The plant life of Fire Island is diverse and reflects the great variation in such environmental factors as wind, salinity, the availability of soil moisture,and the extent of human activity. Many habitats, like the beach and primary dune face, are so severe that only a few plant species can survive. However, just a few feet away in a more protected habitat, many species may thrive.
When the park was surveyed in 1971 and 1974, fourteen major vegetation types or subtypes were identified on Fire Island. These included the beach grass grasslands, beach heather and bearberry dwarf scrubs, thickets, pitch pine woodland, broadleaf forest, and a variety of wetlands and salt marsh. Vegetation recorded at that time for the William Floyd Estate included upland forests, lowland forests, thickets, upland meadow, cultivated fields, residential land, common reed grassland, and tidal marsh.
In recent years, more advanced classification and recording systems have been adopted to help us better understand plant species associations. More than 30 vegetation associations were mapped for Fire Island National Seashore by 2002.
At least 237 plant species have been identified within the Seashore. The casual observer, however, may only be interested in knowing a few of the most obvious plants.
Plants on the Primary Dune
Eventually a dynamic equilibrium becomes established: the plants help stabilize the dunes and the vegetated dunes ameliorate the harsh environmental conditions for plants growing behind the dunes.
The diversity of plant species generally increases with distance from the ocean and the density of cover.
Common Plants of the Interdunal Swale and Dune Shrubland
In swales behind the dunes, the availability of soil moisture, the salinity of the water, and the depth to the water table are major determinants of the distribution of vegetation types on Fire Island.
Winds and salt spray that pass over the foredunes or through gaps in their crests control the height of the shrub canopy, and the height increases northward, away from the ocean. The shrubs of the backdune zone can tolerate limited burial by sand.
Plants of the Thickets and Forests
The pitch pine woodland, predominated by Pinus rigida, eastern poison ivy (Toxicodendrum radicans), northern bayberry (Myrica pensylvanica) and catbrier (Smilax sp.), may grow in protected depressions near the northern portion of the island.
Maritime forests comprised of American holly (Ilex opaca), sassafras (Sassafras albidum), serviceberry (Amelanchier canadensis), and other hardwoods are able to develop behind tall secondary dunes.
In low depressions where fresh water can accumulate, bog species may grow. Red maple (Acer rubrum), blackgum (Nyssa sylvatica), blueberry (Vaccinium sp.) and other shrubs, and sphagnum moss and ferns are found in this habitat.
Plants of the Salt Marsh
Many of the plant species of the barrier island have large edible fruits that serve as food sources for a wide variety of bird species. In return, migrating birds provide a means of plant dispersal as they follow the Atlantic flyway.
Plants also provide homes for nesting birds, and food and cover for other forms of wildlife.
List of Plant Species from USGS-NPS report, see pages 177 - 186.
Ecological Studies of the Sunken Forest, Fire Island National Seashore, New York; 1976 NPS Scientific Monograph No. 7