EVAPOTRANSPIRATION FROM SEDGE-DOMINATED WETLAND SURFACES

The evapotranspiration (ET) regimes of two sedge communities in a subarctic coastal wetland were investigated during non-vegetated and vegetated periods. Surface moisture availability strongly controlled ET during non-vegetated conditions, but was less important during the vegetated period. The results suggest that the evaporation efficiency of these sites changed in response to vegetation growth. Vegetation cover reduced the evaporating efficiency of the wet site and slightly increased evaporation efficiency of the dry site. Simple linear regression models based on Penman's open water evaporation formula were found to predict ET accurately at each site under all surface cover conditions. However, model coefficients for the two sites differed substantially. Dividing the data set into non-vegetated and vegetated periods improved the model performance only marginally. © 1990.