Landscape Change in an Agricultural Watershed: The Effect of Parcelization on Riparian Forest Cover

Abstract

In this research we address factors contributing to landscape change in a midwestern (USA) watershed. Specifically, the relationship between the parcelization of agricultural land (ownership subdivisions) and changes in amounts of riparian forest cover are explored. The study area is the River Raisin Watershed in southeastern Michigan, which is typical of rural watersheds in the lower Great Lakes region. Two townships within the watershed were sampled from data spanning a 20-year time period. Using land-use and land-cover data for 1968, 1978, and 1988, combined with ownership records for the same years, we determined a relationship between rates of parcelization and changes in forest cover. These findings indicate that increasing trends in riparian forest area follow increases in land parcelization at the township scale. For these two townships, agricultural decline and land-use diversification seem positively related to larger areas and widths of riparian forests. As the number of acres being farmed and the number of farms have decreased, the land has been divided into more and smaller lots and the forests along rivers like the Raisin and its tributaries have increased in area. There are several possible factors at the township and farm scale which may influence this landscape phenomenon, including land-use policies, governmental programs, agricultural mechanization, and agricultural economics.