Marine Planning
Practical Approaches to Ocean and Coastal Decision-Making
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Establish Analysis Units

Stratification Units

Regions are divided into subunits or strata to:

Stratification can be based on:

Assessment Units

Assessment units are the smallest elements in which targets and the suitability factors are tracked. Attributing target, threat, and human use information to a finite set of assessment units makes subsequent decisions more manageable and reduces the relative complexity of the process.

coastal conditions map

One of the maps from the Carolinian Assessment showing stratification units. Click on image to enlarge.

Case Study: Carolinian Ecoregion

Six subregions were identified and conservation goals had to be met not only overall but in every sub-region in which the target occurred. The first step was to establish northern, central and southern stratification units. Ecologically, the region's estuaries can be classified into three broad types: the extensive, poorly flushed sounds of southeastern Virginia and North Carolina, the well-flushed bar-built and riverine estuaries of South Carolina and Georgia, and the poorly flushed bar-built estuaries of northeastern Florida. These stratification units follow well understood transition zones where different assemblages of species were found.

The ecoregion was then divided into inshore and offshore zones corresponding to the 50 meters isobath to account for variation in diversity across this gradient.

The ecoregion was divided into 11,903 hexagonal “assessment units,” each representing 1,500 hectares.

 

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