Spatiotemporal dynamics of evapotranspiration at the Glacial Ridge prairie restoration in northwestern Minnesota

Among the various indicators of success in wetland restoration, hydrology is the most important and relatively easy to monitor. Evapotranspiration (ET) was used to assess the ecohydrologic changes at the Glacial Ridge prairie restoration site in northwestern Minnesota. Twelve Landsat images from 2000-03 for the months of June, July and August were used to study the spatial ET changes. Spatial monthly and seasonal ET were estimated using a surface energy budget technique from Landsat images. Five sub-basins within the study area were delineated to represent the different conditions of the wetlands. Their spatial and temporal ET responses to the restoration activities (native species planting, burning and ditch closures) were studied. Spatial statistics showing mean and standard deviation of monthly ET were computed. Comparisons were made between these watersheds and the preserved sub-watershed of the study area. The average annual ET increases for the five sub-basins were in the range of 9% (2002-03) to 25% (2001-02). Over the study period, ET increased by nearly 50%. After considering the effect of variations in precipitation, wind speed and solar radiation on the resulting ET, the results show that ET increased in recent years as result of the restoration activities. Copyright (c) 2005 John Wiley & Sons, Ltd.