The Palisades

SIGNIFICANT HABITATS AND HABITAT COMPLEXES
OF THE NEW YORK BIGHT WATERSHED

I. SITE NAME: The Palisades

II. SITE LOCATION: The Palisades is a narrow ridge located along the western shoreline of the Hudson River in northeastern New Jersey and southeastern New York, at the northern end of the metropolitan New York City region.

TOWNS: Fort Lee, NJ; Orangetown, Clarkstown, Haverstraw, NY

COUNTIES: Bergen, NJ; Rockland, NY

STATES: New Jersey; New York

USGS 7.5 MIN QUADS: Central Park, NY-NJ (40073-78), Yonkers, NY-NJ (40073-88), Nyack, NY-NJ (41073-18), Thiells, NY (41074-21), Haverstraw, NY (41075-28)

USGS 30 x 60 MIN QUADS: Long Island West, NY-NJ (40073-E1), Bridgeport, CT-NY-NJ (41073-A1), Middletown, NY-NJ (41074-81)

III. BOUNDARY DESCRIPTION AND JUSTIFICATION: The eastern boundary of the Palisades habitat complex follows the west shore of the Hudson River from just south of the George Washington Bridge in Fort Lee, New Jersey, north about 35 kilometers (22 miles) to Haverstraw, New York, and then west another 6.5 kilometers (4 miles). The inland (western) boundary of the complex parallels the river boundary; the two encompass the open space on the Palisades Ridge. The habitat complex ranges from about 1 kilometer (0.6 mile) to 2.5 kilometers (1.5 miles) in width. The Palisades includes regionally rare talus slope and traprock communities, and is important open space within the urban core along the Hudson for migratory and resident raptors and songbirds.

IV. OWNERSHIP/PROTECTION/RECOGNITION: The majority of land in this complex is owned and managed by the states of New York and New Jersey as part of the Palisades Interstate Park Commission; lands included, from south to north, are Palisades State Park in New Jersey and Tallman Mountain, Blauvelt, Nyack Beach, Rockland Lake, Hook Mountain, and High Tor State Parks in New York. Greenbrook Sanctuary is a small refuge in northern New Jersey owned by the Palisades Interstate Park Commission and managed by the Palisades Nature Association. State parks encompass 2,220 hectares (5,550 acres) or about 45% of the land in this complex. Other significant landowners include the U.S. Department of Defense with a facility at Mt. Nebo, New York, and Columbia University with the Lamont-Doherty Geological Observatory in Palisades, New York. The rest of the land in this complex is in a mixture of local public and private ownership. The New Jersey Natural Heritage Program recognizes the bluffs and talus slopes along the Hudson River as a Priority Site for Biodiversity with a biodiversity rank of B3 (high biodiversity significance). The New York State Natural Heritage Program, in conjunction with The Nature Conservancy, recognizes South Mountain (B3 - high biodiversity significance) as a Priority Site for Biodiversity. The New York State Department of State recognizes Hook Mountain as a Significant Coastal Fish and Wildlife Habitat. Adjacent designated habitats along the Hudson River include Lower Hudson Reach, Piermont Marsh, and Haverstraw Bay (see habitat narrative and map for Lower Hudson River Estuary, p. 629). Piermont Marsh is one of four sites comprising the Hudson River National Estuarine Research Reserve.

V. GENERAL AREA DESCRIPTION: The Palisades is part of the Northern Triassic Lowlands (Newark Basin) of the Piedmont physiographic province. The Palisades form the eastern edge of a sill made up of intrusive lava known as diabase or traprock that was intruded during the Triassic period (approximately 200 million years ago). The traprock is more resistant to erosion than are the surrounding shales and sandstones that have been worn down to lower elevations. The resulting ridges, with elevations over 190 meters (600 feet), stand out dramatically above the Hudson River; in addition, the ridges, cliffs, and talus slope communities support a number of regionally rare communities and species (see also traprock ridge communities chapter).

