太湖贡湖湾水生植被分布现状(2012年)

The distribution of aquatic vegetation in Gonghu Bay,Lake Taihu,2012

贡湖湾是无锡和苏州两市的重要水源地,随着近些年太湖水质的急速恶化,贡湖湾蓝藻暴发现象日益严重,危及饮水安全.为提供贡湖湾水资源管理的理论依据,于2012年开展贡湖湾水生植被野外调查.对8个断面进行为期5天的调查,结果表明:(1)共记录贡湖湾水生植物20科27属34种,单子叶植物和沉水植物分别为优势分类群和生态型;(2)贡湖湾水生植被分布区面积占总水域面积的45.35%,为典型半草型湖泊;(3)共有8种水生植物群落分布,其中马来眼子菜群落分布区面积和生物量最大;(4)贡湖湾水生植被总体表现出北部无水生植被分布,东部生物量高、群落及物种组成复杂,其他区域生物量小、群落组成单一的分布格局.水质恶化和插网捕鱼对贡湖湾水生植被分布现状存在影响,过度清淤可能是造成北部水域裸露的原因.结合贡湖湾水生植被分布现状分析结果,建议在贡湖湾水生植被管理中要开展北部裸水区植被修复,促进湾口区域马来眼子菜群落生长,加强对"引江济太"工程上游来水和贡湖湾水质的监测,并注重外来入侵植物尤其是水盾草群落的监测.

Gonghu Bay is an important drinking water resource area for Wuxi City and Suzhou City. With the rapid deterioration of water quality, cyanobacteria bloom has become progressively worse, which might endanger human healthy through water utilization. In order to provide a theoretical basis for managing water resources of Gonghu Bay, an aquatic vegetation survey was undertaken. Eight transects were set, and boat-based survey was performed. The results indicated：1） There were 34 species, belonging to 27 genus and 20 families, distributed in Gonghu Bay. Monocotyledons and submerged plants were the dominant taxa and ecotypes, re-spectively. 2） Grass-dominated state and algal-dominated state were coexisted in Gonghu Bay, as the results of the percentage of aquatic vegetation distribution area to total area was 45. 35%, while the percentage of bare water area to total area was 54. 65%. 3） The aquatic vegetation in Gonghu Bay could be divided into 8 community types, and the Potamogeton malaianus community was the biggest in terms of distribution area and biomass. 4） Overall, the distribution pattern of aquatic vegetation in Gonghu Bay illustrated that north area was associated with bare water, east area was dominated by macrophytes, and other areas were taken by macrophytes with low coverage and biomass. The distributions of aquatic macrophytes in Gonghu Bay might have responded to the deterioration of water quality and fishing practice by trap nets. Furthermore, we also speculated that over-excavated dredging wasthe reason that aquatic macrophytes disappeared in north area. The current research suggested that, in order to improve the vegeta-tion growth, aquatic vegetation restoration projects should be carried out in the north and the bay mouth of Gonghu Bay. Mean-while, water quality monitoring of Yangtze River-Lake Taihu water transfer project should be further strengthened. What’s more, invasive plants, especially Cabomba caroliniana, should be effectively monitored.