Shallow-Water Benthic Habitats of the Republic of Palau

Project Methods

Developing the Habitat Classification Scheme

A hierarchical classification scheme was created to define and delineate shallow-water benthic habitats. The classification scheme was influenced by many factors including:

Zone
  1. Requests from the management community,
  2. NOS’s coral reef mapping experience in the Pacific and U.S. Caribbean
  3. Existing classification schemes for the U.S. Pacific Territories, Northwestern and Main Hawaiian Islands (NCCOS 2005 Shallow-Water Benthic Habitats of American Samoa, Guam, and the Commonwealth of the Northern Mariana Islands; NOAA 2003 Atlas of the shallow-water benthic habitats of the Northwestern Hawaiian Islands; Battista et al. 2007)
  4. Quantitative habitat data for the U.S. Pacific Territories and Hawaiian Archipelago
  5. The minimum mapping unit (MMU - 1 acre for visual imagery interpretation)
  6. Analysis of the spatial and spectral limitations of satellite IKONOS imagery

Structure

The hierarchical scheme allows users to expand or collapse the thematic detail of the resulting map to suit their needs. This is an important aspect of the scheme as it will provide a "common language" to compare and contrast digital maps developed from complementary remote sensing platforms. Furthermore, it is encouraged that additional hierarchical categories be added in the resulting geographic information system by users with more detailed knowledge or data for specific areas. For example, habitat polygons smaller than the MMU can be delineated, such as reef holes found in parts of the U.S. Pacific Territories, or habitat polygons delineated as colonized pavement using this scheme could be further attributed with health information (i.e., bleached, percent live cover) or species composition.

Cover

The hierarchical scheme was prepared through consultation, meetings, and workshops that included key coral reef biologists, mapping experts, and professionals throughout the pacific territories. Modifications were made throughout the development process based upon feedback provided by workshop participants and other contributors. Additional modifications were made during the mapping process to ensure that each category definition reflected the intended habitats and zones encountered in the field as accurately as possible. For instance, the separation of biological cover and geomorphological structure in the present scheme represents a significant evolution of previous versions of the classification schemes developed for mapping of the U.S. Caribbean, U.S. Pacific Territories, Northwestern and Main Hawaiian Islands (2003).