%0 Journal Article %A Ming NI %A Xi-Yue ZHANG %A Chao JIANG %A He-Song WANG %T Responses of vegetation to extreme climate events in southwestern China %D 2021 %R 10.17521/cjpe.2021.0042 %J Chinese Journal of Plant Ecology %P 626-640 %V 45 %N 6 %X

Aims The occurrence of extreme climate events is becoming more frequent worldwide because of the global warming. This study investigated the responses of vegetation to climate extremes in southwestern China, in order to assess the regional eco-security of natural ecosystems related to global climate change.

Methods The normalized difference vegetation index (NDVI) data from the GIMMS V1.0 datasets with a resolution of 0.083° × 0.083° for the period of January 1982 to December 2015 were used in this study for analysis of the spatiotemporal dynamics of vegetation in the study region. The grid data of regional meteorological variables from the CN05.1 for the period of January 1961 to December 2016 were used to develop the overall climate extreme variables, and the values matching the data period of NDVI were eventually adopted in the analysis on the interrelationships between NDVI and the climate extremes using Pettitt test and trend analysis both before and after detrending.

Important findings Results show that in the study region, NDVI generally increased from 1982 to 2015, with occurrence of an abrupt change in 1994. Prior to 1994, the change in NDVI was not significant, but the increase became significant from this point onward. Before data detrending, only the maximum 1-day precipitation was significantly and positively correlated with NDVI in the precipitation-extremes during 1982-2015. The temperature- extreme variables were all significantly correlated with NDVI except the diel air temperature range. From 1994 to 2015, the maximum 1-day precipitation was significantly and positively correlated with NDVI and the number of wet days was significantly and negatively correlated with NDVI. none of the precipitation-extreme variables was significantly correlated with NDVI. The yearly maximum value of daily minimum air temperature, warm days, summer days, length of growing season and diel air temperature range were all significantly and positively correlated with NDVI, but the cool days, frost days, cool nights and icing days were significantly and negatively correlated with NDVI. During 1982-2015, the NDVI was more strongly correlated with annual mean air temperature than with any of the temperature-extreme variables; whereas during 1994-2015, NDVI was more strongly correlated with summer days and diel air temperature range than with annual mean air temperature. After eliminating the trend, there was no significant correlation between the precipitation-extreme variables and NDVI, but the yearly maximum value of daily maximum air temperature, warm days, summer days and diel temperature range were significantly and positively correlated with NDVI for the entire period of 1982-2015 as well as for the period 1994-2015. The response of NDVI to extreme warm events was more pronounced during 1994-2015 than during 1982-2015, with the strongest correlation between diel air temperature range and NDVI. There was a significant and negative correlation between cool days and NDVI for the period 1982-2015.

%U https://www.plant-ecology.com/EN/10.17521/cjpe.2021.0042