贵州不同石漠化阶段喀斯特植被的植物群落学研究

Study on the Plant Community in the Karst Areas at Different Rock Desertification Stages in Guizhou Province

将石漠化阶段和研究地点作为影响因素,对各个生活型的多样性指数的Kruskal-Wallis进行检验,结果表明,不同石漠化阶段之间及不同研究点之间,乔木层和灌木层的4种多样性指数(物种丰富度指数、Simpson多样性指数、Shannon-Wiener指数和Alatalo均匀性指数)均有显著差异(P<0.01),但草本层的多样性变化并无此规律。三个研究区群落总体Shannon-Wiener指数和Simpson指数随着石漠化程度的加剧而呈现减小的趋势,但Alatalo均匀性指数却没有此规律,反而表现出随着石漠化程度的加剧,群落向着物种均匀化方向发展的趋势。由石漠化造成的土壤养分、水分的分布不均对乔木生长影响很大。无石漠化阶段和轻度石漠化阶段灌木层组成以乔木树种的幼树为主,至中度石漠化阶段和重度石漠化阶段,灌木层成为优势层片,以耐旱、喜阳的物种为主。

Considering the rock desertification stage and the study locations as the main influencing factors, plant community in the Karst areas were investigated and studied, with the Kruskal - Wallis test for the biodiversity indices of different life types being carried out. The Result showed that at different rock desertification stages and in different locations, the tree layer and the shrub layer had significant difference in the four biodiversity indexes, i. e. , the species richness index, the Simpson＇s index, the Shannon - Wiener index, and the Alatalo evenness index, while the herbeous layer showed no such change trend.. As the level of the rock desertification increased, the total eommunity＇s Shannon -Wiener index and Simpson index showed dicreasing trends, while the Alatalo evenness index showed an increasing trend. Uneven distribution of the water and nutrient caused by rock desertification exsert great influence on the growth of the tree species. A heliophiloust the stage of non - desertification or low level rock deser- tification, the shrub Iayer are mainly composed of the young tree species, while at the middle and high level stage,the shrub species become the dorminant layer, which mainly consist of drought - resistant heliophilous species.