Combining agent functional types, capitals and services to model land use dynamics

Models of land use change are becoming increasingly complex as they attempt to explore the effects of climatic, political, economic and demographic change on land systems and the services these systems produce. 'Bottom-up' agent based models are a useful method for exploring the effects of local processes and human behaviour, but are generally limited to small spatial scales due to the complex parameterisations involved. Conversely, 'top-down' land allocation models can be applied at large spatial scales, but are less adept at accounting for human behaviour and non-economic factors such as the supply of ecosystem services. Models that combine the strengths of these two approaches are required for the advancement of land use science. Here, we present an agent based land use modelling framework designed to be run over large spatial extents and to be capable of accounting for relevant forms of human behaviour, variations in land use intensities, multifunctional ecosystem service production and the actions of institutions that affect land use change. We give a full description of this framework, called CRAFTY (Competition for Resources between Agent Functional TYpes), and provide details of how it can be applied and extended, including some simple examples of its ability to model important processes of land use change. These include changes in demand for and supply of ecosystem services, variation in land use intensity and multi-functionality, and heterogeneous behaviour amongst land managers.