Wolfe's Pond Park

New York City once contained 224,000 acres of freshwater wetland. This valuable ecosystem can slow erosion, prevent flooding by retaining storm waters, filter and decompose pollutants, and slow global warming by converting carbon dioxide into oxygen at a prodigious rate. In the past 200 years, the increasing demands of a growing metropolis have resulted in most of this land being filled for construction, or dredged for transport. Only 2,000 acres of freshwater wetland remain in the city today, and many species that once called the wetland home have been lost forever.

Wolfe’s Pond is unusual because it is a freshwater pond that is just yards from the sea. The pond was once a tidal inlet with very different plants and animals than it contains today. Over time, the action of wind and waves pushed sand and clay into the mouth of the inlet, damming it and forming a pond. The outflow from Acme Pond, and the gradual accumulation of rain and overland runoff, transformed Wolfe’s Pond from a brackish body of water to a freshwater pond. Wolfe’s Pond Park also contains Acme Pond.

The formation of wetlands can be traced back to the most recent ice age. A massive ice sheet called the Wisconsin Glacier advanced on New York City 75,000 years ago, pushing rock, soil, and boulders ahead. When the ice melted 17,000 years ago, water flowed to the sea, creating streams and rivers that carved through rock. Large glacial fragments broke off, melted, and left depressions called kettles. If layers of fine silt and clay were deposited on the bottom of the depressions, the kettles collected water and ponds formed. Where waters were shallow or flowed slowly, seeds and spores were able to take root and flourish. Generations of plants grew and decomposed, building peat-rich sediments. As wind and water eroded the soil, the steep slopes grew gentler, slowing the passage of water. Plant communities diversified under these favorable conditions, attracting animals that fed on the plants. The sophisticated food web that developed brought advanced predators to the wetlands: snapping turtles (Chelydra serpentina), wolves (Canis lupus), several species of hawks, and humans (Homo sapiens).

Water levels in wetlands are variable, influenced by the underlying rock and soil makeup, rainfall, season, and ground water inputs. Despite these variable conditions, freshwater wetlands teem with life. Sweet pepperbush (Clethra alnifolia), highbush blueberry (Vaccinium corymbosum), and serviceberry (Amelanchier arborea) all provide food and cover for many birds. Along the vegetated sections of the Wolfe’s Pond grow heavy tangles of Asiatic bittersweet (Celastrus orbiculatus), and Japanese honeysuckle (Lonicera japonica), plants that are quick to colonize disturbed areas. These species are exotic (not native to this area), and can become invasive, reducing the floral and faunal biodiversity of natural areas by preventing the growth of native plant species which serve as food and habitat for local wildlife. In the spring, common yellowthroats (Geothylpis trichas), redstarts (Setophaga ruticilla), and other warblers forage in the thickets at the pond edge and in the surrounding forest. Wood ducks (Aix sponsa) and mallards (Anas platyrhychos) feed and nest among aquatic plants such as arrow arum (Peltandra virginica), swamp rose mallow (Hibiscus palustris), and buttonbush (Cephalanthus occidentalis). Red-winged blackbirds (Agelaius phoeniceus) are conspicuous members of the pond community. Black-crowned night herons (Nycticorax nycticorax) and great blue herons (Ardea herodias) roost and hunt for fish and frogs along the pond edge. Another pond-edge hunter is the belted kingfisher (Ceryle alcyon), a bold blue and white bird that dives for its prey from the tree limbs above. The edges of Acme Pond are less disturbed than Wolfe’s Pond because they have been protected by swampy conditions. This allows pungent skunk cabbage (Symplocarpus foetidus), tussock sedge (Carex stricta), and cinnamon fern (Osmunda cinnamomea) to grow. While these conditions deter human traffic, the area serves as a haven for wildlife. Opossums (Didelphis marsupialis) and raccoons (Procyon lotor) roam the wood and forage around the edges of the pond. Eastern (rufous-sided) towhees (Pipilo erythrophthalmus), brown thrashers (Toxostoma rufum), and bright red cardinals (Cardinalis cardinalis) flash through the treetops. A variety of reptiles and amphibians also reside at Acme Pond, including painted turtles (Chrysemys picta), snapping turtles, and red-backed salamanders (Plethodon cinereus). The pond contains several types of bass and carp. In addition to housing these native species, freshwater wetlands also provide resting, breeding, and feeding grounds for hundreds of thousands of migrating birds. Many of these birds arrive in New York City only twice a year as they travel along the Atlantic flyway, a major migratory route.