Monday, 7 November 2005
6

Influences of Riparian Buffers and Soil Variability on the Hydrology of Seasonal Wetlands in Northern Minnesota.

Daniel P. Tersteeg1, James C. Bell1, Randall Kolka2, and Brian J. Palik2. (1) University of Minnesota, Department of Soil, Water, Climate, 1991 Upper Buford Circle, St. Paul, MN 55108, (2) USDA - Forest Service, North Central Research Station, 1831 Hwy 169 East, Grand Rapids, MN 55744

Forest management guidelines are generally lacking for seasonal wetlands, instead focusing on riparian forests adjacent to stream ecosystems. The abundance of these wetlands in northern, glaciated, forested landscapes and the importance of their habitat function have drawn attention to these systems in recent years. This study tests the effectiveness of buffering seasonal wetlands following harvesting of adjacent upland forest; as well as investigating the soils to better understand factors influencing their hydrology. Hydroperiods were studied to distinguish any change associated with harvest treatments. A block design consisting of four treatments, replicated in four blocks was established in north central Minnesota in 2000. Experimental units consist of approximately 70-year-old aspen (Populus spp.) stands (>15 ac), each containing several seasonal wetlands. Treatments were assigned randomly to each stand and they include: 1) uncut forest; 2) upland clearcut, with 50-ft uncut buffers surrounding wetlands; 3) upland clearcut, with 50-ft buffers thinned to 50 ft2/ac surrounding wetlands; and 4) upland clearcut with no buffers around wetlands. One wetland per stand, ranging in size from 0.1-0.5 acre, was instrumented with staff gauges, piezometer nests, and shallow groundwater monitoring wells installed along transects running from the upland into the wetland. Measurements have been taken year round to monitor surface and subsurface hydrology. Current data indicates minimal variation in hydroperiods among treatments. An underlying layer of fine-textured glacial till across the landscape acts as an impeding layer, perching a surficial water table that influences the duration of the hydroperiod of these systems. Soils capping this till have higher rates of infiltration, therefore precipitation results in subsurface lateral flow from the uplands to the wetlands. Factors such as landscape position and catchment area may override any influence that treatments have on wetland hydrology.

Back to Constructed Wetlands and Wetland Delineation: II
Back to S10 Wetland Soils

Back to The ASA-CSSA-SSSA International Annual Meetings (November 6-10, 2005)