Heatwaves Significantly Slow the Vegetation Growth Rate on the Tibetan Plateau

Abstract

In recent years, heatwaves have been reported frequently by literature and the media on the Tibetan Plateau. However, it is unclear how alpine vegetation responds to the heatwaves on the Tibetan Plateau. This study aimed to identify the heatwaves using long-term meteorological data and examine the impact of heatwaves on vegetation growth rate with remote sensing data. The results indicated that heatwaves frequently occur in June, July, and August on the Tibetan Plateau. The average frequency of heatwaves had no statistically significant trends from 2000 to 2020 for the entire Tibetan Plateau. On a monthly scale, the average frequency of heatwaves increased significantly (p < 0.1) in August, while no significant trends were in June and July. The intensity of heatwaves indicated a negative correlation with the vegetation growth rate anomaly (ΔVGR) calculated from the normalized difference vegetation index (NDVI) (r = −0.74, p < 0.05) and the enhanced vegetation index (EVI) (r = −0.61, p < 0.1) on the Tibetan Plateau, respectively. Both NDVI and EVI consistently demonstrate that the heatwaves slow the vegetation growth rate. This study outlines the importance of heatwaves to vegetation growth to enrich our understanding of alpine vegetation response to increasing extreme weather events under the background of climate change.

Impacts of Extreme-High-Temperature Events on Vegetation in North China

“…According to Wei [77], high-temperature extremes have adverse effects on vegetation growth in some arid areas of Central Asia and the Mongolian Plateau, which are mostly covered by sparse vegetation and grasses. Similarly, heatwaves significantly reduce the rate of vegetation growth on the Tibetan Plateau [78]. However, the correlations between the NDVI and extreme-high-temperature events in some regions, such as Guangdong Province [70], the Yangtze River Basin [49] and Southwest China [71], differ from this negative correlation.…”

“…We note that this study is subject to some limitations and uncertainties. Firstly, although it has been proved that the GIMMS NDVI data can accurately capture extreme vegetation states [49,78] and are reliable for investigating the impacts of extreme climate events on vegetation, there are still some limitations and uncertainties that need to be acknowledged [88]. As the GIMMS NDVI data are indirect remote sensing data, errors may arise in the modeled NDVI due to the fragmented terrain and saturation issues.…”

Identifying and Predicting the Responses of Multi-Altitude Vegetation to Climate Change in the Alpine Zone

“…Concurrently, there have been discernible shifts in the biological population characteristics of the vegetation, demonstrating increasingly distinct regional patterns [29]. Gao [30] analyzed the future vegetation distribution and net primary productivity (NPP) of the Tibetan Plateau using the cmip6 dataset and explored the possible changes in vegetation types; Deng [31] combined terrestrial water storage anomalies data and vegetation indices to analyze their interactions; Jiao [32] analyzed the spatial response pattern of NDVI data and seasonal variation characteristics based on station meteorological data; and Dong [33] studied the response of alpine vegetation on the Tibetan Plateau to heat waves and the change pattern of heat waves over the past 20 years. It can be seen that these current studies mainly focused on the response of vegetation to environmental factors, but the quantitative study of the factors and the analysis of different elevation zones are still lacking.…”