Wildfires provide important benefits to ecosystems, nourishing soils, clearing brush and making room for new plants, and sometimes killing off damaging pests or disease. But as climate change progresses, large grassland wildfires are becoming more frequent, raising concerns about their long-term effects on vegetation.
In new research, however, Donovan et al. suggest that at large spatial scales, vegetation in the U.S. Great Plains is largely resilient to major wildfires. Building on previous field studies, the researchers analyzed 18 years’ worth of recently released high-resolution, satellite-derived data on plant cover across the Great Plains. They combined this information with data on drought severity and the locations and sizes of 1,390 Great Plains wildfires that occurred during 1984–2017.
At the biome level, the analysis showed rapid recovery to prefire conditions across varying Great Plains ecosystems for all forms of vegetation studied: shrubs, trees, annual forbs and grasses, and perennial forbs and grasses. The only exception was a persistent postwildfire decline in tree cover in the northwestern Great Plains.
Severe drought intensified the short-term responses of vegetation to wildfire, but subsequent recovery still occurred. On smaller scales, some areas did experience persistent postfire changes in plant cover, but these appeared to be extreme local cases within larger wildfires.
The new findings add to a growing body of research that suggests that certain postfire management techniques used to help rehabilitate grassland ecosystems, such as reseeding, may not actually be needed. Still, the authors noted, as wildfire and drought patterns change with global warming, continued research and advancements in techniques for monitoring vegetation and wildfires will be needed. (Earth’s Future, https://doi.org/10.1029/2020EF001487, 2020)
—Sarah Stanley, Science Writer