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Eleocharis rostellata

beaked spikerush

Classification Comments: In Montana, Hansen et al. (1995) lumped all combinations of E. rostellata and E. pauciflora into an E. pauciflora habitat type due to similarities in environmental conditions and management concerns. Observations in Montana by Lesica (1990), indicate that the E. rostellata association is distinct, and at least partially thermophilic, unlike the E. pauciflora type. In some cases, Eleocharis rostellata may be confused with E. palustris, especially if the stolons of E. rostellata are not present or not obvious. Be sure of the plant's true identity. A misidentification will result in the wrong plant association and the sites on which they occur are very different ecologically.

Distribution: Eleocharis rostellata is widespread from southern Canada to South America. It occurs in disjunct populations and may not be present in every state (USDA 2000). In the western United States Eleocharis rostellata is a minor association in Idaho, Montana, and Yellowstone National Park, Wyoming. Stands may occur in Washington, British Columbia, Colorado, and other parts of Wyoming.

Soils: This association is known to occur in a variety of soils from relatively deep organic, to alkaline and calcareous soils, to coarse wet mineral soils that are directly in contact with thermal waters.

Environment: This association occurs in thermal areas or areas with alkaline or calcareous soils, especially at the northern edge of its distribution. It is also found around cold springs in desert canyons. Water tables are at or near the surface throughout the year.

Vegetation Composition: The association forms near monocultures, and may occur as a quaking mat, or may be more open with considerable areas of bare soil, gravel, rock, and open water (Moseley 1995). Moseley (1995) notes that there are two distinct phases of the community: stands with 90% cover of E. rostellata, occurring on relatively deep organic soils and sometime forming a quaking mat; and stands with less than 70% cover that are more open, with considerable areas of bare soil, gravel, rock, and open water on the surface. The open phase appears restricted to mineral substrates and occurs on gentle as well as very steep slopes. Low species diversity is characteristic of the E. rostellata plant association. Common associated species with low cover include Deschampsia cespitosa, Polypogon monspeliensis, Juncus balticus, Muhlenbergia asperifolia, Potentilla fruticosa, Aster ascendens, Berula erecta, Mimulus guttatus, Helianthus nuttallii, Castilleja exilis, Scirpus americanus, Carex simulata, C. nebrascensis, and C. scirpoidea.

Wildlife Functions: This association is a source of green forage early in the spring and attracts wildlife (especially elk and deer). Waterfowl will eat the stems, roots, achenes of the diagnostic species of this plant association (Hansen et al. 1995, USDA 2000).

Successional Dynamics: Little is known about the successional dynamics of this association. It is reported to be an early colonizer of bare substrates. It is presumed to be a stable association once established, unless water tables are altered (USDA 2000).

Management Considerations: This association is threatened by development of thermal areas for recreation (Lesica 1990). Because of the wet, often unstable nature of the substrate, soil disturbance and grazing by livestock is probably minimal. Yet trampling damage of the wet, organic soils of this association occurs readily with any livestock utilization. Livestock may graze forage plants in this association, but overgrazing can cause compositional changes to species of lower palatability (Hansen et al. 1995).

References:

Hansen, P. L., R. D. Pfister, K. Boggs, B. J. Cook, J. Joy, and D. K. Hinckley. 1995. Classification and Management of Montana's Riparian and Wetland Sites. Montana Forest and Conservation Experiment Station, School of Forestry, Missoula, MT. 646 pp.

Lesica, P. 1990. Vegetation and sensitive plant species of wetlands associated with geothermal areas in the greater Yellowstone ecosystem in Montana. Unpublished report. 9 pp.

Moseley, R. K. 1995. The ecology of geothermal springs in south-central Idaho. Cooperative study, Sawtooth National Forest and Conservation Data Center, Idaho Department of Fish and Game. 47 pp. plus appendices.

U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. 2000. Fire Effects Information System, [Online]. Available: http://www.fs.fed.us/database/feis/

Author/Date(Update): L. Williams/1995-12-20(2001-01-05)