SIGNIFICANT HABITATS AND HABITAT
OF THE NEW YORK BIGHT WATERSHED
Valley Calcareous Wetlands Complex
List of Species of Special Emphasis
I. SITE NAME: Harlem Valley Calcareous Wetlands Complex
II. SITE LOCATION: The Harlem Valley calcareous wetlands complex is composed of the valleys and adjacent ridges in the Taconic Highlands of easternmost Putnam, Dutchess, and Columbia Counties in New York and small adjacent areas of the Taconic Mountains and valleys in Connecticut and Massachusetts. Two separate wetland complexes are recognized: the Great Swamp from Brewster, New York north to South Amenia, New York, and the Northeast-Ancram fen complex from Sharon, Connecticut, north to Copake Falls, New York. The lowlands occupy a long north-south valley west of the Taconic Mountains called the Harlem Valley (after the railroad line) from which this complex takes its name.
TOWNS: Amenia, Ancram, Dover, Northeast, Patterson, Pawling, Pine Plains, Southeast, NY; Kent, New Fairfield, Salisbury, Sharon, CT; Mount Washington, MA.
COUNTIES: Putnam, Dutchess, Columbia, NY; Fairfield, Litchfield, CT; Berkshire, MA
STATES: New York, Connecticut, Massachusetts
USGS 7.5 MIN QUADS: Brewster, NY (41073-45), Lake Carmel, NY (41073-46), Pawling, NY (41073-55), Poughquag, NY (41073-56), Kent, CT (41073-64), Dover Plains, NY (41073-65), Amenia, NY (41073-75), Sharon, CT (41073-84), Millerton, NY (41073-85), Bashbish Falls, MA (42073-14), Copake, NY (42073-15)
USGS 30 X 60 MIN QUADS: Bridgeport, CT-NY (41073-81), Waterbury CT-NY (41073-E1), Pittsfield MA-NY (42073-A1)
III. BOUNDARY DESCRIPTION AND JUSTIFICATION: The Great Swamp boundary follows the ridgetops that form the immediate watershed of the wetlands from just north of the East Branch and Bog Brook Reservoirs to just north of the Wassaic State School. The habitat complex also includes adjoining East Mountain and West Mountain. The Great Swamp habitat area includes the wetlands of the Harlem Valley adjacent and proximate to the East Branch of the Croton River, Swamp River, and Ten Mile River; marble hills emerging from the floor of the Harlem Valley; and mountainous slopes on the east and west sides of the Harlem Valley. There is a drainage divide between the Hudson River and the Housatonic River watersheds at the village of Pawling where the East Branch of the Croton River flows to the south into the Hudson and the Swamp River flows to the north into the Housatonic watershed. Although the watersheds are separate, the swamp itself is continuous over both watersheds.
The habitat boundary for the Northeast-Ancram fen complex follows the ridgetop of the Taconic Mountain range (Washburn, Alander, Brace, and Thorpe Mountains) from Copake, New York, southward to State Line, Connecticut. Included is the wetland complex at State Line and the ridges just west of Indian Lake south to Sharon Station Road. The southern boundary follows Sharon Station Road west and Sheffield Hill Road-Coleman Station Road northwest almost to Route 22, then trends northwestward along hilltops past the hamlet of Pulvers Corners into Columbia County and approximately northward from Prospect Hill to Smith Hill; it then proceeds west of Drowned Lands Swamp and Miller Pond to Copake and eastward to the ridge. This site includes the wetlands and immediate watershed of the Drowned Lands Swamp, Punch Brook, and Bashbish Brook on the western half of this complex, and the chain of wetlands along the Noster Kill and Webatuck Creek on the eastern half of this complex; it includes the Panhandle or Oblong of the northeastern corner of Dutchess County southward towards Millerton, and the western escarpment of the Taconic Mountains. The southern portion of the Panhandle wetlands and the wetlands south of Millerton drain southeastward to the Housatonic watershed. The northern portion of the Panhandle wetlands and the Drowned Lands area drain into the Roeliff-Jansen Kill, which is part of the Hudson River watershed. The boundary encompasses the calcareous wetlands and uplands and ridgetop habitat which support rare reptiles, waterfowl, and raptors, as well as rare plant habitats and communities.
