Howellia aquatilis (water howellia) ponds of the Swan Valley : conceptual hydrologic models and ecological implications /

Hydrologic controls on the survival of Water Howellia (Howellia aquatilis) and implications of land management

“…1972). Pleistocene lateral moraines, basal moraine and glaciofluvial sediments deposited by one of the two major diverging trunk glaciers occupying the Swan-Clearwater Valley during the late Pleistocene are exposed at the land surface (Shapley and Lesica, 1997). The thickness of the glacial till is unknown.…”

“…Seeds germinate in October under aerobic conditions and remain as a small seedling beneath the winter snowpack (Shapley and Lesica, 1997). They are then submerged as snow melt refills the wetlands in early spring (Shapley and Lesica, 1997). This wetland hydrological cycle of wetting and drying is necessary to maintain H. aquatilis populations.…”

“…The majority of Water Howellia research in the Swan Valley has focused on H. aquatilis habitat from a biological standpoint (Lesica, 1992;Shelly and Gamon, 1996;Mantas, 1998) with only limited characterization of wetland hydrology (Shapley and Lesica, 1997;Shapley, 1998). Shapley (1998) classified H. aquatilis wetland morphology into four distinct basin types based on pond geometry, size, and slope.…”

“…By the end of the summer or early fall, the wetlands dessicate, exposing the seeds to air. Seeds germinate in October under aerobic conditions and remain as a small seedling beneath the winter snowpack (Shapley and Lesica, 1997). They are then submerged as snow melt refills the wetlands in early spring (Shapley and Lesica, 1997).…”

“…Specific objectives included: (1) generation of wetland water balances; (2) identification of controls on the seasonal variation in water input; and (3) analysis of how natural and anthropogenic modification of the wetland watershed may alter wetland hydrology. Formulation of land management plans in the Swan Valley that allow multiple land use and protection of Water Howellia habitat is of local, state and federal interest (Shapley and Lesica, 1997;Shapley, 1998).…”