Legacies of Precipitation Extremes: Divergent Responses Across Steppe Types

Steppes are essential ecosystems that provide vital services, such as carbon sequestration, biodiversity support, and grazing resources. However, these ecosystems are highly susceptible to the effects of climate change, particularly extreme precipitation events, including droughts and heavy rainfall. This study integrates data from an 11-year desert steppe experiment with multi-decadal observations from China's meadow, typical, and desert steppes to investigate the legacy effects of extreme precipitation on steppe productivity. The results demonstrate that aboveground net primary productivity (ANPP) responds differently to precipitation extremes across steppe types. In the meadow steppe, ANPP follows a linear relationship with precipitation, whereas in typical and desert steppes, the relationship becomes saturating. Ecosystem resilience varies substantially across the steppes: desert steppe exhibits rapid recovery after drought, meadow steppe shows persistent suppression of productivity, and typical steppe experiences community restructuring. Both drought and excessive rainfall disrupt plant phenology and competition, resulting in long-term changes to ecosystem productivity. Structural equation modeling reveals that ANPP serves as the primary driver of legacy effects, with plant functional group (PFG) shifts influenced by climatic variables. Specifically, grass ratios exacerbate the legacy effects, while higher plant diversity indices appear to mitigate them. This study emphasizes the importance of understanding vegetation-type-specific responses to extreme precipitation in accurately predicting the ecological consequences of climate change. Our findings suggest that Earth System Models must incorporate vegetation-type-specific parameterizations to improve projections of long-term productivity outcomes under future climate scenarios. Overall, this research provides important insights into the resilience of steppe ecosystems and highlights the need for enhanced management strategies to mitigate the impacts of extreme precipitation events in the context of global climate change.