新疆喀纳斯树种丰富度垂直格局特征

Distribution pattern of tree species richness along an altitudinal gradient in Kanas of Xinjiang

采用样带调查法,通过直接梯度、变异函数和分形函数分析,对新疆喀纳斯旅游区内设置的3条样带的树种比例及树种丰富度沿海拔梯度的变异特征进行了研究。结果表明:直接梯度刻画的不同树种所占比例在海拔梯度上的变化趋势各异;树种丰富度在整个调查尺度范围内随海拔的升高呈现明显的下降态势(P<0.01);半方差分析揭示:树种丰富度在中小尺度范围内的空间异质性主要由空间自相关引起的变异组成;分维分析反映出树种丰富度的分形维数偏大,且在中小尺度范围内无拐点,说明树种丰富度受随机生态学过程的影响在相应尺度范围内具有很强的空间异质性。

By using direct gradient analysis, semivariogram analysis and fractal analysis, the distribution pattern of tree species richness in three transects along an altitudinal gradient in Kanas tourism district of Xinjiang was studied by transect method, and the variation characteristics of the tree species richness were described. The results indicated that the percentages of different tree species along the gradient had different change trends with altitude, and the tree species richness displayed a distinct decreasing trend along the gradient across all scales. Semivariogram analysis showed that the spatial heterogeneity of trees species richness was mainly caused by spatial autocorrelation at small or middle scale. Fractal analysis suggested that the fractal dimension of tree species richness was larger, and there was not inflexion at small or middle scale, reflecting that tree species richness had distinct spatial heterogeneity along altitudinal gradient in the same scale ranges because of the effects of random ecological processes.