Making a good prairie better: Plant diversity increased in a formerly-hayed remnant prairie now managed with fire

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Charlotte M. Reemts, The Nature Conservancy, Austin, TX and Brandon Belcher, The Nature Conservancy, Celeste, TX

Background/Question/Methods: Protection and management of tallgrass prairie remnants are critical to the continued existence of this highly converted ecosystem. While effects of individual management events (especially fire and grazing) are understood relatively well, their combined and cumulative effects are more difficult to predict. We examined how a large (283 ha) tallgrass prairie remnant in Texas responded to a varied management regime over 24 years (1996 through 2020). Previously, the site had been hayed annually for ~100 years. Starting in 1987, management changed to prescribed fire in multiple seasons (average fire return interval of 3.5 years) and occasional grazing and haying.
Results/Conclusions: Since 1996, native species richness has increased from 39±3 species (mean ± standard error, 7.5 m2 sample area) to 47±1 species on slopes and from 33±5 to 44±4 species on summits. The number of specialist species (coefficient of conservatism ≥ 7) remained stable (slopes: 7±0.4 to 10±1 species; summits: 5±1 to 8±1 species). Forb cover increased dramatically (slopes: 44±3% to 66±5%; summits: 39±7% to 65±6%). While overall graminoid cover remained similar, cool-season graminoid cover increased (slopes: 4±2% to 14±2%; summits: 12±9% to 18±2%) and warm-season graminoid cover decreased (slopes: 49±4% to 35±3%; summits: 30±6% to 26±3%). Tree and shrub cover remained low (<3%); non-native plants were uncommon. The site’s large size and the moderately frequent use of prescribed fire in multiple seasons likely contributed to these changes. Prairie remnants can and should be actively managed with a diversity of approaches to avoid conversion to woodland and to maintain specialist species.