为揭示国家级自然保护区生态系统格局构成及变化状况,基于2000年和2010年319个国家级自然保护区生态系统类型与分布数据,根据生态系统类型转化及其转化幅度,考虑自然保护区各功能区的重要性,构建生态系统格局变化指数,分析国家级自然保护区生态系统格局动态变化.结果表明,国家级自然保护区草地生态系统面积最大,2000年和2010年分别占全国国家级自然保护区总面积的57.88％和57.74％,其次为荒漠生态系统,两期占比约17％,其他依次是湿地、森林、灌丛、农田、冰川/永久积雪、海洋、城镇等生态系统类型.2000-2010年,国家级自然保护区内森林、湿地面积明显增加,城镇有一定程度扩张,冰川/永久积雪略微减少.总体上,国家级自然保护区生态系统格局基本保持稳定,基本维持的保护区数量219个,占国家级自然保护区总数的68.65％,生态系统格局改善的保护区数量略多于退化的数量,10年来国家级自然保护区生态系统格局保护取得一定效果.国家级自然保护区生态系统格局在基本维持的基础上,表现出一定的地域不平衡性.生态系统改善的保护区多分布在秦岭、大巴山、大娄山、南岭一带,而东部省份、内蒙古高原、东北平原一带生态系统退化的保护区数量较多,主要是荒漠、内陆湿地和水域、野生动物、自然遗迹等类型自然保护区.最后,提出3点建议为提高国家级自然保护区管理水平提供参考.%Nature reserves provide the cornerstone of most national strategies to conserve biodiversity,and establishing nature reserves is perhaps the most important of all conservation tools focused on the preservation of wildlife habitat.Human encroachments and threats are generally perceived to be very common in many nature reserves.Therefore,it is necessary to assess variation in the ecosystem patterns of national nature reserves.To reveal ecosystem composition structure and its variation in national nature reserves of China,based on the ecosystem transition types and extents,and considering the importance of different functional zones in the nature reserve,we developed an ecosystem pattern variation index to examine the dynamic change of the ecosystem pattern,using ecosystem distribution data collected in 2000 and 2010 for 319 national nature reserves.The results showed that the grassland ecosystem accounted for the largest area,comprising 57.88％ and 57.74％ of the total area of the ecosystem in national nature reserves in 2000 and 2010,respectively,followed by the desert ecosystem,accounting for about 17％ both in 2000 and 2010,and then wetland,forest,shrub,field,glacier and permanent snow,marine and town ecosystems successively.From 2000 to 2010,the area of forest and wetland ecosystems showed obvious increases,and the town expanded to some extent,but the glacier and permanent snow ecosystem decreased appreciably in the national nature reserves.Overall,the ecosystem pattern of nature reserves essentially remained stable.There were 219 nature reserves that showed stability,accounting for 68.65％ of the total.The number of nature reserves tending to improve was slightly higher than the number of those tending to degenerate.These results reflect the fact that ecosystem conservation in national nature reserves has been effective to a certain extent.The improved nature reserves were mostly distributed in Qin Mountain,Daba Mountain,Dalou Mountain and South Mountain,while the degenerated nature reserves were mostly distributed in the eastern provinces,Inner Mongolian Plateau and the northeast plain.The degenerated nature reserves were mainly desert ecosystems,inner wetland and aquatic ecosystems,reserves for the protection of wild animals,and natural monuments.Finally,we put forward three suggestions to improve the management level for national nature reserves.
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