民勤连古城自然保护区异质生境中沙木蓼群落结构及物种多样性

以民勤连古城自然保护区不同生境条件下的沙木蓼群落为研究对象，分别测定各样方物种组成、沙木蓼生长特征、优势种重要值、物种多样性指数，分析各指标之间的关系。结果表明，沙木蓼群落物种稀少，组成简单，以旱生、超旱生灌木和多年生草本占主导地位，表现出明显的荒漠草原植被特征。沙木蓼群落以旱生灌木层为优势层片，多年生草本层数量次之，1年生草本数量最少，群落稳定性主要由灌木层和多年生草本层决定。群落所处生境决定了群落重要值、生长量指标以及多样性指数。生境类型Ⅲ中沙木蓼生长量最大，表明该生境是适宜沙木蓼生长的生境类型，而生境Ⅱ中的群落多样性指数、均匀度指数为最高，群落优势度较低，表明该生境是适宜群落中大部分植物生长的生境类型。生境类型Ⅰ和生境类型Ⅲ相似，在群落特征上也表现出一定的相似性。

Community Structure and Species Diversity of Atraphaxis bracteata in Minqin Liangucheng Nature Reserve

The community structure and species diversity of Atraphaxis bracteata community in heterogeneous environment,located in Minqin Liangucheng National Nature Reserve,were studied by the sample-plot survey method.The results showed that the vegetative composition was simple and dominated by xeric,and hyper-xeric small shrubs and perennial herbage plants,which represented the characteristics of desertification steppe vegetative community,the herbage layer took the second place,and the quantity of annul herbage was the least.The stability of community was determined by shrub layer and perennial herbs.The importance value,growth indexes and diversity index were determined by the habitat of their living environments.The growth of habitat Ⅲ was the highest,indicating that this habitat was suitable for the growth A.bracteata,but the diversity index and the evenness index of habitat Ⅱwere the highest,and ecological dominance was lower,that showed habitat Ⅱ was suitable for the growth of most species.And community characteristics exhibited a similar characteristic between habitat Ⅰ and habitat Ⅲ.