The narrative and map focus on those rare animal and plant populations and rare communities that are in or contiguous to the Hudson River watershed at the southern (Great Swamp) and northern (Northeast-Ancram) ends of the Harlem Valley. It should be noted that similar calcareous wetlands and adjacent upland habitats occur between these two habitat subunits as well as in northwestern Connecticut and southwestern Massachusetts. This entire tri-corner area of New York, Massachusetts, and Connecticut likely supports many of the same rare species and communities described in this narrative. Additional studies both inside and outside the Hudson River watershed are necessary in order to accurately identify, delineate, and link the full array of wetlands and rare species populations that doubtlessly occur over the greater region, particularly in the Housatonic watershed in Massachusetts and Connecticut.
IV. OWNERSHIP/PROTECTION/RECOGNITION: Most of the wetlands and uplands in this habitat complex are in private ownership. The Nature Conservancy owns and manages two small preserves in the Great Swamp, Nellie Hill Preserve and Great Swamp Preserve. The New York State Department of Environmental Conservation owns the Bog Brook Unique Area at the south end of Great Swamp, Cranberry Mountain Wildlife Management Area in central Great Swamp, and the Wassaic Multiple Use Area at the north end of Great Swamp. The New York State Office of Parks, Recreation and Historic Preservation owns large areas in the easternmost part of the Northeast-Ancram fen complex near the state line north of Millerton (portions of Taconic State Park). Wetlands are regulated in New York under the state's Freshwater Wetlands Act of 1975 and Tidal Wetlands Act of 1977; these statutes are in addition to federal regulation under Section 10 of the Rivers and Harbors Act of 1899, Section 404 of the Clean Water Act of 1977, and various Executive Orders. The New York State Natural Heritage Program, in conjunction with The Nature Conservancy, recognizes several Priority Sites for Biodiversity within the Harlem Valley calcareous wetland habitat complex. These sites are listed here along with their biodiversity ranks: Dutchess Meadows (B2 - very high biodiversity significance), Miller Pond (B2), Brace Mountain (B3 - high biodiversity significance), Dover Sand Hills (B3), Drowned Lands Swamp (B3), Great Swamp (B3), Mount Riga Fen (B3), Nellie Hill (B3), and Overmountain Road (B3). There are some large, unprotected, private holdings in the mountains, e.g., those of the Preston Mountain Club (a sporting club) on Dover East Mountain, and of the Mount Riga Corporation, which owns Grassy Pond and areas northward, adjoining corporation lands in Connecticut.
V. GENERAL AREA DESCRIPTION: In the lowlands of the Harlem Valley, there is a variety of calcareous wetlands belonging to the Great Swamp proper, including red maple (Acer rubrum) hardwood swamps, cattail (Typha spp.) marshes, shrub carr, wet meadows, and fens. The contiguous wetlands along the East Branch and the Swamp River total several square miles; there are, in addition, many wetlands close to the East Branch and Swamp River floodplains and connected to them by short stream channels, although some of these peripheral wetlands have been isolated by fill. The extent and the alkaline nature of these wetlands make them especially significant biologically. The Metro North Harlem Line railroad runs through portions of the Great Swamp. There are also a circumneutral bog lake and associated fens at Swift Pond (town of Amenia), and a cattail marsh at Cleavers Swamp southwest of Swift Pond.
Several marble hills such as Nellie Hill, Dover Sand Hills, and Sherman Hill project above the outwash valley floor at elevations averaging about 180 meters (600 feet). Most of the marble hills are covered with forest or abandoned pasture communities; eastern red cedar (Juniperus virginiana) is often an important species in the latter. These hills are marble outcrops and areas of highly calcareous fine sand derived from weathering of the marble and/or glacial till.
Ridges on the east and west sides of the Harlem Valley are underlain by metamorphic rocks, predominantly schist, and the bedrock and soils in these areas tend to be acidic. Extensive areas of these ridges are characterized by ledges, slabs, talus, and associated "rocky crest" vegetation of grasses, shrubs, and stunted or widely spaced trees. The mountains also have a number of acidic wetlands and ponds interspersed over their slopes.
