贡嘎山东坡植被垂直带谱的物种多样性格局分析

PATTERNS OF BIODIVERSITY ALONG THE VERTICAL VEGETATION SPECTRUM Of THE EAST ASPECT OF GONGGA MOUNTAIN

为了探讨贡嘎山东坡海拔梯度上植物多样性的结构特征及格局变化 ,基于植被垂直带谱的样带和样方调查 ,分析了物种丰度与种 -面积关系的垂直变化 ,物种多样性生态和地理成分的海拔梯度格局 ;去势对应分析(DCA)和典范对应分析 (CCA)被用于分析 17种环境因子之间的相关性 ,和环境因子对 2 7个多样性结构成分和 6 7个样方空间格局的影响 ;并定量分离不同尺度的环境变量对多样性格局分异的贡献。结果表明 :1)贡嘎山东坡的植物物种多样性总体上表现了自下而上降低的梯度 ,但从河谷干旱灌草丛带到常绿阔叶林带和高山灌丛带到草甸带显示了相反的梯度变化 ;2 ) 10种分布区类型的物种有各不相同的垂直丰度格局 ,9种生活型的物种多样性垂直格局则反映了草本与木本类型的明显差异 ;3)从河谷干旱灌草丛到山地针阔混交林的生物多样性结构变化主要反映水分梯度的影响 ;而从山地针阔混交林到高山草甸 ,多样性结构变化的主导因子是气温 ;4 )气候的垂直梯度和生境的局部异质性是物种多样性格局两组不同作用尺度和性质的影响因子 ;总体上 76 .83%的多样性变异得到了解释 ,其中寒冷指数的作用最为突出。分析结果支持了关于生物多样性格局机理的不同假说 ;同时表明 。

This paper explores the structural properties and altitudinal patterns of plant biodiversity on the east aspect of Mt. Gongga through analysis of transect and plot data. Analyses of altitudinal variations in species richness and species area relationships, the altitudinal patterns of the structural components of species diversity counting on their areal types and lifeforms were completed. Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were applied to detect relationships among 17 measured environmental indices, as well as the effects of environmental factors on the spatial patterns of 27 structural indices of biodiversity and 67 sampling plots. These analyses also permitted the quantitative partitioning of contributions of the environmental factors acting at different scales. While the study detected a generally decreasing gradient of plant species diversity with elevation locally opposite patterns were also found. These abnormalities were notable between the valley arid shrub and meadow zone and the evergreen broad leaved forest zone and between the alpine shrub and alpine meadow zones. Ten groups of geographical components (the areal types of species) showed a range of vertical pattern with richness: a vertical comparison of species richness among 9 ecological components (lifeforms) mainly revealed differences between the herb and woody types. From the valley arid shrub and meadow zone to the mixed coniferous and deciduous forest zone, the vertical change of biodiversity structure is mainly controlled by habitat humidity, whereas the temperature gradient dominates the change from the mixed coniferous and deciduous forest zone to the alpine meadow zone. The vertical gradient of climate and the local heterogeneity of habitat are two groups of causal factors with different properties and scales of activity. Seventy seven percent of biodiversity variation was associated with the environmental indices, among which the cold index (CL) is most effective. Several hypotheses about the mechanisms of biodiversity patterns were supported by these results. It is also argued that, as modern environmental factors control the geographic pattern of biodiversity at Mt.Gongga, the effects of regional environmental changes and the history of the flora development should also be considered.