Northeast Coastal Areas Study
Significant Coastal Habitats
Site 14 (NY)
I. SITE NAME: Flanders Bay Wetlands Complex
II. LOCATION: The area is located on Long Island's South Fork along the south shore of Flanders Bay and a small section of Great Peconic Bay. The general location is at the western end of the semi-enclosed system of bays between the two forks of eastern Long Island, a few miles southeast from the mouth of the Peconic River.
TOWN: Southampton
COUNTY: Suffolk
STATE: New York
USGS 7.5 MIN QUADS: Mattituck, NY 40072-85;
Riverhead, NY 40072-86
USGS 30x60 MIN QUAD: Long Island, East 40072-E1
III. GENERAL BOUNDARY: This predominantly wetlands complex of tidal estuarine marshes, nearshore bay waters and freshwater swamps, ponds, marshes and beaches is situated on the south shore of Flanders Bay between, and including, Goose Creek and Goose Creek Point on the west, and Red Creek Pond and Red Cedar Point on the east, a distance of about 2.5 miles (4 km). The complex extends inland (south) approximately 2.5 to 3 miles (4-5 km) to the northern edge of the Ronkonkoma Moraine (Flanders Hill). The general area is outlined in the accompanying map.
Within this wetlands complex are several individual habitat sites of particular significance to fish, wildlife and plant species of special emphasis in the region or to regional biological diversity. These significant areas may be grouped into: 1) saltmarshes, mudflats and nearshore bay waters; 2) sandy beaches of importance to beach-nesting colonial birds; 3) Coastal Plain ponds; and 4) a white cedar swamp. The saltmarshes and sandy beaches (Red Cedar Point and Goose Creek Point) occur along the shores of Flanders Bay, while the majority of Coastal Plain ponds occur a mile or two inland, particularly near the southeast border of the complex. The more important ponds in this latter group, known collectively as the Flanders Pond System, are: Penny Pond, Grass Pond, House Pond, Division Pond and Bellows Pond, as well as a few small unnamed ponds. The Owl Pond cedar swamp is located near the southwest border of the complex. All of these individual sites and groups of sites are delineated within the overall boundary outline on the accompanying map.
IV. OWNERSHIP/PROTECTED STATUS: A good portion of this area, particularly the saltmarshes and coastal ponds, is owned by Suffolk County and is within the County park system. The cedar swamp area and a few of the important beach areas are privately-owned.
V. GENERAL HABITAT DESCRIPTION: The saltmarsh vegetation of this complex is generally rather typical of that found throughout the region, dominated by cordgrasses (Spartina alterniflora and S. patens) and with a prominent edge zone of groundsel-bush (Baccharis halimifolia), but is remarkable both for its undeveloped and undisturbed condition as well as for its major salt panne system with salt-induced bare spots. The marsh area is approximately 800 acres (324 ha) in size. Four freshwater tributaries flow through the marsh complex into Flanders Bay: Goose Creek, Birch Creek, Mill Creek and Hubbard Creek. The beaches at Goose Creek Point and Red Cedar Point, along the shoreline of Flanders Bay, are low in profile, composed of coarse sands or pebbles, and generally bordered by low dunes with beachgrass (Ammophila breviligulata) and sometimes by saltmarsh vegetation. Tidal amplitude in this area is about 2.7 feet (0.8 meters).
The Coastal Plain ponds in the Flanders Ponds System are relatively small, shallow, generally isolated and undisturbed, and surrounded by pine barrens vegetation dominated by pitch pine (Pinus rigida). Water levels in these groundwater ponds fluctuate both seasonally and annually, and in some years certain ponds may dry up completely. The vegetation and floristic composition of the pond shores vary with the water levels, but often include many annuals, several of which are considered regionally rare. Some of the ponds have small islands in them dominated by Atlantic white cedar (Chamaecyparis thyoides).
The Atlantic white cedar swamp at Owl Pond is located near the southwest corner of this complex in a round kettlehole depression with a floating peat mat. It is dominated by young white cedar trees and red maple (Acer rubrum), with an understory of sedges (especially Carex walteriana), pitcher plants (Sarracenia purpurea), sundews (Drosera rotundifolia and D. intermedia) and peat mosses (Sphagnum spp.). The surrounding area is upland pine barrens.