The Northeast-Ancram fen complex is a network of rolling hills and wetlands underlain by carbonate bedrock in the Harlem Valley south and north of Millerton and in the Drowned Lands area; it includes higher hills of metamorphic rocks, mostly or entirely schist, and a high schist ridge, reaching about 600 meters (2,000 feet) elevation, that includes Brace Mountain. Agricultural lands, extensive upland forests, rocky crests, and very extensive wetlands characterize the site. The wetlands include wooded swamps with hardwoods, shrub carr with alder (Alnus spp.), tussock sedge meadows, wet pastures, wet hay meadows, beaver ponds, marshes with cattail, and fens. Some of the fens are of high quality, i.e., low, sedge-dominated plant communities with minimal obvious disturbance. The higher hills are partly or largely forested with hardwoods. Brace Mountain has extensive hardwood forests and large areas of acidic rocky crest habitat with herbaceous and shrubby vegetation. Grassy Pond is bordered by acidic bog vegetation.
VI. ECOLOGICAL SIGNIFICANCE/UNIQUENESS OF SITE: The mosaic of calcareous wetlands and adjacent uplands in the Harlem Valley supports regionally significant rare reptile populations and rare calcareous communities and plant species, incorporating 99 species of special emphasis, and including the following federally and state-listed species and other national and regional species of concern. (Living resources and their habitats are dynamic; therefore, the ecological significance and species information presented here may not be complete or up-to-date. State and federal environmental agencies [see Appendix III for office contacts] should be consulted for additional information.)
bog turtle (Clemmys muhlenbergii)
Federal species of concern(1)
northern goshawk (Acciptiter gentilis)
handsome sedge (Carex formosa)
New England blazing star (Liatris scariosa var. novae-angliae [= L. borealis])
1Species of special concern listed here include former Category 2 candidates.
side-oats gramma grass (Bouteloua curtipendula)
Torrey's mountain mint (Pycnanthemum torrei)
2Noted species are listed in New York State; several of these species are also listed by the adjacent states of Connecticut and Massachusetts.
timber rattlesnake (Crotalus horridus)
red-shouldered hawk (Buteo lineatus)
mountain spleenwort (Asplenium montanum)
southern yellow flax (Linum medium var. texanum)
spreading globe flower (Trollius laxus ssp. laxus)
scarlet Indian paintbrush (Castilleja coccinea)
marsh valerian (Valeriana sitchensis spp. uliginosa)
State-listed special concern animals
eastern hognose snake (Heterodon platyrhinos)
spotted turtle (Clemmys guttata)
wood turtle (Clemmys insculpta)
eastern bluebird (Sialia sialis)
long-eared myotis (Myotis septentrionalis)
State-listed rare plants
Atlantic white cedar (Chamaecyparis thyoides)
Bicknell's sedge (Carex bicknellii)
Bush's sedge (Carex bushii)
red-rooted flatsedge (Cyperus erythrorhizos)
blunt spikerush (Eleocharis obtusa var. ovata)
large twayblade (Liparis lilifolia)
blazing star (Chamaelirium luteum)
green milkweed (Asclepias viridiflora)
swamp birch (Betula pumila)
Virginia false-gromwell (Onosmodium virginianum)
Carolina whitlow-grass (Draba reptans)
field-dodder (Cuscuta campestris)
soapwort gentian (Gentiana saponaria)
rough pennyroyal (Hedeoma hispidum)
grooved yellow flax (Linum sulcatum)
swamp agrimony (Agrimonia parviflora)
These calcareous wetlands have concentrations of rare elements that are truly exceptional for an inland site in the New York Bight watershed, i.e., away from the Hudson River east of the Hudson Valley. This species concentration and the requirements of certain species, such as the bog turtle for large undeveloped habitat complexes, are responsible for the large areal extent of the currently delineated site. There are at least six documented bog turtle populations at the Great Swamp complex, some of which are in extensive habitat units. There are also historical records and isolated recent records of bog turtles that may represent extant populations in need of further field studies and verification, and probably additional populations not yet represented by any record. Bog turtles appear to be widespread, especially in fens peripheral to the Great Swamp proper, i.e., above the floodplain. There are five known bog turtle populations in the Northeast-Ancram area, plus additional single records of bog turtle, some of which were in or near suitable habitat, and large areas of potential habitat that have not yet been surveyed for bog turtle. The two best-studied bog turtle populations are located in extensive continuous areas of habitat, one of which is of very high quality. With further field work, it is likely that several additional bog turtle populations will be discovered; even with current knowledge, the site is considered the best bog turtle habitat complex in this Hudson Valley region. Bog turtles are at the northeastern extreme of their geographic range in southern New England and are restricted there to "marble valley" habitat complexes with apparently mild spring microclimates. A small number of extant bog turtle sites are found in southwestern Massachusetts and the western edge of Connecticut continuous with this delineation (see calcareous habitats chapter).
