渝东北生态系统服务价值时空演变及地形梯度效应

Temporal and spatial evolution of ecosystem service value and topographic gradient effect in Northeast Chongqing

为研究山丘区生态系统服务价值(ecosystem service value,ESV)时空演变及地形梯度效应,以渝东北11个区县为研究区,利用2000年、2010年和2020年3期土地覆被数据和相关统计资料,分析研究区ESV的时空演变及不同地形要素ESV的梯度效应。结果表明:(1)2000—2020年研究区土地覆被以耕地和林地为主,面积占89%以上。随着时间变化,林地、水体、建设用地面积增加,耕地和草地面积减少,土地覆被具有明显空间差异性。(2)研究区森林ESV占主导地位,面积占67%以上。随着时间变化,ESV逐渐增加,其中水域ESV增加最显著,为39.19亿元,次为林地,17.92亿元,草地和耕地ESV分别减少16.27,2.09亿元。研究区ESV的空间分布呈显著正向自相关关系,高值与低值呈明显集聚特征。(3)2000年,2010年和2020年,研究区ESV随海拔梯度增加而减少,随坡度和地形起伏度梯度增加呈先增加后减少趋势,随地形位梯度增加,整体呈波动减少趋势。研究结果可为区域土地资源合理规划、长江上游生态环境修复和生态文明建设提供理论依据与参考。

In order to study the temporal and spatial evolution of ecosystem service value(ESV)and its topo-graphic gradient effect in hilly area,taking 11 districts and counties in Northeast Chongqing as the study area,the temporal and spatial evolution of ecosystem service value and the gradient effect of ecosystem service value of different topographic elements in the study area were comprehensively analyzed by using three periods of land cover data and relevant statistical data in 2000,2010 and 2020.The results showed that:(1)From 2000 to 2020,the land cover in the study area was mainly cultivated land and forest land,accounting for more than 89%.With the change of time,the area of forest land,water body and construction land increased,the area of cultivated land and grassland decreased,and the land cover had obvious spatial differences;(2)The forest ecosystem service value in the study area was dominant,accounting for more than 67%.With the change of time,the total value of ecosystem services gradually increased,of which the service value of water ecosystem increased by 3.919 billion yuan,followed by forest land 1.793 billion yuan;The ecosystem service value of grassland and cultivated land decreased by 1.627 billion yuan and 209 million yuan respectively.The spatial distribution of ecosystem service value in the study area had significant posi-tive spatial auto-correlation,and the high value and low value showed significant agglomeration characteristics;(3)The ecosystem service value of the study area decreased with the increase of altitude and slope,and increased first and then decreased with the increase of gradient grade;On the topographic relief gradient,the overall change increased first and then decreased;On the topographic potential gradient,its change trend showed a fluctuating type,and the overall change showed a fluctuating decreasing trend.This study could provide theoretical basis and reference for regional rational planning of land resources,ecological envi-ronment restoration in the upper reaches of the Yangtze River and ecological civilization construction.