A functional trait perspective on restored temperate grassland responses to changing winter insulation and managed disturbance by fire

PREMISE: Understanding how disturbance regimes influence temperate grasslands is crucial for adapting management strategies to climate change, particularly in response to the loss of winters. The interaction between disturbance and climate can alter winter soil insulation and potentially the plant community. Examining the role of functional traits in determining community outcomes can help inform whether grasslands will remain resilient to climate change or whether management will need to be adapted proactively. METHODS: We analyzed 7 years of data from a restored temperate grassland experiment to assess how the interaction between management type and timing (i.e., unmanaged control, spring burn, fall burn, and fall mow) and winter snow manipulations (i.e., snow reduction, snow control, and snow addition) affects plant community composition and whether functional traits are related to community turnover. RESULTS: Changes in the plant community were driven mainly by management type and timing, with minimal influence from winter snow manipulations. While greater stress tolerance was associated with colonization when winter soil insulation was low, overall functional traits had a relatively minor relationship with community turnover. CONCLUSIONS: The minimal effects of winter snow manipulations, combined with the community's shift toward stress-tolerant strategies when winter soil insulation was low, suggest that grasslands may be resilient to winter snow loss in the short term. However, limited colonization by species that are not stress tolerant could drive local extinctions over time. Management strategies that support colonization and retain soil insulation, such as spring burns that maintain disturbance while preserving insulating litter, may help prevent longer-term impacts.