Passaic Meadows

List of Species of Special Emphasis



I. SITE NAME: Passaic Meadows


II. SITE LOCATION: The Passaic Meadows is located in northeastern New Jersey 18 kilometers (11 miles) west of Newark, New Jersey.

TOWNS: Bernards, Chatham, East Hanover, Harding, Fairfield, Lincoln Park, Livingston, Long Hill, Montville, Parsippany-Troy Hills, Roseland, West Caldwell

COUNTIES: Essex, Morris, Somerset

STATE: New Jersey

USGS 7.5 MIN QUADS: Roselle, NJ (40074-63), Chatham, NJ (40074-64), Bernardsville, NJ (40074-65), Caldwell, NJ (40074-73), Morristown, NJ (40074-74), Pompton Plains, NJ (40074-83)

USGS 30 x 60 MIN QUAD: Newark, NJ-NY (40074-E1)


III. BOUNDARY DESCRIPTION AND JUSTIFICATION: The boundary of the Passaic Meadows habitat complex encloses the wetlands and wetland buffer areas in the Passaic River valley from Basking Ridge northeast to Wayne Township, New Jersey. Specific wetlands include the Great Swamp, Black Meadows, Troy Meadows, Hatfield Swamp, Lee Meadows, Little Piece Meadows, Great Piece Meadows, and Bog and Vly Meadows. Developed upland areas within this boundary in the municipalities of Madison, Florham Park, Hanover, and East Hanover are excluded. This approximately 88-square kilometer (34-square mile) wetland area is one of the largest freshwater wetland complexes in the region and is especially significant given its location within the highly urbanized and suburbanized Northern Triassic Lowlands (Newark Basin). These wetlands support regionally significant populations of fish and wildlife, including several federal candidate and state-listed species. The wetlands are particularly significant for seasonal concentrations of waterfowl and waterbirds.


IV. OWNERSHIP/PROTECTION/RECOGNITION: Wetlands are regulated in New Jersey under the Freshwater Wetland Protection Act and Wetlands Act of 1970; 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. At the southwest end of the wetland complex is the 2,964-hectare (7,409-acre) Great Swamp National Wildlife Refuge managed by the U.S. Fish and Wildlife Service. The eastern half of the Refuge is designated as a Wilderness Area and is left undisturbed except for a small network of trails. The western half of the Refuge is actively managed to maintain a diversity of wildlife habitat. Several local and county parks, including Lord Stirling Park, Southard Park, the Somerset County Park and Environmental Education Center, and the Morris County Outdoor Education Center, abut the refuge. Troy Meadows Natural Area consists of six separate small parcels of freshwater marsh, swamp, and floodplain communities in the northern part of the habitat complex managed by the New Jersey Division of Parks and Forestry. Great Piece Meadows at the northernmost end of the complex is a state park also managed by the Division of Parks and Forestry. West Essex Park is a county park managed by Essex County that includes about 9 kilometers (5.6 miles) along the east side of the Passaic River. The Morristown Municipal Airport is located in the middle of Black Meadows. The rest of the habitat complex is privately owned. Canoe Brook Reservoirs just south of West Essex Park are owned by the New Jersey American Water Company. Wildlife Preserves, Inc. owns some of Troy Meadows. The New Jersey Natural Heritage Program recognizes four Priority Sites for Biodiversity within the habitat complex: Passaic Meadows Macrosite, which includes Troy Meadows and Great Piece Meadows, and Great Swamp, all with a biodiversity rank of B4 (moderate biodiversity significance). The U.S. Fish and Wildlife Service has designated the glacial Lake Passaic wetlands as a priority wetland site under the federal Emergency Wetlands Resources Act of 1986.


V. GENERAL AREA DESCRIPTION: Passaic Meadows is a large freshwater wetlands complex located in the upper Passaic River drainage in the Newark Basin of the Piedmont physiographic province. The wetlands complex is surrounded by low ridges; the Watchung Ridges composed of basalt (traprock) lie to the east and south, and the New York - New Jersey Highlands composed of crystalline rocks lie to the west. The Passaic River valley itself lies over soft red shale and sandstone laid down during the Triassic (about 200 million years ago). The creation of the wetlands in the basin began about 25,000 years ago as the most recent (Wisconsin) glacier began to retreat, trapping the meltwater between the glacier, glacial till, and ridges to form a large (78,000-hectare or 300-square mile) glacial lake referred to as Glacial Lake Passaic. About 10,000 to 12,000 years ago, the glacier scoured an outlet for the lake at Little Falls Gap, allowing the lake to drain out north and east following the present course of the Passaic River. The lake sediments from that glacial lake form the basis of the wetlands found in the valley today. Elevations in the Passaic Meadows range from about 73 meters (240 feet) above sea level at the southern end of Great Swamp to 49 meters (160 feet) in elevation where the Passaic River drains Great Piece Meadows at the northern end of the complex.