The top of the Palisades Ridge is mostly forested, and is typically a mixed-oak forest community dominated by red oak (Quercus rubra), with white (Q. alba) and black oak (Q. velutina), black birch (Betula lenta), sugar maple (Acer saccharum), tulip tree (Liriodendron tulipifera), ash (Fraxinus spp.) and chestnut oak (Quercus prinus), and a shrub layer dominated by maple-leaved viburnum (Viburnum acerifolium) and various vines including poison ivy (Toxidendron radicans), wild grape (Vitis spp.), catbrier (Smilax rotundifolia), Asiatic bittersweet (Celastrus orbiculatus), and moonseed (Menispermun canadense). Other forested areas include hemlock-hardwood forest dominated by eastern hemlock (Tsuga canadensis) and forested swamps dominated by red maple (Acer rubrum). More xeric (dry) areas are more sparsely vegetated with chestnut oak, red oak, red cedar (Juniperus virginiana), and hickory (Carya spp.), with bare rock and grassland openings with bluestem grasses (Schizachyrium scoparium and Andropogon spp.), Indian grass (Sorghastrum nutans), asters (Aster spp.), and goldenrods (Solidago spp.).

The talus slopes that occur at the base of the cliffs along the Palisades consist of large barren traprock boulders and little or no soil. Water, snow, and ice trapped under the boulders create microhabitats with temperatures from 6 to 8°C (10 to 15°F) below the ambient temperatures. Dominant trees and shrubs in this area include paper birch (Betula papyrifera), black birch (Betula lenta), white pine (Pinus strobus), Eastern hemlock, sassafras (Sassafras albidum), American basswood (Tilia americana), and Virginia creeper (Parthenocissus quinquefolia).

VI. ECOLOGICAL SIGNIFICANCE/UNIQUENESS OF SITE: The Palisades habitat complex supports four community types of special emphasis and a total of 42 species of special emphasis, including the following federally and state-listed species. (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.)

Federally listed endangered
bald eagle (Haliaeetus leucocephalus)

Federal species of concern⁽¹⁾Allegheny woodrat (Neotoma magister)

¹Species of special concern listed here include former Category 2 candidates.

State-listed endangered - New Jersey
Cooper's hawk (Accipiter cooperii)
wafer ash (Ptelea trifoliata)

State-listed threatened - New Jersey
wood turtle (Clemmys insculpta)
red-headed woodpecker (Melanerpes erythrocephalus)

State-listed endangered - New York
Torrey's mountain mint (Pycnanthemum torrei)

State-listed special concern animals - New York
wood turtle (Clemmys insculpta)
spotted salamander (Ambystoma maculatum)

State-listed rare plants - New York
Bicknell's sedge (Carex bicknelli)
rattlebox (Crotalaria sagittalis)
yellow harlequin (Corydalis flavula)
slender knotweed (Polygonum tenue)

Talus slope communities such as the one at the base of the Palisades occur in only a few locations in New Jersey and the New York Bight region. The only known remaining occurrence for the Allegheny woodrat in the New York Bight study area occurs in the Palisades. This species was recently common in the region but declined rapidly, probably due to parasitic roundworm spread by raccoons. The talus slope community also provides dens and basking areas for regionally rare reptiles including the northern copperhead (Agkistrodon contortrix) and five-lined skink (Eumeces fasciatus).

At several locations on the Palisades Ridge, most notably on South Mountain at the northern end and at the cliff edge in New Jersey, there are examples of dry grass and forb-dominated openings classified by New Jersey as traprock glade/rock outcrop communities and by New York as rocky summit grasslands. These occur at only a few locations in the region (see narrative on Preakness Mountain). The South Mountain site supports several rare plant species, including Torrey's mountain mint, hay sedge (Carex argyrantha), Bicknell's sedge, slender knotweed, and dittany (Cunila originoides).

