Land Use in Rural New Zealand: Spatial Land-use, Land-use Change, and Model Validation

Land is an important social and economic resource. Knowing the spatial distribution of land use and the expected location of future land-use change is important to inform decision makers. This paper documents and validates the baseline land-use maps and the algorithm for spatial land-use change incorporated in the Land Use in Rural New Zealand model (LURNZ). At the time of writing, LURNZ is the only national-level land-use model of New Zealand. While developed for New Zealand, the model provides an intuitive algorithm that would be straightforward to apply to different locations and at different spatial resolutions. LURNZ is based on a heuristic model of dynamic land-use optimisation with conversion costs. It allocates land-use changes to each pixel using a combination of pixel probabilities in a deterministic algorithm and calibration to national-level changes. We simulate out of sample and compare to observed data. As a result of the model construction, we underestimate the “churn” in land use. We demonstrate that the algorithm assigns changes in land use to pixels that are similar in quality to the pixels where land-use changes are observed to occur. We also show that there is a strong positive relationship between observed territorial-authority-level dairy changes and simulated changes in dairy area.