Exploring the resilience of global vegetation ecosystem: Nonlinearity, driving forces, and management

Vegetation resilience, characterized by the ability of vegetation to maintain stable states, is considered fundamental to ecosystems' structural and functional stability. Under the background of vegetation ecosystems being increasingly endangered by numerous disturbances, determining the nonlinear changing trend of the recovery rate of vegetation to external disturbances and its response to various forces is paramount. Herein, we quantified the global vegetation resilience and its regime shifts by measuring the lag-1 autocorrelation to the interannual kernel Normalized Difference Vegetation Index (kNDVI) from 1982 to 2020, clarified the contribution rates of driving forces on vegetation resilience variation by partial correlation analysis. Results revealed that global vegetation resilience experienced abrupt change and reversed to a decreased trend after the turning point of 2004, with a rate of -3.17 × 10^-4 (p < 0.05), especially in Australia, Africa, and southern South America, revealing the vegetation degradation masked by linear analysis. Spatially, nearly a quarter of the global land faced persistent reduction in vegetation resilience, mainly concentrated in tropical, temperate, and arid zones. CO₂ concentration dominated the vegetation resilience variation in the past three decades and showed an increased effect over time, covering an area proportion from 37.0% to 42.5%. However, there were obvious differences in the driving forces of resilience variation among different vegetation types. Among them, rising CO₂ concentration and temperature caused the resilience decreasing of needleleaf forests; the increase of precipitation and CO₂ concentration enhanced the resilience of tropical forests; soil moisture was the primary force limiting the resilience enhancement of shrubs; a moderate rise in vapor pressure deficit could enhance vegetation resilience, particularly for deciduous needleleaf forest and closed shrubland; surface solar radiation played an important role in resilience enhancement of forests, and showed notable scale variations. Further, the compounding effects between different forces were identified, and targeted measures must be implemented to mitigate the disturbance of climate change to vegetation ecosystems.