土地利用/覆被变化对太湖贡湖湾水质影响的研究

土地利用/覆被变化对湖泊水质的定量化影响研究是湖泊生态学的研究热点之一。运用贡湖湾遥感影像数据,四季的总氮、总磷、叶绿素a、透明度水质参数,从5个不同缓冲区和贡湖湾尺度,深入分析了土地利用/覆被变化对湖区水质的影响。研究结果发现贡湖湾水体污染物浓度与农业用地、建设用地呈显著正相关,与林地呈显著负相关,与草地、未利用地相关性不明显;农业用地、建设用地和林地对贡湖湾水质的影响存在尺度效应,贡湖湾近域地带的土地利用/覆被对湖泊水质的影响比远离湖泊地带更为显著。研究表明,贡湖湾林地具有较强的减水减沙效应,对水质改善有着积极作用。在贡湖湾沿岸0~2 km内开展植树造林、退耕还林工作,实施湿地恢复工程,有利于防治水土流失,保护生态环境。

Impacts of land use/cover on the water quality of Gonghu Bay in Taihu Lake

The quantitative impact of land use/cover (LULC) on the receiving water quality is one of research highlights of lake ecology. By using Landsat Thematic Mapper (TM) images and water quality indices (TN, TP, Chl-a, Secchi depth) of four seasons, this paper analyzed the relationship between land use/cover and water quality of Gonghu Bay based on five different buffer zones and the whole bay scale. Results showed that the land use pattern in Gonghu Bay had a significant impact on surface water quality. In which, construction land and cultivated land had a significant positive effect on water quality in Gonghu Bay, while forest land exhibited significant negative effect on water quality; grass land and non-used land had not significant effect. There was a scale effect between land use pattern and water quality indices in Gonghu Bay. The land use/cover type near to Gonghu Bay had more significant influence on water quality than that away from Gonghu Bay. Studies have shown that the forest land in Gonghu Bay had a strong effect on reducing water and sand, positively improving the receiving water quality. Developing afforestation, returning farmland to forest, and implementing wetland restoration project along the littoral zones within 0-2 km of Gonghu Bay will positively prevent soil erosion and protect the ecological environment.