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1期63-74,共12页Biodiversity Science
基 金:国家自然科学基金项目资助 (No .499710 0 2和 3 983 0 0 5 0 ) ~~
摘 要:利用福建黄岗山东南坡 30个样方和西北坡 13个样方的资料 ,研究该地区乔木物种丰富度的垂直变化。东南坡共记录到乔木物种 15 1种 ,隶属于 4 2科 73属 ;西北坡 10 2种 ,隶属于 32科 5 4属。两坡面的乔木树种组成相差不大。物种丰富度随海拔的变化趋势是 :随海拔升高 ,科、属、种的数量呈下降的趋势 ;东南坡科、属、种的数量在海拔 80 0 - 10 0 0m达到最大值 ,西北坡在海拔 15 0 0 - 16 0 0m达到最大值。东南坡乔木物种Shannon Wiener指数 (H′)与海拔呈负相关 ;西北坡在海拔 12 0 0 - 180 0m范围内H′高于东南坡 ;S renson指数 (IAc)在不同植被类型交替时出现上下波动 ,从常绿阔叶林向针阔混交林转化时 ,物种更替强烈 ,S renson指数明显下降。乔木物种生长特征的分析表明 ,最大树高 (Hmax)和最大胸径 (DBHmax)出现在中海拔 ,在相同海拔范围内西北坡的Hmax和DBHmax高于东南坡 ;东南坡Hmax和DBHmax的峰值出现在海拔 80 0 - 90 0m ,西北坡出现在海拔 180 0m。东南坡立木密度在海拔 15 0 0m处达最高值 ,而西北坡立木密度变化不明显 ,仅在海拔 190 0m以上明显下降。将全部乔木种划分为常绿阔叶、针叶和落叶阔叶等三种生活型 ,分析不同生活型的生长特征发现 ,常绿阔叶种类的胸高断面积和 (totalbasalarea,TBA)To investigate altitudinal changes of tree species biodiversity and community structures, we investigated 30 plots on the southeastern slope and 13 plots on the northwestern slope of Mt. Huanggang, Wuyi Mountains, Fujian Province. We recorded 151 tree species from 42 families and 73 genera on the southeastern slope, and 102 tree species from 32 families and 54 genera on the northwestern slope. There was no significant difference of tree species composition between these two slopes. The number of families, genera and species in the tree layer decreased as altitude increased. The richest families, genera and species were recorded at the altitudes between 800-1000 m a.s.l. on the southeastern slope, and between 1500-1600 m a.s.l. on the northwestern slope. The species diversity of tree layer on the northwestern slope was higher than that of the southeastern slope from 1200-1800m a.s.l.. Shannon-Wiener index (H′) correlated negatively with elevation on both slopes. Srenson index (IAc) varied in transitional zones between vegetation types, and was lowest at the ecotone between evergreen broad-leaved forests and mixed coniferous and broad-leaved forests. Considering community structures, larger maximum tree height (H max ) and maximum diameter of breast height (DBH max ) were recorded at middle elevations than at upper or lower elevations. H max and DBH max were higher on the northwestern slope than on the southeastern slope at the same elevations. Total basal area (TBA) of evergreen broad-leaved trees was greater than those of deciduous broad-leaved trees and coniferous trees at low elevations. TBA of coniferous trees showed two peaks, corresponding to two different types of coniferous species while that of deciduous broad-leaved species stayed stable along the altitudinal gradient. TBA of deciduous broad-leaved trees was greater on the northwestern slope than on the southeastern slope. TBA patterns of these three life forms along the altitudinal gradient were similar on both slopes.
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