Vegetational communities found at Great Swamp at the southern end of the Passaic Basin include swamp woodland, hardwood ridges, cattail marsh, and grassland. The swamps are dominated by red maple (Acer rubrum), pin oak (Quercus palustris), and ash (Fraxinus spp.), with an understory of highbush blueberry (Vaccinium corymbosum), swamp rose (Rosa palustris), willow (Salix spp.), and a variety of herbaceous species. Low ridges and knolls rising from 1.5 to 4.6 meters (5 to 15 feet) above the swamp support mixed hardwood forests dominated by American beech (Fagus grandifolia), oaks (Quercus spp.), gray birch (Betula populifolia), sugar maple (Acer sacchaarinum), black gum (Nyssa sylvatica), white ash (Fraxinus americana), and shagbark hickory (Carya ovata). Smaller areas of other wetland communities include robust emergent marshes dominated by cattail (Typha latifolia and T. angustifolia) and bulrush (Scirpus fluviatalis and S. cyperinus), scrub-shrub swamps dominated by buttonbush (Cepahalanthus occidentalis), nonpersistent marshes dominated by arrow arum (Peltandra virginica), and several small ponds. There are about 220 hectares (540 acres) of open field and about 225 hectares (560 acres) of brush habitat maintained by mowing. The U.S. Fish and Wildlife Service also manages water levels in five impoundments for a total of 230 hectares (569 acres), with a few additional areas totaling about 12 hectares (30 acres). The watershed of the Great Swamp is 144 square kilometers (55.6 square miles). Great Swamp receives flow from Passaic River, Black Brook, Great Brook, Loantaka Brook, and Primrose Brook. Troy Meadows is a large wetland area of approximately 1,255 hectares (3,600 acres), about half of which is a large emergent marsh composed of cattails, common reed (Phragmites australis), and sedges (Carex spp.); the remainder is a mix of forested and scrub-shrub swamps, ephemeral ponds, floodplain, and grasslands. Troy Meadows receives flow from the Whippany, Rockaway, and Passaic Rivers, and is less disturbed than are the other central basin wetlands because it has been owned and protected by Wildlife Preserves, Inc. Great Piece Meadows is a mainly forested wetland with some scrub-shrub and emergent marsh areas of about 1,730 hectares (4,275 acres) in size with a mix of wetland community types similar to those of the Great Swamp. Great Piece Meadows receives flow from the Pequannock, Wanaque, and Ramapo Rivers.

Analysis of National Wetlands Inventory data (based on 1976 aerial photography) indicates that there is a total of 88 square kilometers (34 square miles) of wetlands in the basin. About 71% of the total wetland area, or 6,230 hectares (15,400 acres), is palustrine, forested, deciduous wetlands; about 16%, or 1,400 hectares (3,470 acres), is scrub-shrub wetlands; 10%, or 860 hectares (2,120 acres), is palustrine emergent marsh, with smaller amounts of riverine and lacustrine open water habitat. Analysis of wetland cover types completed in 1995 for the U.S. Army Corps of Engineers flood control project for the Passaic River basin (excluding Great Swamp) indicates a total of about 61% or 5,552 hectares (13,720 acres) of forested wetlands, 10% or 533 hectares (1,318 acres) scrub-shrub swamp, and 29% or 1,634 hectares (4,037 acres) of emergent marsh.

Passaic Meadows is surrounded by suburban residential and commercial land use, and much of the area has been impacted directly or indirectly by suburbanization. Several major highways run through or near the complex. Although some of the remaining open space in the watershed is publicly owned, much of it is privately owned and under increasing pressure for development.


VI. ECOLOGICAL SIGNIFICANCE/UNIQUENESS OF SITE: Passaic Meadows is a large, undeveloped wetland complex on the outskirts of the metropolitan New York City region that supports a diversity of regionally rare wildlife, especially migratory birds. Passaic Meadows supports 116 species of special emphasis, including 82 species of birds. (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.)

