Wetlands, Habitat and Threats
Wetlands are ecological systems located in the transition between land and water. Some wetlands are inundated with water all the time, others only part of the time or have saturated hydric soils. Because eastern North Carolina has low elevation lands with poor drainage and a warm temperate climate, many different types of wetlands have formed depending on salinity of the water, hydrology and the plants that thrive in those conditions. Intertidal marshes are found in estuarine areas with low energy tides. Swamps and bottomland forests are found along freshwater rivers.
Wetlands provide a number of ecosystem services that benefit people. Many wetlands filter and purify rainwater that contains pollutants from farmland, roads, and urban areas. Water emerging from wetlands is naturally cleaner and nutrients that could harm rivers are used by plants within the wetland to thrive. Wetlands can also protect urban areas from flood by acting as a sponge, absorbing water and then slowly releasing it. Many wetlands provide critical habitat for wildlife including endangered birds and mammals. Coastal marshes provide critical nursery areas for important seafood species.
Significant wetland areas make important contributions to the water quality, hydrologic function and habitat quality of the ecosystem. The North Carolina Coastal Region Evaluation of Wetland Significance, or NC-CREWS, is a watershed-based wetlands functional assessment model that uses geographic information systems (GIS) software and data to assess the level of water quality, wildlife habitat, and hydrologic functions of individual wetlands. The NC-CREWS wetland functional assessment provides users with information about the relative ecological importance of wetlands for use in planning and the overall management of wetlands. Threats to wetland survival and function include changes in land use which alter the existing hydrology, such as ditching, draining, road construction, mining and water withdrawl, sea-level rise and shoreline protective structures which may not allow marshes to migrate in response to water level changes.
Intertidal wetland response to sea-level rise depends on the rate of rise, the slope of the land and the amount of sediment the wetland receives from riverine sources. If sea-level rise is gradual, the land adjacent to the wetland is low-lying, and enough sediment is available, wetlands are likely to grow up the slope as the lowest parts are permanently inundated and converted to open water. Shorelines that are protected by hard structures, especially vertical bulkheads, inhibit marsh movement and may lead to a permanent loss of the intertidal wetland ecosystem. Researchers at East Carolina University have been examining how sea level rise affects the salt marsh ecosystem in North Carolina and have developed models to examine the extent of ecological change that can occur. Models, such the Marsh Equilibrium Model developed by Dr. Jim Morris at the University of South Carolina, use the rate of sea level rise, tides, sedimentation, and biological factors to calculate marsh elevation change over time. Models are used to help coastal managers identify where wetlands can reduce hazards-related vulnerabilities to coastal communities, set management priorities, determine areas in need of study and many other applications.
Please note: the SLAMM Marsh Migration layer used in this map is restricted to a maximum scale of 1:100,000. Zooming beyond 1:100,000 will result in this layer being hidden from view.
United States Fish and Wildlife Service National Wetlands Inventory
North Carolina Division of Coastal Management North Carolina Coastal Region Evaluation of Wetland Significance (NC-CREWS)
The Estuarine Shoreline layer is provided the North Carolina Department of Environment and Natural Resources Division of Coastal Management Estuarine Shoreline Mapping Project
How Can This Map Be Used?
The Wetlands, Habitats and Threat map can be used to locate the types and quality of wetland areas in coastal North Carolina. It can be used to support decisions about protection of lands, the placement of roads and other infrastructure and to locate appropriate areas for research projects.
Where to Find More Information
Maps, Marshes and Management: The Ecological Effects of Sea Level Rise Project:
http://www.cicsnc.org/projects/thomas_allen/ and http://www.cop.noaa.gov/stressors/climatechange/current/slr/slr_new_intro.aspx
North Carolina Division of Coastal Management’s Wetland Pages:
United States Fish and Wildlife Service National Wetland Inventory:
How Sea Level Rise Affects Salt Marshes:
K-12 Education: A Blackwater River from sea to source:
K-12 Teachers: PBS Coastal Consequences of Sea Level Rise