LONG-TERM VEGETATIONAL CHANGE IN A NEW YORK CITY FRESHWATER WETLAND

This study is a stratigraphic examination of a 200 cm deep sediment core sample collected from Turtle Pond in Alley Pond Park, Queens, New York (40^o45’21.55”N; 73^o45’38”W) on January 30, 2008. In addition to wetlands’ scientific importance as carbon storage pools in the global carbon cycle, wetlands also preserve water quality and water supply, and serve as protection against flooding and erosion; they also provide essential habitat for fish and wildlife. Unfortunately, in the 20^th century wetlands suffered tremendous loss; New York City alone has experienced the loss of 99% of its natural wetlands. As global warming becomes increasingly more challenging, wetland preservation becomes more critical. Therefore, establishing an understanding of the history of NYC remaining wetlands is useful.

Turtle Pond, one of a series of three kettles in Alley Pond Park, was considered to be in its original state; an unusual glacial-age remnant within the New York City limits left from the northeastern US glacial age 15,000 years ago. We examined paleoecological changes in vegetation, drought and fire history through the examination of preserved fossil seed remains, charcoal particles and sand from the Turtle Pond core.

Seed macrofossils were found included the remains of aquatics such as Potamogeton, Brasenia, Najas, and Zannichellia in the upper 20 cm of the core. Viola, Carex and a Picea (spruce) needle were found in the basal sediments. Charcoal fragments suggest a large increase in fire near the pond above 20cm in depth continuing to the surface of the core sample. At lower depths, charcoal showed a steady low pattern of accumulation throughout. Sand abundance was variable, but highest at 160-140 cm depth. This information could become important for three reasons: first, records over time of climate change in the immediate New York City region are sparse. Second, further research is needed to document human impact by comparing natural frequencies of fire to human-induced fire activity. And finally, a record of species at the site could establish a pattern of drought for further inquiry and comparison.