2000-2018年鄂尔多斯市植被覆盖度变化及驱动因素分析

Analysis of Vegetation Coverage Change and Driving Factors in Ordos City from 2000 to 2018

植被变化是一个复杂而漫长的过程,受气候变化、土地利用、生态工程、城市化等多种因素的影响,其中人类活动是植被覆盖度变化的重要影响因子,评估区域植被覆盖度的人为影响值具有重要的研究意义.鄂尔多斯市融入新一轮西部大开发、黄河流域生态保护和高质量发展、黄河“几”字湾都市圈及内蒙古自治区的重要经济增长极等国家和区域战略,是国家重要能源和战略资源基地,且位于我国北方防沙带的南侧,对维护国家整体生态安全具有重要作用.本文以鄂尔多斯市为研究区,利用遥感数据、气象数据、土地利用数据,采用基于变异系数的人为影响模型,分析鄂尔多斯市2000—2018年植被覆盖度的时空变化,定量探究气候与人类活动对植被变化以及生态环境的影响,识别人类活动影响区域,区分正向、负向影响.结果表明:2000—2018年鄂尔多斯市植被覆盖度平均值呈现波动性上升趋势,从0.23升至0.35,总体呈现由低、中覆盖向中高、高覆盖转化的趋势.2000—2018年NDVI变异系数为0.005~4.360,植被稳定性较弱,变异系数高值区与气候因子的相关性未达到显著性水平.人为变异系数为−0.25~1.50,研究区西部受人类干扰程度较大,而东部受干扰程度较小.人类活动的正向影响区域主要集中在研究区东部,占研究区总面积的54.00%,与近年来生态保护修复治理密不可分.人类活动的负向影响区域主要分布在鄂托克旗西北部等区域,土地利用类型为工矿用地,且这些区域是采矿场增加区域之一,很大程度上受到矿产开发的影响,同时该区域处于防风固沙屏障区和生物多样性优先区,不仅关系到鄂尔多斯市的人居安全保障,而且关系到内蒙古自治区乃至京津冀、华北及西北地区的生态安全.因此需进一步加强人类活动管控工作,协调好经济发展与环境保护的关系,保障生态环境质量持续改善,为地方政府生态环境监管与干旱半干旱区生态保护修复提供科学依据,同时为黄河流域高质量发展以及我国北方生态安全屏障构筑提供重要保障.

The relationship between vegetation cover and environmental evolution is currently a major research component of global change ecology.In the context of global warming and sustainable development,the study of vegetation dynamics and its driving factors is becoming a research focus worldwide.Vegetation dynamics is a complex and long process,which is affected by many factors such as climatic change,land use change,ecological engineering,and urbanization in different regions.Among them,human activities are the important influencing factors of vegetation coverage,and it is of great significance to evaluate the anthropogenic impact value of vegetation coverage.Ordos City into a new round of western development,the Yellow River Basin ecological protection and high quality development,‘a few’of the Yellow River bay city circle and the autonomous region of the important economic growth pole and other countries and regional strategy,is the national important energy and strategy resources base,and is located in the south of‘the North Sand Belts’in our country,plays an important role in maintaining national ecological security.Taking Ordos City as an example,this study investigated the temporal and spatial variation of vegetation coverage from 2000 to 2018,explored the impact of climate and human activities on vegetation change and ecological environment,identified areas affected by human activities,and distinguished positive and negative impacts.The remote sensing data,meteorological data,land use data,and mining data were analyzed by using the linear regression model,correlation analysis,and human impact model based on coefficient of variation.It was found that:(1)From 2000 to 2018,the mean of NDVI showed an upward trend of fluctuation,rising from 0.23 to 0.35.The vegetation coverage of the whole city showed a trend of transformation from low and medium coverage to medium and high coverage.(2)From 2000 to 2018,the variation coefficient of NDVI of vegetation ranged from 0.005 to 4.360,indicating that the vegetation stability was weak.The regions with high coefficients of variation showed the most intense fluctuation of vegetation change,while none of the correlations between NDVI values and climatic factors(precipitation and evapotranspiration)reached the significant level.(3)The anthropogenic coefficient of variation ranged from−0.25 to 1.50,with the western part of the study area being strongly disturbed by human activities,while the eastern part was relatively less disturbed by human activities.(4)The positive impact areas of human activities are mainly concentrated in the eastern part of the study area,accounting for 54.00%of the total land area,which is closely related to ecological restoration and management in recent years.(5)The negative impact area of human activities is mainly distributed in the Kubuqi Desert and the northwest Otoki Banner,which is one of the areas with increasing mining and is mainly affected by mineral development.The areas with a greater degree of negative disturbance from human activities are located in the windproof sand barrier area and the priority area of biodiversity,which have important ecological functions.The ecosystem function is not only related to the security of human settlements in Ordos City,but also related to the ecological security of the autonomous region and even the Beijing-Tianjin-Hebei Region,North China and Northwest China.Therefore,it is necessary to further strengthen the protection of biodiversity and the management and control of human activities in the western region,coordinate the relationship between economic development and environmental protection,scientifically formulate ecological restoration suggestions,and ensure the continuous improvement of ecological and environmental quality.It provides scientific basis for local government's ecological environment supervision and ecological protection and restoration in arid and semi-arid areas.It will provide an important guarantee for the high-quality development of the Yellow River Basin and the construction of our northern ecological security barrier.