Some of the fens and fen-like areas of the site also support regionally rare plants. Great Swamp has several rare calcareous communities and plants, including swamp birch, Long's bittercress (Cardamine longii), and field-dodder in the wooded swamp. Red-rooted flatsedge occurs on a disturbed site within the swamp. A small but exemplary occurrence of a rich, sloping fen community appears on the Muddy Brook tributary to Great Swamp. Two rare plants, spreading globe flower and blazing star, occur in the mosaic of old pasture and fen communities at this site.
Drowned Lands Swamp and Miller Pond in the Northeast-Ancram area are sizable wetland areas with good occurrences of red maple-tamarack peat swamps grading into rich shrub fens with several rare plants, including swamp birch, marsh valerian, and handsome sedge. Mount Riga Fen is a good occurrence of a medium fen grading into a shrub fen and red maple swamp.
Several marble hills or marble knolls on the valley floor support an assemblage of rare plants associated with old pasture and/or calcareous soils and outcrops. Good examples of calcareous rocky summit communities occur on these marble hills. Rare plants include green milkweed, Carolina whitlow-grass, grooved yellow flax, Bicknell's sedge, New England blazing star, Virginia false gromwell, rough pennyroyal, Torrey's mountain mint, blazing star, large twayblade, and side-oats gramma grass. Nellie Hill is the best example of this community type; Dover Sand Hills and Sherman Hill are also good examples.
In the mountains on both sides of the Harlem Valley northwards, timber rattlesnake populations occupy a number of den sites, most notably on West Mountain and East Mountain. The ledges, talus, acidic rocky crest savannas, woodlands, burn areas, and associated habitats also support northern copperhead (Agkistrodon contortrix mokasen) and five-lined skink (Eumeces fasciatus). Common raven (Corvus corax) probably nests in these areas. The summit of Brace Mountain has a grass and sedge meadow grading into a woodland with dwarf red oak (Quercus rubra), gray birch (Petula populifolia), and the rare hay sedge (Carex argyrantha). Depressions contain small and large wetlands, some quite acidic. One such wetland, Tamarack Swamp, between East Mountain and Schaghticoke Mountain, is an eastern hemlock (Tsuga canadensis) bog. Several warbler species that are rare breeders in the watershed are known to nest in the mountains.
In addition to the state-listed species, the Northeast-Ancram site supports many regionally rare species such as bladderwort (Utricularia geminiscapa) in the Panhandle wetlands, three-toothed cinquefoil (Potentilla tridentata) on Brace Mountain, and the dogwood thyatirid moth (Euthyatira pudens) in a lowland area adjoining the site. There is at least one known limestone cave, Indian Oven Cave on Round Ball Mountain, that provides a hibernaculum for wintering bats, including the special concern long-eared myotis. Biological survey work has been limited; many more occurrences of rare elements are expected to be found. For example, there has been no field work on invertebrates or mammals, and many areas of likely habitat have not been surveyed for bog turtle or rare plants.
The deeper marshes and some of the ponds in this complex are important habitats for waterfowl and marsh birds. Rudd Pond is used by many diving ducks during migration, and dabbling ducks use the wetlands widely in migration and during the breeding season. The extensive wooded swamps support breeding red-shouldered hawk and concentrations of migrating warblers. One area on the East Branch just upstream of the Route 22 crossing near Haines Corners is an extensive, old-growth, hardwoods floodplain savanna with huge ashes (Fraxinus spp.) and maples (Acer spp.), unlike anything else in the region.
