The primary threat to this community is invasion by common reed (Phragmites australis). Additional threats to this community and to salt marsh complexes generally include dredging and filling for development, ditching and draining for mosquito control, poor water quality (from sewage and stormwater discharge; nonpoint source runoff; landfill leachate; boat traffic; particulate aircraft, vehicular, and power plant emissions; jet fuel; ethylene glycol from aircraft deicing; and pesticides used in mosquito management), diking and impoundment, inlet stabilization, shoreline hardening, wrack accumulation, altered sediment budget (decreased sediment input to marshes), subsidence, changes in water circulation patterns because of changes in shoreline and benthic topography, restricted tidal connection, and altered tidal hydrodynamics resulting from changes to hydrology (including groundwater levels, overland flow, and in-channel volume) in the surrounding watershed, road construction, and urbanization (GNRA and JBWPPAC 2007, Niedowski 2000, New York State Department of Environmental Conservation 2009b, 2009c, 2009d). Response to sea level rise is uncertain.
|Conservation Strategies and Management Practices||
Monitor the abundance of invasive species, particularly common reed (Phragmites australis), in this community and, as needed, control their encroachment. Remove excessive wrack accumulation. Remove shoreline armoring to increase overland sediment input; improve water quality by reducing or eliminating sewer and stormwater discharge and pesticide application; restore tidal regime by removing culverts, dikes, and impoundments, plugging ditches, and replacing static flow restriction devices with those that are calibrated for local tidal hydrology. Restoration and monitoring protocols are available (Niedowski 2000).
|Development and Mitigation Considerations||
Strive to minimize or eliminate hardened shorelines and maintain low-sloped shorelines within the tidal zone to increase overland sediment input. Maintain functional connectivity between the open ocean and bays with salt marsh complexes to enable full tidal flushing during each tidal cycle. For example, barriers such as railway causeways should have numerous culverts to allow sufficient hydrologic connectivity. If flow restriction devices are needed, those that are calibrated for local tidal hydrology can be used. Avoid dumping dredge spoil onto salt shrub communities. This community is best protected as part of a large salt marsh complex. Protected areas should encompass the full mosaic of low salt marsh, high salt marsh, marine intertidal mudflats, saltwater tidal creek, salt panne, and salt shrub communities to allow dynamic ecological processes (sedimentation, erosion, tidal flushing, and nutrient cycling) to continue. Connectivity to brackish and freshwater tidal communities, upland beaches and dunes, and to shallow offshore communities should be maintained. Connectivity between these habitats is important not only for nutrient flow and seed dispersal, but also for animals that move between them seasonally. Development of site conservation plans that identify wetland threats and their sources and provide management and protection recommendations would ensure their long-term viability.
Additional inventory is needed on the north and south shore of Long Island and in Peconic Bay. Leads include the sixteen sites that were not selected as reference wetlands by MacDonald and Edinger (2000). North shore leads include Lloyd Neck Marsh, Flax Pond, and Crab Meadow Marsh. Peconic Bay leads include Orient Point Marsh, Accabonac Harbor Marsh, Cow Neck Marsh, Mashomack Point Marsh, Downs Creek, West Creek, and Northwest Creek. South shore leads include Moriches Inlet Backbarrier Beach, West Beach-Tiana Beach, Floyd Point Marsh, Gilgo Beach Back Barrier Marsh, Hempstead Bay Wetlands, and Apple Tree Neck Wetlands.
Research on salt shrub should include monitoring common reed (Phragmites australis) encroachment in conjunction with indicators of community health to determine whether healthy communities are more resistant to invasion. Additional work could investigate community response to rising sea level (MacDonald and Edinger 2000).