Marxan is a conservation planning software that allows a systematic approach to the design of efficient conservation areas.


Marxan is a suite of tools designed to help decision makers find good solutions to conservation planning problems. Initially designed to address conservation area design goals where a benchmark representation of biodiversity was required at the smallest cost possible. These tools has been applied to hundreds of spatial conservation planning problems around the world.

This tool is primarily a product of Ian Ball's PhD thesis (Ball 2000). In the initial stages, it was called SPEXAN, a combination of the words Spatially Explicit Annealing. Marxan was developed as a modified version of SPEXAN to meet the needs of the Great Barrier Reef Marine Planning Authority (GBRMPA) in their 2003-2004 rezoning plans. The US National Marine Fisheries Service (NMFS) have funded further advancement of Marxan to provide technical advice on its application to Salmon recovery planning.

Marxan is free software that can be used to solve several types of planning problems and includes extensive documentation and examples describing a framework for approaching conservation planning.

The software package assesses different sets of potential conservation areas, within a defined region, in which conservation areas are compared with user defined targets and costs and the configuration of areas that most efficiently meets the pre-defined objectives coupled with cost effectiveness are chosen as outputs.

Marxan flowchart

Flow chart for running Marxan with calibration and sensitivity testing (after Ardron, J. et. al. 2010)

In the software process combinations of planning units (each unit with associated attributes) are assessed to meet objectives and cost effectiveness as above, however, a key output from this process is selection frequency output (i.e. planning units that are selected more than 50% of the time are thought of as being important for efficiently meeting biodiversity goals). From this output various scenarios can be compared with sites of importance easier to identify.     

Given these key processes, Marxan provides decision support to a range of conservation planning problems, including:

  • The design of new reserve systems to meet objectives and budgeting concerns
  • Reporting on the performance of existing reserve systems
  • Developing multiple-use zoning plans for natural resource management

Marxan analyses focuses on several inputs, these include;

  • Planning unit status
  • Planning unit cost
  • Boundary cost
  • Conservation feature abundances
  • Conservation targets
  • Cost threshold

From these inputs calibration must occur (adjusting the parameters of Marxan) and a sensitivity analysis which shows which input data seem to have the largest consequences in scenarios. After this initial set up the user can then explore different scenarios and outputs. These outputs are variable depending on the focus of planning; examples of outcomes include conservation-value maps, priority area maps.

Although Marxan is not integrated with GIS software, the tabular output is readily imported into a GIS through linking output tables to the spatial planning units if the ArcView format is selected in the input parameter file. Reviewing the tabular output spatially will provide further clarity to the results of the analysis and may ease communication to internal and external users.

Marxan is supported by a comprehensive website.

State of Development Released and updated

Development Contact

Matt Watts


Outcome Areas Environmental, Economic
Management Domains Land, Biodiversity, Coastal
Intended End Users
  • Researcher
  • Regional Council Scientist
Spatial Resolutions 100-500m
Spatial Extents Local (i.e. Catchment or District), Regional
Spatial Dimensions 2D
Temporal Resolutions Years
Temporal Extents Years
Steady State or Dynamic Unknown
Level of Integration Environmental, Economic

Input & Output Data

Input Data Formats Test File(s)
Output Data Formats Text File(s)


Open/Closed Source Open Source
Licence Type Free to download - must register to download

User Information

Software Needed Pluggin for QGIS avaiable
User Interface No user interface
Ease of Use Moderate
Use in Policy Process Plan (Policy Formulation), Do (Policy Implementation), Review (Issue Identification)

See Marxan - Documentation Page

Technical Considerations

Keywords Biodiversity, conservation planning, priorities
Key References

See Marxan Website - Publications

Ardron, J. H.P. Possingham and C.J. Klein (Eds.), 2010. Marxan good practices handbook Version 2. University of Queensland, St. Lucia, Queensland, Australia, and Pacific Marine Analysis and Research Association, Vancouver, British Columbia, Canada.

Associated Case Studies

Other Key Case Studies

Use of ' MARXAN' for selection of waters of national importance for biodiversity. Image, L.; Weatherhead, M. (2004): NIWA Client Report: CHC2004-072. 24 p.

Exploration of the use of reserve planning software to identify potential Marine Protected Areas in New Zealand's Exclusive Economic Zone.  Leathwick, J., et. al. (2006): NIWA Client Report: HAM2006-064,  Report for Department of Conservation

Marxan - International case studies