Active management is being undertaken to restore native ecosystems in the Midwest Driftless Area ecoregion, but with little attention to historical vegetation and disturbance dynamics in the region. An understanding of ecological history can assist by providing reference conditions from which to assess change and by providing an understanding of the potential outcomes of management activities. Here we use the U.S. General Land Office’s original Public Land Survey (PLS) records to map pre-Euro-American (c. 1850) vegetation cover within the Driftless Area ecoregion. Using cluster analysis, we develop a vegetation classification system based on surveyor designations of ecosystem types and bearing-tree data recorded within their notebooks. We further assess the statistical robustness of our classification using cross-validation techniques.
Results/Conclusions
We found a mosaic of prairie, savanna, and forest ecosystems. Finer-scale, patchily distributed ecosystem types (e.g., wetlands, thickets) were not well represented as a result of the coarse resolution of our classification. Dominant tree species in savanna and forest ecosystems included white oak (Quercus alba), bur oak (Q. macrocarpa), and black oak (Q. velutina). Riparian forests, though confined to river valleys, were composed of a more diverse mixture of tree species (Ulmus
