The number and severity of hurricanes in the Gulf Coast is increasing, resulting in intensified disturbance to coastal forest communities. Coastal swamp-cedar (Chamaecyparis thyoides (L.) B.S.P.) grows no further than one hundred miles from the coast, making the species and associated plant communities particularly vulnerable to large-scale disturbances such as hurricanes. Occurring primarily along the Atlantic Coast from Maine to Florida, this species does form isolated communities along the Gulf Coast regions of Florida, Alabama, and Mississippi. Coastal swamp-cedar is imperiled and at risk of extirpation by extreme weather events, altered disturbance regimes, changes in hydrology, and management. The aim of this study was to evaluate the recovery of coastal swamp-cedar and associated plant communities 14-years post Hurricane Katrina. Pre- and post- Hurricane Katrina data was compared with recent data to determine how Southern Mississippi’s coastal swamp-cedar has recovered post Hurricane Katrina. The two primary objectives of this study are to document the plant biodiversity in extant Mississippi coastal swamp-cedar communities and evaluate the recovery of these systems post hurricane disturbance.
All coastal swamp-cedar ≥ 2.5 cm at breast height (1.37 m) were inventoried within a ~4.85 ha study area located within Grand Bay National Wildlife Refuge, Jackson County, Mississippi. This inventory was compared with data obtained after Hurricane Katrina in 2005 to evaluate the long-term impacts of hurricanes on the stand density for this species. Extant plant diversity was also compared across the community with data obtained just after Hurricane Katrina. Variable length, 10 m wide, belt transects were used to inventory overstory plant communities. Mid-story woody plant communities were inventoried with 10 m2 plots at 10 m intervolves along each transect. The herbaceous plant community was sampled using 1 m2 plots nested within each of the mid-story plots.
Results/Conclusions
Following the 2005 hurricane, coastal swamp-cedar has increased in density across the study site. This increase was spatially correlated with wind damaged and toppled trees previously recorded within this population just after the hurricane. There has also been an increase in exotic, invasive plant species since the 2005 storm. The structural changes caused by the hurricane disturbance both supported the regeneration of this imperiled species but also encouraged exotic, invasive species that threaten these systems. Understanding the long-term recovery of forest communities containing coastal swamp-cedar and other forest species will allow land managers and conservationists to more effectively manage these systems for greater resiliency.