OOS 50-10: Ecological restoration of a longleaf pine savanna in the Southeastern Coastal Plain
Susan C. Carr1, Kevin Robertson2, Richard Martin3, Nelwyn McInnis3, and Latimore Smith3. (1) University of Florida, (2) Tall Timber Research Station, (3) The Nature Conservancy
Ecological restoration often involves modification or restitution of community structure and natural disturbance regimes, particularly if significant native populations remain. Restoration methods and intensity are dependent on initial site conditions, as they are compared to predetermined restoration goals (i.e. “reference condition”). Our study area is a southern Louisiana pine savanna remnant that was cleared of longleaf pine (Pinus palustris), fire suppressed, and overstocked with off-site slash pine (Pinus elliottii). We restored estimated natural fire regimes and manipulated timber density via mechanical logging to determine if the native savanna plant community could be restored from remnant plant populations. Presence and abundance of ground cover plant populations were measured in logged and un-logged plots, before pine removal and over an eight year period after treatment. All sites were burned twice, beginning in the third year post-logging. Species richness was enhanced by pine removal in the first two years, mainly due to increases in detectable graminoid species in the ground cover. However, species richness converged among logging treatments with the advent of prescribed fire. Species composition also responded immediately to pine removal, but similarly converged among logging treatments over time. Thus, successional trajectories of ground cover vegetation converged between the treatments, in both magnitude and direction. Succession was toward presettlement conditions, as suggested by comparisons of current to historic reference conditions. Pine removal via carefully supervised mechanical logging does not appear to adversely affect savanna vegetation recovery, and may expedite overall community restoration. Our program of off-site pine removal coupled with introduction of frequent fire was effective in restoring a species-rich ground cover in a degraded remnant longleaf pine savanna.