The Palisades Ridge is also important as a migratory corridor and nesting area for raptors and songbirds. The hawk watch each fall at Hook Mountain counts about 25,000 hawks, as well as other landbirds and waterfowl, and constitutes the largest fall counts of any hawk watch in New York State. The birds fly close to the ridge to take advantage of the updrafts created by the steep cliffs. The hawks most frequently seen include broad-winged (Buteo platypterus) and sharp-shinned (Accipter striatus). These numbers indicate the importance of this ridge and the Hudson River valley as a migratory corridor. The federally listed endangered peregrine falcon (Falco peregrinus) historically nested on the Palisades cliffs. Reintroduction efforts in natural habitats have failed, primarily due to predation by great horned owl (Bubo virginianus). In 1995, bald eagles were observed overwintering at Stateline Lookout in New Jersey. This is the first year since the 1950s that eagles have been regularly seen here. This corridor is especially significant because of its location adjacent to the Hudson River and because it represents some of the only remaining open space in the greater New York City metropolitan area. The northern end of the Palisades Ridge curves west and abuts the Hudson Highlands (see narrative and map of New York - New Jersey Highlands). The open space at the southern end of the Palisades connects to the Hackensack Meadowlands through linear riparian open space corridors along the upper Hackensack River and Overpeck Creek. On the ridge, the forest communities support breeding and migratory stopover areas for a variety of landbirds, including Neotropical migrant songbirds such as ovenbird (Seiurus aurocapillus) and wood thrush (Hylocichla mustelina), which need relatively unfragmented forest for successful nesting. Regionally rare birds nesting in the Palisades include the red-headed woodpecker and the Cooper's hawk. Over 230 birds have been identified at Greenbrook Sanctuary (northern New Jersey part of the Palisades), and typically over 80 species of birds can be observed in one day during migration. A study comparing breeding bird populations in 1957 and 1983 showed declines in many of the species that were once numerous in the Sanctuary, especially the forest-nesting Neotropical migrants such as vireos, warblers, and flycatchers. The relatively unfragmented forest habitats on the Palisades also support populations of two declining turtle species, the wood turtle and the eastern box turtle (Terrapene c. carolina).

VII. THREATS AND SPECIAL PROBLEMS: The Allegheny woodrat population is threatened, probably by parasitic roundworm. Rare traprock glade communities will become degraded with excessive human disturbance. The county leaf composting operation at South Mountain has resulted in loss of rare plants at the traprock glade community found there. Development of land around the parks in the Palisades is fragmenting the forest and may result in loss of rare communities and plants.

VIII. CONSERVATION RECOMMENDATIONS: Active protection of the Allegheny woodrat may be necessary, including trapping and removing raccoons, inoculating rats against roundworm, and reintroducing them to historically occupied habitats. Additional restoration efforts for peregrine falcons to their former nesting sites in the Palisades and protection of these sites, including predator control, may be appropriate. At present, peregrines only nest on artificial structures (bridges and buildings) in the region. Roosting habitat for wintering bald eagle should be maintained along the Hudson River. Protection of the rare talus slope and traprock glade communities should be continued, and additional surveys conducted to determine the full extent of these communities in the Palisades. If necessary, hiking trails should be redirected away from rare traprock glade communities. The county leaf dump at South Mountain should be closed and removed. Protection of privately owned parcels in the Palisades through acquisition, conservation easements, or other means should be pursued. Any activities that would interfere with migration along the ridge, such as the construction of towers, should be avoided.

IX. REFERENCES:

Collins, S. 1956. The biotic communities of Greenbrook Sanctuary. Ph.D. dissertation, Rutgers University Graduate School, New Brunswick, NJ.

Mack, A.C. 1982 (original 1909). The Palisades of the Hudson: their formation, tradition, romance, historical associations, natural wonders and preservation. Walking News Inc., New York, NY. 58 p. and map.

New Jersey Natural Heritage Program. 1993. Site report on Palisades scree. New Jersey Department of Environmental Protection, Division of Lands and Forests, Trenton, NJ.

New York State Department of State. 1987. Significant coastal fish and wildlife habitats program, a part of the New York coastal management program. Hook Mountain habitat narrative and map. New York State Department of State, Division of Coastal Resources and Waterfront Revitalization, Albany, NY.

Puffer, J.H., J.M. Husch, and A.I. Benimoff. 1992. The Palasades sill and Watchung basalt flows, northern New Jersey and southeastern New York: a geological summary and field guide. New Jersey Department of Environmental Protection and Energy, Division of Science and Research Geological Survey, Trenton, NJ. Open-File Report OFR 92-1. 27 p.

Robichaud, B. and M.F. Buell. 1973. Vegetation of New Jersey. Rutgers University Press, New Brunswick, NJ. 340 p.

Serrao, J. 1986. The wild Palisades of the Hudson. Lind Publications, Westwood, NJ.

Serrao, J. 1985. Decline of forest songbirds. New Jersey Audubon Society Records of New Jersey Birds 11(1):5-9.

Slowik, N. and S. Bonardi. 1994. A comprehensive survey of a talus slope, a unique natural community on the Hudson River. Greenbrook Sanctuary, Alpine, NJ.

List of Species of Special Emphasis

Maps

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