Floating marshy peat mat (S3S4)
Floating marshy peat mats consist of thin, flat, loosely consolidated skims of peat and vegetation along calm margins of lakes, ponds, and slow-moving streams. They are transitional between aquatic bed or emergent marsh communities in deeper water and open peatlands on thicker, more consolidated peat landward. This community occurs statewide, usually at the edges of open waterbodies.
The depth of the floating peat mat ranges from a few to more than 50 cm, and measured pH ranges from 4.4 - 5.7. The pH values are influenced by proximity to open water. The mat surface is flat with occasional, very low micro-relief. Width ranges from less than a meter to several meters wide.
Characteristic vegetation: Species composition is variable, but often includes water-lilies (Nymphaea spp.), pond-lilies (Nuphar spp.), spike rushes (Eleocharis spp.), white beak-rush (Rhynchospora alba), spatulate-leaved sundew (Drosera intermedia), bladderworts (Utricularia spp.), cotton-grass (Eriophorum spp.), St. John's-wort (Hypericum boreale), northern blue flag (Iris versicolor), and other forbs and graminoids. Shrubs are either sparse and stunted or completely absent.
Good examples can be seen at Binney Pond (New Ipswich), World End Pond (
Floating marshy peat mats sometimes occur as part of larger medium level fen systems, and less often as part of kettle hole bog systems and emergent marsh - shrub swamp systems.
Floating marshy peat mat at Ponemah Bog in Amherst (photo by Ben Kimball)
Floating marshy peat mat at Pondicherry Wildlife Refuge (photo by Ben Kimball)