Climate, Deer and Hogs: Drivers of Rapid Change in a Hickory-Dominated Maritime Forest on St. Catherines Island

Abstract

Maritime forests in the southeastern United States are very susceptible to climate change and have experienced dramatic reductions in extent following anthropogenic disturbances over the past two hundred years. St. Catherines Island, Georgia, an undeveloped barrier island, is home to an un usual pignut hickory ( Carya glabra ) maritime forest that is experiencing rapid rates of change, including a reduction in basal area from 23 m 2 · ha -1 in 1996 to 15 m 2 · ha -1 in 2014. Nine permanent forest plots and associated animal exclosures were installed across this 37 ha stand in 2012 to track forest change and seedling recruitment. From 2012 to 2014, declines in total basal area were caused by mortality of pignut hickory in the overstory and redbay ( Persea borbonia ) in the midstory. Pignut hickory continues to be ranked first in relative frequency, density and dominance, while Sabal palm ( Sabal palmetto ) is slightly increasing in relative density. In 2012, there were no woody species regenerating in any of the plots and following one year of animal exclosures, we found 478 pignut hickory seedlings ha -1 ; thus, deer browse and feral hog predation of nuts may be important drivers of change in this stand. The interplay among deer browse, exotic animal pressures, exotic insects and a drier climate has resulted in a very open forest with the regeneration of few woody plants. Without management of the feral hog and deer population, this unusual maritime forest, with trees as old as 250 years, may continue to decline.