基于景观指数和空间自相关的吉林大安市景观格局动态研究

以松嫩平原西部盐碱化严重的典型区域大安市为研究对象,基于2000和2010年两个时期的土地利用和增强植被指数（EVI）数据,利用移动窗口法和局部空间自相关分析,研究大安市景观格局的变化。结果表明,大安市优势景观类型是农田、草地和盐碱地,2000年农田、草地和盐碱地分别占景观类型总面积的40.20%、19.09%和19.26%,2010年分别占景观类型总面积的41.69%、18.16%和19.94%。2000-2010年,农田和盐碱地面积增加,最大斑块指数增加,景观形状变得复杂,并且盐碱地的景观连通性增强,而草地的面积减少,最大斑块指数降低,景观形状变得复杂。大安市景观格局空间分布特征明显,优势度较高的景观类型分布的区域包括草地、农田和盐碱地,景观连通性强,景观破碎化程度和异质化程度低。而各种景观类型交错分布的区域景观破碎化程度较高,景观异质性较强。大安市2000和2010年EVI的局部Moran’s I分别为0.73和0.75,在空间分布上呈现出明显的空间自相关性。2000和2010年EVI呈高-高自相关的地区大多为农田,这些区域的植被覆盖较好,EVI呈低-低自相关的地区大多为盐碱地,植被覆盖较差。大安市不同景观类型的Moran’s I和斑块密度（PD）以及斑块形状指数（LSI）呈负相关关系,和最大斑块指数（LPI）以及蔓延度指数（CONTAG）呈正相关关系。移动窗口法和空间自相关法的结合分析,有助于了解大安市景观格局的空间变化特征及植被覆盖的空间聚集规律,从而为该地区生态环境保护提供依据。

Landscape Pattern in Da’an City of Jilin Province Based on Landscape Indices and Local Spatial Autocorrelation Analysis

As one of the typical salinization regions in the western Jilin Province, Da’an city was taken as the study area. Based on remote sensing data and enhanced vegetation index (EVI) data in 2000 and 2010 and by using moving window method and local spatial autocorrelation analysis, the landscape pattern of Da’an city was analyzed. The results showed that the dominant landscape types in this region were farmland, grassland and saline land. The proportion of farmland, grassland and saline land were 40.20%, 19.09% and 19.26% in 2000, respectively, and 41.69%, 18.16% and 19.94% in 2010, respectively. From 2000 to 2010, the area of farmland and saline land increased, LPI increased and the shape become complex, and landscape connectivity of saline land increased. The area of grassland decreased, LPI decreased and the shape become complex. The spatial heterogeneity of landscape pattern in Da’an city was significant. The area with the dominant landscape types including the grassland, farmland and saline land, showed higher landscape connectivity, lower fragmentation and heterogeneity, while the area with various landscape types showed higher fragmentation and stronger heterogeneity. The local spatial auto-correlation of EVI in 2000 and 2010 were 0.73 and 0.75 respectively, indicating a significant spatial correlation. In the two periods, the high-high self-related areas are mostly farmland, where vegetation cover are excellent, and the low-low self-related areas are mostly saline land with lower vegetation cover in these areas. Moran’s I of Da’an city showed negative correlation with PD and LSI, and positive correlation with LPI and CONTAG. The moving window method combined with spatial autocorrelation analysis method will contribute to the understanding of spatial variation of landscape pattern and spatial aggregation of vegetation cover, thus providing the basis for ecological environment protection.