Sago Pondweed (Potamogeton pectinatus L.):
A Literature Review
Habitat
Habitat--Wetland type
Sago normally occurs in water bodies or those portions where water is permanently
present (Mirashi 1954; Verhoeven 1980a; Grillas and Duncan 1986) or absent for
no more than 1 to 3 months (Coetzer 1987.) Stream environments favor linear-leaved
species like sago that tend to grow from the base (Madsen 1986), but Pip (1987)
found no significant tendencies for sago to occur more frequently in either
lentic or lotic habitats. Sago occurs in the estuarine, riverine, lacustrine,
and palustrine wetland systems of Cowardin et al. (1979). Under this classification
scheme, sago is a dominance type in the class Aquatic Bed in wetlands with subtidal
and irregularly exposed water regimes in estuarine systems; in tidally-influenced
riverine systems, sago occupies permanently flooded and intermittently exposed
sites. In inland systems, sago variously grows in wetlands with permanently
flooded, intermittently exposed, semipermanently flooded, or artificially flooded
water regimes.
In a wetland classification system developed specifically for basins in
the glaciated prairie region of North America (Stewart and Kantrud 1971),
sago is restricted to the deep marsh zone of permanent and semipermanent ponds
and lakes. Sago occasionally occurs in seasonal (Stewart and Kantrud 1971)
wetlands if surface water is continuously present for more than 3 years, and
the presence of sago in these wetlands suggests that they have experienced,
or can be expected to experience, several years of continuous flooding (Miller
1973). Sago became well established when formerly dry sites in Utah were continuously
flooded to a depth of 30 cm for 2 years (Nelson 1954). Sago reaches peak frequency
in the regenerating and degenerating phases of prairie wetlands defined by
Van der Valk and Davis (1978). The former phase occurs just after basins refill;
the latter, just before a variety of agents causes a rapid decline in emergent
hydrophytes.
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