基于景观邻接特性的吉林省西部生态风险分析

Analysis on the ecological risk in western Jilin Province based on landscape adjacency characteristics

以1986—2008年吉林省西部遥感影像解译资料为基础数据,利用GIS软件提取土地景观信息,计算主要景观与障碍景观类型的空间邻接特性,构建吉林省西部风险指标,在空间格局上对由于景观格局带来的生态风险进行评价。结果表明:景观类型中耕地与沙地的邻接边长与面积最大,分别占总边长与总面积的65.37%和78.65%,但个数比最多的是草地,表明沙化对耕地威胁最大,其次是对草地的威胁;与盐碱地的相邻分析中,无论是边长、面积、还是斑块统计,耕地受胁程度均比较显著,其次受影响比较大的是草地和水域;20多年来,林地、草地与沙地邻接边长、面积和斑块比例均有所下降,而耕地与沙地的邻接边长、邻接面积比例呈上升趋势,但斑块比例从1986年起呈现下降趋势;与盐碱地的邻接性变化分析中,耕地、林地、草地和水域均呈大幅度上升,草地和水域尤为突出;耕地受沙化、盐碱化胁迫最为严重,且盐碱化的胁迫远大于沙化;1986—2008年,由于沙地和盐碱地障碍景观结构变化引起的生态风险有增无减,且盐碱化胁迫远大于沙化的胁迫,盐碱化成为威胁该区生态环境可持续及保持生态稳定性的关键因素,盐碱化治理及开发利用将是该区未来面临的一个重大课题。

Based on the remote sensing image data of the western Jilin Province during 1986- 2008, this study extracted the landscape information using the GIS software, computed the spatial adjacency characteristics between the main landscapes and the obstacle landscape types, con- structed the risk indexes of the western Jilin Province, and assessed the ecological risk based on the landscape pattern. The desertification showed more impact on arable land than on the others and the effect was also obvious in the analysis of the adjacency to the saline-alkali land. In the past 20 years, the adjacency indexes of length, area and patch number of forest and grassland to the sand land decreased while that of arable land increased. From 1986 to 2008, the arable land was seriously threatened by desertification and salinization. The stress caused by desertification and salinization increased and the stress caused by salinization was more serious than that by desertification. Our results indicate that salinization becomes a threatening factor on the regional ecological environment sustainability.