珠穆朗玛峰自然保护区植被变化分析

Analysis of Vegetation Change in Mt.Qomolangma Natural Reserver

利用1981～2001年美国NASA Pathfinder NOAA/NDVI数据,以11∶00万植被图为基础,结合气温降水资料、DEM数据和2000年人口空间化数据,研究了珠穆朗玛峰自然保护区植被变化空间格局和海拔梯度特征及其影响因素。结果表明:①1981～2001年珠峰自然保护区植被变化以稳定为主,有5.09%的区域发生严重退化,13.34%的区域发生退化,54.31%的区域保持稳定,26.31%的区域变好以及0.95%的区域植被显著变好。退化和严重退化区域主要分布在保护区南部,国境沿线;植被变好地区集中分布在保护区北部,雅鲁藏布江南岸。稳定区域位于退化区域和变好区域之间。植被退化区域主要分布在海拔2400m￣4000m带上。②针叶林、针阔混交林和灌丛构成了区域植被退化的主体。③从空间上看,主要是气温变化对植被变化有影响。在海拔梯度上,气温变化和坡度共同影响植被变化。④在珠峰自然保护区内,人类不合理的资源利用方式造成了部分地区的植被退化。

Based on the NOAA AVHRR-NDVI data from 1981 to 2001, digitalized China Vegetation Map （1：1 000 000）, temperature and precipitation data, DEM, and spatial people density data in 2000, the spatial patterns and characteristics along the altitude gradients of the vegetation change as well as their factors in Mt. Qomolangma Natural Reserver have been stud- ied. The results show that： （a） there are notable spatial differences of vegetation change in Mt. Qomolangma Natural Reserver and stability is the most common status. 5.09 percent of the whole area is becoming serious degradation, 13.34 percent degraded, 54.31 percent keeping stable, 26.31 percent turning better and 0.95 percent notably turning better. The degradation and serious degradation areas mostly lie in the south of the Reserver, which are along the national boundaries. The areas of vegetation turning better lie in the north of the Reserver and the south side of the Yarlung Zangbo River. The stable areas lie between the better and worse areas. Along with the increase of stability. At the altitude elevation, the states of vegetation changes transit from degradation to from 2400m to 4000m vegetations are in degraded change condition die-leaf and broad-leaf mixed forests. Plant changes can be divided into three types： （1）Stable to growing better. They are steppes and meadows. （2）Stable to degraded. They are shrubs and alpine sparse vegetation. （3）Degraded. They are needle-leaf forests and needle-leaf and broadleaf mixed forests. （c） The temperature change affects vegetation change in space while the integration of temperature changes and slopes affects vegetation change along the altitude gradients. Spatial correlation coefficient of temperature change and NDVI change is 0.51. Correlation coefficients along the altitude gradients of temperature change and NDVI change and slope and NDVI change are 0.946 and -0.896. （d） Unconscionable resource use mode made by human beings leads to the vegetation degeneration in some parts of Mt. Qomolangma Natural Reserver. Bio-resources are continually used to meet the need of economic development and human living, which are hard to regenerate in such a rigorous environment. Because of poverty and severe environment in Mt. Qomolangma Natural Reserver, sustainable development should be consistent with economic development. A series of adaptive policies and modes such as protecting bio-resources, altering industry structures and eliminating hunger and poverty should be taken to keep sustainable development.