定西市安定区退耕还林地植物群落特征研究

本文选择Shannon-Wiener物种多样性指数、Pielou均匀度指数、Margalef丰富度指数和生物量作为研究的基本指标，分别探究了安定区不同林型下群落稳定性和植物的水土保持功能。结果表明：从物种多样性对群落稳定性的影响来看，应选择适生树种及合理的配置体系以提高物种多样性，进而促进群落的稳定；从对各植物种的生物量定量分析来看，山桃、柠条生物量，尤其是枯落物生物量较高，可以发挥其减少地表径流、增加土壤养分，蓄水保水的作用。

Community Characteristics of Returning Farmland to Forest Land in Anding District Dingxi City

Selected Shannon-Wiener species diversity index, Pielou evenness index, Margalef richness index and biomass as the basic indicators, and explore the stability of community and vegetation effect on soil and water conservation of the different forest types in Anding district. The results showed that we should select the suitable trees and the rational allocation system so as to increase species diversity and thus promote the stability of communities in term of the effect that species diversity plays on community stability. Besides, viewing from the biomass of plant species quantitative analyzing, the litter biomass of mountain peach and caragana microphylla which were 790.00 kg/hm 2 and 652.30 kg/hm 2 were especially higher. So it can play the role of reducing runoff, increasing soil nutrients and storing water.