Response of normalized difference vegetation index in main vegetation types to climate change and their variations in different time scales along a North-South Transect of Eastern China

Abstract

Aims Climate change characterized by global warming has posed a great threat to terrestrial ecosystems and sustainable development of human society.Our objective was to examine the response of major vegetation types to climate change.Methods We used the biweekly dataset of the National Oceanographic and Atmospheric Administration/Advanced Very High Resolution Radiometer (NOAA/AVHRR) normalized difference vegetation index (NDVI) and climatic data from 752 standard stations in China for 1982-2006 to study the responses of 12 major vegetation types to changes in air temperature and precipitation.Important findings The NDVI trend was controlled by air temperature and precipitation at the transect scale,while the NDVI trend showed large spatial heterogeneity,possibly associated with changes in regional climate,land use and vegetation type.At the biome scale,annual NDVI of temperate deciduous shrubland (TDS) was significantly correlated with air temperature and that of temperate grass steppe (TGS) and subtropical and tropical coniferous forest (STCF) was significantly correlated with both air temperature and precipitation.No significant relationships were detected between NDVI and climatic factors in other types of vegetation.NDVI was most significantly correlated to the air temperature of the preceding four months.In addition,the time lag of NDVI responses to air temperature gradually decreased from January to April.Negative correlations were found between NDVI and air temperature from May to August in temperate coniferous forest (TCF),temperate deciduous broad-leaved forest (TDBF),TDS,STCF and subtropical and tropical grassland (STG).Results indicated a positive relationship between NDVI and precipitation of the same month in shrub and grassland types and a negative relationship between NDVI and precipitation of the same month in forest.