Coastal Interdunal Swale
within Freshwater Non-forested Wetlands
Vulnerability:
General Information
Coastal interdunal swales are a mix of grasslands, small ponds and depression marshes. The water levels are strongly tied to local rainfall events and thus the community varies from flooded to completely dry, depending on rainfall. This community is found in the Florida panhandle to central peninsula, associated with large barrier islands. They are typically rich with species from the sedge family, with other plants including umbrellagrass, St. John's wort, redroot, and yellow-eyed grass. Other plants found, depending on hydrology include sawgrass, hairawn muhly, seashore paspalum, Baker’s cordgrass, saltmeadow cordgrass, wax myrtle, and coastal plain willow.
Fires occasionally burn through the swales but the dominant factor in this community's development and maintenance is hydrology. Hurricanes and tropical storms can flood swales with salt water, after which they are colonized for a time by more salt-tolerant species.
Area
- 1,167 hectares within Florida (modeled)
- 1,004 hectares (86%) is located on public lands
Area impacted by up to 3 meters sea level rise:
Climate Impacts
Coastal interdunal swale is likely to have 59% of the current area inundated by 1 m of sea level rise and 95% inundated by 3 m of sea level rise.
Decreased precipitation coupled with increased temperature will likely alter species composition and increase fragmentation of larger systems through reduced flow and connectivity. Decreases in water quantity and quality will continue to stress the system and cause degradation.
Increased precipitation and floods will cause increased run-off, erosion, siltation, and pollutants, all contributing to habitat degradation and loss. In some circumstances these impacts could cause decreased reproductive success, increased stress and increased mortality.
For species whose reproductive cycle is linked to wet/dry cycles, changes in the timing and amount of precipitation could affect these life cycle events, potentially causing mismatches of phenological processes, leading to reduced reproductive success, reduced recruitment and increased mortality.
More information about general climate impacts to habitats in Florida.
Climate Impacts to Species
Increased saltwater intrusion and sand burial from storm overwash may lead to increased invasion by exotic plants, including, torpedo grass, Chinese tallow, Brazilian pepper and Australian pine. Loss of native plants to exotic plants will alter the communities structure and could lead to loss of critical forage plants for species such as beach mice.
Changes in fire regime will also impact species dependent upon coastal swale as the loss of fire will lead to hardwood species invading. This may be particularly true for species such as the beach mice and Sanibel Island rice rat.
More information about general climate impacts to species in Florida.
Other Non-climate Threats
- Coastal development
- Incompatible fire
- Incompatible recreational activities
- Invasive animals
- Invasive plants
- Nutrient loads - agriculture and urban
- Roads
More information about climate change interactions with existing threats and stressors in Florida.
Vulnerability Assessment Details
This habitat was assessed as part of the Standardized Index of Vulnerability and Value Assessment - Natural Communities (SIVVA).
This habitat is within the top 5 most vulnerable natural communities in one but not all of the SIVVA vulnerability categories.
Read more information about SIVVA natural communities.
Adaptation Strategies
Protection
- Acquire and protect wetlands with the largest carbon stores.
- Protect buffer zones to allow for future system shifts/migration through easements, acquisition or purchase of development rights.
- Preserve the structural complexity and biodiversity of vegetation.
- Protect areas that are naturally positioned to be more resistant/resilient to climate change.
- Facilitate wetland migration through setbacks, easements, or purchase.
- Protect aquatic corridors.
- Identify and protect ecologically significant areas such as breeding/nesting sites, wintering sites, and areas of high species diversity that will continue to serve these functions under climate change.
- Install water control structures at the outlets of freshwater wetlands to better manage water levels during dry periods.
- Establish rolling easements, especially in those areas that will allow for plant migration.
Restoration
- Restore hydrologic connections, implementing designs that will accommodate both increased and decreased flow.
- Promote restoration to fill gaps in wetland corridors.
- Control invasive species in climate-stressed wetlands.
- Replace culverts with those designed to accommodate future flow conditions and allow for fish and wildlife passage.
- Implement management practices that accommodate shifts in the timing of the rainy season and eliminate or reduce application of pesticides during this period.
- Develop adaptive stormwater management practices (e.g., promoting natural buffers, adequate culvert sizing).
- Replace impervious surfaces with permeable pavement to allow runoff to flow through and be temporarily stored prior to discharge, in areas adjacent to wetlands.
- Replicate habitat types in multiple areas to spread risks associated with climate change.
Planning
- Expand the planning horizons of land use planning to incorporate longer climate predictions.
- Incorporate wetland and climate change ecosystem protection goals into watershed management, water planning, and comprehensive land planning including smart growth, and infrastructure development programs.
- Develop adaptive stormwater management plans (e.g., promoting natural buffers, adequate culvert sizing, remove impervious surfaces).
- Beginning with existing management plans, determine the processes and actions needed to increase the resiliency of wetlands and watersheds in the face of climate change.
- Study and better understand and address invasive species in climate-stressed wetlands.
Policy
- Create permitting rules that constrain locations for landfills, hazardous waste dumps, mine tailings, and toxic chemical facilities.
- Manage water demand (through water reuse, recycling, rainwater harvesting, desalination, etc.).
- Prevent or limit groundwater extraction from aquifers during periods of drought.
- Increase regulatory protection for wetlands most threatened by climate change to reduce stresses, provide opportunity for wetlands to migrate, and protect carbon stores.
- Strengthen control of drainage of wetlands.
Education and Outreach
- Develop training on the use of existing and emerging tools for managing wetlands under climate change (e.g., vulnerability and risk assessments, scenario planning, decision support tools, and adaptive management).
- Develop focused outreach efforts and materials aimed at local, state, tribal, and federal government authorities involved in water management.
- Collaborate with water managers, including floodplain programs, drinking water programs, and drain engineers and others to consider wetland options for climate strategies.
- Collaborate with EPA, Corps of Engineers, Water Management Districts, Department of Environmental Protection to define and address regulatory concerns. Some wetlands may need added protection in light of climate change.