气候变化下珠穆朗玛峰自然保护区南北坡植被变化差异

Differentiation of Vegetation Changes in the South and North Slopes of Mount QNNP Under Climate Change

在全球气候变化背景下,为探究珠穆朗玛峰自然保护区南北坡植被变化差异,采用样方调查数据,MODIS/NDVI数据和气候数据,基于TS趋势分析和偏相关分析研究了珠峰保护区2000—2018年南北坡植被变化及其对气候变化的响应,并预测了其未来植被变化。结果表明:(1)总体上,保护区植被NDVI在2000—2009年呈下降趋势,2009—2018年呈上升趋势,且年内NDVI与温度相关性强于降水。(2)南坡地区NDVI值大于0.6且变化稳定,主要分布着喜马拉雅冷杉(Abies spectabilis)等高大乔木;北坡地区NDVI值小于0.4且易波动,主要分布着苔草(Artemisia younghusbandii)等灌草丛。(3)南坡地区NDVI在整个2000—2018年均呈轻微上升趋势;北坡地区NDVI在2000—2009年下降,在2009—2018年上升,且Hurst指数预测未来NDVI变化不稳定,大部分区域可能会出现下降趋势。(4)南坡地区NDVI与气候因子相关性弱,北坡地区NDVI与温度呈负相关,与降水呈正相关;北坡定日和定结县居民地附近区域植被对人类活动较为敏感。研究为当地可持续发展和保护区生态环境建设提供了新的思路。

The distribution of vegetation in the Mount Qomolangma National Nature Preserve region(Hereinafter referred to as QNNP) differs in the southern and northern slope areas. Survey data, MODIS normalized difference vegetation index(NDVI) data, and climate data were used to study the difference of vegetation changes and their responses to climate change in the south and north slopes of the QNNP region from 2000 to 2018, as well as predict future changes in vegetation. The results are as follows.(1) In general, NDVI decreased from 2000 to 2009 and increased from 2009 to 2018, and the correlation between NDVI and temperature was stronger than that of precipitation during the year.(2) In the southern slope area, tall trees such as Abies spectabilis were common;NDVI was greater than 0.6 and showed little spatial variation. In the northern slope area, shrubs and grasses such as Artemisia younghusbandii were common;NDVI ranged from 0.1 to 0.4 and showed high spatial variation. In the southern slope area, NDVI slightly increased from 2000 to 2018.(3) By contrast, NDVI decreased from 2000 to 2009 and increased from 2009 to 2018 in the northern slope area. Hurst exponent calculations predicted future fluctuations in vegetation in the study area, and vegetation status might change from good to poor level in most regions.(4) The correlation between NDVI and climatic factors was weak in the southern slope area, while the NDVI in the northern slope area was negatively correlated with temperature and positively correlated with precipitation. Dingri and Dingjie counties on the north slope are more sensitive to human activities. Generally, the results of this study can provide new insights that can be used to aid local sustainable development and improve the ecological environment in the QNNP.