Differences in Bacterial Communities on Decaying Leaf Litter of Different Tress in Response to Burning as a Forest Restoration Technique

Decomposition is the process by which organic matter gets degraded into basic components to provide energy for decomposer microorganisms and to also make nutrients available for plant uptake. Leaf litter decomposition is an important process and influences the nutrient cycling and the productivity and structure of the entire ecosystem; however, few studies have examined the bacterial communities on decomposing litter, especially how they may vary between tree species or in woodlands subject to ecological restoration. Such restoration has become important, as fire suppression beginning in the 1920s has impacted the structure of forest ecosystems through the process of mesophication, diminishing the abundance of fire-dependent species and favoring more shade-tolerant, fire-intolerant trees. These changes likely influence the composition of the litter microbial community. This study used next generation sequencing of 16S rRNA genes to characterize the bacterial communities on litter from six different tree species, including representatives of upland oak woodlands (oaks) and mesophytic species (non-oaks), in a north Mississippi forest undergoing restoration. Results suggest that the bacterial community on leaf litter changes significantly as decomposition proceeds, and that there are differences in bacterial communities present on litter from oak versus non-oak species. Comparing the bacterial communities on leaf litter collected from a site that experienced a prescribed burn within the collection year, to a non-burned site suggested that fire did affect the bacterial community present on the decaying leaf litter. Together, these results indicate that both ecological restoration (fire) and the effects of restoration (a change in tree species) are likely to influence the composition of the litter bacterial community