城市河流改造工程对河流生态系统野生维管植物的影响

随着城市化的发展,许多城市对流经市区的河流进行了大规模工程改造,在获得了多种效益的同时,也引起了诸如生物多样性破坏和物种组成改变等一系列生态问题,因此对城市河流改造工程的生态影响进行研究非常重要,将有助于在未来城市河流改造中更有效地保护河流生态系统。该文以汾河太原段的河道改造工程为研究对象,用Shannon-Weiner 多样性指数、Sørensen群落相似性指数和单因素方差分析方法,研究了河流改造工程对河流生态系统中的野生维管植物物种多样性、频度和群落物种组成相似性的影响。结果表明:太原汾河段改造后比改造前的野生维管植物物种数和Shannon-Weiner 多样性指数显著降低;低频度的物种数明显增加而高频度的物种数明显减少;河流改造前后的群落相似性明显降低。由此可见,城市河流改造工程对河流生态系统中的野生维管植物物种多样性、频度和群落相似性有明显影响。

IMPACTS OF URBAN RIVER RECONSTRUCTION ON NATIVE VASCULAR PLANTS IN A CHINESE RIVER ECOSYSTEM

Aims Some urban river segments are reconstructed, resulting in benefits as well as ecological problems including reduced species diversity and altered species composition. Therefore, better understanding of the ecological impacts of urban river reconstruction projects is important for effectively protecting river ecosystemsin future projects. Methods We studied a 4.2 km river reconstruction project of Fenhe River in Taiyuan, using 30 random sample plots before (1997) and after (2003) reconstruction. We examined impacts of the project on species diversity, frequency and community similarity of native vascular plants using the Shannon-Weiner index, Srensen index and one-factor analysis of variance. Important findings Species richness and Shannon-Weiner index values decreased after reconstruction. In addition, the number of low frequency species increased, the number of high frequency species decreased and the similarity of species composition before and after reconstruction was low. Therefore, the impacts of this urban river reconstruction project on the species diversity, frequency and community similarity of native vascular plants were substantial.