Novel ecosystems can be used for the recovery of endangered species. In the southeastern United States, loss of the longleaf pine ecosystem has threatened species reliant on open pine forest, including the Red-cockaded woodpecker (RCW). Due to legacies from past land use high densities of early successional pine species (e.g. loblolly, shortleaf, and slash pine) dominate areas once occupied by longleaf pine on many federal lands. Federal land management programs have used these early successional pine forests to create an ecosystem structure that resembles natural longleaf pine forest for the recovery of the RCW using a combination of prescribed fire, timber harvest, and vegetation management. Despite the importance of this novel ecosystem, its’ structure, composition, and function has not been quantified and its long-term sustainability for RCW remains unclear.
Using Fort Benning, Georgia as a case study, we have used a mixture of longitudinal plot data and landscape-level simulation modeling to quantify (1) the structure, composition, and function of the novel pine forest managed for RCW, and determine (2) how these forest attributes relate to longleaf pine forest, and (3) whether the novel forest condition is sustainable for RCW habitat in the coming years.
Results/Conclusions
The novel ecosystem at Fort Benning is composed of loblolly and shortleaf pines, and has a similar density and basal area of overstory pines to the longleaf pine forest (P<0.001). Despite similar diameter distributions, loblolly/shortleaf forest have fewer pines in the smallest size classes (0-5 cm, 5-10 cm, P<0.01), and instead have high densities of small hardwood trees. Greater densities of understory hardwoods and shrubs contributes to higher woody groundcover (P<0.001), which may be explained by differing fire dynamics between ecosystems. Total understory herbaceous cover was similar between ecosystems (P=0.7895).
The loss of overstory cover in loblolly/shortleaf forest leads to increased hardwood cover in the midstory, which is not true for longleaf pine forest. Results from landscape-level simulation modeling supports findings from plots that with prescribed burning alone, the novel loblolly/shortleaf forest is poised to transition to mixed hardwood-pine forest over the next century.
The overstory forest structure in the novel ecosystem mimics that of longleaf pine forest. However, the inability to recruit new pine trees in the presence of fire suggests it functions much differently. Although this novel forest may be useful for increasing RCW populations in the short-term, its’ sustainability and effectiveness in the long-term is in question.