Federal candidate
bog turtle (Clemmys muhlenbergii)

State-listed endangered
blue-spotted salamander (Ambystoma laterale)
red-shouldered hawk (Buteo lineatus)
northern harrier (Circus cyaneus)
buttonbush dodder (Cuscuta cephalanthi)
Louisiana sedge (Carex louisianica)

State-listed threatened
wood turtle (Clemmys insculpta)
great blue heron (Ardea herodias)
American bittern (Botaurus lentiginosus)
long-eared owl (Asio otus)
barred owl (Strix varia)
red-headed woodpecker (Melanerpes erythrocephalus)
grasshopper sparrow (Ammodramus savannarum)
bobolink (Dolichonyx oryzivorous)

Two hundred and twenty-two species of birds have been identified in Great Swamp since 1960; typically, over 90 species of birds nest in the area. Breeding waterfowl include Canada goose (Branta canadensis), wood duck (Aix sponsa), green-winged teal (Anas crecca), American black duck (Anas rubripes), mallard (Anas platyrhynchos), blue-winged teal (Anas discors) and, occasionally, hooded merganser (Lophodytes cucullatus). Troy Meadows is also a productive waterfowl breeding area. The Great Swamp National Wildlife Refuge maintains about 350 wood duck nesting boxes. Breeding waterbirds within the habitat complex include great blue heron, American bittern, king rail (Rallus elegans), Virginia rail (Rallus limicola), sora (Porzana carolina), common moorhen (Gallinula chloropus), marsh wren (Cistothorus palustris), and, occasionally, sedge wren (Cistothorus platensis). Barred owl and red-shouldered hawk, two rare raptors that prefer wooded swamps, nest at several locations in the habitat complex. Northern harrier and long-eared owl, which prefer nesting in marsh and grassland habitat, have been sighted in Troy Meadows and Great Swamp during the breeding season and may nest there. The Watchung Ridges to the south, east, and north of the Passaic Meadows are an important migration route for raptors in both the spring and fall, as evidenced by hawk watches at several locations, including Montclair Hawk Lookout Sanctuary, Chimney Rock, and High Mountain. Autumn hawk flights contain predominantly osprey (Pandion haliaetus), northern harrier, sharp-shinned hawk (Accipiter striatus), broad-winged hawk (Buteo platypterus), red-tailed hawk (Buteo jamaicensis), American kestrel (Falco sparverius), and merlin (Falco columbarius). Spring flights contain similar species composition but are less concentrated along well-known corridors. The New York - New Jersey Highlands to the west and north of the habitat complex are also an important migratory raptor route. The variety of aquatic and upland habitat in the Passaic Meadows supports a prey base for those migrating raptors that stop in the area. Red-headed woodpecker nest and overwinter in Great Swamp; in one year (1983) 52 were recorded on a Christmas bird count. Several species of forest interior-nesting warblers, vireos, and thrushes nest in the area, and many more species of songbirds use the wetlands and uplands in the complex as migratory stopover habitat. Great Swamp has one of the largest eastern bluebird (Sialia sialis) breeding populations in the state, due to habitat and nest box programs. Migrant songbirds that are consistently abundant in spring mist-netting studies include veery (Catharus fuscescens), gray catbird (Dumetella carolinensis), yellow warbler (Dendroica petechia), yellow-rumped warbler (Dendroica coronata), black-and-white warbler (Mniotilta varia), and common yellowthroat (Geothylpis trichas). Grassland birds that utilize the wet meadows and upland grasslands include eastern meadowlark (Sturnella magna), grasshopper sparrow, and bobolink. November aerial waterfowl surveys of the Passaic Meadows average over 5,000 birds, primarily Canada goose, mallard, and American black duck with lesser numbers of green-winged teal, ring-necked duck (Aythya collaris), and American wigeon (Anas americana). Mid-winter (January) aerial survey data of the Passaic Meadows area average nearly 1,000 Canada geese and lesser numbers of mallard, scaup (Aythya spp.), American black duck, hooded merganser, and common merganser (Mergus merganser).

Twenty-nine species of finfish, dominated by warmwater species, have been found in the Great Swamp National Wildlife Refuge. Trout production waters occur just upstream of Great Swamp in Primrose Brook and the Passaic River. Thirty-five fish species have been identified for the central Passaic River basin, including the anadromous alewife (Alosa pseudoharengus) and the catadromous American eel (Anguilla rostrata). There are 18 species of amphibians and 21 species of reptiles in the Great Swamp. Twenty-four species of amphibians and 20 species of reptiles have been identified in the central Passaic River basin. The diversity of amphibian and reptile species is unusual in the highly developed Newark Basin. The Passaic Meadows has the only known occurrences of the blue-spotted salamander in New Jersey and the only remaining bog turtle habitat in the Piedmont physiographic province in New Jersey. Other regionally rare reptiles and amphibians include the wood turtle, eastern mud turtle (Kinosternon subrubrum), eastern box turtle (Terrapene carolina), five-lined skink (Eumeces fasciatus), eastern hognose snake (Heterodon platyrhinos), spotted salamander (Ambystoma maculatum), four-toed salamander (Hemidactylium scutatum), and northern cricket frog (Acris crepitans). Thirty-two species of mammals are known to occur in Great Swamp, including river otter (Lutra canadensis), mink (Mustela vison), coyote (Canis latrans), red fox (Vulpes vulpes), gray fox (Urocyon cinereoargenteus), and beaver (Castor canadensis).

