丹江口库区湿地植被对南水北调中线工程响应研究

Wetland Vegetation in the Danjiangkou Reservoir in Response to the Middle-Route of the South-to-North Water Transfer Project

丹江口水库是我国南水北调中线工程的水源地,维护其库区湿地生态系统的健康对调水工程具有非常重要的意义,而良好的植被条件则是湿地健康和功能完整性的必要基础。通过对丹江口库区湿地植被的全面调查,表明目前的库区湿地具有较为丰富的植物资源,分布着多种类型的湿地植物群落。丹江口水库大坝加高后,大部分的消涨带植被永久被淹没,并在更高海拔的区域形成新的消涨带湿地植被。进而,通过构建目前库区湿地植被与环境因子的CCA和逐步回归模型预测了新消涨带的潜在植被。结果表明,丹江口大坝加高蓄水后,在高坡度的湿地生境下,植被将由狗牙根(Cynodon dactylon)等偏旱生群落组成,物种多样性也较低;而在坡度平缓的区域,双穗雀稗(Paspalum paspaloides)等湿生群落将占优势,物种多样性也相对较高。

The Danjiangkou Reservoir is the water source area of the Middle-Route of the South-to-North Wa- ter Transfer Project. Wetland vegetation in the Danjiangkou Reservoir region is essential for the water trans- fer project. Vegetation survey indicates that there are abundant aquatic plant species and various plant com- munities in the reservoir wetlands. However, almost all kinds of current wetland vegetation in the reservoir shorelines will be permanently inundated and new wetland vegetation will develop at higher elevation after Danjiangkou Dam heightened. According to canonical correspondence analysis （CCA） and stepwise regres- sion analysis based on the relationships between vegetation and environmental factors, we predict that new wetland vegetation will be dominated by Cynodon dactylon and mesophyte characterized by low species diver- sity in the areas of large slope, and Paspalurn paspaloides and hygrophyte are dominant species in the flat areas with relatively high species diversity.