A New Grazing–Vegetation Tradeoff and Coordination Indicator: The Grazing Intensity and Vegetation Cover Harmonization Index (GVCI)

Overgrazing typically leads to grassland vegetation degradation and reduction, which in turn triggers a series of ecological problems. Therefore, it is crucial to understand the effects of different Grazing Intensities (GIs) on the Vegetation Ecosystem (VE) to achieve sustainable grazing development. This study proposes a new quantitative index, the Grazing Intensity and Vegetation Cover Harmonization Index (GVCI), based on multiple indicators such as fractional vegetation cover (FVC), net primary productivity (NPP), and GI. The GVCI was used to quantify the “Harmonization and Conflict” status between GI and the VE in 39 Prefecture-Level Cities (PLCs) of the Qinghai-Tibet Plateau (QTP) and to evaluate the sustainable development level of grazing in different regions. In addition, the Random Forest (RF) model was used to simulate the GVCI development trend of various PLCs from 2015 to 2040. The results showed the following: (1) The GVCI can effectively quantify the response relationship between GI and the VE. The overall GVCI of the QTP was in the “Harmonization” state, with the proportion of areas in the “Harmonization” state fluctuating upwards. (2) The level of economic development intuitively affects the harmonization between grazing and the VE. Gross Domestic Product (GDP) is one of the important indicators of economic development level. PLCs with higher GDP levels exhibited a strong positive correlation between the GVCI and regional GDP. (3) The simulation results indicate that an increasing number of PLCs on the QTP will shift toward a “Harmonization” state. However, some PLCs in the western regions were still in an “Overload” state, and there is a need for close monitoring of their grazing activities and VE dynamics. The GVCI proposed in this study provides a novel methodology for quantifying the complex relationship between GI and the VE. It offers important scientific support for the sustainable development of grazing in ecologically fragile areas such as the QTP. The research results can be a robust scientific basis for the government to formulate reasonable grazing plans.