Responses of vegetation growth to climate change over the Tibetan Plateau from 1982 to 2018

Abstract

The Tibetan Plateau (TP) plays a critical role in Earth’s climate system and is highly sensitive to global warming. However, comprehensive analysis of the interaction between various climatic factors and vegetation growth across the TP is still limited. Using daily NDVI series interpolated from the 16-day satellite measurements and climatic data during 1982-2018, we investigated the spatiotemporal changes in growing season NDVI (NDVIGS) and associated climatic drivers over the TP and analyzed the responses of NDVIGS to climatic drivers for different vegetation types. Our results show that NDVIGS of the TP as a whole exhibits a significant rising trend (0.0011 year-1; P<0.01) from 1982 to 2018. However, trends in NDVIGS show apparent spatial heterogeneity over the TP with higher growth rates in forests (trend=0.012 de-1; P<0.01) and shrubs (trend=0.009 de-1; P<0.01) in the east and southeast than in alpine steppe (trend=0.003 de-1; P<0.01) and alpine meadow (trend=0.006 de-1; P<0.01) in the west and north. Air temperature, precipitation, and VPD serve as the dominant climatic factor affecting the NDVIGS trends in 62%, 19%, and 12% of the TP, respectively. Additionally, climatic factors show differential impacts on NDVIGS among different vegetation types. Air temperature has a predominantly positive correlation with NDVIGS for all vegetation types, while precipitation has a negative impact on plant growth in the eastern humid forest region but a generally postive impact in the other areas. Our results also highlight that the effect of VPD on NDVIGS varies among different vegetation types. These findings contribute to a systematic understanding of the possible mechanisms underlying the response of vegetation growth to various climatic drivers across the TP.

Quantitative Analysis of Desertification-Driving Mechanisms in the Shiyang River Basin: Examining Interactive Effects of Key Factors through the Geographic Detector Model

“…These findings align with the negative trends in the aridity index affecting natural vegetation in the upper reaches of the Shiyang River Basin, as illustrated in Figure 8. Similar patterns have been observed in previous studies that explore ecosystem vulnerability to climate change in the Tibet plateau [113][114][115]. Furthermore, the research highlights the impact of temperature and evaporation gradients, coupled with a decrease in rainfall, on the gradual decline in vegetation cover from upstream to the lower reaches.…”

The Minimum Temperature Outweighed the Maximum Temperature in Determining Plant Growth over the Tibetan Plateau from 1982 to 2017

“…Other factors, such as changes in cloud cover, solar radiation, and vegetation growth activity, may also contribute to this decrease in diurnal temperature range, and these factors also warrant further investigation in the future. Moreover, in addition to temperature, precipitation, wind speed, humidity, and snowmelt also have an impact on vegetation dynamics [21,68], although the mechanisms underlying the joint influence of air temperature and these other factors on vegetation growth are not yet fully understood. Given the spatial heterogeneity of climatic conditions, it is crucial to conduct comprehensive attribution analyses that link spatiotemporal changes in vegetation growth on the TP with multiple climatic variables.…”

“…The latest study has indicated that the annual marsh net primary productivity (NPP) on the TP significantly increased with the rising minimum temperatures during winter and spring [20]. However, there is limited research that compares the impact of diurnal and nocturnal warming on vegetation growth across the TP [21]. Considering the asymmetric rise in daytime and nighttime temperatures worldwide, it is imperative to investigate how changes in these temperatures can impact plant growth on the TP, especially on different types of frozen soils.…”