Effects of Summer Fires on Woody, Succulent, and Graminoid Vegetation in Southern Mixed-prairie Ecosystems: a Review

Interest in the use of summer fires to restore southern Great Plains prairie ecosystems infested with woody plants and cactus is increasing, but information regarding effects on target and nontarget plant species is needed before this practice can be recommended. We review effects of summer and winter fires on mortality and growth of honey mesquite (Prosopis glandulosa), prickly pear (Opuntia phaeacantha), and grasses common to the southern mixed prairie, including C4 midgrass sideoats grama (Bouteloua curtipendula), C4 shortgrass buffalograss (Buchloe dactyloides), and C3 midgrass Texas wintergrass (Nassella leucotricha). Summer fires were more effective than winter fires at top-killing mature mesquite, but plant mortality was 4% in all fire treatments. Prickly pear plant mortality was much greater following summer than winter fires. Sideoats grama, buffalograss, and Texas wintergrass were all tolerant of summer fire, although post-fire recovery rate was slower in sideoats grama than in the other species. Clipping once each spring reduced sideoats grama and Texas wintergrass standing crop in all treatments when measured 1 y after clipping, but effects of clipping summer fire were not negatively additive. The only time fire negatively affected Texas wintergrass was when spring clipping followed winter fire. In contrast, buffalograss standing crop was not reduced by clipping or clipping summer fire at 1 y after treatment. Results suggest that summer fire will not eradicate mesquite and that frequent fires either in summer or winter are necessary to maintain suppression. Grasses studied thus far have demonstrated a tolerance to fire in either season. keywords: cactus, grassland, herbaceous production, mesquite, prescribed fire, southern Great Plains, species composition, summer fire, woody plants. Citation: Ansley, R.J., and M.J. Castellano. 2007. Effects of summer fires on woody, succulent, and graminoid vegetation in southern mixed-prairie ecosystems: a review. Pages 63–70 in R.E. Masters and K.E.M. Galley (eds.). Proceedings of the 23rd Tall Timbers Fire Ecology Conference: Fire in Grassland and Shrubland Ecosystems. Tall Timbers Research Station, Tallahassee, Florida, USA.