Class: Vaccinium macrocarpon - Myrica pennsylvanica Dwarf Shrubland (Northern Interdunal Cranberry Swale) TNC Alliance Code: IV.A.1.N.g.3.  6141 CMI Code:  6141 Type Locator: Restricted to Fire Island Cross-Section:

TNC Alliance Description:  This association occurs in small seasonally flooded depressions and swales behind primary dunes.  The substrate is characterized by shallow peat over sand. This maritime interdunal swale community is variable in species composition but is characterized by Vaccinium macrocarpon, which grows as a prostrate dwarf shrub below the herbaceous layer. In some swales, Vaccinium macrocarpon is present only at low cover. Scattered taller shrubs may be present, including most commonly Vaccinium corymbosum and Aronia melanocarpa.  The herbaceous layer is dense with Cladium mariscoides, Juncus candensis, Scirpus pungens, and Rhynchospora spp. also common. Other herbaceous associates may include Rhynchospora capitellata, Drosera rotundifolia, Lycopodium inundatum, Eleocharis olivacea, Xyris torta, Triadenum canadense, Juncus dichotomus, and Panicum virgautm. One occurrence on Fire Island is dominated by Typha angustifolia. Sphagnum species are usually present, but with low overall percent cover.
 

Photo Interpretation: This association is found in the interdune zone as small, pond-like bodies of shallow water. They appear dark, like open water, but do have a partially submerged layer of Vaccinium macrocarpon. These small polygons are found mostly in the Otis Pike Wilderness Area of Fire Island.
 

Aerial Photo Samples:

 

Field Notes: Vaccinium macrocarpon is the characteristic species but only occurs as low cover.  Vaccinium corymbosum is often present in and around V. macrocarpon.
 

Ground Photos:

V. macrocarpon (low shrub), V. corymbosum (tall shrub)	Overview of Cranberry Swale

Similar Alliances:  None