鄱阳湖滨沙地植物多样性特征

采用线路踏查法和空间代替时间的方法，调查统计鄱阳湖滨多宝沙山沙地植物组成、优势类群以及风沙化过程中植物组成、多样性、生态习性和生活型的变化特点。结果表明：（1）鄱阳湖滨多宝沙山沙地植物有129种，隶属于58科104属，其中被子植物为研究区沙生植物的重要组成部分；生活型谱以高位芽植物居首位，其次为一年生植物，具有明显的亚热带荒漠属性；优势类群主要为蔷薇科(Rosaceae)、蝶形花科(Papilionaceae)、菊科(Compositae)和禾本科(Gramineae)植物。（2）土地风沙化过程中，植物组成变化较大，固定沙丘上以特有种占优势，流动沙丘上主要是共有种，半流动沙丘上以共有种和稀有种组成；植物丰富度、多样性指数逐渐降低；旱生植物比例增多，中生植物减少，湿生植物仅在固定沙丘阶段出现；一年生植物的减少，地下芽植物的增加，变化幅度较大的为半流动沙丘至流动沙丘阶段。

Plant Diversity Characteristics in Poyang Lakeside

In this paper, sand plant composition and dominant groups in the Duobao sand dunes in Poyang Lakeside were described by using line investigation. The change characteristics of plant composition, species diversity，ecological habits and life-form in the process of desertification were analyzed. The results show that:（1）There are 58 family, 104 genera and 129 species in the studied area, among which Magnoliophyta play important role in the plant composition. In life-form spectrum, Phanerophytes are the most common and Therophytes are in the middle, which reflects the vegetation of region have the properties of Subtropical desert. Dominant groups are made up of Rosaceae, Papilionaceae, Compositae and Gramineae.（2）In the process of desertification, the plant composition have great changes. The dominant species on fixed dunes and unfixed sand dunes are respectively specialized and general species, and semifixed sand dunes consist of general and rare species. Species richness and diversity index are decreasing gradually with desertification. The change characteristics of ecological habits are that the percent of xerophytes are increasing gradually and mesophytes are decreasing on desertification. Hygrophytes only appear on fixed sand dunes. The increasing of Cryptophytes and decreasing of Therophytes are the main change characteristics of life-form. The life-form has changed significantly from semifixed to unfixed sand dunes stage.