VII. THREATS AND SPECIAL PROBLEMS: Residential and industrial development are preempting habitat in many areas and altering the margins of the Great Swamp proper. Construction of residences and driveways in the rocky, mountainous areas will interfere with rattlesnake movements and result in accidental and intentional killing of snakes. There are active and proposed mining (soil and hard rock) operations that are likely to pollute wetlands and streams, alter habitats, and result in the death of small animals such as reptiles and amphibians that wander into work areas. The river waters are purportedly causing eutrophication of floodplain wetlands, and further nutrient loading from sewage, industrial effluents, highway runoff, and agricultural runoff is undesirable. Invasion by exotic species, especially purple loosestrife (Lythrum salicaria), is displacing native species in many wetland areas. Proposed disposal areas for construction and demolition debris are of real concern and illegal dumping in wetlands is already a problem. Many fens have been degraded by nutrient loading, alteration of groundwater discharge, or overgrazing. Construction of dams has affected marshes and wet meadows. Fill and other alterations have apparently obliterated a former wetland connection across the drainage divide between the East Branch and the Swamp River in the village of Pawling. There are serious concerns that expansion of residential and commercial areas, roads, and railroads will further fragment and isolate bog turtle populations in this area. Collecting of timber rattlesnake, bog turtle, and other vulnerable reptiles, as well as rare plants, is a problem and should be guarded against through education and enforcement. Succession, canopy closure, and shading by red cedar and other tall plants are affecting the rare plants of the marble hills in some cases. Existing and proposed soil mines are widespread and need to be monitored for environmental problems such as siltation, dust, and encroachment on significant habitats. Widening of Route 22 and other roads in this area will result in loss of wetland and upland habitat, destroy rare plant populations, and create barriers to migration for bog turtles. Moderately heavy recreational use is a potential problem on the Brace Mountain-Alander Mountain ridge where there is localized trail erosion and degradation of rocky crest habitats.
VIII. CONSERVATION RECOMMENDATIONS: Further study and field surveys of the distribution, population status, habitat use, and movement patterns of the bog turtle, in particular, and other species are needed throughout the entire complex of calcareous wetlands in this tri-state region. Protection of wetlands and their buffer zones, as well as of the movement corridors and road crossings connecting wetlands, is a high priority. Posted speed limits and Wildlife Crossing or Turtle Crossing signs are needed locally. It is especially important to determine, protect, and maintain buffer zones and corridors between populations or metapopulations of bog turtles. Protection of the known bog turtle habitats is greatly needed, as is additional bog turtle survey work. More information is needed on wetlands and other features within and outside the site boundaries so informed actions can be taken. Levels of grazing beneficial to bog turtle habitats and fen communities will need to be determined; light grazing is likely to be beneficial, but heavy grazing harmful. Fire management and/or control of exotics may be needed to maintain the calcareous rocky summit communities and associated rare plants. Light grazing by dairy cows would help maintain these areas as cedar glades, but management studies are clearly indicated. Control of purple loosestrife in the wetlands should be investigated and actions implemented. Cumulative and offsite impact assessment for new projects proposed under the National Environmental Policy Act and State Environmental Quality Review Act will be crucial. Landscape and habitat conservation should involve local citizens and allow continuation of viable economic activities such as agriculture in a sustainable manner. The U.S. Fish and Wildlife Service, New York State Department of Environmental Conservation, The Nature Conservancy, Hudsonia, and other agencies and organizations, should work together to set priorities for bog turtle sites in the Harlem Valley and determine relationships between populations in close proximity.
Mining and quarrying proposals should be carefully reviewed for impacts on rare species and communities, and post-mining restoration to rare species habitats, rather than lakes or farmland, should be required in some instances. All applications for permits for residential, commercial, and industrial development must be reviewed with habitat considerations in mind, and permits should regulate activities so that levels of silt, nutrients, and other pollutants are not increased downstream or downhill of activity. Off-site impacts and cumulative impacts, especially of water pollutants, should be assessed during the environmental planning process. Better enforcement of wetlands laws and other environmental laws is needed, probably with considerable assistance from local people. Most of all, education and collaboration are needed to help local citizens and decision makers understand the importance of landscape and habitat conservation as part of sustainable development. The Nature Conservancy Lower Hudson Chapter is active in study and conservation in the Great Swamp; the Friends of the Great Swamp, a local group, is also involved.
