The research program was undertaken in recognition of the applicability of wetland hydrology to all fields of wetland study. The Minesing Swamp, a 70 km² wetland in southern Ontario, was selected as the research site because of its varied soil, hydrological, and ecological conditions. The 10 km² study area, located within the southeastern basin, was characterized by diverse fen and swamp communities.

A water balance analysis, using data collected between May and October in 1997 and 1998, was done for a portion of the fen. In 1998, each component was estimated and the residual for the season evaluated. The atmospheric components, rainfall (413 mm) and evapotranspiration (602 mm), were estimated using a tipping bucket rain gauge and the Bowen ratio energy balance method, respectively. A late October snowfall (26 mm) was added to the measured rainfall. The change in w ater storage (-54 mm) was determined from water table fluctuations and an estimate of the peat’s specific yield (23 %) which incorporated the effects of compressibility. Net groundwater inflow, quantified using a new approach, was not large (10 mm), but its importance increases for short-term water balances. It is important for calculating accurate chemical balances and understanding hydrological processes in the fen.

Vegetation sampling yielded 290 species, including several rare plants. Cluster analysis and ordination supported the definition of 11 communities. Peat, with depths to 2.9 m and variable composition was classified. W ater chemistry was generally homogeneous, but water levels fluctuated from 0.03 to more than 0.95 m, and the average depth to the water table ranged from -0.06 to 0.80 m. The environmental factors related to the vegetation distribution appear to have been measured and account for 35 % of the variability in vegetation. Leaf area index, microtopography, maximum fluctuation and average depth of the water table, peat depth, and several ions were highly correlated with the vegetation distribution in the principal directions of variability.

This research highlights the importance of groundwater as a source of moisture and nutrients for the vegetation within Minesing Swamp and the need to manage land uses within the recharge areas to ensure that degradation of this internationally significant wetland does not occur