生态环境学报Issue(10)：1591-1598,8.DOI:10.16258/j.cnki.1674-5906.2015.10.001
藏北高原不同海拔高度高寒草甸植被指数与环境温湿度的关系
Relationships between Vegetation Indices and Environmental Temperature and Moisture in An Alpine Meadow along An Elevation Gradient in the Northern Tibet
摘要
Abstract
The alpine meadow in the Northern Tibet is an important component of the alpine grasslands worldwide, and it is also one of the most sensitive vegetation types to climatic changes. There are large uncertainties on the relationship between vegetation indices and environmental temperature and moisture, which limits our ability to accurately predict the responses of the vegetation growth in alpine grasslands to future climatic changes. Quantifying the relationship between vegetation indices and climatic factors improves the prediction of vegetation growth in alpine grasslands under future climatic change. Using the correlation analysis and the multiple stepwise regression analysis, we explored the relationships between vegetation indices (i.e. Normalized Difference Vegetation Index, NDVI;Enhanced Vegetation Index, EVI) and soil temperature, soil moisture, air temperature, relative humidity or vapor pressure deficit at three elevations (4 300, 4 500 and 4 700 m) in an alpine meadow from June─September in 2011─2014. The correlation analyses showed that all the correlation coefficients between vegetation indices and environmental temperature and moisture varied with elevation. The NDVI at elevation 4300 m decreased significantly with increasing soil temperature (r=-0.54, P= 0.003) and air temperature (r = -0.42, P = 0.028). The EVI at elevation 4300 m decreased significantly with increasing soil temperature (r=-0.41, P=0.030), but was not correlated with air temperature (r=-0.31, P=0.113). Both the NDVIs and EVIs at elevation 4500 m and 4700 m were not correlated with soil temperature (4 500 m NDVI:r=-0.27, P=0.165;4 500 m EVI:r=-0.12, P=0.529;4 700 m NDVI:r=0.23, P=0.250;4 700 m EVI:r=0.28, P=0.156) and air temperature (4 500 m NDVI:r=-0.21, P=0.276;4 500 m EVI:r=-0.06, P=0.748;4 700 m NDVI:r= -0.03, P=0.876;4 700 m EVI:r=-0.08, P=0.688).The NDVIs (4 300 m:r=0.79, P=0.000;4 500 m:r=0.80, P=0.000;4 700 m:r=0.52, P=0.005)and the EVIs (4 300 m:r=0.61, P=0.001;4 500 m:r=0.66, P=0.000;4 700 m:r=0.53, P=0.004) at all the three elevations increased significantly with the increasing soil moisture, but the NDVIs (4 300 m:r=-0.68, P=0.000;4 500 m:r=-0.56, P=0.002;4 700 m:r=-0.40, P=0.037) and the EVIs (4 300 m:r=-0.56, P=0.002;4 500 m:r=-0.49, P=0.008;4 700 m:r=-0.46, P=0.014)at all the three elevations decreased significantly with the increasing vapor pressure deficit. The EVIs at all the three elevations increased significantly with increasing air relative humidity (4 300 m:r=0.48, P=0.010;4 500 m:r=0.50, P=0.006;4 700 m:r=0.39, P=0.039). The NDVIs at elevation 4 300 m (r=0.63, P=0.000) and 4500 m (r=0.57, P=0.001)increased significantly with increasing air relative humidity, but the NDVI at elevation 4700 m was not correlated with air relative humidity (r=0.35, P=0.070). The correlations between the NDVIs or EVIs and environmental temperature or moisture varied with elevation. The correlations between the NDVIs and environmental temperature and moisture were different from those between the EVIs and environmental temperature and moisture. The multiple stepwise regression analyses showed that the soil moisture alone explained the variation of the NDVIs at all three elevations and also explained the variation of the EVIs at 4300 m and at 4500 m, but at 4700 m the soil moisture and the soil temperature together explained the variation of the NDVI with relative greater contribution of soil moisture than soil temperature. Therefore, in the alpine meadow of the Northern Tibet, (1) the sensitivity of vegetation indices to climatic changes may change with elevation; (2) the sensitivity of NDVI to climatic change might differ from that of EVI; and (3) Soil moisture may play a predominant role in determining the seasonal variation of the NDVIs and the EVIs in the alpine meadow in the Northern Tibet.关键词
高寒草甸/归一化植被指数/增强型植被指数/藏北高原/气候变化Key words
alpine meadow/normalized difference vegetation index/enhanced vegetation index/the Northern Tibet/climatic change分类
农业科技引用本文复制引用
沈振西,孙维,李少伟,何永涛,付刚,张宪洲,王江伟..藏北高原不同海拔高度高寒草甸植被指数与环境温湿度的关系[J].生态环境学报,2015,(10):1591-1598,8.基金项目
国家自然科学基金项目（41171084；31470506；31370458）；中国科学院西部之光项目“藏北高寒草甸牲畜承载力对气候变化和放牧的响应”；国家星火计划项目“优质饲草种植与奶牛健康养殖技术集成与示范”；西藏饲草专项；科技支撑计划（2013BAC04B01）“西藏高原典型退化生态系统修复技术研究与示范” （）
