Characterization of Long Term Fire-Suppresses and Recently Burned Vegetation Communities of Naval Live Oaks, Gulf Islands National Seashore

Jose, Shibu; Miller, Deborah; Ruth, Andrew

The current project's goals included elucidating the effects of fire suppression and past cultural activities on the pine flatwoods, scrub, and ecotonal communities ofNaval Live Oaks (GulfIslands National Seashore), classifying and delineating the aforementioned communities, and determining the effects of recent burns in each ofthe aforementioned communities. Aerial photograph chronosequences (1949-1997) and literature specific to Naval Live Oaks were used to determine historical changes in vegetation structure and composition. Vegetation surveys and physical/chemical soil variable measurements were incorporated into the study to delineate the present day pine flatwoods, scrub, and ecotonal communities. In addition, seed bank characteristics of the communities of interest were analyzed in order to quantify this potential revegetation source. It was determined that the pre-Colonial vegetation communities ofNaval Live Oaks still exist in the present day Naval Live Oaks; however, past cultural activities and frre suppression had appreciably altered species abundance and structure compared to idealized flatwoods and scrub communities. The most notable effect of fire suppression, as evidenced by the aerial photographs, was the reduction in gaps necessary for seedling germination, especially longleaf pine and herbaceous species. The vegetation surveyssuccessfully classified the scrub and the pine flatwoods communities; however, the ecotonal area was further subdivided into a community more closely aligned with scrubby flatwoods (lower, moderately-drained sites) and a community more closely aligned with scrub (higher, well-drained sites). Because seed banks had low densities, contained weedy species, and showed little correspondence to extant vegetation, they were considered poor sources of regeneration of species that typify the communities of interest at Naval Live Oaks. Species diversity tended to decline for all burned communities compared to their respective controls; however, characteristic herbaceous scrub and pine flatwoods species were found within the burned areas that were not in their respective controls. The historically correct fire regime applied to each of the studied vegetation communities ofNaval Live Oaks may help to perpetuate the communities' characteristic vegetation structure and composition. Though prescribed fire is a powerful restoration tool, it cannot solve all problems concerning altered ecosystems. Other management options including seeding of desirable species, mechanical thinning, and/or herbicidal treatment of undesirable vegetation may be necessary to restore these communities.