Tivoli Bays Natural Heritage Area

For information on recreation at Tivoli Bays, visit the Tivoli Bays Wildlife Management Area page.

Site Name: Tivoli Bays Natural Heritage Area

State Agency: Department of Environmental Conservation

Location: Dutchess County, Town of Red Hook

Size of Area: 1,722 acres

DEC Region: 3

Date Designated: September 29, 2007

Site Description

Tivoli Bays is dominated by two large river coves partially surrounded by wooded clay bluffs. The north bay is predominantly intertidal marsh (386 acres/156 hectares), with a well-developed network of tidal creeks and pools. A similar network of creeks and pools is beginning to form in the south bay's shallows and mudflats (288 acres/115 hectares). The main tributaries are the Stony Creek and the Saw Kill, which drain a combined watershed of about 48 square miles (124 sq. km).

The tidal marshes at Tivoli North Bay are dominated by narrowleaf cattail (Typha angustifolia), spatterdock (Nuphar advena) and wild rice (Zizania aquatica), interspersed with purple loosestrife (Lythrum salicaria) and common reed (Phragmites australis). Subtidal shallows support communities of submerged plants including water celery (Vallisneria americana). Tivoli South Bay is dominated by Eurasian water chestnut (Trapa natans), a floating, non-native species. Tidal swamps are mixed deciduous communities with a well-developed shrub layer and abundant moss species.

New York State Important Bird Area and Bird Conservation Area

Tivoli Bays was designated as a New York State Important Bird Area in 1997. This designation was awarded on the basis of the documented occurrence of breeding least bitterns (Ixobrychus exilis), Virginia rail (Rallus limicola), sora (Porzana carolina), common moorhen (Gallinula chloropus), and marsh wren (Cistothorus palustris).

Tivoli Bays is also designated as a New York Bird Conservation Area in recognition of its:

• unique breeding marsh bird community;
• prominence as a staging area for migrating waterfowl including large numbers of black ducks (Anas rubripes) and;
• upland forest and shrub areas which provide important migratory stopover habitat for warblers, flycatchers, sparrows, blackbirds, and many other songbird migrants.

A 2005 marsh bird survey observed numerous resident marsh bird species including Virginia rail, red-winged blackbird (Agelaius phoeniceus), marsh wren, least bittern, American bittern (Botaurus lentiginosus), and swamp sparrow (Melospiza georgiana). Raptor species commonly observed at Tivoli Bays include bald eagle (Haliaeetus leucocephalus), osprey (Pandion haliaetus), and northern harrier (Circus cyaneus). Other common wildlife observed include snapping turtle (Chelydra serpentina), muskrat (Ondatra zibethicus) and beaver (Castor canadensis).

Criteria for Natural Heritage Area Designation

Name	Scientific Name	Comments
Shortnose Sturgeon	Acipenser brevirostrum	The Hudson River, including the waters of Tivoli Bays, supports one of the largest populations of the endangered shortnose sturgeon on the Atlantic Coast.
Tawny Emperor	Asterocampa clyton	One of only seven occurrences in NY of a butterfly that is uncommon in the state
Least Bittern	Ixobrychus exilis	A state-threatened bird whose breeding occurrences are uncommon and whose non-breeding occurrences are critically imperiled
Estuary Beggar-ticks	Bidens bidentoides	One of the five best occurrences in NY, plus another, of this globally uncommon wildflower, which is uncommon and listed as rare in the state
Estuary Beggar-ticks	Bidens hyperborea var. hyperborea	One of only three occurrences in NY of this globally uncommon wildflower variety, which is critically imperiled and listed as endangered in the state
Fissidens	Fissidens fontanus	The only recorded occurrence in NY of this moss, which appears to be uncommon in the state
Golden Club	Orontium aquaticum	The two best occurrences in NY of this wildflower, which is imperiled and listed as threatened in the state
Heartleaf Plantain	Plantago cordata	Two occurrences of this wildflower, which is uncommon and listed as threatened in NY
Taxiphyllum	Taxiphyllum taxirameum	Two of only three reported occurrences in NY of this moss, which is critically imperiled in the state
Freshwater Intertidal Mudflats		Two of the best examples in NY of this globally uncommon wetland type, which is imperiled in the state
Freshwater Intertidal Shore		The two best examples in NY of this globally uncommon wetland type, which is imperiled in the state
Freshwater Tidal Marsh		One of the three best examples in NY (plus another) of this globally uncommon wetland type, which is imperiled in the state
Freshwater Tidal Swamp		Two of only 10 examples in NY of this globally imperiled wetland type, which is critically imperiled in the state
Tidal River		A good example of this river type that is significant from a statewide perspective

Operation and Management Considerations

Natural Resources:

Continuation of ongoing stewardship efforts is necessary to maintain the integrity and ecological function of Tivoli Bays's unique natural resources. Overarching management goals include protection and monitoring of the rare, threatened, and endangered plant and animal species and the natural communities for which this site was designated.

That includes management of:

• invasive species;
• collection of improved species and ecological community distribution information;
• maintenance, enhancement, and creation of upland early successional habitat and;
• protection of land adjacent to and buffering Tivoli Bays.

