中文摘要：

生境的破碎化不仅减小了种群的面积、阻碍基因的流动和种群的自由扩散,还改变环境的物理化学性质,甚至会导致边缘效应,对斑块内部生物物种多样性产生多方面的影响。本研究采用样方调查法,对吉安市三种破碎化的生境中植物物种多样性进行调查,结果表明三种生境中植物物种丰富度和多样性指数以井冈山大学前山针阔混交林为最高,物种数为44种,分属28科41属,后山湿地松林次之,有植物35种,分属26科33属,白鹭洲植物物种数最少,植物数30种,分属23科28属。各生境中植物所属的科属数目也呈现相同规律,即物种数目越多,所出现的植物科属也越多。白鹭洲的植物物种数、多样性指数和均匀度都最低,主要的原因是岛屿面积过小,限制了物种的迁入。另一方面,紫藤、山葡萄、络石等藤本植物的大量存在,甚至覆盖了调查样地森林的林冠层,导致林内光照条件变差,加之,葎草等入侵植物已经在白鹭洲形成种群,对植物多样性构成了威胁,这也是导致该生境中物种多样性低下的一个重要因素。

英文摘要：

The fragmentation of habitat not only decreases the area for population living,hinders the flowing of genes and the free spread of plant population,but also changes the physical and chemical properties in the habitats,and even leads to edge effect,affects the biology diversity in patches.The species diversities in three fragmented habitats in Ji＇an City were investigated with quadrat sampling method.The results show that the abundances and diversity index uniformity of plants is the highest in outlying hill in Jinggangshan University,there are 44 species plants witch belong to 28 family and 33 genera in this habitant.There are 35 species plants which belong to 26 families and 33 genera in Pinus elliottii.palntation in back hill in Jinggangshan University which takes the second place.The abundance and diversity index of plants in Bailu Island in which 35 species plants which belong to 26 families and 33 genera are living is the lowest.The mean reason for this phenomenon is that the small area of the Island limited new species to settle in the habitat.On the other side,vines such as Wisteria sinensis,Vitis amurensis and Trachelospermum jasminoides abound in Bailu Island which cover the forest canopy and lead to worse light condition under the forest.In addition,some invasive plants such as Humulus scandens have formed population and threatened the plant diversity which is an important factor cause the low diversity in the habitant.