吉林蛟河次生针阔混交林群落结构与微地形关系

摘要

We studied the associations between spatial community structure species diversity and microtopography with the data of a 320 m×660 m plot in temperate mixed broadleaf-conifer forest in Jiaohe of Jilin province.Topographic variables and space variable can be used to explain 67% of species spatial variance in tree community together.Topographic variables can be used to explain 41%of spatial variability in tree community alone.Topographic variables affect significantly trees size differentiation and stand basal area, which explains 15.47%of spatial variation in trees size differentiation and 41.5%of spatial variation in stand basal area, respectively.The explanation capacity of topographic variables is 15.33%for tree species richness and 22.29% for Shannon diversity.But topographic variables show lower explanation capacity for tree species abundance and aggregation.Tree size differentiation positively relates to elevation, slope, convexity and ridge, but negatively relates to hillside.CCA analysis between community structure and topographic variables shows that community is determined by slope, and exhibits a significant change of elevation gradient.Meanwhile, topographical position ( valley and ridge) affected strongly community structure.The results show the response of community characteristic to microtopog-raphy in temperate mixed broadleaf-conifer forest.%以吉林蛟河次生针阔混交林监测样地调查数据为基础，分析了近熟林群落的空间结构及树种多样性与微地形之间的关系。结果表明：地形变量和空间变量[ a＋b＋c ]共同解释了群落树种组成空间变异的67％，其中：地形变量[ a＋b]对群落树种组成空间变异的解释量高达41％。地形变量[ a＋b]对树木大小分化、林分胸高断面积空间变异影响显著，解释量分别为15．47％和41．5％。地形变量[a＋b]对树种丰富度和Shannon 多样性空间变异解释量分别为15．33％和22．29％，对树种多度的空间变异解释量仅为5．03％，对树木聚集性的空间变异解释量极低。树木大小分化与海拔、坡度、凸凹度和山脊环境正相关，与山腰环境负相关。群落结构与地形因子典范对应分析显示林分群落结构主要由坡度决定，同时表现出显著的海拔梯度变化。地形位置（山谷、山脊）差异也强烈地影响着群落结构。