Factors that threaten low and high salt marsh also threaten salt panne communities. These include dredging and filling for development, ditching and draining for mosquito control, common reed (Phragmites australis) invasion, 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).
|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 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 pannes. 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 sites that were not selected as reference wetlands by MacDonald and Edinger (2000). Sites on the north shore include Lloyd Neck Marsh and Flax Pond. The remaining south shore lead is at Apple Tree Neck Wetlands. Sites in the Peconic Bay are Bass Creek Marsh, Miss Annies Creek Marsh, Northwest Creek, and West Creek.
Future research on salt pannes should address the classification of the pond-like variant dominated by widgeon-grass (Ruppia maritima). A comparison of this community with coastal salt pond also needs to be made. Other research should investigate the role of salt pannes in organic matter decomposition and nutrient cycling to determine their rate of export and import of nutrients to the marsh surface. Additional beneficial research could explain the role of pannes in marsh surface formation (e.g., are they growing, shrinking, or fairly permanent features?) and more study is needed to understand the use of salt pannes by birds (e.g., what species use pannes and why?) (MacDonald and Edinger 2000).