青海湖流域土壤保持服务功能模拟及驱动因素分析

Spatio-temporal Evolution and Driving Factors of Soil Conservation Function in Qinghai Lake Basin Based on InVEST Model

以青海湖流域为研究区,探讨土壤保持服务时空变化特征及空间异质性归因,为流域生态保护与可持续发展提供参考。基于1985~2020年8期土地利用数据,结合地形、土壤和气象数据,运用InVEST模型及地理探测器方法,模拟土壤保持服务、评估土壤保持量及其价值、对其空间异质性归因。结果显示:(1)青海湖流域1985~2020年土壤保持量变化区间为3.36×10~8t~11.73×10~8t,变化明显,表现为先下降后上升再下降的变化趋势;土壤保持量在空间分布上表现为西北高东南低。(2)不同土地利用类型中,草地土壤保持强度和土壤保持总量最大;土壤保持强度随海拔和坡度的增加而增加。(3)流域年均土壤保持服务价值为6.12×10^(10)元,以保持土壤肥力的价值E1为主。(4)地理探测单因子结果显示土壤类型和高程解释力最为显著;土壤保持服务空间分异的影响程度由多因子共同决定,整体上以植被覆盖度与土壤类型的交互作用解释力最高,而高程和土壤类型共同作用于植被覆盖度,植被覆盖度为影响土壤保持服务空间异质性的主导因子。植被覆盖度因子在研究区土壤保持服务空间分异方面发挥着不可替代的作用,应采取相应的水土保持措施,提高植被覆盖度,减少水土流失,增加土壤保持能力,改善生态环境,使生态系统土壤保持服务价值增益显著。

Taking Qinghai Lake Basin as the study area,we explored the spatial and temporal characteristics of soil conservation services and the attribution of spatial heterogeneity to provide reference for the ecological protection and sustainable development.Based on eight periods of land use data from 1985 to 2020,combined with topographic,soil and meteorological data,the InVEST model and geoprobe method were used to simulate soil conservation services,to assess the amount of soil conservation and its value,and to attribute its spatial heterogeneity.The results showed that:(1)The change interval of soil conservation in Qinghai Lake Basin was 3.36x10~8t~11.73x10~8t,showing a trend of decreasing,then increasing and then decreasing;soil conservation was high in the northwest and low in the southeast.(2)Among different land use types,grassland had the largest soil conservation intensity and a total amount of soil conservation;soil conservation intensity increased with the increase of elevation and slope.(3)The average annual soil conservation service value of the watershed was 6.12x10~(10)yuan,dominated by the value of maintaining soil fertility E1.(4)The single-factor results of geodetection showed that soil type and elevation had the most significant explanatory power;the degree of influence of spatial heterogeneity of soil conservation services was jointly determined by multiple factors.The overall explanatory power was highest in the interaction between vegetation cover and soil type,while elevation and soil type jointly acted on vegetation cover,which was the dominant factor influencing the spatial heterogeneity of soil conservation services.The vegetation cover factor played an irreplaceable role in the spatial heterogeneity of soil conservation services,and the corresponding soil and water conservation measures should be taken to improve the vegetation cover,to reduce soil erosion,to increase the soil conservation capacity,and to improve the ecological environment.