永定河流域典型沙区生态状况及修复建议

Eco-environmental condition and eco-restoration suggestions in typical sandy land in Yongding river basin

永定河贯穿整个京津冀核心区域,是京津冀的生态廊道,对京津冀可持续发展有重要作用。然而,京津冀城市群的快速发展已对永定河生态系统造成了剧烈影响,对其河流进行生态修复已成为当前的重要任务。本研究对永定河整个流域的生态环境,包括植被、水、土状况进行了综合调研分析,并对河流典型受损沙区进行了植被与土壤的取样分析,对沙区实际状况进行总结。研究发现,永定河沿河林种结构单一,多为带状杨树林、刺槐林等,典型沙区植被优势种为芦苇、茵陈蒿、白茅、野大豆,植被覆盖度约20%,生物多样性指数低,整体处于较差水平。土壤砂土比例高达90%以上,表层土壤含水率低于3%,土壤氮、磷等养分含量低,严重制约植被的正常生长。结合流域整体状况与受损沙区状况,研究最后提出了永定河典型受损沙区修复建议,以期为永定河流域综合治理提供科学参考。

The Yongding River runs through the core area of Beijing-Tianjin-Hebei(BTH)Region.The river is the ecological corridor of the BTH,which plays an important role in the sustainable development of BTH.However,the rapid development of BTH has resulted in strong impact on the ecosystem of Yongding River.At present,the eco-restoration has become the most important task of Yongding river.This study investigates the eco-environment of the whole Yongding river basin,including the condition of vegetation,water,and soil.The vegetation and soil samples in the typical sand area are further analyzed,the practical condition of sandy land is summarized.We found that the forest structure along the Yongding River was single,mostly composed of Populus L.,Robinia pseudoacacia L.,etc.The dominant species in the typical sand area were Phragmites australis(Cav.),Artemisia capillaris Thunb.,Imperata cylindrica(Linn.)Beauv.,Glycine soja Sieb.et Zucc.The vegetation coverage was about 20%,and the overall vegetation condition was at a poor level,with low biodiversity index.The proportion of sand is more than 90%,the surface soil moisture is less than 3%,and the soil nutrient,e.g.,total nitrogen and phosphorus,is very low,which seriously restricts the growth of vegetation.Finally,we provided some effective suggestions for the eco-restoration of the representative sand in Yongding river,hoping to give scientific reference for the ecological management in Yongding river basin.