新疆阿尔泰山小东沟北坡植物多样性沿海拔梯度分布格局

Distribution Pattern of Species Diversity along Altitudinal Gradient in the Northern Slope of Xiaodonggou in Altai Mountains,Xinjiang

分析新疆阿尔泰山小东沟北坡植物多样性随海拔梯度的变化规律。结果表明:小东沟山区总体上物种种类简单,物种丰富度指数和Shannon-Wiener多样性指数均表现为:乔木层<灌木层<草本层;乔木层和灌木层的物种丰富度和Shannon-Wiener多样性指数均沿海拔上升表现为先升高再降低的单峰趋势,即中间高度膨胀,且多样性峰值均出现在海拔1600～1800m处;草本层的物种丰富度和Shannon-Wiener多样性指数均沿海拔升高,略微有所上升,变化不明显;乔、灌、草总的物种丰富度和Shannon-Wiener多样性指数沿海拔上升均呈现先增加后降低的单峰趋势。针阔叶混交林具有较高的物种多样性,从而使海拔1600～1700m处出现乔木层、灌木层及总的物种多样性峰值。随海拔升高,林分郁闭度减少,从而使得林下草本多样性有所增加。

Patterns of species diversity along the altitude on the northern slope of Xiaodonggou in the Altai mountains were explored. The results indicated that： the vegetation structure and composition were generally simple, and the diversity was low. Diversity order of the following three life forms was： trees 〈 shrubs 〈 herbaceous plants. Diversities of trees and shrubs exhibited a unimodal pattern with increasing altitude, peaking at the range of 1 600 m - 1 800 m. The herbaceous plant diversity exhibited a monotonically increasing trend with the increase of altitude. Change in total diversity of the three life forms along the altitudinal gradient showed a unimodal pattern. Mixed coniferous broad-leaved forest （1 600 m- 1 700 m） had higher species diversity, where peak values for trees, shrubs, and total species diversity appeared. In the study area, tree crown density decreased along the altitudinal gradient, so that the diversity of herbaceous plants had an increasing trend along the altitudinal gradient accordingly.