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

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<strong>1.10</strong>.8.4 Classify<strong>in</strong>g <strong>and</strong> Mapp<strong>in</strong>g Human Impacts <strong>in</strong> Hawaii<br />

Conventional approaches to evaluat<strong>in</strong>g the distribution <strong>and</strong> ecological impacts <strong>of</strong> human<br />

activities to the mar<strong>in</strong>e environment have used expert op<strong>in</strong>ion to evaluate or rank impacts, for<br />

example, the Reefs at Risk (Bryant et al. 1998) used expert op<strong>in</strong>ion to classify the world’s coral<br />

reefs <strong>in</strong>to low, medium <strong>and</strong> high threat categories. Although widely used, these techniques are<br />

sometimes considered lack<strong>in</strong>g <strong>in</strong> objectivity due to bias <strong>in</strong> perceived threats <strong>and</strong> are usually not<br />

spatially articulated <strong>in</strong> a consistent framework. More recently, Halpern et al. (2007, 2008)<br />

developed an analytical grid-based framework for calculat<strong>in</strong>g <strong>and</strong> mapp<strong>in</strong>g the cumulative<br />

impact <strong>of</strong> human activities at a spatial resolution <strong>of</strong> 1 km 2 based on <strong>in</strong>dividually weighted<br />

stressor layers. The cumulative impact mapp<strong>in</strong>g framework has great versatility <strong>and</strong> can be<br />

conducted at a range <strong>of</strong> scales <strong>and</strong> is now be<strong>in</strong>g applied at f<strong>in</strong>er resolution to map smaller<br />

geographical areas around the world. A cumulative impacts approach was applied <strong>and</strong> locally<br />

ref<strong>in</strong>ed for the Papahãnaumokuãkea Mar<strong>in</strong>e National Monument <strong>in</strong> Hawaii to focus more on<br />

locally relevant threats <strong>in</strong>clud<strong>in</strong>g mar<strong>in</strong>e debris, ship strike risk, <strong>in</strong>vasive species, fish<strong>in</strong>g <strong>and</strong><br />

several climate change parameters (Selkoe et al. 2009). These data were comb<strong>in</strong>ed with habitat<br />

maps <strong>and</strong> expert judgment on the vulnerability <strong>of</strong> different habitat types <strong>in</strong> the Monument to<br />

estimate spatial patterns <strong>of</strong> current cumulative impact at 1 ha (0.01 km 2 ) resolution (Figure 24).<br />

Halpern et al. (2007) developed a suite <strong>of</strong> five criteria related to vulnerability to make basic<br />

characterizations <strong>of</strong> how activities impact ecosystems or ecozones differently: (1) the spatial<br />

scale at which the threat acts, (2) the frequency with which it acts, (3) the number <strong>of</strong> trophic<br />

levels impacted, (4) the resistance <strong>of</strong> the ecosystem to impact, <strong>and</strong> (5) the recovery time needed<br />

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