若尔盖高原湿地资源变化过程与机制分析

以整个若尔盖高原为研究区域,综合利用遥感、GIS技术、DEM和野外调查成果,系统分析了湿地资源变化的一般过程和机制。结果表明:①若尔盖高原湿地主要分布在高原内部海拔3380～3550m的丘陵区域,并且呈现出与草地相间分布的空间格局;②自20世纪60年代以来,由于湿地排水和泥炭开采活动,湿地面积萎缩了62%,典型区域达到88%左右;③典型区域植物群落调查表明,该区湿地生态系统发生了严重退化;④过度放牧加速了生态系统退化的程度,导致啮齿类动物的数量不断增大;⑤湿地资源数量减少和质量下降对区域生态平衡造成严重威胁,是区域环境变化的根源。

Changing Process and Mechanism of Wetland Resources in Ruoergai Plateau, China

As a particular type of natural resource in China,wetland resources in Ruoergai(Zoige)Plateau has peculiar resource quantity and quality characteristics in geographical distribution and spatial structure.Changes in wetland resources were mainly due to human activities driven by development of animal husbandry,which induced wetland shrinkage in area and degradation of ecosystem in the Plateau.This phenomenon has resulted in many negative effects on eco-environment,attracting attention of local government and many scientific research groups. Each type of natural resource has close relationship with others in a region.Wetlands and pastures have formed a whole "resources-link" system in Ruoergai Plateau due to their dominant position in area and spatial patterns.By overlaying DEM and information of each type of natural resource in the Plateau,we found that marsh wetlands are distributed in hilly areas with elevations ranging between 3 380-3 465m,accounting for 28.9% of the plateau's total area;meadow wetlands are distributed on terraces between 3 465-3 550m,accounting for 22.3%;and pastures are distributed on hill slopes between 3 550-4 000m,accounting for 40.1%.But,with the economic development and population growth,wetland resources changed greatly both in quantity and quality due to overgrazing in the past years.About 62% of the wetland resources has shrunk 62% since the 1960s,and most of them were converted into pastures.As a result,wetland ecosystems were degraded,biodiversity was changed and some environmental problems such as land desertification and dry climate have occurred in the Plateau.Many factors are attributable to these problems,but drainage of wetland and peatland reclamation induced water condition variation is the major factor resulting in wetland ecosystem succession and species changes.However,overgrazing has speeded up wetland ecosystem degradation by changing plant species composition and constant increasing in rodent animal numbers.So,suggestions for wetland conservation and sustainable utilization were summarized finally.