摘要
以拉萨河谷区域的植物群落为研究对象,设置30个样地、90个植物样方,运用双向指示种分析法(TWINSPAN)进行群落的分类分析,运用除趋势对应分析法(DCA)进行群落的排序分析,运用广义可加模型(GAM)进行转换后的物种丰富度(TSR)与海拔、覆盖度、纬度、经度的关系分析。TWINSPAN分类将拉萨河谷的植物群落分为8组,即落叶阔叶林、落叶阔叶灌丛、根茎苔草草甸和丛生嵩草草甸、常绿针叶灌丛草甸和落叶阔叶灌丛草甸、落叶阔叶灌丛草原、丛生禾草荒漠、落叶阔叶灌丛荒漠、小半灌木荒漠,很好地反映了群落的间断性;DCA排序的样方排序结果与TWINSPAN数量分类结果基本一致,很好地反映了群落的连续性及其生境的异质性,DCA排序结果表明,湿度是拉萨河谷植物分布的主导因素;GAM拟合模型显示,TSR沿海拔梯度的分布格局为低-高-低-高-低的双峰格局。
The plant community structure and the relationship between species richness and envi- ronmental factors in Lhasa valley located in the south central of Tibet Autonomous Region were studied, with 30 plots and 90 quadrats, by using two-way indicator species analysis （TWINS- PAN）, detrended correspondence analysis （DCA） and generalized additive model （GAM）. TWINSPAN classification identified 8 groups of plant communities, including deciduous broad- leaf forest, deciduous broad-leaf shrubs, Carex form rhizomatous meadow and Kobresia form caes- pitose meadow, evergreen needle-leaf scrubs meadow and deciduous broad-leaf shrubs meadow, deciduous broad-leaf shrubs steppe, caespitose grass desert, deciduous broad-leaf shrubs desert, and half-shrub desert, reflecting the intermittency of communities. TWINSPAN classification re- sults were consistent with DCA ordination results, well reflecting the continuity of communities and the heterogeneity of habitats. DCA ordination indicated that moisture was the main factor in- fluencing vegetation composition and distribution in the study area. The fitted line of transformed species richness （TSR） along the elevation gradient based on GAM showed a tendency of bimodal curve.
出处
《生态学杂志》
CAS
CSCD
北大核心
2015年第12期3289-3299,共11页
Chinese Journal of Ecology
基金
国家自然科学基金项目(41362001)资助
