RESEARCH ARTICLE Fire Season Effects on Flowering Characteristics and Germination of Longleaf Pine (Pinus palustris ) Savanna Grasses Benjamin J. Shepherd, 1 Deborah L. Miller, 2,3 and Mack Thetford 4 Abstract Pinus palustris (longleaf pine) savannas depend on con- tiguous grass cover to facilitate frequent surface fires. Enhanced flowering, seed production, and germination may be linked to season of fires. We assessed the effect of month of prescribed fire (February, April, May, and July) on percentage of plants with flowering culms (FCs%), FC/area, FC/plant, seed production, and germination for five warm seasons, fall-flowering grasses. Multivariate analysis indicated the response of flowering and fruiting to burn month varied among the grass species. The domi- nant species, Sporobolus junceus and Schizachyrium sco- parium var. stoloniferum, had greater numbers of most flowering characteristics when burnt during April, May, and July. Aristida purpurascens had increased FC/plant after May and July burns. In contrast, Ar. mohrii had the fewest FC/plant and seeds/FC when burnt in July. Germi- nation was greatest (26–60%) for Ar. purpurascens. Seeds collected following July burns for Ar. purpurascens and Ar. ternarius and after May burns for S. junceus were within the highest germination values recorded. Germina- tion of Sc. scoparium var. stoloniferum was very low after February and July burns (≤5%). With Ar. mohrii, only seed collected following February (2%) and April burns (3%) germinated. April, May, and July fires increased seed production of dominant matrix grasses, thus facilitating the potential for recruitment of these species and facilitating seed collection from potential donor sites for ground-layer restoration projects. Varying prescribed fire burn month captured variation in flowering characteristics among these grasses. Key words: Andropogon ternarius, Aristida mohrii, Aristida purpurascens, Schizachyrium scoparium var. stoloniferum, Sporobolus junceus . Introduction Pinus palustris (longleaf pine) ecosystems of the southeast- ern United States are among the most biologically diverse in North America. In addition to harboring numerous endemic and rare plant species (Peet 2006), several at-risk vertebrates are specialist in longleaf pine ecosystems (Means 2006). His- torically, lightning- or human-caused fires swept through these communities, every 1–5 years, most often during summer months (May–September) (Robbins & Myers 1992; Frost 2006), fueled by ground-layer plants (specifically grasses) that are necessary to sustain the low-intensity surface fires that maintain these ecosystems (Kirkman et al. 2004). However, 1 School of Natural Resources and Environment, University of Florida, 553 Village Lane, Winter Park, FL 32792, U.S.A. 2 Department of Wildlife Ecology and Conservation, West Florida Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 5988 Highway 90, Building 4900, Milton, FL 32583, U.S.A. 3 Address correspondence to D. L. Miller, email dlmi@ufl.edu 4 Department of Environmental Horticulture, West Florida Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 5988 Highway 90, Building 4900, Milton, FL 32583, U.S.A.  2011 Society for Ecological Restoration International doi: 10.1111/j.1526-100X.2010.00759.x current and historical declines due to industrial timber man- agement, fire suppression, and urbanization have reduced the historical range of the longleaf pine ecosystem by 97%, mak- ing it one of the most imperiled ecosystems in the United States (Frost 2006). Consequently, restoration of longleaf pine communities is paramount to a great number of flora and fauna and dependent on restoration of the ground layer. Prescribed fire is emphasized as a management and restora- tion strategy to simulate the natural disturbance regime (Sousa 1984), reduce fuel accumulation, and enhance sexual reproduc- tion of herbaceous species (Platt et al. 1988; Brewer & Platt 1994; Outcalt 1994). However, there is not always agreement as to the appropriate fire regime to use (Glitzenstein et al. 2003). Historically, prescribed fires were set during winter months prior to March when the growth of ground-layer plants had slowed. Recently, growing season burns are suggested as essential to restoration and maintenance of the native ground layer (Streng et al. 1993). However, for some species burn fre- quency and burn characteristics may be more important than burn season (Mulligan & Kirkman 2002). It is presumed that grasses of longleaf pine evolved repro- ductive strategies in response to lightning-season burns (Myers 268 Restoration Ecology Vol. 20, No. 2, pp. 268–276 MARCH 2012