Coastal habitats are critical to the sustained production of many fisheries.
It is important, therefore, that fishery managers obtain accurate estimates of
the extent of these habitats. This study investigated three methods of
estimating the linear extent and area of mangroves (commercially available
topographic data, aerial photographs and Landsat Thematic Mapper satellite
imagery) in two regions in northern Australia: the Joseph Bonaparte Gulf (in
particular, the Berkeley and Lyne Rivers) with typically narrow fringes of
mangroves (<50 m wide), and the Embley River on Cape York
Peninsula,with much broader mangrove stands (50–1000 m wide).
Ground-truthing verified that aerial photographs provided the most accurate
estimates of extents of mangroves in all rivers,because of their high spatial
resolution (2 m). Landsat Thematic Mapper imagery gave good estimates of the
area of habitats, but, because of the 30 m pixel resolution, it underestimated
the linear extent in places where the mangrove fringe was narrow. Topographic
data gave good estimates of the extent of mangroves where the forests were
more extensive and less linear in shape, but were very poor otherwise at this
scale. These findings have implications for the use of remote sensing
techniques in ecological studies in these regions.
Mapping seabird nesting habitats in Franz Josef Land, Russian High Arctic, using digital Landsat Thematic Mapper imagery
