The impacts of sea level rise on Long Island and Connecticut shores are expected to be far-reaching, and will likely affect many other ecological communities. A few more likely ecological impacts are outlined here.
The barrier islands that fringe Long Island's south shore provide protection from storms and storm surge for the human communities along the mainland coast, but they also serve as unique habitats for many species. Fire Island provides critical habitat for several rare and endangered species, and serves as a migratory corridor for birds, sea turtles, and marine mammals. Fire Island also encompasses vital coastal wetlands essential to water quality, fisheries, and the biological diversity of coastal, nearshore, and terrestrial environments. The health of the barrier island complex is fundamental to the health of the bay system overall. The barrier island provides not only the physical boundary of the bay, but also undergoes a variety of geophysical processes that control aspects of water quality in the bay through impacts on the rate at which oceanic water is exchanged with bay water. The natural processes of cross island and long shore sediment movement, particularly the event-driven movements that occur during storm events, are responsible for the natural creation and modification of beaches, dunes, and flood tide deltas which are productive feeding grounds for shorebirds such as the piping plover and ultimately become colonized by marsh plants and submerged rooted vascular plants (SRV).
Although there is a diversity of views on the likely impacts of sea level rise on barrier islands, and the effects are likely to vary substantially from site to site, some generalizations can be made. Accelerated sea level rise will tend to exacerbate barrier island erosion problems, thereby further diminishing the habitat values of barrier islands. At low to moderate rates of sea level rise, the effects will be less than those from storm events and disruptions of the long shore sediment transport in those areas experiencing the most severe erosion problems over the next 30 to 50 years. At higher rates of sea level rise, barrier islands may experience increased erosion, overwashing, and possible breaching in areas with limited sediment volumes. At the highest projected rates of sea level rise, overwashing and breaching would continue to increase, either creating the platforms onto which the barrier islands “roll-over” or migrate, or exposing the bay and mainland shoreline to more oceanic conditions.
Submerged Rooted Vascular plants (SRV) commonly called “seagrass”
Seagrass beds, also known as submerged rooted vascular plants or SRV, serve as shelter and nursery grounds for hundreds of species, including juvenile and adult fish, shellfish, waterfowl, sea turtles, and invertebrates. The plants can contribute significantly to the overall primary productivity of an estuary, and energy present in seagrass enters the estuarine food web as detritus. Seagrass provides structure for benthic (seabed) communities and can slow down currents, thereby decreasing erosion. Seagrasses also contribute greatly to the nutrient and carbon cycling in estuaries by taking up and storing significant amounts of carbon and nitrogen in their tissues and roots. Global climate change and increasing nutrient loads from septic systems are likely to have drastic and irreversible effects on seagrass beds. Elevated temperatures will cause prolonged temperature spikes that are believed to lead to large-scale die-offs and to hamper restoration efforts.
The mapped extent of seagrass meadows is included in the mapping tool.