科尔沁城镇化过程对沙地景观的影响

城镇空间扩展所表征的城镇化过程及其对区域景观的影响,是景观生态学研究中的重要方向之一,也是景观生态学中格局-过程研究的重要组成部分。以1985—2013年遥感数据为基础,GIS技术与景观格局分析方法为手段,采用主要指标构建的城镇化指数定量分析了城镇化过程对科尔沁沙地景观的影响。结果表明:近28 a来,区域城镇化发展较快,年均提高0.64%,并呈现阶段性特征,研究区景观变化明显。在斑块水平上,农田、固定沙丘、林地、居工地的面积增加,其余景观类型的面积减少;农田、居工地与林地的破碎化程度增加;农田、固定沙丘最大斑块面积增加最显著,在区域中的优势作用增强。在景观水平上,区域景观破碎化程度减轻,空间集聚程度增加,景观类型组成趋于简单。区域内城镇化过程对不同类型景观的影响存在差异性,其特征表现为城镇化对农田、居工地的影响最大,对其他类型景观的影响较小。城镇化指数与斑块数量、散布与并列指数、香农多样性指数之间存在显著的负相关关系,城镇化指数与蔓延度指数为显著的正相关关系,表现为研究区景观破碎化程度、空间散布程度、异质性均随城镇化水平提高而减小,反映出城镇化与景观变化存在一定的内在联系,选取的景观指数能够反映城镇化过程对区域景观的影响。

Impact of Urbanization Process on Landscapes in the Horqin Sandy Land

Urbanization process based on urban spatial expansion and its effect on regional landscapes is one of the important directions in landscape ecology research,and also an important part of studying the pattern-process of landscape ecology.The impact of urbanization process on landscape structure in the Horqin Sandy Land was analyzed using GIS technology and landscape index measurement combined with the index of urbanization constructed by main parameters based on Landsat TM data from 1985 to 2013.Results showed that urbanization was very fast with an annual increased rate of 0.64％,and it was periodic.The landscapes were changed dramatically in recent 28 years.At the patch level,the areas of cropland,fixed dunes,woodlands and residential and industrial areas were enlarged,but those of other landscape types were reduced.The fragmentation degree of cropland,residential and industrial areas and woodlands was increased.The maximum patches of cropland and fixed dunes were remarkably enlarged,and their dominant functions were increased.At the landscape level,the fragmentation of landscapes was decreased,degree of spatial concentration was increased,and the landscape types became simple.The impact of urbanization process upon different landscape types was different,especially upon the cropland and residential and industrial areas.There were the significant negative correlations between the urbanization index and the number of patches,IJI index and Shannon diversity index,but positive with Contagion index,but there was a significant positive correlation between the urbanization index and the Contagion index.The fragmentation,spatial scatter and heterogeneity were decreased with the increase of urbanization level.