Rocky Mountains Alpine-Montane Wet Meadow

Ranging in elevation from montane to alpine (1000-3600 m) these wet meadows are found throughout the Rockies. At montane level they typically occur in flattish zones or on gentle slopes, while in alpine regions they are usually found in small depression located below late-melting snow or on snow beds. The vegetation often forms a mosaic of several plant associations but usually comprises a dense layer of graminoids characterized by Agrostis scabra, Calamagrostis canadensis, Carex aquatilis, C. microptera, C. nebrascensis, C. pellita, C. praegracilis, C. stricta, C. utriculata, Deschampsia cespitosa, Eleocharis palustris, Juncus balticus var. montanus, J. drummondii, Scirpus pungens and the endemic Carex scopulorum (Cyperaceae). Forbs have a more scattered distribution but typically include Geum macrophyllum, Parnassia fimbriata, Pedicularis groenlandica, Polemonium caeruleum, Polygonum bistortoides, Rorippa alpina, Senecio triangularis, Symphyotrichum foliaceum, S. spathulatum, Veronica americana and the endemic Caltha leptosepala (Ranunculaceae) and Trifolium parryi (Fabaceae). However, where there as been excessive grazing, species such as Argentea anserina, Dasiphora floribunda, Iris missouriensis and Juncus arcticus become disproportionately abundant.

Rocky Mountains Subalpine-Montane Fen

Mountain fen vegetation is not a common feature of the Rockies but can be found in scattered location from Colorado north to Canada. They require relatively base-rich conditions with minerals such as calcium and magnesium in good supply, but can develop on both peat and perennially saturated soils. The vegetation is largely dominated by graminoids particularly Carex aquatilis, C. lasiocarpa and C. utriculata. Other common ones are Carex buxbaumii, C. simulata, Deschampsia cespitosa, Eleocharis quinqueflora and the endemic grass Poa leptocoma (Poaceae).  Forbs, othe other hand, are more sparsely distributed and include many of the species associated with wet meadows. Others examples include Packera pseudaurea and Rhodiola rhodantha. In places shrubs become important to form so-called ‘carr’. Typical species are Betula nana, Salix planifolia and the endemic Salix wolfii (Salicaceae). In areas of high pH so-called rich or species-rich fen occurs. These tend to be dominated by sedges such as Kobresia myosuroides and K. simpliciuscula. Also found here are various rare or uncommon species like Carex livida, Primula egaliksensis, Ptilagrostis mongholica ssp. porteri, Salix myrtillifolia, Sisyrinchium pallidum, Trichophorum pumilum and Utricularia pumilum. Other interesting fen types include the so-called iron fens as exemplified by Emmon Iron Fen in Gunnison County. These occur in areas where the ground water percolates through rock rich in pyrite. This oxidizes producing sulfuric acid, which leaches cations from any associated bedrock creating nutrient rich, but acidic ground water. In places iron precipitates out of solution and then solidifies into hard rock. Typical iron fen species include trees such as Pinus contorta and Picea engelmannii, and shrub such as Gaultheria humifusa and Vaccinium cespitosa in a carpet of mosses.

References

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Elias, S. A. 2002. Rocky Mountains. Smithsonian Natural History Series. Smithsonian Institution Press. Washington & London.

Habeck, J. R. 1987. Present-day vegetation in the northern Rocky Mountains. Annals of the Missouri Botanical Garden, 74: 804-840.

Holm, T. 1923. The vegetation of the alpine region of the Rocky Mountains in Colorado. Memoirs of the National Academy of Science, 19: 1-45.

Qian, H. 1999. Floristic analysis of vascular plant genera of North America north of Mexico: characterization and phytogeography.  Journal of Biogeography, 26: 1307-1321.

Ricketts, T. H. et al. 1999. Terrestrial Ecosystems of North America - a conservation assessment. World Wildlife Fund, USA and Canada. Island Press, Washington.

Rocchio, J. 2005. Rocky Mountain Subalpine-Montane Fen Ecological System. Colorado Natural Heritage Program. Colorado State University.

Rocchio, J. 2006. Rocky Mountain Alpine-Montane Wet Meadow Ecological System. Colorado Natural Heritage Program. Colorado State University.

Rydberg, P. A. 1916. Phytogeographical notes on the Rocky Mountain region. VI. Distribution of subalpine species. Bulletin of the Torrey Botanical Club, 43: 343-364.

Weber, W. A. 1976. Rocky Mountain Flora. Colorado Associated University Press. Boulder, Colorado.