上海大莲湖湖滨带湿地的生态修复

采用改变土地利用模式、水系改造和植被配置等技术开展了上海青浦大莲湖湿地修复示范工程。本文从2008年8月到2010年3月跟踪调查了土地利用方式、鸟类群落、两栖爬行类、水质等多类指标来对示范工程进行评估。结果表明,实验区生态系统的生境结构和生物多样性组成都发生了明显的变化。实验区内土地利用由主要以人工养殖鱼塘和林地为主的人工湿地(人工鱼塘占50%,林地占25%),转变为以开放性水域和乔灌草相结合的半自然状态下的自然湿地(明水面面积占30%,各类植被群落占50%,人工鱼塘完全消失),植被从只有片段化林地转变为乔木、灌木丛、草本植物及各类水生植物相结合的格局；工程后鸟类种类和数量均高于工程前(新纪录到11种鸟类),鸟类多样性指数和均匀性指数也有明显增加,其中目标鸟类——雁鸭类新增6种,种类和数量都呈显著增加；两栖爬行类种类变化不大,共记录到6科12种,但整体数量比工程前增长了59.1%；水质指标的变化也很突出,与工程前人工鱼塘相比,实验区内水体中总氮(TN)、硝态氮(NO3-N)、总磷(TP)、叶绿素a(Chla)、高锰酸钾指数(CODMn)等主要指标均有显著下降(P<0.05),水质改善显著。由此说明,修复工程改善了大莲湖湖滨带湿地的生态环境,生物多样性得到较好的恢复,呈现出良好的湿地修复效果。

Ecological effects of lakeside wetlands restoration in Dalian Lake, Shanghai

Lakeside wetland (aquatic-terrestrial zone) is a kind of important inter-land between the aquatic ecosystem and land terrestrial ecosystem, its main functions are as follows: keeping biodiversity of the lake wetland ecosystem, working as a buffer zone, protecting the lakeshore against the lake water erosion and so on. However the lakeshore system is also very vulnerable, in recent years, intensive human activities have resulted in deterioration of lake water, destruction of aquatic ecosystem, and especially destruction of lakeshore structure and function. In order to understand how to preserve the ecological functions of the lakeshore wetland properly, an ecological pilot project was carried out in Dalian Lake, Shanghai, and some scientific studies concerning about the restoration of ecological environment and the protection of biodiversity were also developed in the same time. This project covered the wetland ecological restoration process such as changing the land use pattern, developing the new drainage transformation, and reforming the vegetation distribution. From August 2008 to Match 2010, parameters including land use pattern, bird populations, amphibian populations, reptile communities and water quality were collected in the restoration area to assess the effects of the project. The results showed that, the conservation value and biodiversity index have been increased significantly due to the redistribution of the different ecological habitats. During the restoration period, this demonstration area which was dominated by intensive fish ponds (50%) and woods (25%) was reformed into a much more complicated landscape with open water (30%), multi-vegetation communities (50%) and with no fish ponds left anymore. A diverse ecological area which was characterized by vegetation succession with forest, shrub, herbaceous plants and aquatic plants was established instead of small fragmentation of patch woods before the project. The statistic analysis on the total number of species and individuals of the bird communities also showed an positive increase although not in a large part (P>0.05), additionally, eleven bird species were newly recorded after the project, the Shannon-Wiener index (H') and Pielou index (J) also showed a significant increase after the project, the total individual number and species of the targeted species- Geese and Ducks got a significant increase (6 species were newly recorded). On the part of amphibian and reptiles, totally twelve species of amphibians and reptiles were found both before and after the project, but the total number of individuals recorded after the project increased 59.1% comparing with the numbers recorded before the project. In terms of water quality, there was also a significant improvement, the levels of TN, NO^-₃, TP, Chl.a and COD_Mn significantly decreased (P<0.05) in the restoration area comparing with those in the intensive fish ponds, which indicated that the general water quality in the project area had been significantly improved after the project.This study shows that after the implement of the ecological restoration project, the environment and habitat qualities in the lakeside wetlands of Dalian Lake have been improved significantly, and the pilot project would become a case study to promote a reasonable management on lakeside wetlands around Taihu Lake region located in low Yangtze River region.