It is not necessarily best, nor possible, for government agencies or conservation organizations always to acquire all the lands needed to protect a rare community type or important habitat. Various approaches and strategies exist for protecting valuable wildlife habitats; each provides different degrees of protection and requires different levels of commitment by regulatory agencies, conservation organizations, and landowners. These techniques include combined public and private financing, land exchanges, conservation easements, cooperative management agreements, mutual covenants, purchase of development rights, comprehensive planning, zoning and land-use regulations, enforcement of existing local, state, and federal regulations, and fee simple acquisition. Techniques can be combined to develop a strategy for land protection that is tailored to a specific site. Partnerships among individual landowners within habitat complexes offer an exciting, practical, and innovative approach to the large, landscape-scale habitats recognized here.
Barbour, S. 1994. Biological reconnaissance of the Mount Riga uplands. Unpublished report to the New York State Department of Parks, Recreation and Historic Preservation and to the Mt. Riga Corporation. Hudsonia Ltd., Annandale, NY. 13 p.
Barbour, S. 1994. Biological reconnaissance of a proposed extension of the Harlem Valley Rail Trail. Unpublished report to the New York State Office of Parks, Recreation, and Historic Preservation. Hudsonia Ltd., Annandale, NY. 11 p.
Kiviat, E., P. Groffman, G. Stevens, S. Nyman, and G. Hansen. In prep. Characterization of reference wetlands in eastern New York. Unpublished report to the U.S. Environmental Protection Agency, New York, NY, Hudsonia Ltd., and the Institute of Ecosystem Studies.
Kiviat, E., M.W. Klemens, G. Stevens, and J.L. Behler. 1993. Southeastern New York bog turtle survey. Unpublished report to New York State Department of Environmental Conservation, Hudsonia Ltd., and the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. 67 p. [Confidential; filed with NYSDEC.]
Kiviat, E., S. Barbour, R.E. Schmidt, and L. Leonardi. 1989. Ecological assessment of the Neer Mine site and surroundings, towns of Ancram and Northeast, Columbia and Dutchess Counties, New York. Unpublished report to the Taconic Valley Preservation Alliance. Hudsonia Ltd., Annandale, NY. 40 p.
Kiviat, E. 1984. Significant areas in the town of Pawling, Dutchess County, New York. Unpublished report to Town of Pawling Conservation Advisory Board. Hudsonia Ltd., Annandale, NY. 3 p.
Kiviat, E. 1988. Significant habitats of the town of Dover, Dutchess County, New York. Unpublished report to the Town of Dover Planning Board. Hudsonia Ltd., Annandale, NY. 46 p.
Kiviat, E. 1988. Ecological survey and assessment of special habitats and species, proposed mine site, Dover Plains, New York. Unpublished report to O & G Industries. Hudsonia Ltd., Annandale, NY. 45 p.
Kiviat, E. and S. Barbour. 1988. Preliminary ecological survey and assessment of special habitats, Dover Plains proposed mine site, Town of Dover, Dutchess County, New York. Unpublished report to O & G Industries. Hudsonia Ltd., Annandale, NY. 21 p.
Klemens, M.W. 1993. Amphibians and reptiles of Connecticut and adjacent regions. State Geological and Natural History Survey of Connecticut, Bulletin No. 112.
McVaugh, R. 1958. Flora of the Columbia County area, New York. New York State Museum and Science Service Bulletins 360, 360A. 433 p.
Nyman, S. 1987. Report for the Squire Green at Pawling Homeowner's Association: a summary of habitats and a review of the open space management plan. Unpublished report to Highview Development Partnership. Hudsonia Ltd., Annandale, NY. 10 p. (In offering plan for the Squire Green at Pawling Homeowners Association, Inc., p. 129.)
Regional Plan Association. 1991. Great Swamp Conservation Plan. Regional Plan Association, New York, NY.
List of Species of Special Emphasis
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