Aquatic bed (S5)
Aquatic beds occur in permanently inundated areas at the transition between emergent marshes and deeper environments of many rivers, streams, and ponds (ones that lack rooted vegetation). This is a very broadly defined natural community dominated by floating-leaved and submersed herbaceous species; much more study is needed to properly classify all aquatic bed vegetation in New Hampshire.
Floating-leaved and submersed plants are the dominant life forms. Water depths are usually 2-3 feet at low-water in most years, and may be as deep as about 10 feet, the approximate depth limit for the growth of rooted plants. Pond lilies, water shield, water lilies, bladderworts, pondweeds, floating heart, duckweeds, quillworts, water flaxseed, watermeals, tapegrasses, and milfoils are all common plants in aquatic beds. Submersed forms of emergent species may also be present. More than 30 rare plant species are found in aquatic beds in the state.
Characteristic vegetation: Common species include variegated yellow pondlily (Nuphar variegata), water shield (Brasenia schreberi), white waterlily (Nymphaea odorata), common bladderwort (Utricularia macrorhiza), lesser duckweed (Lemna minor), water flaxseed (Spirodela polyrhiza), Columbian watermeal (Wolffia columbiana), pickerel weed (Pontederia cordata), tapegrass (Vallisneria
Less frequent are water bulrush (Schoenoplectus subterminalis), submerged hornwort (Ceratophyllum demersum), water marigold (Megalodonta beckii), bladderworts (Utricularia spp.), mild water pepper (Persicaria hydropiperoides), lesser bur-reed (Sparganium americanum), three-way sedge (Dulichium arundinaceum), and least spike-rush (Eleocharis acicularis).
Some rare floating-leaved or submersed aquatic species found in quiet, relatively deep water or along shallow shores of rivers or ponds include several pondweeds (Potamogeton spp.), common mare's tail (Hippuris vulgaris), water marigold (Megalodonta beckii), wapato (Sagittaria cuneata), pale duckweed (Lemna valdiviana), star duckweed (Lemna trisulca), Engelmann's quillwort (Isoetes engelmannii), large-spored quillwort (Isoetes lacustris), and stiff water crowfoot (Ranunculus subrigidus).
Variants: Two variants are described.
1. Quiet water variant:
This is the typic variant. It occurs in shallow, quiet water areas of ponds, lakes, oxbows, streams, and rivers. Free-floating and emergent species are common. Characteristic species are as described above.
2. Quick water variant:
A lower cover of free-floating species occurs in this variant of moderate to quick water streams. It is characterized by submersed and floating-leaved rooted vegetation such as knotty pondweed (Potamogeton nodosus), other pondweeds (possibly P. foliosus, P. gramineus, and P. richardsonii), white water crowfoot (Ranunculus trichophyllus), and quillworts (Isoetes spp.), and other species.
Good examples of this community can be seen in most ponds and lakes in the state.
Aquatic beds usually occur as part of larger emergent marsh - shrub swamp systems.
Aquatic bed community in a beaver pond at Fall Mountain State Forest (photo by Ben Kimball)
Aquatic bed community in a pond at Saint-Gaudens National Historic Site (photo by Ben Kimball)
Aquatic bed community in a pond in southwest NH (photo by Bill Nichols)