2001—2020年黄土高原生态环境质量对气候及土地利用变化的响应

Response of Eco-environmental Quality to Climate Change and Land Use in Loess Plateau from 2000 to 2020

[目的]分析黄土高原生态环境质量(EEQ)时空变化特征及其对气候与土地利用变化的响应情况,为黄土高原制定合理的生态保护措施及土地开发提供一定的依据,以实现其高质量发展。[方法]基于改进的遥感生态环境指数及气候、土地利用等数据,从像元尺度出发,利用Theil-Sen趋势分析等方法探究了黄土高原2001—2020年EEQ的时空变化特征,同时采用多元回归及叠加分析等手段研究了EEQ对气候变化及土地利用转移的响应情况。[结果]①研究时段内,黄土高原EEQ呈现小幅度波动上升、下降、再上升趋势,相较于2001—2010年,2010—2020年波动有所放缓;空间上,EEQ总体质量一般,呈“东南高,西北低”的格局,2010—2020年相较于2001—2010年而言,显著增加的区域由东南部向中北部区域转移,显著下降的区域由西北部向东部转移。②降水量对EEQ整体呈正面效应,在2001—2007年期间呈现显著的正相关关系,后期由于其他因素的干扰驱动力有所下降,在植被覆盖较少的区域则影响较小;气温在大部分区域与EEQ呈负相关,相较于降水量而言影响较小,在城市密集地区影响较大。③研究时段内,大量的耕地向草地,草地向林地及未利用地向草地的转移是研究区内EEQ呈稳中向好格局的主要驱动力,而耕地向建设用地,草地向未利用地的转移是引起EEQ下降的重要因素。[结论]黄土高原的EEQ受到气候及土地利用的双重影响。降水对EEQ的影响大于温度,土地利用转变对于EEQ整体呈现正面效应,具有空间异质性,对区域内城市群区域生态保护应予以重视。

[Objective]The spatial and temporal changes of ecological environmental quality(EEQ)in response to climate and land use changes on the Loess Plateau were analyzed in order to provide a basis for the formulation of reasonable ecological protection measures and land development on the Loess Plateau that will promote high-quality development.[Methods]Based on an improved remote sensing ecological environmental index and climate and land use data,we determined the spatial and temporal characteristics of EEQ on the Loess Plateau from 2001 to 2020 using Theil-Sen trend analysis at the image pixel scale.[Results]①During the study period,EEQ values on the Loess Plateau showed small fluctuations of rising,falling,and rising,and the fluctuations slowed down from 2010 to 2020 compared with the time period of 2001 to 2010.EEQ values generally showed a spatial pattern of“higher in the southeast and lower in the northwest”.Compared with the period from 2001 to 2010,the period of 2010 to 2020 exhibited an area of significant increase in EEQ that shifted from the southeast to the north-central region,and an area of significant decrease in EEQ that shifted from the northwest to the east.②Precipitation had an overall positive effect on EEQ,with a significant positive correlation from 2001 to 2007.Due to the interference of other factors in the later period,the driving force increased,and the influence was small in areas with less vegetation coverage.Temperature had a negative effect on EEQ in most areas,with less effect compared with precipitation,and greater effect in dense urban areas.③During the study period,large transfers of cropland to grassland,grassland to woodland,and unused land to grassland were the main driving forces for the steady to good pattern of EEQ in the study area,while the transfer of cropland to construction land and of grassland to unused land were important factors causing the decline of EEQ.[Conclusion]EEQ on the Loess Plateau was influenced by both climate and land use.The influence of precipitation on EEQ was greater than that of temperature,and land use shifts generally showed positive effects on EEQ but with spatial heterogeneity.Greater attention should be given to regional ecological conservation in urban clusters within the region in the future.