Tue, 28 Jan 2014 15:55:00 CST — by: Jon Evans, Assistant Provost for Environmental Stewardship and Sustainability
Professor Jon Evans and two of his former EcoBio students, Brett Scheffers '05 and Matt Hess '06 have recently published a 6 year study in the journal Biological Invasions documenting the loss of redbay on St. Catherines Island, GA due to an invasive fungal pathogen.
Redbay (Persea borbonia) joins the ranks of chestnut, hemlock, and American elm as a tree whose populations have been decimated by the introduction of an exotic disease called laurel wilt. Redbay, a member of the avocado family, was once a dominant species in southeastern coastal forests and served as the primary host plant for species such as the palamedes swallowtail butterfly. Professor Evans and his colleagues were among the first in the country to begin tracking the ecological consequences of laurel wilt on redbay. This disease is caused by an Asian beetle, Xyleborus glabratus, that bores within the tree and spreads a pathogenic fungus. The six-year study was conducted on the coast of Georgia and tracked the elimination of redbay trees from forests where it was once very abundant.
The researchers uncovered a unique twist to the fate of the tree species. “Despite redbay’s prolific sprouting ability,” Evans says, “high levels of browse from white-tailed deer is preventing new trees from becoming established and accelerating its demise.” The authors suspect that given its former abundance, the loss of redbay will likely have far-reaching implications for biodiversity in coastal forest ecosystems of the southeastern United States. “Sadly, we’ve lost yet another piece of our country’s natural heritage due to the introduction of exotic species,” said co-author Brett Scheffers.
Brett Scheffers and Matt Hess began their work with Professor Evans as students in Sewanee's Island Ecology Program. Matt subsequently used the work as part of his senior honors thesis as an Ecology and Biodiversity major. Matt is currently an Assistant Program Director and Instructor of Marine Science at the Santa Catalina Marine Institute in California. Brett is finisihing his Ph.D at the National University in Singapore and is currently a post-doctoral student at James Cook University in Australia.