Walking on mudflats can be challenging and in some cases even dangerous. It is very easy to sink up to your waist in the soft mud, unless you wear "mudders." Mudder shoes have expandable wings on the side to provide support when crossing mudflats. Worn over boots or waders, the wings expand as you step onto soft surfaces to increase boot area by four times and then retract when you lift your foot.
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. Ensure connectivity between the open saltwater and low salt marsh.
Factors that threaten salt marsh and maritime beach complexes also threaten marine intertidal mudflat communities. These include dredging and filling for development, ditching and draining for mosquito control, 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).
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).
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 mudflats and low salt marshes. 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.
The marine intertidal mudflats community is located in quiet waters, with substrates composed of silt or sand that is rich in organic matter and poorly drained at low tide. This community is almost completely unvegetated. Cordgrass (Spartina alterniflora) can occur sporadically, colonizing from adjacent low salt marsh communities. The marine alga sea lettuce (Ulva lactuca) can cover 40% or more of the exposed substrate.
This intertidal community is almost completely unvegetated on exposed mudflats adjacent to low salt marshes and saltwater tidal creeks where the salinity is greater than 18 ppt. This community is submerged during high tide, and exposed at low tide.
Marine intertidal mudflats are viewable year round, but are best viewed at low tide from a distance on firm ground or a boat.
This New York natural community encompasses all or part of the concept of the following International Vegetation Classification (IVC) natural community associations. These are often described at finer resolution than New York's natural communities. The IVC is developed and maintained by NatureServe.
Spartina alterniflora (smooth cord grass)
sea lettuce (Ulva lactuca)
American oystercatcher (Haematopus palliatus)
blue mussel (Mytilus edulis)
mudsnail (Ilyanassa obsoleta)
polychaete (Heteromastus filiformis)
polychaete (Lumbrinereis tenuis)
polychaete (Nereis virens)
polychaete (Polydora ligni)
polychaete (Streblospio benedicti)
softshell clam (Mya arenaria)
willet (Catoptrophorus semipalmatus)
This figure helps visualize the structure and "look" or "feel" of a typical Marine Intertidal Mudflats. Each bar represents the amount of "coverage" for all the species growing at that height. Because layers overlap (shrubs may grow under trees, for example), the shaded regions can add up to more than 100%.
Edinger, G. J., A. L. Feldmann, T. G. Howard, J. J. Schmid, E. Eastman, E. Largay, and L. A. Sneddon. 2008. Vegetation Classification and Mapping at Gateway National Recreation Area. Technical Report NPS/NER/NRTR—2008/107. National Park Service. Northeast Region. Philadelphia, PA.
Edinger, G. J., D. J. Evans, S. Gebauer, T. G. Howard, D. M. Hunt, and A. M. Olivero (editors). 2014. Ecological Communities of New York State. Second Edition. A revised and expanded edition of Carol Reschke’s Ecological Communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation, Albany, NY. http://www.dec.ny.gov/docs/wildlife_pdf/ecocomm2014.pdf
Edinger, Gregory J., D.J. Evans, Shane Gebauer, Timothy G. Howard, David M. Hunt, and Adele M. Olivero (editors). 2002. Ecological Communities of New York State. Second Edition. A revised and expanded edition of Carol Reschke's Ecological Communities of New York State. (Draft for review). New York Natural Heritage Program, New York State Department of Environmental Conservation. Albany, NY. 136 pp.
New York Natural Heritage Program. 2020. New York Natural Heritage Program Databases. Albany, NY.
Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.
This guide was authored by: Gregory J. Edinger
Information for this guide was last updated on: May 15, 2020
Please cite this page as:
New York Natural Heritage Program. 2020. Online Conservation Guide for Marine intertidal mudflats. Available from: https://guides.nynhp.org/marine-intertidal-mudflats/. Accessed June 7, 2020.