东江湖流域水供给服务时空格局分析

Spatiotemporal analysis of water supply service in the Dongjiang Lake Basin

与水相关的生态系统服务是生态学研究的热点问题。水供给服务对区域水循环和水量平衡具有至关重要的作用。东江湖流域是国家重点流域和水资源生态补偿试点,水供给服务是该流域生态系统服务保护的重中之重。基于In VEST模型,从流域、子流域两个尺度分析1995—2010年东江湖流域的水供给服务时空格局,并比较了不同土地覆被类型的水供给服务能力。结果表明:(1)1995—2010年,东江湖流域水供给量整体呈现先增加后减少的趋势,年均水供给量在1100—1600 mm之间,2000年的平均水供给量最多。(2)各年水供给量的空间分布格局相似,由湖区向四周递增。(3)平均水供给量较高的土地覆被类型为城镇建设用地、典型草地、灌丛、灌丛草地,在1600 mm左右。平均水供给量较低的土地覆被类型为河湖滩地、内陆水体、水田,在800 mm以下。(4)各个子流域平均水供给量大致在750—1700 mm之间。东北部子流域为水供给服务的高值地区。从水量平衡的角度而言,降水和实际蒸散发是决定生态系统水供给量的两个关键环节。东江湖流域水供给量的时空格局差异是气候和土地覆被共同作用的结果。研究能够为东江湖流域的水资源管理提供科学的参考依据,对东江湖流域生态系统服务功能的提升、生态环境质量的改善、社会经济的可持续发展具有重要的现实意义。

Ecosystem services related to water supply is currently topical in ecology. Water supply service is essential for internal water circulation and water balance in fiver basins. Dongjiang Lake Basin is a national key basin and pilot project of water resource ecological compensation and the water supply service is a basic ecosystem service in the basin. This paper evaluated the water supply service and analyzed the spatiotemporal patterns and variation characteristics from 1995 to 2010 based on the INVEST model from the scale of basin and subbasins, and compared water supply service capacity of different land cover types. （ 1 ） In 1995--2010, the water yield in the basin decreased after an initial increase with the annual water yield between 1000 and 1500 mm and the value in 2000 was the highest. （2） The spatial distribution patterns of different years were similar with water yield increasing from the lake to the surrounding area. （3） The water yield, with an average of 1600 mm, was high in urban and built-up areas, herbaceous steppe, shrub forest, and shrub grassland, while it was less than 800 mm in the area of bottom lands, water bodies, and paddy fields. （4） The water yield in each sub-basin was 750-1700 mm and the water supply capacity increased from the lake to the surrounding area. The subbasins in the northeast were the highest water evapotranspiration yield areas of the whole basin. From the perspective of water balance, precipitation and actual are two key factors determining the water yield. Spatiotemporal variation of the amount of water supply in Dongjiang Lake Basin resulted from interactions between climate and land cover change. The present study provides guidelines for the efficient management of water resources in the Dongjiang Lake Basin. It is of vital practical significance to improve the ecosystem service function and ecological environmental quality, and to promote the sustainable development of the social economy.