Spatiotemporal Variations in the Sensitivity of Vegetation Growth to Typical Climate Factors on the Qinghai–Tibet Plateau

Abstract

Gaining knowledge about vegetation sensitivity in response to climate change is a current research priority in the context of accelerated shifts generated by global warming, especially for the Qinghai–Tibet Plateau (QTP), where vegetation is known to be highly sensitive to ongoing climate change. However, the temporal variability of vegetation sensitivity in response to climate change is still poorly understood on the QTP. Here, we articulate the interannual variability of the vegetation sensitivity in response to typical climate factors, including temperature, solar radiation, and water availability, on the QTP during 2000–2021, using a variety of indicators characterizing vegetation dynamics, including the Leaf Area Index (LAI), the Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI), and solar-induced chlorophyll fluorescence (SIF) data. The results indicate that temperature exerted positive impacts on forests, grasslands, and barren or sparsely vegetated areas (BSVs). However, all the land-cover types showed decreasing sensitivity to temperature variability. Solar radiation had a positive impact on forests, while it had a negative impact on grasslands and BSVs. An increasing trend was observed for forests, while a decreasing trend was found for grasslands and BSVs regarding their sensitivity to solar radiation. Water availability exerted a positive impact on grasslands and BSVs, and no obvious impact direction could be determined for forests. Over the last two decades, forests and BSVs exhibited increasing sensitivity to water availability, and no obvious trend was observed for grasslands. Overall, temperature was the most important climate factor, followed by solar radiation and water availability, regarding the regulation of vegetation sensitivity on the QTP. Spatially, temperature and solar radiation jointly dominated the vegetation sensitivity in the central to eastern QTP. Conversely, water availability dominated the sensitivity of forests in the southeastern QTP and grasslands in the northeastern and southwestern QTP. This study provides theoretical support for the ecological conservation and management of the QTP in the context of ongoing climate change.

Sensitivity of Grassland Coverage to Climate across Environmental Gradients on the Qinghai-Tibet Plateau

“…The temperature sensitivity of alpine grasslands has a positive sensitivity in the central and eastern parts of the plateau and a negative sensitivity in the southwest, which is also consistent with previous studies [37]. While the sensitivity of alpine vegetation to solar radiation spatially indicates a positive sensitivity of vegetation in the eastern and southern parts of the plateau and a negative sensitivity response in the predominantly central part of the plateau, this is also consistent with previous studies in this area [38]. Of all the factors affecting vegetation, apart from thermal factors, moisture conditions are also the most immediate and critical [39].…”

Assessment of the Spatiotemporal Impact of Water Conservation on the Qinghai–Tibet Plateau

“…Moreover, actual evapotranspiration plays a key role in the water cycle and is linked to a variety of surface processes [72]. In addition, the vegetation on the Qinghai-Tibet Plateau is very sensitive to climate change [73], and NDVI can reflect the surface vegetation cover status [74,75]. Therefore, in this study, precipitation and actual evapotranspiration were selected as factors for climatic factors, and NDVI was selected as a factor for vegetation factors.…”

Estimation of Daily Mean Land Surface Temperature over the Qinghai–Tibet Plateau Based on an RTM-DTC Model

“…The Qinghai-Tibet Plateau acts as a heat source in summer and a cold source in winter, directly acting on the middle part of troposphere and affecting the energy exchange between the plateau's land-atmosphere system [26,27]. The Qinghai-Tibet Plateau is regarded as "the driver and amplifier of global climate change" [28][29][30], "the most natural laboratory for the unified research of global change and earth system science" [31]. It has an important impact on the climate of China, and even around the world, and the study on the plateau climate change has always attracted the attention of scientists [32,33].…”