Dutchess and Putnam Counties, NY

Stretching over 4,200 acres in Dutchess and Putnam counties, the Great Swamp is one of the largest freshwater wetlands in New York State. The Great Swamp watershed (drainage basin) covers 63,018 acres. An important wetland for wildlife, recreation and water quality, the Great Swamp harbors 39 rare plants, animals and natural communities including Atlantic white cedar swamp, spreading globeflower, field dodder, and blazing star.

Eleven fen community sites, including three rare fens, have been identified there. Many of these fen areas are prime habitat for the state-rare bog turtle which has been found in nine different locations throughout the Great Swamp.

Recent preliminary studies have revealed 31 species of amphibians and reptiles, more than 60 species of butterflies and 53 species of dragonflies and damselflies living in the Swamp. The Great Swamp is also a valuable resource for birds: 175 bird species use the wetland as a migratory flyway and/or nesting area, including great blue herons, ospreys, vireos, wood ducks and many others.

The Great Swamp, like all wetlands, acts as a giant sponge to absorb rainwater and reduce otherwise destructive flooding. It filters out sediments and pollution to maintain a clean, dependable source of drinking water for people in Dutchess, Putnam, and Westchester Counties; it also supplies water to New York City's Croton Reservoir System.

Threats to the Great Swamp

Although guarded by local, state and federal regulations, the Great Swamp continues to be threatened by:

As population and development increases in the region, the potential for destructive pollution and other threats also increases.

The Nature Conservancy in the Great Swamp

The Lower Hudson Chapter has taken the lead working with public and private agencies to design a careful community-based conservation strategy for this important watershed. In the fall of 1996, the Conservancy set up the Great Swamp office and hired a Great Swamp Program Director. Since then, the Conservancy has mapped the Swamp and has begun performing scientific surveys on plants, animals and natural communities. The Conservancy also undertook a public opinion survey to determine the views of the local communities regarding the Great Swamp. Results showed that the overwhelming majority of the participants placed a high value on the Swamp and its protection.

In October 1997, the Great Swamp Watershed Conference brought together representatives from local government, business, recreation and conservation groups, and state agencies to help define the actions necessary to conserve the Great Swamp and maintain a healthy economy. The results from the conference are being incorporated into a watershed conservation strategy that will chart a course forward for the Conservancy, our partners and the entire community living in the Great Swamp. Additionally, the Conservancy has fostered the creation of a local community group, Friends of the Great Swamp (FrOGS), and is working with this group to promote awareness of issues affecting the Great Swamp.


The Great Swamp actually consists of two rivers flowing in opposite directions. From just south of Pawling, the Swamp River flows north to the Ten Mile River near Dover Plains. The East Branch Croton River flows south from Pawling to the East Branch Croton Reservoir system. About ninety percent of the Great Swamp wetlands are privately owned and recreational access to the Swamp is limited. For information, contact the Lower Hudson Chapter at (914) 244-3271 or the Great Swamp Program Director, Dan Siemann, at (914) 855-0661.


The Nature Conservancy

Acer rubrum (red maple)
Betula pumila (swamp birch)
Chamaecyparis thyoides (Atlantic white cedar)

Gaylussacia dumosa (dwarf huckleberry)
Vaccinium corymbosum (highbush blueberry)

Cuscuta pentagona (five-angled field dodder)

Cardamine longii (Long's bittercress)
Castilleja coccinea (scarlet Indian-paintbrush)
Chamaelirium luteum (Carolina whitlow grass)
Cuscuta obtusiflora (southern dodder)
Draba reptans (Carolina whitlow-grass)
Gentiana saponaria (soapwort gentian)
Lespedeza violacea (violet lespedeza)
Linum sulcatum (yellow wild flax)
Liparis liliifolia (large twayblade)
Phlox maculata (wild sweet William)
Potamogeton pulcher (spotted pondweed)
Trollius laxus ssp. laxus (spreading globeflower)

Carex albicans var. emmonsii (Emmon's sedge)
Carex bicknellii (Bicknell's sedge)
Cyperus lupulinus ssp. lupulinus (hop sedge)

Adiantum pedatum (maidenhair fern)
Asplenium platyneuron (ebony spleenwort)
Asplenium rhizophyllum (walking fern)
Athyrium filix-femina (lady fern)
Botrychium virginianum (rattlesnake fern)
Cystopteris bulbifera (bulblet fern)
Cystopteris tenuis (fragile fern)
Dennstaedtia punctilobula (hay-scented fern)
Deparia acrostichoides (silvery glade fern)
Dryopteris carthusiana (spinulose woodfern)
Dryopteris clintoniana (Clinton's woodfern)
Dryopteris cristata (crested woodfern)
Dryopteris intermedia (evergreen woodfern)
Dryopteris intermedia x marginalis (hybrid)
Dryopteris marginalis (marginal woodfern)
Equisetum arvensis (common horsetail)
Equisetum hyemale (scouring rush)
Huperzia lucidula (shining clubmoss)
Matteuccia struthiopteris (ostrich fern)
Onoclea sensibilis (sensitive fern)
Osmunda cinnamomea (cinnamon fern)
Osmunda claytoniana (interrupted fern)
Osmunda regalis (royal fern)
Phegopteris hexagonoptera (broad beech fern)
Polypodium appalachianum X virginianum (hybrid fern)
Polypodium virginianum (rock cap fern)
Polystichum acrostichoides (Christmas fern)
Pteridium aquilinum (bracken fern)
Thelypteris noveboracensis (New York fern)
Thelypteris palustris (marsh fern)
Woodsia obtusa (blunt-lobed woodsia fern)