Evolution characteristics of ecosystem functional stability and ecosystem functional zoning on the Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau (QTP), also known as the Third Pole of the Earth, is a vital ecological security barrier for China. It is a tremendously sensitive region affected by the impacts of global climate change. The escalating intensity of climate change has presented profound challenges to its ecosystem functions and stability. This study first analyzes the spatiotemporal variations of the QTP ecosystem patterns and the key functions of the Plateau including water conservation, soil conservation, and windbreak and sand fixation from 2000 to 2020. It clarifies the regional differences in ecosystem functions and their importance, further evaluates the stability of ecosystem functions, and lays a scientific foundation for an ecological civilization on the Plateau by implementing conservation and restoration projects. The main results show that: (1) From 2000 to 2020, the wetland area in the QTP increased, while the grassland area significantly decreased. There were improvements in water conservation and windbreak and sand fixation capacities, with annual rates of change being 3.57 m3 center dot ha-1 center dot a-1 and 0.23 t center dot ha-1a-1, respectively. However, the overall soil conservation trend declined during the same period, with an annual change rate of -0.16 t center dot ha-1a-1. (2) The core areas of water conservation, soil conservation, and windbreak and sand fixation on the QTP accounted for 12.7%, 13.9%, and 14.2% of the total area, respectively. The core water conservation areas are mainly the southeastern QTP, Sanjiangyuan, and Naqu, while the core windbreak and sand fixation areas were concentrated in the central and western parts of the Plateau. The core soil conservation areas surrounded the entire interior of the Plateau. (3) From 2000 to 2020, the water conservation, soil conservation, and windbreak sand-fixation function on the QTP had higher stability in the southeastern and central parts, while stability was lower in the western region. Considering the stability assessment and ecological protection and restoration practices, the QTP can be divided into three major categories and 16 ecological functional zones. Differentiated ecological protection and restoration efforts can be implemented based on the different core ecosystem functions and zoning.