塔里木河干流生态系统变化与生态效益分析OA北大核心CSTPCD

In this study,remote sensing ecological indices such as vegetation coverage,remote sensing ecological index,and human disturbance index were extracted from 1990 to 2020 to reflect the evolution trend of ecological status before and after the implementation of the ecological water conveyance project of Tarim River.Taking re-mote sensing ecological indices as driving factors,an improved ecosystem service value calculation algorithm was proposed to quantify the ecosystem service value of provisioning,regulating,supporting,and cultural func-tions and to analyze the dynamic evolution relationships between trade-offs and synergistic effects among the functions.Cumulative ecological benefits from 1990 to 2020 were estimated.The results showed that the ecologi-cal condition of approximately 1/3 of the mainstream of the Tarim River had improved because of the implemen-tation of the ecological water conveyance project.The proportion of lower,medium,higher,and high vegetation coverage increased by 17%,5%,2%,and 2.9%,respectively.The results of the ecosystem service value calcula-tion showed that the ecosystem service value of the upstream increased and then stabilized,whereas that of the midstream and downstream increased,decreased,and then increased again,indicating a period of lag in the mid-stream and downstream in response to the ecological water conveyance and was significantly affected by the amount of incoming water.There was a synergistic effect between the regulating and supporting functions and a trade-off effect between the provisioning function and the regulating and supporting functions.Cumulative eco-logical benefits after 2010 followed the"marginal benefit decreasing law".Accordingly,for ecological restora-tion,the annual runoff should not exceed 42.5×108 m3 upstream,21.5×108 m3 midstream,and 3.5×108 m3 downstream.This study can provide scientific guidance for optimizing the allocation of ecological water quantity.