基于原生植被的长山群岛植被退化分析

Analysis of vegetation degradation in Changshan islands based on original vegetation

为揭示海岛开发利用对植被格局的干扰和破坏程度,科学评价海岛植被退化方向和程度,选取了黄海北部的长山群岛作为研究区域,在遥感和GIS空间分析技术支持下,构建了研究区域的原生植被格局,以此为基准对该区域植被退化的空间态势进行了评价.研究结果表明:落叶阔叶林是长山群岛最主要的原生植被类型,包括农业种植开垦和城乡建设占用在内的各种人类活动对海岛植被的强度干扰和破坏,使原生植被落叶阔叶林面积由13 784.19 hm2减少到6 729.43 hm2,其中19.12%被开垦为农作物,15.04%被开发为城乡建设地.受人类活动干扰的区域差异,海岛植被退化表现出明显的空间分异性,距离大陆较近的石城岛群和广鹿岛群植被退化最为严重,落叶阔叶林仅分别留存了24.48%、32.13%,而远离大陆的獐子岛群和海洋岛群植被保护较好,落叶阔叶林的保持面积在65%以上.实践证明基于原生植被的长山群岛植被退化分析方法能较好地反映海岛植被退化方向与程度,是海岛植被宏观评价分析的可行方法.

Aimed to reveal degrees of disturbed and destroyed vegetation landscape in island by human activities sci-entific analyze is conducted for the direction and degree of vegetation degradation of island.Changshan islands,lo-cated in north of Yellow Sea,were chose as the assessing region.Remote sensing techniques and spatial analysis techniques of Geographical Information System were employed to rebuilt original vegetation of the islands according historical data.Then degradation of vegetation landscape was analyzed based on the rebuilt original vegetation.The result show that warm temporal deciduous broad leaves forest was mostly the original vegetation types in Changshan islands.Human activities,including agricultural cultivation and urban-rural construction,have destroyed and dis-turbed original vegetation which was reduced from 13 784.19 hm2 to 6 729.43 hm2 .Only 48.82% of the warm temporal deciduous broad leaves forest in Changshan islands was remained,while 19.12% of original vegetation re-gion was turn to agricultural cultivation,15.04% was destroyed for urban-rural construction.The vegetation degra-dation shows obviously regional difference among islands by interferes of human activities.However,Shicheng islands and Guanglu islands,the closest islands to mainland,are suffering the most vegetation degradation that there are only 24.48% and 32.13% of warm temporal deciduous broadleaves forest left,respectively.In contrast, these vegetations remains 65% of the total in Zhangzi islands and Haiyang islands where they are farthest from ma-inland.The study indicates that analysis methods based on original vegetation can reflecting the direction and de-gree of vegetation degradation in the islands.It is a feasible method for vegetation macro analysis in islands.