Transformation of a landscape in the upper mid-west, USA: The history of the lower St. Croix river valley, 1830 to present

Learning the history of a landscape is critical to understanding present land-use patterns. We document the history of landscape change in the lower St. Croix River valley from 1830 to the present. Significant changes in land use and cover have occurred during this time. Because of the convergence of prairie, savanna and forest vegetation in this area, and because of the proximity of the St. Croix River valley to metropolitan Minneapolis/St. Paul (MN), the region is ecologically and culturally very important. A variety of information sources was used to reconstruct the lower St. Croix landscape over time. The primary sources of material were federal census records, records of lumber and agricultural production, descriptive accounts by early settlers and historians, scientific reports, the General Land Office land survey records, maps and photographs. Two periods of rapid change were identified. Change was rapid from 1850 to 1880 as first loggers and then farmers converted a lightly populated landscape of oak savanna, prairie, mixed hardwood and conifer forests and wetlands, maintained by frequent fires, into a largely deforested agricultural landscape. A second period of rapid change was from 1940 to the present as the urban area has expanded outward. Urbanization has further fragmented the remaining areas of natural habitat and has the potential to accelerate soil erosion, stream sediment transport, and oxidation of organic matter. The results of this study illustrate how landscape change can have significant impacts on ecological systems. Understanding the history of landscape change in the lower St. Croix River valley provides an analogue to help understand how other mid-western US landscapes have changed over time.