1990-2018年中国生态系统水源涵养功能时空格局与演变

Spatio-temporal pattern and evolution of ecosystem water conservation in China from 1990 to 2018

探明生态系统水源涵养服务格局演变对中国生态系统水源涵养保护和管理具有重要意义。采用水量平衡模型,探明1990—2018年中国生态系统水源涵养分布特征,从全国、分区和栅格3个尺度揭示中国水源涵养演变规律。结果表明:(1)中国生态系统水源涵养时空异质性显著,整体南高北低、东高西低。不同植被水源涵养服务差异显著,以常绿阔叶林最高,草地最低。(2)中国水源涵养服务随高程升高呈阶梯式下降,随坡度变化因坡度梯度而不同,平坡区随坡度升高而升高,缓坡—陡坡区随坡度升高而降低。(3)中国多年平均水源涵养量为1.54×10^(12)m^(3)/a,以热带-亚热带季风区为主导,约占总量的77.9%。水源涵养服务演变全国尺度显著下降,分区尺度仅温带大陆气候区显著下降。(4)栅格尺度仅16.0%栅格变化显著,主要为极显著降低和显著降低,约占栅格总数的7.61%和5.30%,主要分布于藏东南、云贵高原西部、冀东北、浑善达克沙地、天山东麓和中国台湾省等地,它们是中国水源涵养保护与建设的重点区域。

Water conservation is one of the important ecological services restricting regional sustainable development,which is of great significance to regional industrial and agricultural production,life and ecological protection and construction.Therefore,the research on ecosystem water conservation has become an important field of ecological service research.It is of great significance for the protection and management of ecosystem water conservation for China to explore the spatio-temporal variation of ecosystem water conservation.To reveal the spatio-temporal pattern and evolution of ecosystem water conservation in China,the water balance equation was used to estimating ecosystem water conservation in China from 1990 to 2018.Based on the Matlab platform,the spatio-temporal patterns and change trends of China′s ecosystem water conservation were revealed on national,regional and grid scales using spatial statistics and trend analysis method.The main results were as follows:(1)The spatial and temporal heterogeneity of water conservation in the Chinese ecosystem was significant,which decreased from south to north,and from east to west.There were significant differences in water conservation capacity among different vegetation types,which was highest in evergreen broadleaved forests and lowest in grasslands.(2)The ecosystem water conservation decreased with altitude,however,its variation characteristics were different in different slope gradients.The ecosystem water conservation increased with the increase of slope in flat slope area,while in gentle slope to steep slope area,it decreased with the increase of slope with little fluctuation.(3)The amount of annually average ecosystem water conservation in China was about 1.54×10^(12)m^(3)/a,which was dominated by the tropical and subtropical monsoon zonal with 1.20×10^(12)m^(3)/a,accounting for about 77.9%of the total.The ecosystem water conservation in China decreased significantly at national scales from 1990 to 2018.Only the temperate continental climate zone had a significant decrease in ecosystem water conservation,and no significant change in the others at regional scales during the study period.(4)The ecosystem water conservation of most grids did not change significantly from 1990 to 2018 on grid scales,accounting for about 84.01%of the total grids.The grids with significant changes in ecosystem water conservation were mainly extreme decrease and significant decrease,accounting for 7.61%and 5.30%of the total grids,respectively,which were mainly distributed in southeastern Tibet,western Sichuan,northern,central and western Yunnan,northeastern Hebei,Hunshandake Sandy Land,eastern Tianshan Mountain and China Taiwan province,where were the key areas of water conservation,protection and construction in China.The total of grids with extreme and significant increase in water conservation totally accounted for 2.36%of the total grids,which mainly scattered in central Qinghai,Qinling Mountains,Northeast Plain and the northern Greater Khingan Mountains.Based on the distributions of significant changs in the ecosystem water conservation in China on grid scales from 1990 to 2018,the leading driving factors for ecosystem water conservation changed significantly could be revealed by combining the spatial data of China′s ecological protection and construction,climate variations,landuse change and urbanization construction.Therefore,the study can provide data support for the conservation and regulation of water resources in China′s ecosystem.