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1 1.10 Application of estuarine and coastal classifications in marine ...

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(e.g., Guisan et al., 1999; Jones et al. 2000; Weiss 2001). Positive BPI cell values denote features<br />

or regions that are higher than the surround<strong>in</strong>g area (e.g., ridges). Negative cell values denote<br />

features or regions that are lower than the surround<strong>in</strong>g area (e.g., valleys). BPI values near zero<br />

are either flat areas (where the slope is near zero), or areas <strong>of</strong> constant slope where the slope at<br />

the po<strong>in</strong>t is significantly greater than zero). The relationships between grids derived at f<strong>in</strong>e <strong>and</strong><br />

coarse scales can then be exam<strong>in</strong>ed <strong>and</strong> mapped out as a f<strong>in</strong>al terra<strong>in</strong> classification map us<strong>in</strong>g an<br />

algorithm developed by the user through the creation <strong>of</strong> a classification dictionary (Figure 7).<br />

The <strong>in</strong>tegration <strong>of</strong> <strong>in</strong> situ diver surveys (Bra<strong>in</strong>ard et al., 2008), <strong>and</strong> submersible dives (Wright et<br />

al., 2005, 2006) with bathymetric characteristics is ref<strong>in</strong><strong>in</strong>g the development <strong>of</strong> classified benthic<br />

habitat maps for the region.<br />

Hogrefe (2008) developed a geomorphological classification <strong>of</strong> both the terrestrial isl<strong>and</strong><br />

<strong>and</strong> surround<strong>in</strong>g seafloor terra<strong>in</strong> to def<strong>in</strong>e mar<strong>in</strong>e-terrestrial units based on watershed hydrology<br />

<strong>and</strong> catchment characteristics. The approach employs analysis tools associated with the Arc<br />

Hydro data model (Maidment, 2002) to derive dra<strong>in</strong>age patterns from watersheds <strong>and</strong> affiliated<br />

catchments around the isl<strong>and</strong>, which were then used to identify contiguous mar<strong>in</strong>e/terrestrial<br />

units (Figure 8). Spatiotemporal correlation analyses <strong>of</strong> population density <strong>and</strong> coral reef health<br />

<strong>in</strong>dices with<strong>in</strong> each <strong>of</strong> the mar<strong>in</strong>e/terrestrial bas<strong>in</strong>s revealed a decl<strong>in</strong>e <strong>in</strong> coral reef health<br />

associated with <strong>in</strong>creased population density. The model was then used to identify mar<strong>in</strong>e areas<br />

with long-term monitor<strong>in</strong>g sites that were most at risk from development <strong>in</strong> the watershed.<br />

The seamless l<strong>and</strong>-sea <strong>coastal</strong> terra<strong>in</strong> model provided geomorphological detail <strong>of</strong><br />

sufficient resolution <strong>and</strong> accuracy to enhance the study <strong>of</strong> ecosystem <strong>in</strong>terconnectivity <strong>and</strong> the<br />

effects <strong>of</strong> anthropogenic <strong>in</strong>puts to coral reef habitats. The American Samoa examples underscore<br />

the utility <strong>of</strong> mapp<strong>in</strong>g from “ridge to reef” (i.e., the connectivity between upl<strong>and</strong> watersheds,<br />

24

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