博斯腾湖流域景观生态风险评价与时空变化

Landscape Ecological Risk Assessment and its Spatiotemporal Changes of the Boston Lake Basin

以博斯腾湖流域为研究区,利用eCognition软件对博斯腾湖流域1990年、2000年、2010年和2015年4期Landsat遥感影像分类。基于土地利用类型的生态脆弱度和景观干扰度指数构建景观生态风险评价模型,并利用空间自相关分析方法,开展博斯腾湖流域景观生态风险评价的时空变化研究。结果表明:(1)1990-2015年,博斯腾湖流域景观格局变化明显,主要特征为水域景观面积减少了64.33%,景观优势度降低;林地、耕地和城镇用地增幅显著,三者分别增加了47.96%、44.77%和85.15%;草地仍是流域主导景观类型。流域整体斑块数量减少,景观破碎化程度减弱。(2)低风险区和较低风险区主要分布在流域北部,土地利用以草地为主;高风险区主要分布在流域东南部,土地利用以未利用地为主;较高风险区主要围绕高风险区分布;中等风险区分布比较零散。(3)1990-2015年间,高风险区面积增加了386 263 hm2,低风险区面积减少了217 216 hm2,研究区总体生态风险等级增加,博斯腾湖流域生态质量存在进一步退化的趋势。

Taking the Boston Lake Basin as the study area, Landsat remote sensing images of the Boston Lake Basin in1990, 2000, 2010 and 2015 were classified by using e Cognition software. The ecological risk assessment model of the land-scape was constructed based on the ecological vulnerability of land use type and the index of landscape disturbance, and the spatial auto-correlation analysis method was used to evaluate spatial-temporal change assessment of landscape ecological risk in Boston Lake basin. Results show that:(1) During 1990-2015, the landscape pattern of the Boston Lake Basin changed sig-nificantly. The main features were that the water area decreased by 64.33%, landscape dominance decreased, and forestland,cultivated land, and urban land increased significantly. The three increased by 47.96 %, 44.77%, and 85.15%, respectively. The grassland is still the dominant landscape type in the basin.(2) The low-risk areas and the lower-risk areas are mainly distribut-ed in the northern part of the basin. The land use is mainly grassland; the high-risk areas are mainly distributed in the south-east of the basin, and the land use is mainly unused land; the higher risk areas are mainly distributed around high-risk areas.The distribution of medium-risk areas is relatively fragmented.(3) From 1990 to 2015, the area of high-risk areas increased by 386 263 hm2, the area of low-risk areas decreased by 217 216 hm2, the overall ecological risk level in the study area increased, and the ecological quality of the Boston Lake Basin was further degraded.