Long-term effects of haying and prescribed fire on the composition and diversity of wet prairie plant communities
Disturbance‑dependent ecosystems like wet prairies require management that mimics historical regimes, yet long‑term comparisons of fire and haying are rare. In a 23‑year experiment in northwestern Minnesota, researchers tested annual haying, spring burns every four years, fall burns every four years and no‑management controls. Spring burns maintained the highest species richness, while fall burns produced intermediate richness similar to controls. Annual haying initially matched other treatments but after a decade caused a rapid 30% decline in richness and accelerated shifts in community composition. Many species responded only after long delays, underscoring the need for extended monitoring. Results show haying and fire are not interchangeable: continuous haying degrades diversity, whereas periodic spring fire best sustains wet‑prairie plant communities.
Subject Tags
- Biodiversity
- Fire management
Abstract
Plant species composition and diversity in many terrestrial ecosystems depend on frequent disturbances. Management of these historically disturbance-dependent habitats often requires replicating past disturbance regimes or implementing management approaches that mimic their ecological effects. For example, efforts to manage North American tallgrass prairie frequently utilize prescribed fire to maintain these historically fire-dependent grasslands. However, alternatives to prescribed fire, such as haying, have attracted the interest of conservation practitioners and landowners. The paucity of long-term experiments, especially in wet prairies and sedge meadows, limits our understanding of how these different management techniques influence the composition and diversity of such perennial-dominated plant communities. We conducted a 23-year experiment within a remnant wet prairie complex in northwestern Minnesota, USA, to evaluate the effects of haying and prescribed burning on plant species richness and community composition. Experimental treatments—no active management (control), annual late-summer haying, spring burns at 4-year intervals, and fall burns at 4-year intervals—were applied continuously between 1999 and 2021. Spring burning at 4-year intervals tended to maintain the highest species richness while fall burning at 4-year intervals supported intermediate levels of species richness similar to control plots. For the first 10 years of the experiment, species richness in the annually hayed plots was comparable to the burned and control plots. Thereafter, richness declined rapidly in the hayed plots, leading to a 30% drop in species richness between 2010 and 2021. Annual haying also altered plant composition at a rate that far outpaced compositional changes in other treatments. Temporal shifts in plant community composition reflected idiosyncratic species' responses to experimental treatments. Many of these species-specific responses to treatments were delayed, becoming apparent more than a decade after treatments were initiated. Annual haying and prescribed fire have distinctive long-term ecological effects on wet prairie plant communities and should not be considered interchangeable management options. Continuous annual haying erodes plant diversity in wet prairies and shifts plant composition while periodic spring fires tend to maximize local plant richness. This study exemplifies the importance of conducting long-term experiments to better inform management of disturbance-dependent habitats.
Citation
Beck, J. J., Kiefer, G., Johnson, R., Winter, B., Dana, R., & Wagenius, S. (2025). Long‐term effects of haying and prescribed fire on the composition and diversity of wet prairie plant communities. Ecological Applications, 35(5), e70080. https://doi.org/10.1002/eap.70080
TNC Authors
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Brian Winter
The Nature Conservancy