中文摘要：

亚热带地区是外来种入侵的活跃区,林改后人类活动增加可能会加大外来种入侵风险。对地处我国亚热带北缘地区的九江、星子两县不同生境的外来植物种组成丰富度和区系起源等情况进行了抽样调查。在森林、林缘、田边、路缘4类生境中共计调查发现外来植物28种,因为光照条件和人为干扰状况的不同,基于种数的方差分析结果显示外来植物种种数在林内、林缘、农田边缘和路边呈依次增高的趋势;盖度方差分析结果显示外来植物种数在林内、林缘、道边、农田边缘呈增高趋势,支持干扰促进外来种发生的假说。对各个生境内部本地种和外来种的相关性分析结果显示,基本上各个生境内部本地种种数和外来种种数呈显著的负相关;而本地种盖度和外来种盖度呈负相关性但不显著,支持丰富度高的群落入侵抵抗力强的假说。最后,分析了亚热带北缘地区各类生境中外来种组成的特征,对亚热带地区不同生境的外来种防控提出了建议。

英文摘要：

Vegetation in subtropical is vulnerable to biological invasion.After the forest property reform,human activities in the forests increased and the natural vegetation was disturbed,these probably led to the higher risk of biological invasion in this region.Four types of habitats were randomly sampled in Jiujiang and Xingzi County in the north rim of subtropical region and the number and coverage of native and alien plant species were recorded.The statistical analysis based on species number and coverage were carried out.The results show that there were 28 alien plant species occurred in four types of habitats and there were significant differences in number and coverage of alien species among forest interior,forest edge,farmland border and roadside.ANOVAs in terms of species number resulted in the increase of alien species from forest interior,forest edge,farmland border to roadsides,whereas the ANOVAs in terms of coverage led to an increase of alien plant from forest interior,forest edge,roadside,to farmland border.Overall,the ANOVAs results support the hypothesis that disturbance enhances biological invasion.The correlation analysis between native species and alien species showed that the number and coverage of native and alien plant species were negatively correlated,although p value was lower than 0.05 only for analysis based on species number.Thus correlation analysis supports the hypothesis that the species-rich community was more resistant than species-poor communities.The composition of alien plants species in the region was analyzed and some suggestions on prevention and management of alien plant invasion for different habitats were put forward,especially in area closed to the Nature Reserves.