ANALYSIS AND CONSERVATION IMPLICATIONS OF LANDSCAPE CHANGE IN THE WISCONSIN RIVER FLOODPLAIN, USA

Abstract

River floodplain landscapes are diverse and dynamic, yet little is known about long-term changes in land-cover patterns in these systems. We quantified floodplain land-cover change between the 1930s and the 1990s along nine 12–21-km reaches of the Wisconsin River by analyzing and digitally classifying 200 historic aerial photos corrected against modern orthophotographs. Several metrics of landscape structure were used to determine changes in amount and connectivity of deciduous forest, wetlands, grassland, and agriculture within the 100-yr floodplain. Deciduous forest increased by up to 51% between the 1930s and the 1990s. However, number of patches declined, and edge density increased in almost every reach, indicating that amount and connectivity of forest cover increased but that forest patches became more complex in shape. Grasslands declined, and the number, edge density, and mean size of grassland patches illustrated a progression to fewer, smaller, isolated remnants. Wetland patch dynamics demonstra...