Marxan

MARXAN is software designed to aid systematic reserve design on conservation planning. With the use of stochastic optimisation routines (Simulated Annealing) it generates spatial reserve systems that achieve particular biodiversity representation goals with reasonable optimality.

Computationally, MARXAN provides solutions to a conservation version of the 0-1 knapsack problem, where the objects of interest are potential reserve sites with given biological attributes. The simulated annealing algorithm attempts to minimise the total cost of the reserve system, while achieving a set of conservation goals (typically that a certain percentage of each geographical/biological feature is represented by the reserve system).

History

MARXAN is a portmanteau acronym, fusing MARine, and SPEXAN, itself an acronym for SPatially EXplicit ANnealing. It was a product of Ian R. Ball's PhD thesis, while he was a student at the University of Adelaide in 2000, and was supervised and funded by Hugh Possingham, who currently holds a Federation Fellowship at the University of Queensland. It was an extension of the existing SPEXAN program.

Application

MARXAN is the most widely used systematic reserve planning software in the world ^[1], and has been used to create the marine reserve network on the Great Barrier Reef, in Queensland, Australia, the largest marine protected area in the world ^[2]. It has been used for many other marine reserve planning applications, including:^[3]

• Channel Islands of California ^[4]
• Gulf of Mexico [1]
• Galapagos Islands
• South Australia [2]
• British Columbia^[5]
• Connecticut/New York
• Central Coast of California
• Baltic Sea^[6]

MARXAN has been used extensively by The Nature Conservancy, and is a major part of the systematic planning tools being used in the Global Marine Initiative. The World Wildlife Fund used MARXAN to define a Global set of Marine Protected Areas, the Roadmap to Recovery, which they used to petition the UN about the creation of open ocean marine reserve networks.

The software has also been used in terrestrial applications, such as:

• The North American Wildlands Project.
• Selecting priority areas for Global Mammal Assemblages^[7].
• Planning the conservation of ecosystem services ^[8].
• The Great Sand Hills of Saskatchewan Regional Environmental Study [3]

Shortcomings

One shortcoming of MARXAN is its inability to deal with issues of demographic inter-connectedness. In marine systems, the presence of a biological feature does not guarantee the persistence of that feature in the absence of the surrounding ecosystem. This is a concept generally known as "connectivity". MARXAN considers that including into a reserve system a site that contains a particular feature will ensure the persistence of that feature, even though surrounding sites may not be included in the reserve system, and may therefore be ecologically compromised. MARXAN does employ a "boundary length modifier", which attempts to minimise the boundary length to area ratio, thus increasing the continuity of the reserve systems. This ad-hoc alteration may go some way to addressing the problem ^[9].

References

1. ^ Airamé et al. (2003) Applying ecological criteria to marine reserve design: a case study from the California Channel Islands, Ecological Applications, 13(1), S170-S184.
2. ^ Environment News Service - International Daily Newswire (2004). Fish Boats Barred From One-Third of Great Barrier Reef [online]. Available: http://www.ens-newswire.com/ens/jul2004/2004-07-01-06.asp [Access date: 28 May 2006]
3. ^ For more details of these applications, see the Ecology Centre MARXAN Homepage.
4. ^ Airamé et al. (2003) Applying ecological criteria to marine reserve design: a case study from the California Channel Islands, Ecological Applications, 13(1), S170-S184.
5. ^ Using Computer Software To Design Marine Reserve Networks: Planners Discuss Their Use Of Marxan
6. ^ Baltic Sea Environment Proceedings No. 124A
7. ^ Ceballos, G. et al. (2006) Global Mammal Conservation: What Must We Manage?, Science, 309(5734), 603-607.
8. ^ Chan, K.M.A. et al. (2006) Conservation planning for ecosystem services?, Public Library of Science: Biology, 4(11), e379.
9. ^ Leslie, H. et al. (2003) Using siting algorithms in the design of marine reserve networks, Ecological Applications, 13(1), S185-S198.

External links

• MARXAN Homepage, information and download
• A thorough rundown of the software specifications by the National Commission on Science for Sustainable Forestry
• This article in Marine Protected Area News discusses the pros and cons of the software in the context of MPA planning.