Marine Planning
Practical Approaches to Ocean and Coastal Decision-Making
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Case 2: Marxan Data and Results

In Case 2, the wetlands identified in Case 1 are included as a factor or target with other information compiled as part of the Florida regional assessment for biodiversity. This information is used as input in Marxan to identify a set of natural areas that may most efficiently meet objectives for conserving biodiversity and mitigating coastal hazards.

Caution: The results of these examples, like all similar model outputs, provide decision support for managers and other stakeholders and should never be assumed to represent final results or “the answer.”

Data on Coastal Wetlands and Coastal Hazards
Select Data Area

Study Area

The panhandle of northern Florida, USA

Wetlands with Mitigation Value

Coastal wetlands withing 5 miles of the human communities identified most at risk and vulnerable from coastal hazards. These wetlands have high potential for mitigating coastal hazards.

Biodiversity Targets

Dozens of biodiversity targets identified in a regional assessment including coastal and marine ecosystems (e.g. salt marsh, tidal flats) and imperiled species (e.g. manatees, sea turtles, piping plovers).

Compare the Marxan results: In the first two cases there is not a great change in the results when the data on Biodiversity are analyzed first alone and the together with the data on wetlands with mitigation value (WMV). When the WMV data are added there is little change in the total number of cells selected (only 2 percent greater in second analysis) and only minor change in the sites that are selected. These results suggest that goals can be jointly met for both hazard mitigation and biodiversity conservation with little change in total priority area (spatial efficiency). In the third analysis, all the WMV are locked in to the analysis (i.e., 100 percent goals for potential hazard mitigation) and then the biodiversity targets are included. Locking targets creates solutions that are much less spatially efficient (total area in the third analysis increases by more than 36 percent from the first two analyses); the results are clumped in to fewer sites.

Marxan Results for Coastal Biodiversity and Coastal Hazards
Select Result

Study Area

The panhandle of northern Florida, USA

Marxan - Biodiversity Only

The results of a Marxan analysis with only biodiversity targets. The goals for all targets were set at 30% of existing distributions.

Marxan - Biodiversity + Wetlands
with Mitigation Value

The results of a Marxan analysis with data on biodiversity targets and wetlands with mitigation value for coastal hazards. Goals for all targets set at 30% of distributions.

Marxan - Biodiversity + Wetlands
with Mitigation Value (locked)

The results of a Marxan analysis with data on biodiversity targets and wetlands with mitigation value for coastal hazards. Goals for wetlands with mitigation value - 100% (i.e., locked in analysis), Goals for biodiversity targets- 30% of distribution.

 


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