珠穆朗玛峰国家级自然保护区退化湿地分布及影响因素研究

Distribution of Degraded Wetlands and Their Influence Factors in Qomolangma National Nature Reserve

以珠穆朗玛峰国家级自然保护区为研究区,利用2000～2008年的增强型植被指数(Enhanced Vegetation Index,EVI)数据、气象数据和野外实地调查资料,对研究区退化湿地分布及其影响因素进行了研究。结果表明,2000～2008年期间,珠穆朗玛峰国家级自然保护区湿地出现退化现象;退化湿地主要分布在吉隆县折巴乡、聂拉木县波绒乡和门布乡、定日县岗嘎镇和定结县多布扎乡;退化湿地面积约为71.3 km2,其占研究区湿地总面积的1.8%;退化湿地多分布在保护强度较弱的保护区的试验区内。人类过度放牧和连年的降水量偏少是造成研究区湿地退化的主要原因。

As wetland is a unique and complex ecosystem with water,soil,air,biological and other components.It is sensitive to global change,therefore,the Qinghai-Tibet Plateau wetlands occupies an important place in the global change research.Learning more about the change mechanism of wetlands in the Everest region,monitoring and analyzing high-altitude wetlands,it has very important significance to get earlier global changing warning information.The current researches in the Everest region were mainly focused on snow,ice,atmosphere,geology,vegetation,disease,etc.At present,many scholars have used NDVI to analyze wetlands systematically.At the same time,some scholars with NDVI studied vegetation changes in the Qinghai-Tibet Plateau.At present,using vegetation index to study wetlands interannual variability was less.As Enhanced Vegetation Index（EVI） could be more truly reflected the growth of vegetation than NDVI,and EVI range,standard deviation and coefficient of variation were higher than that of NDVI in the same spatial resolution.In this article,EVI data covering the Qomolangma National Nature Reserve from 2000 to 2008,meteorological data,and social economy data combined with collected data in field were used to study the degraded wetlands and their influence factors,in order to find the regular pattern of wetland degradation,a slope of linear regression was used to calculated inter-annual trend of wetlands.The results showed that the wetlands kept stable in Qomolangma National Nature Reserve from 2000 to 2008,there was not significantly change for main part of wetlands,and some wetlands existed the phenomenon of degradation,which area was about 71.3 km2,account for 1.8% of the total wetlands.Degraded wetlands was focused in experiment zones with weaker protection,including Zheba of Giyrong county,Borong and Menbu of Nyalam county,Gangga of Tingri county,Duobuzha of Dinggye.The wetland degradation were the result of the interaction of human activities and nature,such as rising temperature,reducing annual precipitation,over-grazing and not enough protection.EVI is a proper index to analyze wetlands changing in this area.