Northeast Coastal Areas Study
Significant Coastal Habitats
Site 5 (NY)
I. SITE NAME: Peconic River - Pinelands Complex
II. LOCATION: The headwaters of the Peconic River arise near Brookhaven National Laboratory and the community of Ridge in the heart of the central Long Island Coastal Plain pine barrens, or pinelands. Just east of the Laboratory, the river flows in a west to east direction past the Town of Riverhead and enters into Flanders Bay, a distance of about 12 miles (19 km). The pinelands in this area extend in a broad belt several miles in width north, south and west of the river.
TOWNS: Brookhaven, Riverhead, Southampton
COUNTY: Suffolk
STATE: New York
USGS 7.5 MIN QUADS: Moriches, NY 40072-77;
Mattituck, NY 40072-85; Riverhead, NY 40072-86; Wading River, NY
40072-87; Middle Island, NY 40072-88
USGS 30x60 MIN QUAD: Long Island, East 40072-E1
III. GENERAL BOUNDARY: The boundary outline of this area is delineated on the accompanying map. Although the river itself begins a short distance west of Brookhaven National Laboratory in the Town of Brookhaven, just south of Ridge, the primary area of focus on the river is from its headwater ponds east and northeast of the Laboratory eastward for a distance of approximately 15 miles (24 km) to the river's terminus in Flanders Bay, between the two forks of eastern Long Island. The pinelands of eastern Long Island as a whole cover an area approximately 25 miles (40 km) in an east-west direction and 7-8 miles (12 km) in its widest dimensions in a north-south direction. The Peconic River bisects the pinelands into northern and southern sections, with the majority of the areas of interest and significance lying immediately adjacent to and south of the river.
At least three major areas of significance to fish and wildlife resources, unique plant communities or regional biological diversity can be recognized within this complex, but because of their functional and structural interrelatedness and proximity to each other, as well as the need to consider their management in the aggregate, they are grouped here as part of a greater ecological entity, the Peconic River-Pinelands complex. These areas are: 1) Peconic River and Headwaters; 2) Dwarf Pine Plains; and 3) Bald Hills Pine Plains. Each of these major areas, or macrosites as they are sometimes called, is delineated on the accompanying map. The approximate dimensions of this rectangular core area of significant habitats is 12 miles (19 km) in an east-west direction and 6 miles (10 km) in a north-south direction.
IV. OWNERSHIP/PROTECTED STATUS: Approximately half of the area is owned by Suffolk County and managed in cooperation with The Nature Conservancy, and the rest by multiple private landowners and the U.S. Government.
V. GENERAL HABITAT DESCRIPTION: Throughout most of its length, the Peconic River is a rather warm, slow-moving, naturally acidic, and nutrient poor freshwater stream ecosystem. In its upper reaches the river has a wilderness character, bordered by marshes dominated by such species as water willow (Decodon verticillatus), blunt manna-grass (Glyceria obtusa), tussock sedge (Carex stricta), and bluejoint grass (Calamagrostis canadensis), red maple (Acer rubrum) and Atlantic white cedar (Chamaecyparis thyoides) swamps, upland forests of pitch pine (Pinus rigida) (including excellent stands of pine barrens) and white oak (Quercus alba), and a small number of houses. In this headwater area the river is generally very narrow, heavily vegetated, and bordered with a variety of bog plant species, including leatherleaf (Chamaedaphne calyculata), pitcher plant (Sarracenia purpurea), round-leaved sundew (Drosera rotundifolia), and several species of sphagnum or peat mosses. Further downstream, commercial and residential development increases as the river approaches the Town of Riverhead. Shallow, groundwater-fed Coastal Plain ponds, some formerly cultivated for cranberries (Vaccinium macrocarpon), are found throughout the headwaters area, many in pristine condition. These ponds are characterized by seasonally and annually fluctuating water levels with well-developed shoreline vegetation.
South of the Ronkonkoma Moraine, along the outwash plain, is the dwarf pine plains area where a pygmy forest of dwarf pitch pines and scrub or bear oaks (Quercus ilicifolia) forms the dominant vegetation. The canopy is generally less than 6 feet (2 meters) in height and often forms a dense thicket. Almost all of the cones produced by these pine trees are of the closed cone (serotinous) type, characteristic of pineland areas experiencing frequent wildfires. Soils in this area are extremely sandy and nutrient poor. The shrub and herb layers are generally dominated by ericaceous plants such as huckleberry (Gaylussacia baccata), bearberry (Arctostaphylos uva-ursi), blueberry (Vaccinium pallidum) and wintergreen (Gaultheria procumbens), as well as little bluestem (Schizachyrium scoparius). The groundcover frequently consists of a dense and diverse lichen flora.
