宁蒙沿黄地带城镇用地变化及其生态效应

Urban Land Change and Its Ecological Effect in the Areas Along the Yellow River in Ningxia Hui and Inner Mongolia Autonomous Regions

基于1990、2000年和2008年土地利用数据,采用城镇用地变化强度和生态环境指数,对宁蒙沿黄地带城镇用地变化时空特征及其生态环境效应进行定量分析,结果表明:1 1990—2000年和2000—2008年2期城镇用地变化强度指数分别为0.0092和0.046,1990—2000年城镇用地的主要来源是耕地、草地和水域,2000—2008年是耕地、草地和农村居民点。2 1990—2000年区域生态环境价值降低1 270.58,草地退化的贡献达50.16%;2000—2008年则上升343.76,其中林地的贡献最大,达49.48%。1990—2008年生态环境价值持续上升地区主要分布在沿黄河3大平原和山区过渡带,持续恶化地区主要分布在2大沙漠区。3 1990—2000年城镇用地对耕地变化的贡献最大(1.95%),2000—2008年对林地变化贡献最大(6.81%),前后两期城镇用地对草地变化的贡献扩大了15倍;耕地、草地、林地和水域对城镇用地引起生态环境价值变化的贡献依次降低。总体而言,1990—2008年宁蒙沿黄地带生态环境价值先降低后小幅上升;城镇用地变化对研究区生态环境价值净变化贡献较小,但增强趋势显著;耕地向林地和草地的转入是研究区近期生态环境价值略升的主要原因。

Based on the data of land use in 1990,2000 and 2008,urban land transformation intensity（ ULTI）and ecological index（ EI） were employed to measure the spatial features and ecological effect of urban land transformation in the areas along the Yellow River in Ningxia Hui and Inner Mongolia autonomous regions. The main results are as follows： 1 The ULTIs were 0. 009 2 and 0. 046 during the periods of 1990- 2000 and 2000- 2008 respectively,the new urban land was mainly transformed from arable land,grassland and waters during the period of1990- 2000,and from arable land,grassland and rural residential land during the period of 2000- 2008; 2 During the period of 1990- 2000,regional ecological value（ EV） was reduced by 1 270. 58,the contribution from grassland degeneration reached to 50. 16%; during the period of 2000- 2008,EV was increased by 343. 76,in which the contribution of forest was the highest and reached to 49. 48%; during the period of 1990- 2008,EV improving areas were mainly distributed continually in 3 large plains along the Yellow River and the plain-mountain ecotones,while the worsening areas were mainly located in two large arid desserts; 3 The contribution of urban land to arable land change was the highest（ 1. 95%） during the period of 1990- 2000,it was the highest to woodland change during the period of 2000- 2008（ 6. 81%）,and the contribution of urban land to the grassland change was increased by 15 time during these 2 periods; as for EV change from the transformation of other land use types to urban land,the sort by contribution was as： arable land,grassland,woodland and waters. Holistically,during the period of 1990- 2008,the EV in the areas along the Yellow River in the Ningxia Hui and Inner Mongolia autonomous regions was reduced at first and then increased slightly; the contribution of urban land change to EV change was low,but its increase trend was remarkable; the recent slight EV increase was mainly caused by the transformation from arable land to woodland and grassland.