MinPatch is a software package that lets users design viable protected area networks, where each protected area is larger than a specified minimum size threshold. It modifies outputs from the Marxan conservation planning software. It was originally developed by Bob Smith, together with input from Simon Linke and Dan Segan, and funded by the National Directorate of Conservation Areas, Ministry of Tourism, Mozambique.
Marxan was developed by researchers at The Ecology Centre of the University of Queensland. It is designed to identify priority areas for conservation that meet biodiversity targets, whilst minimising costs and achieving connectivity.
One of the most efficient approaches for designing protected area (PA) networks is to use systematic conservation planning software. A number of software packages are available and all of them include a spatial cost or constraint component in their prioritisation algorithms, which allow the user to determine the level of fragmentation of the final PA system.
Many conservation planners want to set minimum PA size thresholds, as small PAs are less viable and more expensive to manage. However, this can only be achieved with existing software packages by repeatedly reducing the fragmentation levels of the PA system until every PA meets the threshold. Such an approach is inefficient because it increases the size of every PA, not just the smaller ones.
MinPatch was developed to overcome this problem by manipulating outputs from the Marxan conservation planning software, so that every PA meets the user-defined size threshold. It does this by taking a Marxan output and: (1) removing PAs that are smaller than required; (2) adding new low-cost patches that are needed to meet any missing targets, and; (3) using “simulated-whittling” to remove any superfluous planning units.
Research has shown MinPatch is a much more efficient approach for achieving minimum PA size thresholds than using Marxan alone (Smith et al, 2010). Moreover, applying this minimum PA threshold can have important effects on where new PAs are located when compared with Marxan outputs.
MinPatch is now incorporated into the CLUZ QGIS plugin and so can be used by downloading QGIS and using the Plugins Manager.