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Eleocharis palustris

common spikerush

Vegetation Composition: Eleocharis palustris is an aggressive, rhizomatous species that nearly excludes all other species from establishing any significant cover. Common associates in high quality sites include Alopecurus aequalis, Mentha arvense, Rumex crispus, Eleocharis acicularis, Carex utriculata, and Glyceria spp. On some sites aquatic species, such as Hippuris vulgaris, Utricularia vulgaris, and Potamogeton natans, have high cover.

Classification Comments: The Eleocharis palustris plant association is widespread and has been described in numerous classifications throughout the United States. In Idaho two plant associations dominated by Eleocharis palustris are recognized. The one described here represents stands that occur along streams, rivers, and lakeshores. An Eleocharis palustris vernal pool association is also recognized that occurs in vernal lake beds that dry completely by the end of the growing season. In some cases, Eleocharis palustris may be confused with E. rostellata, 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 community type and the sites on which they occur are very different ecologically.

Environment: The Eleocharis palustris plant association is found at low to moderate elevations, generally in wide, low gradient valleys of all shapes. Sites are wet basins, floodplains, meadows, gravel bars, and lake edges. It is typically in sites that are prone to yearly flooding or persistent surface water. Where streams are present, they are Rosgen's C and E stream types. Elevations range from 2,200 to at least 8,700 feet, depending on latitude (Hansen et al. 1995; Manning and Padgett 1995; Crowe and Clausnitzer 1997; Hall and Hansen 1997).

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Soils: Soils of this plant asociation are classified as Mollisols, Entisols, Histisols, and Inseptisols. Textures are variable, ranging from sites that are very coarse-fragment rich to others that are deep and fine-textured. The surface is usually rich in organic matter and the litter accumulation may blend into rich, black organic muck soils. The fine-textured upper horizons often arise from alluvial deposition. Sands, gravels, and cobbles usually constitute the main body of deeper subsurface materials (Manning and Padgett 1995; Crowe and Clausnitzer 1997; Hall and Hansen 1997).

Management Considerations: Seasonally wet conditions and low palatability of Eleocharis palustris limit the grazing value of this type for livestock, even during drought years when upland forage dries early and dies back (Kovalchik 1987). Sites occupied by this type are typically inundated or at least saturated for much of the year so as to preclude most development. Trampling damage and soil churning occurs readily with livestock use and may result in a shift toward more disturbance tolerant species such as Hordeum jubatum, Carex nebrascensis, and Juncus balticus (Hall and Hansen 1997).

Successional Dynamics: Padgett et al. (1989) suggest that Eleocharis palustris can represent an early seral species on ponds and streambanks where water is at or above the ground surface. As siltation occurs over time, other communities, such as Carex rostrata, may replace it. However, due to the continual saturated conditions and dense growth of Eleocharis palustris, once formed, stands appear difficult to displace and may persist as climax vegetation. If water levels rise, Scirpus spp. and Typha latifolia may be able to supplant E. palustris. Hansen et al. (1995) have observed that disturbance can drastically shift the vegetative composition of this type toward increaser or invader species such as Hordeum jubatum.

Wildlife Functions: Broad zones of this type along streams, rivers, lakes, and reservoirs provide valuable feeding and nesting areas for waterfowl. Eleocharis palustris and associated plants are a valuable source of food and cover for waterfowl. Wild ungulates seldom browse the diagnostic species of this association due to its low palatability (Hall and Hansen 1997).

Distribution: Eleocharis palustris is a common type in California, Colorado, Idaho, Montana, Nevada, Oregon, Utah, Washington, Wyoming, and Saskatchewan. Essentially it has been documented from every western state except Arizona and New Mexico (Bourgeron and Engelking 1994; Anderson et al. 1998).

References:

Anderson, M., P. Bougeron, M. T. Bryer, R. Crawford, L. Engelking, D. Faber-Langendoen, M. Gallyoun, K. Goodin, D. H. Grossman, S. Landaal, K. Metzler, K. D. Patterson, M. Pyne, M. Reid, L. Sneddon, and A. S. Weakley. 1998. International classification of ecological communities: terrestrial vegetation of the United States. Volume II. The National Vegetation Classification System: list of types. The Nature Conservancy, Arlington, Virginia, USA.

Bourgeron, P. S., and L. D. Engelking, editors. 1994. A preliminary vegetation classification of the Western United States. Unpublished report prepared by the Western Heritage Task Force for The Nature Conservancy, Boulder, CO. Not paged.

Crowe, E. A., and R. R. Clausnitzer. 1997. Mid-montane wetlands classification of the Malheur, Umatilla, and Wallowa-Whitman National Forests. USDA Forest Service R6-NR-ECOL-TP-22-97. Pacific Northwest Region, Portland, OR. 299 pp.

Hall, J. B. and P. L. Hansen. 1997. A preliminary riparian habitat type classification system for the Bureau of Land Management Districts in Southern and Eastern Idaho. Bureau of Land Management Technical Bulletin No. 97-11. 381 pp.

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.

Kovalchik, B. L. 1987. Riparian Zone Associations: Deschutes, Ochoco, Fremont, and Winema National Forests. USDA Forest Service R6-ECOL-279-87. Pacific Northwest Region, Portland, OR. 171 pp.

Manning, M. E., and W. G. Padgett. 1995. Riparian community type classification for the Humboldt and Toiyabe National Forests, Nevada and eastern California. USDA Forest Service R4-ECOL-95-01. Intermountain Region, Ogden, UT. 274 pp.

Padgett, W. G., A. P. Youngblood, and A. H. Winward. 1989. Riparian community type classification of Utah and southeastern Idaho. USDA Forest Service R4-ECOL-89-01. Intermountain Region, Ogden, UT. 191 pp.

Author/Date(Update): R. K. Moseley/1998-12-08(2001-10-01)