One of the common plants in brackish subtidal aquatic beds are coontails (Ceratophyllum spp.). The name originates from the shape of their leaves and branches, which resemble the tail of a raccoon. Their flowers have tiny green scales, and are located at the leaf base. Male and female flowers develop separately on the same plant. The male flowers occur in pairs on opposite sides of the stem while the female flowers are solitary.
There are probably far fewer than 50 occurrences statewide. Very few documented occurrences have good viability and very few are protected on public land or private conservation land. This community is restricted to brackish portions of estuaries in the state. The current trend of this community is probably stable to declining slightly due to moderate threats that include alteration of the natural hydrology and invasive species.
The number of brackish subtidal aquatic beds in New York have probably remained stable in recent decades. The quality of the water in tidal rivers, and thus their associated brackish subtidal aquatic bed communities, has probably improved in recent decades.
The number of brackish tidal marshes in New York probably declined substantially from historical numbers as a result of shoreline development and river channel dredging.
The brackish subtidal aquatic beds on the Hudson River are recovering from several hundred years of pollution, shoreline development, dredging, commercial shipping, recreational overuse, invasive species, etc. Smaller brackish subtidal aquatic beds on tidal rivers on Long Island have had similar impacts, but at a smaller scale. Although water chestnut (Trapa natans) is a serious threat to freshwater subtidal aquatic beds, large patches are not generally located within the brackish portions of the Hudson River.
Maintain tidal regime in coves cut off from the Hudson River by railroad tracks. Control and remove invasive exotic species, such as water chestnut (Trapa natans).
Development activities that involve the manipulation of the river substrate (e.g., dredging, installing submerged structures, etc.) should be avoided in areas where mudflats naturally occur. Marinas adjacent to mudflats should use buoys to direct boat traffic away from these shallow areas.
Review subtidal aquatic vegetation (SAV) maps and data collected by partner organizations, and incorporate this information into the New York Natural Heritage database. Resurvey and update occurrences with records greater than 10 years old.
Research the effects of invasive exotic plants and animals on brackish subtidal aquatic beds.
The range of this community primarily corresponds to the brackish tidal range of the Hudson River (i.e., from between New Hamburg/Poughkeepsie downstream about 25 miles to Hastings-on-Hudson), and perhaps within the brackish tidal range of the smaller tidal rivers of Long Island.
This community occurs along the Atlantic coast from Maine to Virginia and possibly to South Carolina.
Brackish subtidal aquatic beds are continuously flooded aquatic communities, characterized by rooted aquatic vegetation. The water salinity values range from 0.5 to 18 parts per thousand (ppt), and the water depth at low tide is typically less than 2 m (6 feet). Plant species may include sago pondweed (Stuckenia pectinata), widgeon grass (Ruppia maritima), coontail (Ceratophyllum demersum), and naiad (Najas guadalupensis).
A brackish aquatic community of continuously flooded substrates with rooted aquatic vegetation and water salinity values in the range of 0.5 to 18 ppt. The water depth at low tide is typically less than 2 m (6 feet).
Known examples of this community have been found at elevations between -3 feet and -1 feet.
The aquatic plants that are characteristic of brackish subtidal aquatic beds are best observed during the growing season.
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.
This New York natural community falls into the following ecological system(s). Ecological systems are often described at a coarser resolution than New York's natural communities and tend to represent clusters of associations found in similar environments. The ecological systems project is developed and maintained by NatureServe.
Ruppia maritima (widgeon-grass, ditch-grass)
Ceratophyllum demersum (common coon-tail)
Elodea nuttallii (Nuttall's waterweed)
Najas guadalupensis (Guadalupe water-nymph, Guadalupe naiad)
Stuckenia pectinata (Sago pondweed)
Zannichellia palustris (horned pondweed)
This figure helps visualize the structure and "look" or "feel" of a typical Brackish Subtidal Aquatic Bed. 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., 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. https://www.nynhp.org/ecological-communities/
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.
Kiviat, Erik and Gretchen Stevens. 2001. Biodiversity assessment manual for the Hudson River Estuary Corridor. New York State Department of Environmental Conservation. Albany, NY.
Macomber, R.T. and D. Allen. 1979. The New Jersey submersed aquatic vegetation distribution atlas final report. Prepared for the New Jersey Department of Env. Protection, Division of Coastal Resources, Bureau of Coastal Planning and Development. Trenton, New Jersey.
Metzler, K. and R. Rosza. 1982. Vegetation of fresh and brackish tidal marshes in Connecticut. Newsletter of the Connecticut Botanical Society 10(1): 1-3.
Muenscher, W.C. 1937. VII. Aquatic vegetation of the Lower Hudson area. 1936. Biological Survey. 11:231-248.
New York Natural Heritage Program. 2023. 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.
Senerchia-Nardone, P., A. Reilly, and M.M. Holland. 1985. Comparison of vascular plant zonation at Iona Island Marsh (Hudson River Estuary) and Lord's Cove Marsh (Connecticut River Estuary). In: Polgar Fellowship Reports of the Hudson River National Estuarine Sanctuary Program 1985. J.C. Cooper, Editor. Hudson River Foundation, New York, New York.
This guide was authored by: Gregory J. Edinger
Information for this guide was last updated on: April 6, 2021
Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Brackish subtidal aquatic bed. Available from: https://guides.nynhp.org/brackish-subtidal-aquatic-bed/. Accessed June 6, 2023.