Community Field Guide
Scientific Name:
Stuckenia pectinatus - Myriophyllum spicatum Herbaceous Vegetation
Common Name:
Sago pondweed - water-milfoil Submerged Wetland
Community Description
Summary:
This sago pondweed - water-milfoil pond community is found in glacial ponds in the northwestern Great Plains of the United States and Canada. Stands occur in the permanently inundated, 'deep water' zone of glacial ponds in gentle, rolling, glacial terrain. Water is usually 15-100 cm deep. The type can occur in fresh to brackish water, but is characteristic of mildly brackish water. Underlying parent material is mixed sedimentary (partly calcareous) glacial till. Pond bottoms are composed of mud or mud mixed with gravel and stones. The vegetation is characteristically poor in species, and canopy cover is low (<50%). Submerged aquatic macrophytes dominate the vegetation. Stuckenia pectinata (= Potamogeton pectinatus) was present in all stands sampled; Myriophyllum spicatum can be locally dominant and was present in about 50% of stands. Ranunculus aquatilis, Utricularia macrorhiza (= Utricularia vulgaris), and Potamogeton richardsonii were occasionally present. Chara spp., a calciphile macroalgae, was often present.
Environment:
This community occurs in the permanently inundated, "deep water" zone of glacial ponds of the western Great Plains in gentle, rolling, glacial terrain. Water is usually 15-100 cm deep. The type can occur in fresh to brackish water (270-44,000 ohms/cm), but is characteristic of mildly brackish water (median of 2500 ohms/cm) (Lesica 1989). These ponds occur at an elevation of 1300-1500 m (4300-5000 feet). Underlying parent material is mixed sedimentary (partly calcareous) glacial till. Pond bottoms are composed of mud or mud mixed with gravel and stones.
Vegetation:
These communities are characteristically poor in species, and canopy cover is low (<50%). Submerged aquatic macrophytes dominate the vegetation. Stuckenia pectinata (= Potamogeton pectinatus) was present in all stands sampled; Myriophyllum spicatum can be locally dominant and was present in about 50% of stands. Ranunculus aquatilis, Utricularia macrorhiza (= Utricularia vulgaris), and Potamogeton richardsonii were occasionally present. Chara spp., a calciphile macroalgae, was often present (Lesica 1989, 1994; Lesica pers obs.).
Range:
This sago pondweed - water-milfoil pond community is found in glacial ponds in the northwestern Great Plains of the United States and Canada, but may range more broadly. This community was recorded for 13 of 84 ponds sampled in Glacier County, Montana. Many hundreds of ponds exist in the same general area.
Dynamics:
These communities probably experience little natural disturbance except inter- and intra-annual water level fluctuations.
Global Rank: G3G4 State Rank: S1Q
Global Rank Comments:
More than 18 occurrences of this community type have been documented in Montana, ranging from the glacial potholes of the Ovando Valley (west-central portion) to those of Missouri Coteau Subsection (northeastern most Montana) and including the area most intensively sampled, the prairie potholes of the Blackfeet Indian Reservation (just east of the Continental Divide, Lesica 1989); related or identical communities (supporting same dominant species) have been documented from Saskatchewan, North Dakota, and California. This is a common aquatic type of open-water portions of prairie ponds (sloughs in Canadian parlance) with slightly brackish to saline water and a variety of bottom conditions. This habitat is not unique and the dominants (indicator) species for the community type are broadly distributed, so this type can be expected to occur from at least Manitoba and Minnesota westward and south to California. This association was initially rated as rare because investigators had not previously differentiated aquatic assemblages at the community type level.
Community References
Identifier:
CEGL002003
Author:
P. Lesica
Citations:
Bourgeron and Engelking 1994, Driscoll et al. 1984, Ferren et al. 1996, Lesica 1989, Lesica 1992, Lesica 1993, Lesica 1994, MTNHP n.d., Stewart and Kantrud 1971, Stewart and Kantrud 1972, Walker and Coupland 1970
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This information is from the:
Montana Natural Heritage Program
Montana State Library--Natural Resource Information System
1515 East Sixth Ave., Helena, MT 59620-1800
406 444-3989
mtnhp.org
mtnhp@mt.gov
