Spatiotemporal variation of ecological environment quality and extreme climate drivers on the Qinghai-Tibetan Plateau

Protecting the ecological security of the Qinghai-Tibet Plateau (QTP) is of great importance for global ecology and climate. Over the past few decades, climate extremes have posed a significant challenge to the ecological environment of the QTP. However, there are few studies that explored the effects of climate extremes on ecological environment quality of the QTP, and few researchers have made quantitative analysis. Hereby, this paper proposed the Ecological Environmental Quality Index (EEQI) for analyzing the spatial and temporal variation of ecological environment quality on the QTP from 2000 to 2020, and explored the effects of climate extremes on EEQI based on Geographically and Temporally Weighted Regression (GTWR) model. The results showed that the ecological environment quality in QTP was poor in the west, but good in the east. Between 2000 and 2020, the area of EEQI variation was large (34.61% of the total area), but the intensity of EEQI variation was relatively low and occurred mainly by a slightly increasing level (EEQI change range of 0.05-0.1). The overall ecological environment quality of the QTP exhibited spatial and temporal fluctuations, which may be attributed to climate extremes. Significant spatial heterogeneity was observed in the effects of the climate extremes on ecological environment quality. Specifically, the effects of daily temperature range (DTR), number of frost days (FD0), maximum 5-day precipitation (RX5day), and moderate precipitation days (R10) on ecological environment quality were positive in most regions. Furthermore, there were significant temporal differences in the effects of consecutive dry days (CDD), consecutive wet days (CWD), R10, and FD0 on ecological environment quality. These differences may be attributed to variances in ecological environment quality, climate extremes, and vegetation types across different regions. In conclusion, the impact of climate extremes on ecological environment quality exhibits complex patterns. These findings will assist managers in identifying changes in the ecological environment quality of the QTP and addressing the effects of climate extremes.