Modeling Historic Rangeland Management and Grazing Pressures in Landscapes of Settlement

Defining historic grazing pressures and rangeland management is vital if early landscape threshold crossing and long–term trajectories of landscape change are to be properly understood. In this paper we use a new environmental simulation model, Búmodel, to assess two contrasting historical grazing landscapes in Mývatnssveit Iceland for two key periods—the colonization period (ca. Landnám, A.D. 872–1000) and the early eighteenth century A.D. Results suggest that there were spatial and temporal variations in productivity and grazing pressure within and between historic grazing areas and indicate that land degradation was not an inevitable consequence of the livestock grazing introduced with settlement. The results also demonstrate the significance of grazing and livestock management strategies in preventing overgrazing, particularly under cooler climatic conditions. The model enables detailed consideration of historic grazing management scenarios and their associated landscape pressures

Early-Norse home-field productivity in the Faroe Islands

In the early Norse settlement period throughout the North Atlantic, effective management of the land area surrounding the domestic settlement, the home-field, was essential. In the Faroe Islands, the extent of home-field land suitable for growing fodder or cereal crops is limited by topography and by drainage highlighting the need to optimize the management of these land areas. In this paper we examine the management of home-fields through a modeling approach, allowing the long-term sustainability of the past agrarian system in the home-field area to be examined. The CENTURY agroecosystem model is used to predict soil organic carbon levels and the potential hay meadow and cereal production for locations around three settlements on the islands of Sud–eroy, Sandoy, and Eysteroy. Using paleoclimatic data and measurements from buried soil materials alongside ethnographic and historical evidence on land management, the results from this model reveal maximum hay and barley yields attainable through early agrarian practices. Comparisons between modeled outputs and recorded yields from the nineteenth century show that there is a strong moderating influence on longer-term climatic fluctuations. The role of soil management is emphasized through comparison of long-term climate/yield data. This has been undertaken using statistical time series analyses, which reveal fluctuations in yield related to climate are relatively slight, except going into the twentieth century. It is concluded that intensity of soil management is the primary determinant of yield and could buffer cereal and hay yields against climatic downturns,and that from a low yield baseline in the early Norse settlement period, yield improves to an equilibrium level by the twelfth century