1.4.1 The NWHI supports more than 7,000 species
of fishes, mammals, plants, coral, and other invertebrates (Bush 2006).
Discoveries of species in the NWHI are continuing to be made, as demonstrated
by a 2006 research expedition in French Frigate Shoals which yielded
over 100 species not previously known to exist in the area and many
of which may be previously unknown to science (Associated Press 2006).
The rich diversity of the NWHI is in part due to the relative isolation
of the area and minimal impact from humans, which is underscored by
the starkly contrasting lower levels of diversity found in the marine
areas of the main Hawaiian Islands (DeMartini and Friedlander 2004;
Friedlander et al. 2005a; NOAA 2004g). Coral reefs are
among the most highly diverse of all ecosystems on the planet; the
coral reef ecosystem of the NWHI exemplifies this point.
1.4.2 Further contributing to diversity, the ecosystem
of the NWHI contains a wide variety of habitats, extending from the
shoreline to depths of approximately 14,000 feet. For example, within
the pristine coral reefs of the NWHI, the percentage of coral cover
varies widely, creating a series of interconnected but distinct types
of coral reef habitats, or zones (e.g., shelf, fore reef, reef crest,
back reef, and lagoon). Wave exposure is the primary factor causing
zonation in the NWHI, but gradients in sediment, salinity, and temperature
are also important (Friedlander et al. 2005a). As a result
of this zonation, the coral reefs of the NWHI contain a variety of
environmental niches and resources that support a diverse array of
species.