2000—2007年珠峰自然保护区植被时空变化与驱动因子

采用遥感与GIS相结合的方法研究了珠峰自然保护区2000—2007年之间的植被时空变化过程和驱动机制问题。通过一元线性回归斜率计算获取了基于EVI数据的珠峰自然保护区植被变化趋势,以及表现2000—2007年植被变化的矢量图层。利用GIS时间动画技术,建立了7个时间点内不同间隔的植被时空演化过程快照,并结合ArcEngine构建了植被变化监测的时序分析流程,提取和分析了植被变化过程的时空特征。依据年平均温和年降水量观测记录进行了植被变化的气候因子分析,依据道路、河流缓冲区的居民点密度与植被退化面积比例的相关性,分析了人类活动影响,并讨论了不同植被退化区域在多重因素作用下的变化驱动因子。拟合了主要社会经济发展指标与植被变化的相关性,从统计数据方面讨论了珠峰自然保护区社会经济发展对植被变化的影响作用。结果表明：珠峰自然保护区植被变化的总体趋势以稳定为主,但植被退化趋势超过了变好趋势。同时,核心区植被变好趋势明显,实验区植被退化趋势严重。保护区南坡植被受气候变化干扰小,保持了大部分变好趋势;北坡由于降水减少造成湿地植被退化,对草地的长势带来消极作用。人类活动与植被状态变化有密切关系,在沟谷地带的破坏作用明显。并且,植被退化趋势与农业耕地面积扩大以及放牧影响关联紧密,而牲畜饲养与林业发展都未对保护区植被变化造成明显影响。

Vegetation spatio-temporal changes and driving factors in the Mt. Qomolangma Nature Reserve in 2000-2007

In this paper, the vegetation spatio-temporal change process and drive mechanism of the Mt. Qomolangma Nature Reserve during 2000-2007 were studied by using the combination of remote sensing and GIS method. Through one-dimensional linear regression slope calculation of EVI （enhanced vegetation index） data, it obtained the vegetation change trends in the Mt. Qomolangma Nature Reserve, and it extracted the vector layers of vegetation change from 2000 to 2007. Using GIS time animation technology, the GIS system established seven time points at vegetation spatio-temporal evolution snapshots, and built a temporal analysis workflow of vegetation change monitoring based on ArcEngine. By which, it extracted and analyzed the temporal and spatial characteristics of vegetation change. Based on mean annual temperature records and annual precipitation records, the climatic factors on vegetation changes were analyzed. Based on the correlation between the settlements density and vegetation degradation area ratio that calculated by buffer zones analysis of roads and streams, human activities influences were analyzed, and multiple factors on vegetation changes in different degraded regions were discussed. By fitting the correlation between the main indicators of socio-economic development and the vegetation changes based on statistical data from statistical yearbooks, the social and economic development impacts on the vegetation change were discussed. The integrated research results showed that the general trend of vegetation change in the Mt. Qo-molangma Nature Reserve is stable, but stable area has been decreasing, and the trend of vegetation degradation than the trend changed for the better. Meanwhile, vegetation changed for the better increasing trend in the core zones significantly greater than the growth trend of degraded areas. While vegetation changed for the better in the experimental zones is of decreasing trend, the deterio-ration trend in recent years is more severe. The southern slope vegetation in the protected areas affected by climate change of a small disturbance, maintaining most of the trend changed for the better. Reduced rainfall caused wetland vegetation degradation and imposed the negative effect on the growing grass crop in the northern slope of the protected areas. Human activities and vegetation state change has the closed relationship, and the damaging effects in the valley are particularly apparent. Also, vegetation degradation trends and agricultural land area expand as well as grazing impacts have the closed association, but none of livestock and forestry development on the protected areas cause obvious effect on vegetation changes.