贡嘎山海螺沟冷杉群落物种多样性与群落结构随海拔的变化  

Altitudinal changes in species diversity and community structure of Abies fabri communities at Hailuo Valley of Mt. Gongga, Sichuan

作　　者：沈泽昊[1] 刘增力[1] 方精云[1] 

机构地区：[1]北京大学环境学院生态学系

出　　处：《生物多样性》2004年第2期237-244,共8页Biodiversity Science

基　　金：国家重点基础研究发展规划(G2000046801);国家自然科学基金(No.49971002 39830050)

摘　　要：冷杉(Abies fabri)是贡嘎山东坡亚高山暗针叶林主要的建群种和林线树种。在海螺沟沿海拔梯度调查了19个冷杉林样方,以此分析冷杉在其垂直分布范围内,物种多样性、群落结构及生物量沿海拔梯度的变化。结果表明:(1)二元指示种分析(TWINSPAN)可将全部样方分为5个群落类型:a.冷杉+麦吊云杉(Picea brachytyla)+云南铁杉(Tsuga dumosa)混交林群落;b.冷杉+阔叶树-杂灌群落;c.冷杉+阔叶树-冷箭竹(Bashania fangiana)群落;d.冷杉-杂灌-苔藓群落;e.冷杉-杜鹃(Rhododendron spp.)-苔藓群落。群落类型的空间分异主要受海拔和坡度、坡位等小地形因素控制。(2)群落乔木层、灌木层的物种丰富度和Shannon-Wiener指数随海拔上升而减小;但草本层没有明显的变化趋势。(3)各层的β多样性指数随海拔上升均有减小趋势;海拔3300 m以上的群落构成差异较小。(4)冷杉群落和冷杉种群的最大高度、平均高度、最大胸径、平均胸径都随海拔上升而逐渐减小;海拔3550 m以上,冷杉个体的高和直径生长因受到林线环境制约而明显减小,而DBH>5 cm的冷杉和全部种的密度随海拔上升而增大。(5)冷杉林材积随海拔上升而下降,平均值为846.4 m^3/hm^2。Abies fabri is the dominant species of sub-alpine coniferous forest on the east slope of Mt. Gongga, distributing up to the alpine treeline. Nineteen tree plots dominated by A. fabri were sampled a-long the altitudinal gradient, covering the vertical range of the species in Hailuo Valley. Altitudinal patterns of community structure and species diversity were analyzed. Major results include; (1) The 19 plots were classified into 5 community types by TWINSPAN, including mixed A. fabri + Picea brachytyla+ Tsuga dumosa community, A. fabri + deciduous tree-mixed shrub community, A. fabri + broadleaf trees -Bashania fangiana community, A. fabri-shrubs-lichen community, and A. fabri-Rhododendron spp.-lichen community. The spatial differentiation between the community types were mainly controlled by elevation and micro-topographic features, e. g. slope and position. (2 ) Species richness and the Shannon-Wiener index of the canopy and shrub layers decreased with increasing elevation, whereas no trend was detected in the herb layer. (3) The β diversity indices of each layer decreased with increasing elevation. The difference in species composition decreased above an elevation of 3300 m. (4) Maximum tree height, mean tree height, maximum DBH, and mean DBH of A. fabri forests decreased with increase of elevation. Environmental limitations near timberline to the height and girth growth of A. fabri individuals became clear above 3550 m a. s. 1. , whereas stem densities of all species or A. fabri with DBH >5 cm increased as elevation rose. (5) The average timber volume of A. fabri was 846. 4 m3/hm2, and declined with increase of elevation.

关 键 词：贡嘎山海螺沟 冷杉 群落 物种多样性 群落结构 高度 海拔 胸径 

分 类 号：Q948[生物学—植物学]