64%,respectively.With the elevation rising,the coverage of herb layer and community showed a decreasing and then increasing trend,whereas the coverage of shrub layer formed an opposite trend,and fluctuated markedly.Patrick index,Shannon-Wiener index,Simpson index and Pielou index all significantly decreased with increasing elevation.Along the altitudinal gradient,Cody index peaked at 2201-2296 m and 2800-2903 m,but the Sorensen index reached the lowest value.It is suggested that theβdiversity of 2201-2296 m and 2800-2903 m were the largest,which these were transitional zones with a rapid replacement of plant species.Therefore,we concluded that the shrub-meadow communities were distributed from 2200 to 2800 m in the subalpine-alpine zone,and the variation of community diversity of shrub meadow were significantly affected by elevation change in the Wutai Mountain.Our observations are helpful to understand the vertical distribution patterns of species composition and species diversity in the in Wutai Mountain,and provide a scientific reference for the ecological conservation and management of mountain shrub-meadow vegetation.