Grassland management actions influence soil conditions and plant community responses to winter climate change

Restoring ecosystems in a changing climate requires understanding how management interventions interact with climate conditions. In tallgrass prairies, disturbance through fire, mowing, or grazing is a critical force in maintaining herbaceous plant diversity. However, unlike historical fire regimes that occurred throughout the growing season, management actions like prescribed fire and mowing are commonly limited to the spring or fall seasons. Warming winters are resulting in less snow, causing overwintering plants to experience reduced insulation from snow and these more extreme winter conditions may be exacerbated or ameliorated depending on the timing of management actions. Understanding this novel interaction between the timing of management actions and snow depth is critical for managing and restoring grassland ecosystems. Here, we applied experimental management treatments (spring and fall burn and fall mow) in combination with snow depth manipulations to test whether the type and timing of commonly implemented disturbances interact with snow depth to affect restored prairie plant diversity and composition. Overall, snow manipulations and management actions influenced soil temperature while only management actions influenced spring thaw timing. Burning in the fall, which removes litter prior to winter resulted in colder soils and earlier spring thaw timing. However, plant communities were mostly resistant to these effects. Instead, plants responded to management actions such that burning and mowing, regardless of timing, increased plant diversity and spring burning increased flowering structure cover while reducing weedy cool season grass cover. Together these results suggest that grassland plant communities are resistant to winter climate change over the short term and that burning or mowing is critical to promoting plant diversity in tallgrass prairies.