The general approach for assessing biodiversity is described fully in Biodiversity Conservation. The basic objectives of a regional assessment are to characterize the region's biodiversity as well as the human uses and threats to this diversity.
The biodiversity and suitability data illustrated in this case study were developed as part of a statewide assessment, Marine/Estuarine Site Assessment for Florida: A Framework for Site Prioritization. This work was prepared for the state as part of its Florida Fish and Wildlife Comprehensive Management Plan. The work presented here expands on that study towards the development of an approach to jointly examine coastal hazard mitigation and biodiversity conservation objectives.
In this case only the Northwest Coast of Florida (i.e., Panhandle Coast) is examined. It is an area where hazards from coastal storms such as tropical storms and hurricanes are important to human communities and biodiversity. The Panhandle Coast has a wave dominated energy regime with barrier islands, well developed beaches and foredunes and widely spaced inlets. The Apalachicola River, which drains much of Georgia and Alabama, ends in a large fluvial delta that drops gradually into deep waters.
Some of the main ecosystem targets included in the case study of the Panhandle Coast included salt marsh, submerged aquatic vegetation (e.g, seagrass and tidal freshwater grasses), tidal flats, beach/surf zone, coastal tidal river or stream, bivalve reef (oyster reefs), and inlets.
Some of the main species targets on the Panhandle Coast included Florida manatee, snowy plover, Alabama shad, Gulf sturgeon, opossum pipefish and diamondback terrapin. Statewide 36 targets represented species or aggregations of species. Targets were included if they were globally, regionally or state imperiled species, IUCN red-listed, federally listed/candidate species and American Fisheries Society threatened or endangered distinct population segments, as well as species aggregations, such as breeding concentrations and important nursery areas.
To run Marxan, the region was divided in to 1,500 hectare hexagons.
For this case study the goals for all the biodiversity targets were set at 30% of existing distributions. That is, the set of conservation areas identified by Marxan needed to include at least 30% of the existing distribution of the targets (for example 30% of the total distribution of seagrasses across the Panhandle).