Several rare plants occur in the Great Piece Meadows, including one of the northernmost known (and the only New Jersey) occurrence of Louisiana sedge as well as exemplary occurrences of cattail sedge (Carex typhina) and buttonbush dodder. Several regionally rare plants were recorded on a 1970 plant list for the Great Swamp. It is not known if any of them now occur. These include spearwort (Ranunculus pusillus), stonecrop (Sedum telephoides), and soapwort gentian (Gentiana saponaria). Along the Pompton River just north of the Great Piece Meadows are two rare plants, the variegated horsetail (Equisetum variegatum) and hemicarpha (Hemicarpha micrantha).


VII. THREATS AND SPECIAL PROBLEMS: The major threat to this wetland complex is the continued development of lands within the watershed. Increased development will result in increased flooding, sedimentation, and increased point and nonpoint source pollutant loads, including nutrients, suspended solids, and organic matter. There is contamination from landfills, especially Rolling Knoll landfill adjacent to the Great Swamp National Wildlife Refuge. Part of an asbestos Superfund site is located adjacent to the Refuge. Models and studies have indicated that changes in the watershed will result in increased volumes of runoff to, but possibly not through, Great Swamp, resulting in an increase in the duration and depth of water in the swamp. Flooding causes problems with management of impoundments for wildlife, displacement of bog turtles from shallow marsh habitat, introduction of predatory fish into vernal ponds used by blue-spotted salamanders, inability to control nuisance fish (carp), failure of waterfowl nesting and other low nesting species due to flooding, increased mortality of shrubs and trees in swamps due to standing water, changes in species composition (e.g., increase in cattail at the expense of bulrush), and reduced public access. The natural assimilative capacity of tributaries and wetlands is hindered by high loading rates and channelized flow. The flow of tributaries during dry periods will also be lower with increased development in the watershed, adversely affecting fish and wildlife that depend on these tributaries. The exotic purple loosestrife (Lythrum salicaria) has invaded many of the open wetland areas within this complex.


VIII. CONSERVATION RECOMMENDATIONS: A Great Swamp Watershed Advisory Committee was formed in 1989 by the state of New Jersey to review existing water quality and quantity, to review other studies involving the Great Swamp, and provide recommendations to the New Jersey Department of Environmental Protection on appropriate amendments to water quality plans and surface water quality standards. This committee has developed a report with recommendations for federal, state, and local governments to "enhance, preserve and protect the ecological, aesthetic, recreational, and cultural resources of the Great Swamp basin." The recommendations of this report should be followed, including the recommendations for regional planning. Development of remaining open space in the Great Swamp watershed should be limited and carefully planned in order to recharge groundwater, reduce erosion, reduce nonpoint source pollution, furnish flood control, and provide habitat. Wooded riparian buffers should be maintained or restored to control nonpoint source pollution and provide habitat. Nutrient (especially phosphorus) inputs should be limited by upgrading sewage treatment plants and controlling nonpoint source pollution. Monitoring of water quality and indicator species should happen on a regular basis. The Great Swamp Hydrologic Unit Area Project report by the U.S. Department of Agriculture, Natural Resources Conservation Service, recommends the use of best management practices to reduce nonpoint source pollution and improve water quality in tributaries to the Great Swamp. Initial efforts should focus on the most impaired stream reaches, particularly upper Great Brook, Loantaka Brook, and Black Brook. Best management practices include filter strips, riparian forest buffers, sand or sand-peat filters, multiple pond-wetland systems, enhanced extended detention basins, maintaining and retrofitting existing detention basins, various individual homeowner practices, and conversion of mowed turf to natural vegetation. In less developed tributary watersheds such as the Passaic River, Primrose Brook, and lower Great Brook, the emphasis should be on protection through watershed-based planning and local protection/management ordinances by all of the municipalities. A third group of best management practices specifically applies to the restoration of instream fish habitat and biodiversity, including streambank stabilization, preservation and enhancement of riparian buffers, stream deflectors, instream cover such as boulders and logs, and wedge dams. The remaining privately owned wetlands in the basin should be protected through a combination of easements and acquisition. The Passaic River Coalition, along with several other environmental organization in the state, has recommended that the central Passaic River basin become a National Wildlife Refuge.