Within the central pinelands is a large and undeveloped area marked by low, rolling hills of the Ronkonkoma Moraine which contains a dense pitch pine and oak (Quercus coccinea, Q. rubra, Q. alba., Q. velutina) forest with an understory dominated by scrub/bear oak and ericaceous shrubs (blueberries and huckleberry) in what is commonly called the Bald Hill Pine Barrens or Manorville Hills. The herbaceous layer is often sparse. The area is also characterized by having many kettlehole ponds.
VI. SIGNIFICANCE/UNIQUENESS OF AREA: The Peconic River is one of four major rivers on Long Island and much of its upper watershed remains relatively undisturbed. It is not only the longest river on Long Island, but the longest groundwater river in New York State. It has been nominated as a potential Wild and Scenic River by the U.S. Department of the Interior and is under review by the State of New York for designation as a "Wild, Scenic or Recreational River". The river is a productive warmwater fishery, with naturally reproducing populations of largemouth bass (Micropterus salmoides), chain pickerel (Esox niger), swamp darter (Etheostoma fusiforme) and banded sunfish (Enneacanthus obesus), the latter a native species and occurring here in one of only two localities in New York State and certainly the most significant. Many species of birds inhabit the wetlands bordering the river, particularly several species of special emphasis in the region, including Canada goose (Branta canadensis), American black duck (Anas rubripes), mallard (Anas platyrhynchos), American wigeon (Anas americana), pied-billed grebe (Podiceps grisegena) and American bittern (Botaurus lentiginosus). The headwaters of the Peconic River support a number of extremely rare natural communities in pristine condition, most notably Coastal Plain ponds. Because the water levels of the groundwater-fed Coastal Plain ponds fluctuate seasonally and annually, the composition of the pond shore vegetation varies with the water levels. During dry periods more substrate is exposed and whole assemblages of globally rare plants, mostly annuals, are abundant on the pond shores. Included in this group of rare plants are short-beaked bald-rush (Psilocarya nitens), slender arrowhead (Sagittaria teres), southern bladderwort (Utricularia juncea) and pink tickseed (Coreopsis rosea). In some years the Coastal Plain ponds dry up completely, making them uninhabitable for fish. This phenomenon makes them ideal breeding habitat for salamanders, including the regionally rare tiger salamander (Ambystoma tigrinum), found principally in the Long Island pinelands. The best New York example of a Coastal Plain Atlantic white cedar swamp is found in the Peconic River drainage. This globally rare natural community occurs in depressions on poorly drained organic soils of the Coastal Plain. Dominated by Atlantic white cedar, this community characteristically supports a number of rare butterflies and moths, including several rare and interesting species such as Hessel's hairstreak (Mitoura hesseli) and Lemmer's noctuid moth (Lithophane lemmeri).
Dwarf pine plains are known from only three sites in the world: the New Jersey Pygmy Pine Plains, Shawangunk Mountain Dwarf Pine Plains, and the Long Island Dwarf Pine Plains. The Long Island site harbors several rare plant and animal species including one of the largest and best populations of the rare pine barrens buck moth (Hemileuca maia) in New York. A breeding population of at least three pairs of northern harriers (Circus cyaneus) within the dwarf pine plains is of regional interest and significance.
VII. THREATS: The lowermost reaches of the Peconic River are commercially and residentially developed, and development continues to encroach upstream. Although massive suburbanization has not yet hit the Peconic pineland region, some areas are already threatened with subdivisions and other development schemes. Increased development of the region could degrade water quality, increase turbidity, alter the hydrology and increase discharges of pesticides or hazardous materials into the river or ponds to the detriment of aquatic species. Eutrophication from fertilizers, septic tanks, road runoff and farmlands is of considerable concern, as such over-enrichment of naturally acidic and nutrient-poor waters could lead to invasions and dominance by exotic, nutrient-loving weedy plants and displacement of the native flora. Elimination or disturbance of adjacent wetland and forest habitat would adversely impact rare or uncommon wildlife and plant species. Suppression of wildfires - so essential to the maintenance of the pine barrens ecosystem - could result in marked vegetation changes and loss of the characteristic pinelands biota, including many of its rare species.
VIII. CONSERVATION CONSIDERATIONS: This remarkable river and pinelands complex, particularly its headwater ponds and pygmy pine plains, is of high regional significance and should be protected and managed to the greatest extent possible to ensure the perpetuation of its unique natural communities and rare species, many of which are not found elsewhere in the region, or as well-developed or in such concentrations. Protection of water quality in the river and its tributaries and the maintenance of its resident fish populations should be given high priority by Federal and State regulatory agencies. In addition to developing cooperative conservation and management agreements between or among private landowners, the State, County and Town governments and The Nature Conservancy, acquisition of certain headwater areas and ponds should be considered as an option in certain areas imminently threatened with development, as should also regulatory and zoning options. Fire management plans need to be developed and implemented over the whole of the region, but especially in the Bald Hill and Pygmy Plain areas.
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