A guide for planners and managers - IUCN

PART I
Strategies and Tools
Habitat Classification: In order to produce digital marine ecosystem maps, a
marine habitat classification scheme must exist. Such a scheme should have biological
and physical parameters for the ecosystem. The scheme should be hierarchical and
nest highly detailed habitat descriptions into more generalized habitat descriptions.
The scheme should provide sufficient detail for research, conservation, and management
needs. Finally, the scheme should recognize the limitations of the remote sensing
technology to discriminate features in the marine environment. An accurate, highresolution
shoreline is the base map upon which all other map layers are superimposed.
Shoreline links terrestrial ecosystems to marine ecosystems. In addition, datum
adjustments must be applied to the shoreline to properly place this key feature on
the earth. Efforts must continue to develop accurate, high-resolution, datum-corrected
digital shoreline maps.
Bathymetry: This is a critical thematic data layer for many mapping activities.
Bathymetry depicting water depths of less than 100 m is needed to identify and
locate navigation hazards and shipping channels, predict and manage the damage
from floods and storms, identify and monitor critical fish habitat, and document the
location and extent of shallow coral reef ecosystems. Bathymetry also is required to
fully utilize remotely sensed data to correct for light attenuation. Light received by
the sensor is affected by the distance that it must travel through the water column.
Fortunately, most corals are found in shallow-water environments of less than 30 m.
Remote Sensing Costs: Data acquisition accounts for about 25 percent of the
total cost of producing marine ecosystem maps. The remaining 75 percent goes to
georeferencing the imagery, calibrating the imagery, validating the draft maps, and
producing the final map products.
Airborne LIDAR costs range from US$900 to 1,800 per sq km depending upon
the horizontal spatial resolution needed. Deep water (> 50 m) bathymetry also is crucial
for many mapping activities, including coral reef ecosystem mapping. Ship-based
acoustic surveys using multibeam depth sounders have successfully produced
bathymetric maps with vertical accuracies of +/- 15 cm from depths 10 m to 500 m
and greater. In addition to providing highly accurate bathymetric maps, the system
provides backscatter, which can be used to map the roughness of the seafloor. Costs
of multibeam range from US$1,000 to 4,000 per sq. km depending on the type of boat
required. When assessing airborne remote sensing technology, the cost is most
affected by the altitude flown and the "footprint" of the resulting imagery. Typically,
aerial photography costs about US$125/sq. km.
Due to their large footprint, satellite imagery costs range from $100/sq. km. for
IKONOS to $6/sq. km. for LandSat 7.
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