5. Exotic, Invasive Species and Native Nuisance Species: Both faunal and floral exotic invasive species have the potential to affect biodiversity, structure, and population dynamics. Floral species such as Chinaberry, salt cedar, camphor tree and Chinese tallow have the capacity to alter stand structure, fire susceptibility, and overall biological diversity. Faunal species such as feral cats and fire ants prey on native species. Non-native plant pests such as the red bay ambrosia beetle with its associated fungus and the cactus moth pose threats ranging from landscape altering to concerning. Feral hogs have not been documented on Jekyll but are known to occur within the Park along the causeway, closer to the mainland, and could be extremely destructive to native plants, sea turtle nests, and ground-nesting birds. While desirable from a wildlife viewing perspective, native wildlife can at times adversely affect long-term conservation goals by preferentially foraging on propagules and saplings of desirable native plant species (e.g., white-tailed deer) or feeding directly on another target priority species (e.g., raccoons foraging on sea turtle eggs). Range-expanding North American species such as armadillo and coyote can have both adverse and beneficial effects. Armadillo were first observed on the Island in 2015, and in 2020 the first coyote was documented on the Island. Research is emerging documenting armadillo burrows creating a habitat that is beneficial to other vertebrates. The consensus among Georgia’s coastal natural resource managers is that the coyote’s net negative impacts on conservation of priority wildlife such as depredation of ground nesting birds, especially shorebirds, exceed any potential collateral benefits, such as white-tailed deer population control. Coyote control is notoriously challenging, but if they can be prevented from establishing themselves on Jekyll Island, they should be.
6. Groundwater Variability: Regional changes in groundwater due to withdrawals and drought have affected freshwater wetlands on the Island. In addition to affecting the hydrology of freshwater wetlands, these groundwater changes affect salinity at locations where the groundwater historically discharged through freshwater systems into tidal marshes. The interaction between groundwater variability and the general absence of fire in the State-era of the Island has resulted in the degradation of small, shallow, freshwater wetlands.
7. Tidal Flow Alterations: Tidal flow alterations can occur from a variety of activities from dredging efforts that alter sand shoals to structural impoundments of historical salt marshes to constrictions on tidal flow such as culverts. These alterations can have direct effects on salinity levels and inundation regimes for salt marsh and beach areas. They can also indirectly affect freshwater flow and retention in freshwater wetland systems upstream of tidal creeks and wetlands.
8. Beach Erosion and Sand Starvation: Beach erosion and sand starvation affect both the beach ecosystem and dunes and interdunal swales that provide a habitat for shorebirds and sea turtles and protect the Island from storm damage.
9. Storm Frequency: Though it is unclear if it is a long-term trend, during the past 20 years, tropical storms and hurricanes have become more intense and more rain is falling in heavy downpours (https://19january2017snapshot.epa.gov/sites/production/files/2016-09/documents/climate-change-ga.pdf). Barrier islands have always been uniquely affected by these high-intensity storms, but an increase in the frequency of their occurrence may cause ecosystem-altering changes on Jekyll Island.
10. Sea-level Rise: The 2014 Jekyll Island Master Plan calls for a precautionary approach in anticipation of 1.3 to 2.3 feet of sea-level rise by the year 2060. An acceleration is suggested by the increasing frequency of observed extreme high tides, which are commonly referred to as King Tides and can result in high tide flooding. These trends will continue to affect inundation regimes, estuarine wetland migration, salinity levels, and structural aspects of vegetation zonation for tidal marshes, beaches, dunes, interdunal swales, and other habitats on the Island. The JIA’s sea level-rise planning parameters will be reevaluated and could be revised with the next iteration of the Master Plan.
11. Limited Regeneration of Canopy Species: The limited number of canopy species saplings in several habitats provides a diminished base for canopy recruitment in the event of a natural event (e.g., storm damage, lightning) or human-induced event (e.g., wildfire, canopy removal). Factors affecting sapling number and diversity may include: over-browsing by deer, and other seed/sapling predators/browsers; lack of appropriate conditions for germination (e.g., thick duff layers, lack of fire or sunlight, etc.); and historical management practices.
12. Climate Change: Global emissions of greenhouse gases are altering the chemical composition and physical properties of the Earth’s atmosphere and oceans. This human-induced phenomenon adds to the other threats and stresses and influences their trajectories.
21 ENVIRONMENTAL SETTING
