摘要:
黄河流域内蒙古段目前的生态屏障功能出现严重的退化现象,诊断其景观格局及生态风险对促进内蒙古黄河流域高质量发展具有重要意义。该研究采用内蒙古黄河流域1980年、2000年和2020年的土地利用数据,计算区域景观格局指数和生态风险指数,分析其生态风险空间分布特征和时空演化规律。结果表明: 1980—2020年草地为主要用地类型,面积占50%以上,耕地、草地、水域和未利用地面积分别减少578 km2,1 911 km2,383 km2和255 km2,林地和建设用地面积增加了1 055 km2和2 072 km2,土地转移的主要方向为草地、耕地和水域转变为建设用地和林地; 2000—2020年综合土地利用动态度1980—2000年上升了0.85百分点; 1980—2020年,斑块数量除水域和未利用地减少外其余用地均增加,景观破碎化程度除建设用地外其余用地均增加,景观干扰度除林地上升外其余用地均减少,景观损失度除建设用地有明显下降外其余用地无明显变化; 黄河流域的生态风险值呈下降趋势,较低风险区和低风险区的面积增加9 000 km2,主要集中在北部和中部地区,高风险区和较高风险区的面积减少1 350 km2,分散布局在东部和北部边缘。
Abstract:
The Inner Mongolia reach of the Yellow River basin is suffering severe degradation as an ecological barrier at present. Analyzing its landscape pattern and ecological risk is of great significance for promoting the high-quality development of this reach. Based on the land use data of 1980, 2000, and 2020 of the study area, this study analyzed the spatial distribution and spatio-temporal evolution of the ecological risks by calculating the regional landscape pattern index and the ecological risk index. The results show that: ① During 1980—2020, the land in the study area was dominated by grassland, which accounted for more than 50%. In this period, the areas of cultivated land, grassland, water areas, and unused land decreased by 578 km2, 1 911 km2, 383 km2, and 255 km2, respectively. By contrast, the areas of forest land and construction land increased by 1 055 km2 and 2 072 km2, respectively. In terms of land use types, the land in the study area mainly shifted from grassland, cultivated land, and water areas to construction land and forest land. The comprehensive land use intensity during 2000—2020 was 0.85 percentage points higher than that during 1980—2000; ② During 1980—2020, the patch number of all types of land decreased except for water areas and unused land; the degree of landscape fragmentation of all types of land increased except for construction land; the degree of landscape disturbance of all types of land decreased except for forest land; the degree of landscape loss of all types of land did not change significantly except for construction land, for which the degree of landscape loss decreased significantly; ③ The ecological risk value of the Inner Mongolia reach of the Yellow River basin showed a downward trend during 1980—2020. Areas with fairly low and low ecological risks increased by 9 000 km2 in total and were primarily concentrated in the northern and central areas in this period. In contrast, areas with high and fairly high ecological risks decreased by 1 350 km2 in total and were scattered on the eastern and northern edges.
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