Armstrong, M. and D. Westerling. 1984. Great Swamp National Wildlife Refuge hydrology study of watershed effects on the Refuge. U.S. Fish and Wildlife Service and Morris County Soil Conservation District.

Bosakowski, T. 1983. Status and distribution of raptors in the Great Swamp. New Jersey Audubon Society Records of New Jersey Birds 8(4):63-67.

Bosakowski, T., R. Kane, and D.W. Smith. 1989. Status and management of long-eared owl in New Jersey. New Jersey Audubon Society Records of New Jersey Birds 15(3): 42-46.

Great Swamp Watershed Advisory Committee. 1993. Great Swamp watershed advisory committee report to the New Jersey Department of Environmental Protection and Energy, vols. 1 and 2.

Heintzelman, D.S. 1986. The migration of hawks. Indiana University Press. 369 p.

Kane, R., W.J. Boyle, Jr., and A.R. Keith. 1985. Breeding birds of Great Swamp. New Jersey Audubon Society Records of New Jersey Birds 11(2):29-33.

Mahoney, J. 1989. Final Report, Fall 1989 mist netting study at the Great Swamp National Wildlife Refuge. Kean College of New Jersey, Union, NJ.

Mahoney, J. and S. Marchand. 1991. Spring 1991 mist netting study at the Great Swamp National Wildlife Refuge. Kean College of New Jersey, Union, NJ.

New Jersey Department of Environmental Protection. 1994. Classification of New Jersey waters as related to their suitability for trout. Office of Land and Water Planning and Division of Fish, Game and Wildlife, Bureau of Freshwater Fisheries.

New Jersey Natural Heritage Program. 1993. Site reports for Great Swamp macrosite, Troy Meadows, Great Piece Meadows.

Rutgers Cooperative Extension. 1991-1995. Swamp Sounds: newsletter of the USDA Great Swamp hydrologic unit area project, Piscataway, NJ.

Tiner, R.W. 1984. Wetlands of New Jersey. National Wetlands Inventory, U.S. Fish and Wildlife Service, Region 5, Hadley, MA.

U.S. Army Corps of Engineers. 1995. Draft general design memorandum, Passaic River flood damage reduction project: main report and supplement 1 to the environmental impact statement. U.S. Army Corps of Engineers, New York District, New York, NY.

U.S. Department of Agriculture, Natural Resources Conservation Service. 1996. USDA Great Swamp Hydrologic Unit Area Project. USDA NRSC, Morristown, NJ.

U.S. Fish and Wildlife Service. 1994. Personal communication. Great Swamp National Wildlife Refuge, Basking Ridge, NJ.

U.S. Fish and Wildlife Service. 1992. Annual narrative report. Great Swamp National Wildlife Refuge, Basking Ridge, NJ.

U.S. Fish and Wildlife Service. 1992. Birds of Great Swamp National Wildlife Refuge. Pamphlet for Great Swamp National Wildlife Refuge, Basking Ridge, NJ.

U.S. Fish and Wildlife Service. 1991. Mammals of Great Swamp National Wildlife Refuge. Pamphlet for Great Swamp National Wildlife Refuge, Basking Ridge, NJ.

U.S. Fish and Wildlife Service. 1988. Reptiles, amphibians, and fishes of Great Swamp National Wildlife Refuge. Pamphlet for Great Swamp National Wildlife Refuge, Basking Ridge, NJ.

U.S. Fish and Wildlife Service. 1986. Common wildflowers of the Great Swamp National Wildlife Refuge. Pamphlet for Great Swamp National Wildlife Refuge, Basking Ridge, NJ.

U.S. Fish and Wildlife Service. 1981. Cover type map of the Great Swamp Basin, Morris and Somerset County, NJ.

U.S. Fish and Wildlife Service. 1978. Fish and wildlife resources associated with the Passaic River basin, New Jersey and New York, phase I report, vol. I; planning aid report, 405 pp. Prepared for the U.S. Army Corps of Engineers.

U.S. Fish and Wildlife Service. 1970. Plant list. Great Swamp National Wildlife Refuge, Basking Ridge, NJ.

List of Species of Special Emphasis


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