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首页> 中文期刊> 《生态环境学报》 >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

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

         
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摘要

藏北高寒草甸是全球高寒草地的重要组成部分，是对气候变化最敏感的植被类型之一。关于高寒草地植被指数与环境温湿度因子的关系还存在着诸多不确定性，这限制了准确预测高寒草地植被生长对将来气候变化的响应。定量化高寒草地植被指数与气候因子的关系利于预测将来气候变化对高寒草地植被生长的影响。该研究基于相关分析和多重逐步回归分析探讨了藏北高原不同海拔高度（4300、4500和4700 m）的高寒草甸2011─2014年每年6─9月的归一化植被指数（normalized difference vegetation index，NDVI）、增强型植被指数（Enhanced Vegetation Index，EVI）与土壤温度、土壤湿度、空气温度、相对湿度、饱和水汽压差的相互关系。相关分析表明，3种海拔的NDVI（4300 m：r=0.79，P=0.000；4500 m：r=0.80，P=0.000；4700 m：r=0.52，P=0.005）和EVI（4300 m：r=0.61，P=0.001；4500 m：r=0.66，P=0.000；4700 m：r=0.53，P=0.004）都随着土壤湿度的增加显著增加；3种海拔的NDVI（4300 m：r=-0.68，P=0.000；4500 m：r=-0.56，P=0.002；4700 m：r=-0.40，P=0.037）和EVI（4300 m：r=-0.56，P=0.002；4500 m：r=-0.49，P=0.008；4700 m：r=-0.46，P=0.014）都随着饱和水汽压差的增加显著降低；植被指数与环境温湿度因子的相关系数随着海拔的变化而变化；NDVI和EVI与环境温湿度因子的相关系数存在差异。多重逐步回归分析表明，土壤湿度一个因子解释了3种海拔的归一化植被指数、海拔4300和4500 m的增强型植被指数的变异，而海拔4700 m的土壤湿度和土壤温度共同了解释了增强型植被指数的变异，其中土壤湿度的贡献较大。因此，在藏北高寒草甸，植被指数对气候变化的敏感性可能随着海拔的变化而变化，NDVI和EVI对气候变化的敏感性可能不同，土壤湿度主导着NDVI和EVI的季节变化。%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.

著录项

  • 来源
    《生态环境学报》 |2015年第10期|1591-1598|共8页
  • 作者

    沈振西; 孙维; 李少伟; 何永涛; 付刚; 张宪洲; 王江伟;

  • 作者单位

    中国科学院地理科学与资源研究所 生态系统网络观测与模拟重点实验室 拉萨高原生态系统研究站;

    北京100101;

    中国科学院地理科学与资源研究所 生态系统网络观测与模拟重点实验室 拉萨高原生态系统研究站;

    北京100101;

    中国科学院地理科学与资源研究所 生态系统网络观测与模拟重点实验室 拉萨高原生态系统研究站;

    北京100101;

    中国科学院地理科学与资源研究所 生态系统网络观测与模拟重点实验室 拉萨高原生态系统研究站;

    北京100101;

    中国科学院地理科学与资源研究所 生态系统网络观测与模拟重点实验室 拉萨高原生态系统研究站;

    北京100101;

    中国科学院地理科学与资源研究所 生态系统网络观测与模拟重点实验室 拉萨高原生态系统研究站;

    北京100101;

    中国科学院地理科学与资源研究所 生态系统网络观测与模拟重点实验室 拉萨高原生态系统研究站;

    北京100101;

  • 原文格式 PDF
  • 正文语种 chi
  • 中图分类 植物生态学和植物地理学;生态系统与生态环境;
  • 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;

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