Global shifts in vegetation compositional resilience over the past 8,000 years

Vegetation resilience is critical for sustaining biodiversity and ecosystem services, yet its long-term dynamics and underlying drivers remain poorly resolved. Here, we assess changes in continental-scale vegetation compositional resilience over the past 8,000 years by applying established leading indicators (including autocorrelation, standard deviation, skewness, and kurtosis) to 482 fossil pollen records from all major landmasses except Antarctica. Using a machine learning approach, we evaluate the relative contributions of anthropogenic land cover change (ALCC) and climatic parameters (annual mean temperature, temperature seasonality, annual precipitation, and precipitation seasonality) in driving resilience shifts across continents. We further employ structural equation modeling (SEM) to disentangle how abiotic factors (ALCC and climatic variables) and biotic factors (species richness, evenness, synchrony, and temporal {beta} diversity) jointly shape long-term trends in vegetation resilience at the continental scale. Our results reveal a persistent, millennia-scale decline in resilience during the past 1.6 to 4.4 thousand years before present, with intensified anthropogenic land-use change identified as the dominant global driver. This finding suggests that the global decline in vegetation resilience observed over recent decades likely represents a continuation of the long-term trend established during the preceding Holocene. Notably, North America exhibited a resurgence in resilience over the past 1,200 years, primarily attributed to enhanced resilience in tundra and savanna ecosystems. SEM analyses uncover complex pathways through which abiotic and biotic predictors interact to shape millennial-scale resilience changes across continents. Despite the complexity of these underlying mechanisms, the analyses demonstrate that biotic factors collectively exert substantial, and often predominant, influences on long-term resilience dynamics. This underscores the indispensable role of biotic attributes in modulating long-term vegetation resilience, highlighting their potential as critical targets for ecosystem conservation and restoration.