Response of Tarim River Mainstream Ecosystem to Groundwater Level Changes from 2000 to 2020
The depth to groundwater directly affects the condition of vegetation growth,the pattern of ecological distribution,and the stability of ecosystems.Therefore,studying the response of the ecosystems to groundwater level changes is of great significance to ecological restoration.The change of the groundwater level in the mainstream of the Tarim River is mainly the result of the combined effects of ecological water diversion,climate change,and human activities.The change of groundwater level affects the spatial distribution of ecosystems.With the Tarim River mainstream as the research object,this study is based on long-term groundwater depth monitoring data and multiperiod remote sensing image data.Semivariogram function modeling,dynamic trend analysis,fractal dimension calculation,and trend analysis are employed to analyze groundwater depth and ecosystem spatial and temporal characteristics.Furthermore,it discusses the response of the ecosystem to changes in groundwater depth.The main conclusions are as follows:(1)The groundwater depth increases with increasing distance from the river.Groundwater depth spatial variation is affected by both human factors such as cropping systems and irrigation intensity,and natural factors such as topography,geomorphology,climate,soil types,and aquifers.The spatial correlation increases annually.(2)From 2000 to 2020,the transformation of ecosystem along the Tarim River mainstream was mainly driven by an increase in farmland and decrease in grassland.They accounted for 58%of the total ecosystem transformation,with farmland mainly replacing shrublands,yielding 1118 km2 conversion.Grasslands was transformed on a large scale into other ecosystems,with a conversion area of 1258.69 km2.(3)The ecosystem fractal dimension decreased from 1.4701 to 1.1350,indicating ecosystem complexity reduction.The stability coefficient increased from 0.0299 to 0.3650,indicating increased ecosystem stability.(4)Continuous ecological water diversion has led to an increase in the groundwater depth in the mainstream of the Tarim River,resulting in a significant positive development trend in the ecosystem,with 77.0%of the areas experiencing slight ecological improvement,8.0%moderate improvement,and 1.7%significant improvement.The changes in groundwater depth has a significant impact on the ecosystem along the Tarim River mainstream.When the groundwater depth decreases,the ecosystem recovers obviously.When the depth increases,the ecosystem degrades obviously.
ecosystemsdepth to groundwaterdynamic characteristicsresponseTarim River mainstream
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NSTL
万方数据
