Long-term land use changes in a mesoscale watershed due to socio-economic factors -: effects on landscape structures and functions

To examine the effects of land use changes in peripheral regions on landscape structures and functions, we have developed or adapted three simulation models focused on agricultural economics, ecology and hydrology. These models were linked via GIS and tested in the Aar watershed located in central Germany. The agro-economic simulation model ProLand predicts land use changes resulting from a particular framework of specified natural, economic and political characteristics on a regional scale. This land use prognosis serves as input for the ecological and hydrological models. The ecological model ELLA analyzes and predicts the influence of land use systems on the biodiversity of a landscape indicated by the spread and dispersal of selected species. The present study focuses on modeling the spread of skylark (Alauda arcensis) breeding habitats. The physically based hydrological model SWAT calculates components of the landscape's water balance over a daily time-step. This paper addresses the most relevant problems of integrated modeling approaches, including the use of common databases, metainformation, and interface requirements for data exchange. Initial modeling results are presented to demonstrate the impact of a changing framework in peripheral regions on ecological and economic indicators. The actual land use was compared with a scenario with an incentive for grassland developed by ProLand. The percentage of forested areas declined significantly, while the area of grassland increased from 20 to 41%,. The result was a decline of connected areas suitable for skylark habitats. Stream flow and surface runoff increased due to the change in land use. (C) 2001 Elsevier Science B.V. All rights reserved.