基于生态系统服务价值的塔里木河干流土地利用结构优化

Optimization of land use structure based on ecosystem service value in the mainstream of Tarim river

通过研究塔里木河干流土地利用变化对生态系统服务价值的内在影响机制,基于生态系统服务价值优化了其土地利用结构。结果表明:(1)应急生态输水后塔里木河干流耕地、林地、草地、荒漠、水体的年平均变化率分别为7.26%、2.68%、-1.90%、1.22%、0.08%,耕地、林地面积的增加主要来自草地,水体面积变化主要受来水量影响。(2)1990—2015年应急生态输水使塔里木河下游生态系统服务价值呈“增长-减少-回升”的趋势,共增长2.99×108元;塔里木河干流整体呈现下降的趋势,共减少了39.60×10^(8)元。(3)通径分析发现水体面积变化与塔里木河干流生态系统服务价值的内在联系最大,直接作用为0.610,间接作用为0.345。(4)土地利用类型间转化关系发现,当耕地、林地、草地、荒漠、湿地面积占比分别为3.34%、10.03%、38.22%、45.95%、0.96%时,土地利用结构最优,对应的生态系统服务价值为533.69×108元。随着耕地面积的扩张,农业用水与生态用水矛盾突出,权衡土地利用结构及其耗水特征对于生态系统服务价值维护和水资源合理配置具有重要意义,可为探索塔里木河流域人地关系优化状态提供科学依据。

In this study,the effect mechanism of land use and land cover change(LUCC)on ecosystem service value(ESV)in a complex environment was analyzed,and the land use structure was optimized based on ESV.The results showed that after the implementation of ecological water conveyance(EWC),the average annual variation rates of cultivated land,woodland,grassland,desert,water area in the mainstream of the Tarim River were 7.26%,2.68%,-1.90%,1.22%and 0.08%,respectively.The increase of cultivated land and woodland areas were mainly caused by grasslands,and the inflow of EWC increased the water areas.An increasing-decreasingrecovering tendency of time series in ESV with 299 million yuan in the lower reaches of the Tarim River was observed,and showed a decrease over all of the mainstream of Tarim River with 3.96 billion yuan.The water resources were of great significance to the stabilization and improvement of ESV in arid areas.Based on past analysis,the water area had the dominant influence on ESV,with the direct and indirect effects of 0.610 and 0.345,respectively.Based on the relationship between the different land use types,the optimal structure was calculated for the proportion of cultivated land,woodland,grassland,desert and wetland,which were 3.34%,10.03%,38.22%,45.95%,and 0.96%,respectively.In this circumstance,the ESV can reach a maximum of 53.369 billion yuan.With the expansion of cultivated land areas,the contradiction between agricultural water consumption and ecological water utilization becomes more and more serious.It is of great significance to balance the characteristics of land use structure and water consumption for the maintenance of ESV and the rational allocation of water resources,which can provide a basis for exploring the optimal state of man-land relationships in the Tarim River Basin.