Calcareous fens in Southeast Alaska.

Abstract

Calcareous fens have not been identified previously in southeast Alaska. A limited survey in southeast Alaska identified several wetlands that appear to be calcareous fens. These sites were located in low-elevation discharge zones that are below recharge zones in carbonate highlands and talus foot-slopes. Two of six surveyed sites partly met the Minnesota Department of Natural Resources water chemistry criteria for calcareous fens, with pH values of 6.7 to 7.4 and calcium concentrations of 41.8 to 51.4 mg/L but fall short with regard to specific conductivity (315 to 380 µS/cm). Alkalinity was not determined. The vegetation was predominately herbaceous, with abundant Sitka sedge (Carex aquatilis) and scattered shrubs such as Barclay’s willow (Salix barclayi) and redosier dogwood (Cornus sericea ssp. sericea). The taxa found in these fens have been reported at other sites in southeast Alaska, although many were at the southern limits of their known ranges. The soils were Histosols composed of 0.6 to greater than 1 m of sedge peat. We found no evidence of calcium carbonate precipitates (marl or tufa) in the soil.

Citation

McClellan, Michael H.; Brock, Terry; Baichtal, James F. 2003. Calcareous fens in Southeast Alaska. Res. Note PNW-RN-536. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station