Natural Communities of NH -- Photo Guide

Lake sedge seepage marsh  (S3)



Lake sedge seepage marsh
 is a narrowly defined, but relatively common type of seepage marsh occurring as small patches or bands between emergent marsh and swamp or upland. It is dominated by lake sedge (Carex lacustris), a tall plant that spreads by rhizomes, in slightly sloping marsh areas saturated by perennial near-surface flow or that have reliable groundwater seepage. Settings with this hydrology include the inflow and outflow sections of marshes. Soils are silty, with a shallow muck layer under a thick thatch of dead sedge leaves. Plant species found in the similar herbaceous seepage marsh community may also be present, but they are much less abundant than lake sedge. 

Characteristic Vegetation: Lake sedge dominates, but many other species indicative of mineral-enriched conditions may be present (many of these are also found in herbaceous seepage marsh). Common associates can include sensitive fern (Onoclea sensibilis; high frequency among known examples), marsh fern (Thelypteris palustris), common cattail (Typha latifolia), bluejoint (Calamagrostis canadensis), swamp candles (Lysimachia terrestris), bottle-shaped sedge (Carex utriculata), false nettle (Boehmeria cylindrica), and spotted touch-me-not (Impatiens capensis), among numerous others. Woody species such as red maple (Acer rubrum) and poison ivy (Toxicodendron radicans) may be present in low abundance. Mosses include Mnium spp. and Philonotis fontana, among many others. Other common marsh plants may be present as well, including sallow sedge (Carex lurida).


Good example of this community can be seen at Pawtuckaway State Park (Nottingham), Turtle Pond (Concord), Pickpocket Swamp vicinity (Exeter), Great Bog (Portsmouth), and along the Pine River in Heath Pond Bog Natural Area (Effingham).

Lake sedge seepage marsh sometimes occurs as part of an emergent marsh / shrub swamp system.


lake sedge seepage marsh (photo by Dan Sperduto)
Lake sedge seepage marsh
(photo by Dan Sperduto)

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