5 Conclusion
Despite the large number of available land-use change models, approaches for regional to global scale
land systems which include the key elements of both the human and the environment sub-system, are scarce
in literature. One reason is the levels of complexity and interactions that need to be represented by this
type of models (which is also reflected in the large number of person months required for their
development). The reviewed models all have their individual strengths, but are still limited in their ability
to simulate all the complexities involved in the functioning of land systems. Based on the discussion in the
last section, we have identified five major areas where future research activities should focus
on.
- The first area is the improvement of model components for land-use decision making in order
to facilitate more differentiated scenario analysis (i.e. in the main field of application of the
reviewed models). Open research questions on for large scale include the simulation of changes
of decision making mechanisms over time, the spread of innovation in terms of agricultural
management practices and the influence of national or international institutions on land-use
decision making. Here, future research can build upon experience and techniques from the field
of agent-based modelling.
- There is also need to develop a deeper understanding of feedback effects on the model behaviour.
In this context, a central question for further research will be the development of methods for
testing and validating these highly integrated models.
- On the spatial scales which are subject of this review most models focus on the spatially
dominant land-use and land cover types such as agriculture. Future studies should pay more
attention to processes related to urbanisation which is recognized as an important driver for
environmental change (Grimm et al., 2008).
- Currently, almost exclusively the effect of agricultural management on the environment is taken
into account by the reviewed models. It will be a major step forward to incorporate more
detailed representations of forest and water management. This will open up many new fields
of model applications.
- Finally, on a more technical level we propose to investigate the application of open software
frameworks such as OpenMI (Gregersen et al., 2007) to support integrated model building and
to facilitate the exchange of model components between research groups.
