1 Changing Agrarian Landscapes across America A Comparative Perspective

Over a mere ve or six human generations, agriculture has all but disappeared from rural landscapes in the eastern half of the United States. During an equally brief period, agriculture has transformed forests, val-leys, prairies, and plains in the interior of the continent. Economic models have explained the shift in terms of the lower costs of land, the larger scale of farming, and better connections to export markets, via river transport at rst and then by rail (Fitzgerald, 2003; Gardner, 2002; Hart, 2003). Enormous gains in agricul-tural productivity since the green revolution have accelerated these trends, ensur-ing that the physical extent of agricultural land peaked in the United States in 1950, and the pace of abandonment has quickened (Theobald, 2001; Theobald et al., 2005). In the information age, distance to nearby population centers is an increasingly unimportant factor in predicting the prevalence of agricultural land use. With a nationally integrated market and export-driven demand shaping land-use patterns, the production locations have shifted to landscapes with fertile soils; 2 at, open terrain; and favorable climates. Still, we know that landscapes in the six areas examined have not escaped the legacies of prior patterns of develop-ment. Each was managed in different and path-dependent ways during the past 130 years. Choices framed by the timing of settlement, cultural inheritances, and institutional arrangements continue to shape the overall sustainability of ecosys-tems long after the initial transformation of landscapes. The legacies of these distinct agricultural systems are explored in this chapter primarily through the lens of the agricultural census. Scientists have expressed growing interest in understanding the effect of historical land use on ecosystem dynamics. Land-use data have been used to drive ecosystem models capable o