水资源管理增强下的塔里木河上中游碳储量动态评估

Dynamic assessment of Tarim River carbon storage under enhanced water resources management

自2000年实施流域综合治理和2010年推行流域体制改革以来,塔里木河流域水资源管理能力不断增强。然而,水资源管理对流域生态系统固碳能力的提升效果如何,未曾开展评估。以胡杨林集中分布的塔里木河上中游为研究靶区,采用InVEST模型,基于2000年、2010年、2018年土地利用/覆被变化数据,分析了水资源管理增强下流域生态系统碳储量的变化特点。结果表明:(1)2000年、2010年、2018年塔里木河上中游的总碳储量分别为93.70 Tg、93.92 Tg、93.01 Tg,平均碳密度分别为67.63 t·hm^(-2)、67.78 t·hm^(-2)、67.12 t·hm^(-2),基本保持稳定。林地是塔里木河上中游的主要碳库、草地次之。(2)2000-2010年碳储量增加0.22 Tg,主要由于大量草地类型(69.35 t·hm^(-2))转化成耕地类型(73 t·hm^(-2))。自2000年塔里木河综合治理实施后,植被恢复使得地表生物量增多,林地、草地碳密度和碳储量增加;2010-2018年碳储量减少0.91 Tg,碳损失途径主要源于大量林地类型(73.77 t·hm^(-2))转化成耕地类型(73 t·hm^(-2)),造成草地总碳储量降低。(3)碳储量空间分布具有较强的空间异质性,其特点以塔里木河上中游为条带向四周波动递减。碳储量变化显著区域在空间分布上与土地利用变化区域基本一致。研究可为深入了解干旱区碳循环,提升流域生态系统固碳功能,优化水资源管理提供科学依据。

Since the implementation of comprehensive governance in 2001 and unified management in 2011,the water resources management capacity of the Tarim River Basin has been continuously enhanced.However,the effectiveness of water resources management at improving the carbon storage capacity of watershed ecosystems has not been evaluated.Therefore,based on land use/cover change data from 2000,2010,and 2018,this paper used the InVEST model to analyze the change characteristics of the carbon storage of watershed ecosystems under enhanced water resources management in the upper and middle reaches of the Tarim River where Populus euphratica forest is concentrated.In 2000,2010,and 2018,the total carbon storage in the upper and middle reaches of the Tarim River was 93.70,93.92,and 93.01 Tg,respectively,and the average carbon density was67.63,67.78,and 67.12 t·hm^(-2),respectively.Woodland was the primary carbon pool in the upper and middle reaches of the Tarim River Basin,followed by grassland.From 2000 to 2010,the carbon storage in the study area increased by 0.22 Tg,primarily due to the conversion of a large number of grassland types(69.35 t·hm^(-2))into arable land types(73 t·hm^(-2)).After the implementation of comprehensive management of the Tarim River in2001,vegetation restoration led to an increase in the surface biomass,carbon density,and carbon storage of woodland and grassland.From 2010 to 2018,carbon storage decreased by 0.91 Tg,and the carbon loss pathways primarily originated from the conversion of a large number of woodland types(73.77 t·hm^(-2))to arable land types(73 t·hm-2).Simultaneously,the total carbon storage of grassland decreased.The spatial distribution of carbon storage in the study area had a strong spatial heterogeneity,and its characteristics gradually decreased around the upper and middle reaches of the Tarim River.The areas with significant changes in carbon storage were consistent with the spatial distribution of land use changes.This research provides a scientific basis for an indepth understanding of the carbon cycle and climate change in the study area,informing the improvement of the carbon storage capacity of the watershed ecosystem,optimizing the allocation of water resources,and promoting the sustainable development of river basins.