Invasive Species

As previously noted, numerous rare animal and plant species occur at Tivoli Bays. At present, most populations of these species at Tivoli Bays are considered stable. Further management, outside continued monitoring and control of invasive plant species (discussed later), is not anticipated. However, special concern should be given to preventing disturbance to nesting birds, especially the bald eagles nesting on Cruger Island. Presently, public access to the island is restricted during the nesting season. Continued routine patrols to enforce this closure will be required.

Invasive plant species, specifically common reed (Phragmites) and purple loosestrife, occur in Tivoli North Bay. At present, they are not generally interfering with the health and function of the tidal marsh. However, if allowed to expand unchecked, Phragmites will probably dominate much of Tivoli North Bay within several decades. It could greatly alter the tidal marsh habitat, threatening the breeding marsh bird community and displacing rare plant species.

A Phragmites eradication program was initiated in 2006 with herbicide treatment of 4 Phragmites stands totaling 3 acres. This effort was expanded the following year to include 3 additional stands. The project has resulted in dramatic reduction in Phragmites and recovery of native plant communities in treated areas. Alternating years of mapping and treating remnant Phragmites is required to maintain the sites and continue reduction of Phragmites with the goal of eliminating it from the marsh. Purple loosestrife is not currently a major threat to North Bay's tidal marsh and does not require active control. If monitoring suggests that purple loosestrife is becoming a problem in North Bay, efforts will be undertaken to release the biological control agents available for management of this species.

Biodiversity Inventory Report

Data on the distribution of exceptional ecological communities and rare species at Tivoli Bays were collected and compiled into a Biodiversity Inventory Report. It was prepared by the New York Natural Heritage Program (NYNHP) in 1996. The NYNHP report augmented a cover type map and species inventory produced for the area by Department staff in the 1980s. This information needs to be updated, refined, and expanded in future years as ecological communities and species garnering conservation concern change. For example, future inventories of rare wildlife species at Tivoli Bays may focus on the species of greatest conservation need (SGCN) as classified by the New York Comprehensive Wildlife Conservation Strategy, rather than state or federally "listed" species or NYNHP-tracked species. This broadening of inventory priorities will be important from a conservation perspective. The SGCN list includes previously "untracked" species, such as the map turtle, that while historically widespread, are in danger of becoming imperiled without conservation action.

Upland Early Successional Habitat

In addition to North and South Bays, DEC ownership at Tivoli Bays encompasses a large area of the adjacent uplands. It is comprised of a mixture of mature forests and early successional habitats including several hundred acres of old fields and shrublands. Wildlife species that rely on early successional habitats for breeding, escape cover, and foraging have generally declined across the state. Therefore, maintaining and enhancing existing early successional habitat at Tivoli Bays is and will be an ongoing management priority. Furthermore, creation of additional early successional habitat at Tivoli Bays through sustainable forest management will be considered in the future as these habitats become less common across the landscape. Any habitat management activities will be consistent with the habitat needs of those species and ecological communities for which the site was designated as a Natural Heritage Area.

Land Protection

Land protection adjacent to Tivoli Bays will be a continuing management need and priority to protect the area's natural resources from incompatible land uses. If the opportunity arises, the Department will consider the acquisition (fee or conservation easement) of land from willing sellers in the area adjacent to Tivoli Bays.

Recreational Resources

Tivoli Bays has abundant recreational resources which collectively facilitate public enjoyment of the area's natural resources. It includes four miles of hiking trails, eight parking areas, several miles of unimproved road, and two canoe launches. This infrastructure requires annual routine maintenance and periodic major rehabilitation/replacement - management needs that will continue indefinitely. A better understanding of the amount and distribution of recreational use at Tivoli Bays will facilitate the future allocation of limited maintenance resources. Collection of such data is desirable. None of these management activities are expected to impact on the Natural Heritage resources for which the site was designated.

Cultural Resources

Tivoli Bays has several unique cultural resources that warrant specific management consideration. Magdalene Island has several archeological sites that have been looted numerous times over the last several decades. At present, an inventory of looter pits on the island is being completed to both document past damage to the sites and facilitate future enforcement actions. Continued vigilance in the enforcement of state laws that prohibit exploitation of such sites will be necessary to prevent further damage to these sites. The barn along the Kidd Lane access road is the only remaining structure on the property that predates state ownership and its condition continues to deteriorate. Because the cost of removing the structure is prohibitive, continuing to restrict public access to the building through signage and enforcement will be necessary. Protection of cultural resources at this site will not affect the Natural Heritage resources for which the site was designated.

Compatible Uses

Compatible uses of the wetland area of Tivoli Bays include waterfowl hunting, recreational fishing, trapping, canoeing and kayaking, wildlife viewing, scientific research, and environmental education.

Compatible uses of the upland area of Tivoli Bays include hiking, mountain biking, horseback riding, hunting, trapping, wildlife viewing, scientific research, and environmental education.

Tivoli Bays also provides an opportunity for additional motorized access to a short segment of administrative road for people with disabilities by permit.

Contact

Hudson River National Estuarine Research Reserve, Norrie Point Environmental Center, PO Box 315, Staatsburg NY 12580; 845-889-4745; hrnerr@dec.ny.gov

Tivoli Bays Area Map (PDF)