黄土丘陵区天然群落的植物组成、植物多样性及其与环境因子的关系

选择陕北黄土丘陵区不同立地条件下的4个典型群落,进行群落调查与土壤水分和养分的测定,探索天然群落自然恢复过程中群落的结构组成、植物多样性与环境因子的关系,为该地区的植被恢复提供指导。结果表明:植物群落组成主要集中在菊科、禾本科、豆科和蔷薇科,这4大科植物在该区具有较强的生态适应性;研究区天然群落组成较为简单;铁杆蒿(Artemisia sacrorum)在各立地均有分布,且重要值相对较大,为各个群落的优势种或者亚优势种;植物的生活型中多年生草本植物占优势,其次是半灌木,再其次是一、二年生草本植物,灌木植物所占的比例最少;相同坡向不同坡位的群落较为相似;不同立地条件下群落多样性指数的大小与各立地的水分条件关系密切。植被盖度、坡度、海拔高度和坡向对多样性产生影响,主要是通过直接影响土壤含水量实现的。土壤含水量是影响植物群落组成和多样性最为关键的生态因子,是黄土高原植被恢复和重建的关键性因子。

Composition and Diversity Analysis of Natural-Community Plants in the Loess Hilly Region

The relationships among community structures,plant diversity and environmental factors during the recovery process of a natural community of the loess hilly region were analyzed based on community survey,soil moisture and nutrient contents of four typical communities.Results showed that Gramineae,Compositae,Leguminosae and Rosaceae had strong ecological adaptability and their community composition was relatively simple.Artemisia sacrorum was widespread and dominated the area with importance.Perennial herbs dominated in this area,followed by semi-shrubs,annual or biennial herbs and shrubs.There are similar communities in the same orientation of slopes.Diversity indices of communities with different standing conditions were closely related with the moisture conditions of each site.The effects of vegetation cover,slope,altitude and aspect on diversity were related to soil moisture.Soil moisture,playing an important role in affecting community structure and diversity,is a key factor for the recovery and reconstruction of vegetation.