2000-2015年黄土高原生态系统水源涵养、土壤保持和NPP服务的时空分布与权衡/协同关系

生态系统服务评估决定区域可持续发展,对人类福祉至关重要。以黄土高原为研究区域,基于CASA、InVEST和RUSLE模型,结合土地利用类型、归一化植被指数、气象等数据,分析了2000年、2005年、2010年和2015年的NPP、土壤保持和水源涵养3项关键生态系统服务的时空分布特征,识别了3种生态系统服务的热点区,并基于相关系数法分析了黄土高原地区和不同气候区(干旱气候区、半干旱气候区、高原气候区、半湿润气候区)不同生态系统服务间的权衡/协同关系。结果表明:(1)2000—2015年,黄土高原地区的土地利用类型变化剧烈,其中林地(2.8%)和建设用地(43.1%)显著增加,耕地(-2.7%)明显减少;(2)2000—2015年,净初级生产力(NPP)、产水量和土壤保持均呈现增长趋势,分别增加14.1%,5.3%和101.3%;(3)黄土高原的4类热点区(非热点区、一类热点区、二类热点区、三类热点区)所占面积变化不显著,分布具有明显的地带性,从西北到东南依次为非热点区、一类热点区、二类热点区和三类热点区;(4)在整个黄土高原地区,土壤保持与NPP、水源涵养之间为协同关系,NPP与水源涵养为权衡关系;在4个气候区,NPP与土壤保持之间的权衡/协同关系与黄土高原地区一致,但土壤保持和水源涵养在半干旱气候区和半湿润气候区呈权衡关系,NPP与水源涵养在高原气候区和半湿润气候区为协同关系。为促进区域生态系统可持续管理,应在土地规划过程中考虑生态系统服务之间的相互关系,尽可能减少权衡,增加协同。

Spatial and Temporal Distribution and Trade-off of Water Conservation, Soil Conservation and NPP Services in the Ecosystems of the Loess Plateau from 2000 to 2015

Ecosystem services assessments determine regional sustainable development and are critical to human well-being. This study took the Loess Plateau as the research area, based on the CASA, InVEST and RUSLE model, combined with the data of land use types, normalized vegetation index, meteorology and so on, analyzed the spatial and temporal distribution characteristics of the three key ecosystem services (NPP, soil conservation, and water conservation) in 2000, 2005, 2010 and 2015; and identified the hot spots of three ecosystem services, analyzed the trade-offs between different ecosystem services on the Loess Plateau and different climatic regions (arid, semi-arid, plateau and semi-humid climate zone) based on the correlation coefficient method. The results showed: (1) From 2000 to 2015, land use types in the Loess Plateau region changed drastically, among which forest land (2.8%) and construction land (43.1%) increased significantly, and cultivated land (-2.7%) decreased significantly. (2) From 2000 to 2015, all the average unit area of net primary productivity (NPP), water conservation and soil conservation showed an increasing trend, increased by 14.1%, 5.3% and 101.3% respectively. (3) The areas occupied by the four types of hotspots in the Loess Plateau (non-hotspots, first-type hotspots, second-type hotspots, and third-type hotspots) had not changed significantly, but the distribution had the obvious zonal distribution, that was non-hotspots, first-class hotspots, second-class hotspots, and third-class hot spots respectively from northwest to southeast. (4) Across the Loess Plateau, there was a synergistic relationship between soil conservation and NPP, soil conservation and water conservation. And there was a trade-off between NPP and water conservation. However, soil conservation and water conservation was trade-off in semi-arid and semi-humid regions, and the relationship between NPP and water conservation also was trade-off in arid and semi-arid regions. In order to promote the sustainable management of regional ecosystems, the relationships between ecosystem services should be considered in the land planning process, and trade-offs should be minimized and synergies should be maximized.