Pine Savanna Ecology and Restoration in the Southeastern United States

Ecosystem restoration and management practices should be guided by sound scientific information on ecosystem dynamics. In the southeastern United States, pine savanna ecosystems have experienced widespread decline and are a current focus of restoration activities in the region. We therefore investigated several aspects of pine savanna ecology to provide crucial information for restoration and management approaches. First, we found that both the reproductive response of endemic wiregrass (Aristida beyrichiana) and historical fire records indicate the predominance of summer lightning ignitions in longleaf pine (Pinus palustris)-wiregrass ecosystem dynamics. Practitioners should therefore consider the implications of using summer prescribed fire in restoration and management protocols to mimic the historical fire regime. Additionally, although we failed to detect a relationship between longleaf pine-associated plant species endemism and dispersal ability, we did find a positive relationship between endemism and longevity (life cycle). This result suggests that if dispersal is not limiting, endemic plants may depend on both soil properties and the precise use of fire to enhance their establishment and persistence. We also investigated multi-scale habitat selection in an indigenous and imperiled predator of the southeastern pine savannas, the Eastern Diamondback Rattlesnake (Crotalus adamanteus; EDB). Our results underscore the importance of pine savannas for maintaining rattlesnake populations at a regional and local scale, but management strategies should also consider the potential for vegetation cover types to serve as surrogate habitat on smaller scales. We also summarized long-term data on EDB breeding and reproductive phenology from several populations in the South Carolina Coastal Plain, and found that reproductive activity occurred primarily in late July through mid-October. This information not only contributes to our current knowledge and conservation efforts, but will also facilitate future long-term comparative investigations throughout its geographic range. Finally, we discussed the ecological paradigms that currently guide restoration and management of subtropical pine savannas in the southeastern United States. We contend that in contrast to linear models of vegetation succession, current research supports an evolutionary model of pine savannas as diverse alternate states maintained by vegetation-fire feedbacks. Restoration and management strategies should focus on components of the vegetation-fire feedback to achieve restoration goals. In summary, our results demonstrate that practitioners should carefully consider the relationship between ecosystem structure and function in managing and restoring species and processes (such as fire) to southeastern pine savannas.