VI. SIGNIFICANCE/UNIQUENESS OF AREA: Both piping plover (Charadrius melodus), a U.S. Threatened species, and least tern (Sterna antillarum) have a long history of use of the beaches in this area for nesting, and adjacent bay waters, tidal flats and tidal creeks for feeding. Other bird species of special emphasis in the region nesting in this area include common tern (Sterna hirundo), black skimmer (Rynchops niger), osprey (Pandion haliaetus), green-backed heron (Butorides striatus), black-crowned night-heron (Nycticorax nycticorax), Canada goose (Branta canadensis), American black duck (Anas rubripes), mallard (Anas platyrhynchos) and northern harrier (Circus cyaneus). Sea-beach knotweed (Polygonum glaucum) also occurs on these beaches.
The open waters and wetlands of Flanders Bay in this general area are considered to be one of the more important waterfowl wintering areas in eastern Long Island, especially for American black duck, common loon (Gavia immer), scaup (Aythya marila and A. affinis), Canada goose, red-breasted merganser (Mergus serrator) and oldsquaw (Clangula hyemalis). There are also significant concentrations of waterfowl in this area during spring and fall migrations. Flanders Bay is a productive area for finfish, shellfish and other organisms, and serves as an important nursery and feeding area for many estuarine fishes, including winter flounder (Pseudopleuronectes americanus), summer flounder (Paralichthys dentatus), menhaden (Brevoortia tyrannus), weakfish (Cynoscion regalis) and scup (Stenotomus chrysops). Bay scallops (Aequipecten irradians) and hard-shelled clams (Mercenaria mercenaria) are abundant and of local commercial importance. Northern diamondback terrapins (Malaclemys t. terrapin) are reported for the area and may possibly nest here.
From a biological diversity and rare plant and insect species standpoint, the Flanders Ponds are of considerable regional significance. These high-quality Coastal Plain ponds contain the following rare plants species of special emphasis in the region, though not all are found at any one pond: drowned or inundated horned-rush (Rhynchospora inundata), long-beaked bald-rush (Psilocarya scirpoides) and rush bladderwort (Utricularia juncea). The area also supports a good population of Hessel's hairstreak (Mitouri hesseli), a regionally rare species of butterfly associated with Atlantic white cedar. The Owl Pond Cedar swamp is one of the few remaining white cedar swamps on Long Island and is most notable for its abundance of Walter's sedge (Carex walteriana), a species of relatively restricted and local occurrence along the East Coast. There are unconfirmed reports that the area contains Lemmer's noctuid moth (Lithophane lemmeri) and Hessel's hairstreak. This area is also an important groundwater recharge area for Long Island.
VII. THREATS: The tern and piping plover nesting beaches at Red Cedar Point and Goose Creek Point are highly vulnerable to human-related disturbances during the critical nesting period (mid-April to August), particularly to recreational activities such as beach-walking and picnicking, boat landings and off-road vehicle use, as well as predation and disturbance from dogs and cats. Most of the County lands are protected from any habitat alteration, but at present there is little specific management directed at some of the more rare and vulnerable resources, such as the Coastal Plain ponds and surrounding fire-maintained pineland forests. The encroachment of development is a potential problem throughout the region and is of particular concern to privately held areas such as Owl Pond. Development and construction activities adjacent to the complex could potentially impact water quality both in Flanders Bay and the groundwater, which could, in turn, threaten the fish, wildlife and plant resources using these areas.
VIII. CONSERVATION CONSIDERATIONS: Particular attention needs to be focused on protecting the water quality of Flanders Bay and the value of this body of water and associated wetlands to wintering and migrating waterfowl, shellfish beds, spawning and juvenile finfish, and nesting waterbirds. Protective measures should include stringent regulatory overview and enforcement of existing environmental laws, as well as developing and implementing cooperative and environmentally sound zoning and planning policies. Commercially and recreationally harvested species of waterfowl and fish need to be diligently monitored to ensure that optimum sustainable populations are maintained over the area for the long term. Disturbances to colonial beach-nesting birds and wintering concentrations of waterfowl should be minimized or prevented altogether, particularly for the latter group. Protective exclosures, beach closures, warden patrols predator removal, and public education programs are some of the actions that should be initiated to protect tern and piping plover colonies. Efforts should be made by appropriate Federal and State agencies to identify and implement those objectives and tasks of the piping plover recovery plan that may be applicable to this area. The development of cooperative management agreements and conservation plans should be considered between The Nature Conservancy and Suffolk County for the management and protection of the unique Coastal Plain ponds and surrounding pinelands on County parklands. Protection of specific sites on private lands, such as the Owl Pond site, can be accomplished by a variety of land-protection mechanisms, including easements, cooperative agreements, zoning, tax incentives, land exchanges and acquisition.
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