The software is primarily a product of Ian Ball's PhD thesis (Ball 2000) that was supervised by and funded through Professor Hugh Possingham. In the initial stages, it was called SPEXAN, a combination of the words Spatially Explicit Annealing. At that time, the most substantial funding was from Environment Australia (EA). We owe much to Andrew Taplin for this initial support. An early version of SPEXAN is the site selection algorithm used within the Environment Australia planning software, REST.
The Nature Conservancy (TNC) funded, through UC Santa Barbara, a project where Ian Ball integrated SPEXAN in to ARCVIEW (http://www.biogeog.ucsb.edu/projects/tnc/toolbox.html). Sandy Andelman, Frank Davis and David Stoms wrote a very useful tutorial for this new tool that is now extensively used by TNC. The version of SPEXAN that underpins Sites is now somewhat dated and recent discussions with TNC will hopefully yield an upgraded tool.
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. GBRMPA provided partial support for the modification. Marxan also was used by Adam Lewis and Suzanne Slegers to provide decision support for the GBR representative areas program. Along with the TNC ecoregional planning processes, these represent some of the largest applications of Marxan/SPEXAN.
The US National Marine Fisheries Service (NMFS) have funded us to advance Marxan further and provide technical advice on its application to Salmon recovery planning. Mary Ruckelshaus heads this project. (http://www.nwfsc.noaa.gov/trt/index.html)
The National Centre for Ecological Analysis and Synthesis (NCEAS) has played host during development and sharing of this software. We are grateful to NCEAS for some funding and substantial inkind support.