呼伦贝尔草地风蚀坑分布区土地覆被景观变化

Land-cover landscape changes of blowouts distribution in the Hulun Buir grassland

以呼伦贝尔草地风蚀坑分布区1959、2002、2004、2009年4期影像解译数据为基础,研究该区近50a土地覆被变化情况,揭示景观格局时空演化规律,模拟未来土地覆被变化情景。结果表明:研究区各土地覆被类型变幅较大,除草地面积减少外,其它类型面积总体都呈增加趋势。其中,裸露风蚀坑、流沙区面积呈先增后减趋势,与近5a加大人工固沙力度有关。斑块尺度上,风蚀坑景观数量增加,平均斑块面积先增后减,分维数增加,风蚀坑结构变得复杂;景观尺度上,多样性和破碎度指数增加,蔓延度指数减少,草地遭到风蚀破坏。预测2012-2020年间,土地覆被格局继续保持目前发展态势,但发展速度减慢。若保持目前影响因素不变情况下,风蚀坑的发展将得到有效控制。

The land coverage pattern changes for the past 50 years in blowout distribution region of the Hulun Buir Grassland were interpreted and analyzed based on the remote sensing images of 1959,2002,2004,and 2009.The temporal and spatial evolutions of the landscape patterns were revealed,and future land use scenarios were simulated by cellular automata-Markov model.The results showed that all land use types had large variable amplitudes.The grassland area decreased,whereas other areas increased generally.Owing to artificial sand fixation over the past five years,the areas of flowing blowouts and depositional regions were first increased and then decreased.The number of blowouts increased.The average patch area initially increased,and then decreased.The fractal dimension increased,and blowout structures became complex.The diversity index and degree of fragmentation increased,whereas the contagion index decreased.The predicted land coverage pattern was maintained based on the current development trend for 2012-2020,but the growth rate decreased.Blowout development can be controlled under the same factors in the current situation.