1988−2018年东祁连山农牧交错区景观格局变化及驱动因素

Landscape pattern changes and their driving factors in the farming-pasture ecotone,Eastern Qilian Mountains,from 1988 to 2018

以天祝藏族自治县金强河流域上游的农牧交错区为例,基于4期Landsat影像和GIS技术,利用目视解译和景观格局指数对研究区1988−2018年景观空间格局演变及其驱动因素进行分析。结果表明:1)草地是最大的景观类型,30年间草地总体面积增加了37.2 km^2,其中近10年中覆盖度草地面积增加了102.5 km^2;灌丛面积减少了37.5 km^2,主要转化为草地。2)人口增加了13.9%,建设用地面积显著增加了142.4%,而耕地面积减少了4.4 km^2,人为干扰度增加了20.2%。3)景观形状指数增加了9.09,蔓延度和聚集度指数分别减小了0.45%和2.76%,景观呈复杂化和破碎化趋势。4)人类活动是景观格局变化的主要驱动因素,气候因素次之,政策驱动对环境改善具有重要的导向作用。因此,减少人为活动对东祁连山农牧交错区的过度干扰,是实现生态系统保护和可持续发展的关键。

To explore landscape spatial pattern changes and their driving factors over a 30 year period(1988 to 2018),we used visual interpretation and landscape pattern indexes to analyze remote sensing images of the upper Jinqiang River on a farming-pasture ecotone in the Tianzhu Tibetan Autonomous County.The results showed that:1)Grassland was the largest landscape type with an area increase of 37.2 km^2 over the 30 year period.In particular,the moderate-coverage grassland increased by 102.5 km2 during the last 10 years,and the shrubland decreased by 37.5 km^2,being mainly converted to grassland.2)From 1988 to 2018,the population increased by 13.9%,and the construction land area increased by 142.4%,whereas the cultivated land area decreased by 4.4 km^2,and the degree of human disturbance increased by 20.2%.3)The landscape shape index increased by 9.09,whereas the contagion and aggregation indexes decreased by 0.45%and 2.76%,respectively.The landscape tended to be complicated and fragmented.4)Human activity appears to be the main factor driving the landscape pattern changes,followed by climate factors.National policy plays an important guiding role in environmental improvement.To realize ecosystem protection and sustainable development,reduction of excessive human activity impact on the farming-pasture ecotone in Eastern Qilian Mountains is essential.