Meeting Marxan
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Blogger: Abigail Lynch, a doctoral candidate in the Department of Fisheries and Wildlife and a CSIS member, blogs from Down Under -- she's in Australia to build a framework for her dissertation research. She's interested in developing a decision-support tool to regulate harvest management strategies for lake whitefish in a changing climate.
Meeting Marxan
Tuesday, June 28, 2011
I am fortunate enough to have the opportunity to participate in a two day introduction to Marxan workshop, learning directly from the program’s creators. More so than following along the program manual to conduct the initial exercises, I think the value in the course is hearing from the speakers. Hugh Possingham gave a really strong introduction to the concept of conservation planning, which guides decisions about the location, configuration, and management of conservation areas. Hugh stressed that conservation planning can be on both spatial and temporal scales, looking at biodiversity, ecosystem processes, cost-effectiveness, threats, and conditions -- a vast improvement over the previous philosophy to creating reserves (pick iconic locations of recreational value often with charismatic mega fauna). This old system produced a very poor representation of diversity at any scale. Marxan, on the other hand, follows the CARE idiom: Comprehensiveness (diversity of species, habitats, ecological processes), Adequate (protecting enough to ensure the persistence of biodiversity features), Representative (sampling across the full variation for each feature), and Efficient (in the most cost-efficient manner).
Though Hugh insists that Marxan is a decision support tool, not a decision maker, managers and politicians are often wary of the program because it is a “black box.” Hugh’s very convincing response to these criticisms is: “fine, then don’t fly in a plane, either.” His rationale is that if they won’t use results produced by Marxan because they don’t understand the coding process, then they have no right to fly in an airplane if they do not know how to build one and fly it themselves.
Carissa Klein took this “black box” Marxan one step further -- Marxan with zones, “Marxan on steroids” as she calls it. Presenting on the California Marine Life Protection Act which served as the basis for her PhD, Carissa compared the application of Marxan, Marxan with zones (and costs for different zones), and Marxan with zones and fishing targets. This multitiered approach highlighted the utility of Marxan to both biodiversity and socioeconomic conservation. Her analysis, which provided a equitable distribution of fishing impacts, minimized the loss in fishing value while adhering to biodiversity objectives, informed decision makers who where designing the California reserve system.
Wednesday, June 29, 2011
Hugh and Carissa’s Marxan talks made an interesting coupling with two other talks that I attended downtown. Alex Campbell, of Queensland Primary industries and fisheries, first spoke on integrating spatio-temporal dynamics into Queensland’s scallop fishery. They’ve essentially updated the basic stock-recruitment functions to include random spatial and temporal fluctuations. Though a different approach than Marxan, it is also evaluating management on a spatial scale. For my own research, I saw important potential application in how the project sought to
