中文摘要：

牯牛降国家级自然保护区是我国生物多样性热点地区之一——黄山-武夷山区的一部分,人为干扰较轻,植被保存状况良好,是这一生物多样性中心基本特征的代表性区域。牯牛降地区的植物物种多样性和群落的分布特征尚缺少系统的研究报道。对牯牛降南坡的植被垂直带进行样方和样带调查,探讨其植物群落和植物物种多样性的海拔梯度格局,及其影响因素。通过对样方数据的数量分类和CCA排序,结合分析群落生活型构成、物种丰富度、α多样性、β多样性的结果表明：（1）牯牛降南坡随着海拔的上升,依次出现常绿阔叶林（400-1 100 m）、常绿落叶阔叶混交林（1 100-1 350 m）、针阔混交林（1 350-1 600 m）和常绿针叶林（1 600-1 728 m）。（2）物种丰富度和多样性指数大致表现了沿海拔梯度降低的趋势;但低海拔人为活动的干扰、海拔1 400 m处样方小地形的显著变化、海拔1 500-1 600 m之间历史上的火干扰等因素,导致了物种多样性海拔梯度特征的复杂化;常绿阔叶林和常绿落叶针阔叶混交林的种-面积曲线差异反映了不同植被类型中物种分布的尺度效应的差异。（3）海拔梯度、局部地形及其他生境条件的变化共同影响着物种多样性的格局。山地常绿落叶阔叶混交林、针阔叶混交林和黄山松纯林等是发育在同一气候垂直带条件下,主要由地形引起的土壤与小气候差异导致的植被斑块。山顶效应对植物群落类型和物种多样性变化具有显著影响,对于理解牯牛降植物物种多样性垂直梯度特征和模式具有重要意义。

英文摘要：

Mt. Guniujiang is a representative area to Mt. Huang - Mt. Wuyi Region—— one of the global biodiversity hotspots in China, with fairly light human perturbation and effective protection to the original forest vegetation. But studies about plant biodiversity in this area were sparse, and the basic characteristics of spatial pattern of plant diversity have not been reported. In order to explore the altitudinal gradient of plant communities and plant species diversity, we sampled the vegetation on south slope of Mt. Guniujiang in plots and transects. TWINSPAN was applied for community classification and CCA for gradient analysis and environmental interpretation, along with gradient analyses of growth-form composition, species richness, indices of α and β diversity. The results suggest that, 1 ） Along the elevation gradient appeared evergreen broad-leaved forests （400 - 1 100 m）, mixed evergreen broad-leaved and deciduous forests（ 1 100 - 1 350 m）, mixed broad-leaved and conifer forests（ 1 350 - 1 600 m） and Pinus taiwanensis forest （ 1 600 - 1 728 m）. 2） Species richness and indices of biodiversity roughly followed a decreasing trend along the altitudinal gradient, but the detailed pattern was complicated by the impact of hry at 1 500 - 1 600 m. Different scale effects were shown betwuman activities at low elevation, drastic change of topographic position between the plots at 1 400 m and 1 450 m , and a catastrophic disturbance of forest fire in recent histoeen evergreen broadleaved forest and mixed broadleaved and conifer forest through their species number——plot area curves. 3 ） The data suggested that the altitudinal pattern of plant species diversity was interactively impacted by the elevation gradient at large scale and topography driven habitat heterogeneity at local scale. The patches of evergreen broadleaved forest, mixed evergreen broadleaved and deciduous forest, mixed broadleaved and coniferous forest, and conifer forest are communities types formed in the same vertical clim