长江流域产水功能对土地利用变化的响应及其驱动因素

长江流域产水功能是流域水生态平衡的重要组成部分，在生态安全防护上具有重要战略地位。产水量是指示区域水环境功能的重要生态指标，探讨长江流域土地利用变化对产水量的影响对于深化和揭示土地利用对水环境功能的效应有重要意义。研究基于多元统计方法与InVEST模型产水模块探讨了产水量对土地利用变化的响应模式，以及影响区域产水的驱动因素。结果表明：1.1990年至2015年，长江流域平均产水量呈西北低、东南高、中游>下游>上游的空间分布规律，子流域间的产水空间差异程度呈加剧趋势；2.从总产水量来看，洞庭湖、鄱阳湖和金沙江为主要贡献流域，贡献了总产水量的50%，且农用地与林地为主要土地贡献类型；3.由于长江流域土地利用结构和配置的转变，产水量的响应呈土地类型上的多样性，表现为农用地、草地、未利用地对产水变化具有正向协同效应，而林地和水域具有负向协同效应，建设用地对产水的响应不明显；4.影响产水功能的主要驱动力为建设用地、水域、人口密度、国民生产总值、降雨，农用地、植被覆盖、温度为潜在驱动力，未来长江流域产水功能的调控需要重视不同子流域间产水量的空间异质性与土地利用配置的协调性。

Response of water yield function to land use change and its driving factors in the Yangtze River Basin

With the rapid growth of global climate change and population urbanization, the contradiction of water resources and water security has become increasingly prominent, which has become a key problem restricting the sustainable development of countries and regions, and the impact of land use and cover change on hydrological processes has become the focus of this field. The Yangtze River Basin (YR), as a major ecological and economic development area in China, plays a strategic role in ecological security protection. Because water yield is an important ecological indicator of regional water environmental function, the exploring the effect of land use change on water yield has great significance on revealing and deepening the effect of land use on water environment function. In this study, we explored the response modes of water yield to land use change in the YR area based on water yield module of InVEST model, and the driving factors affecting regional water production were analyzed by multivariate statistical method. The results are as follows:(1) Between 1990 and 2015, the spatial distribution of average water yield in the YR area exhibited the characteristic of lower in the northwest and higher in the southeast. The average water yield between sub-basins showed obviously spatial differences, and the degrees of differences indicated that midstream > downstream > upstream, water yield among sub-basins showed rising trend in spatial differences. (2) The agricultural land and forest land were the main contribution types, and Dongting Lake, Poyang Lake and Jinsha River were the main contributing basins (50%) of the total water yield. (3) Due to the change of land use structure and allocation, the response of water yield exhibited diversity in land type, among which the agricultural land, grassland and unused land had a positively synergistic effects on water yield, while forest land and water area had negatively synergistic effect, and the construction land to water yield was not obvious. (4) Construction land, water area, population density, Gross Domestic Product, and rainfall were identified as the main driving forces, while the agricultural land, vegetation cover and temperature were identified as the potential driving forces. The regulation of water yield function in the Yangtze River Basin should pay more attention to the spatial difference of water yield among different sub-basins, and coordination between water yield spatial difference and the configuration of land use structure.