and Southeast Asian reefs are the most threatened of any region, with greater than 80%
at high risk of destruction (Burke, 1998). This dataset and report were completed due
to the efforts of many collaborators, including WRI, the World Conservation
Monitoring Centre (WCMC), the International Center for Living Aquatic Resources
Management (ICLARM), and the United Nations Environment Programme (UNEP).
Since the Global dataset indicated that the greatest risk to reefs was found in
Southeast Asia, this led to the second Reefs at Risk dataset specific to this region. This
dataset was completed in 2002 by Burke et al. (2000), and is also a georeferenced (GIS)
point database with reefs categorized by threats. Overfishing, tourism, increased
fishing pressure, proximity to cities, coral disease, land cover type, proximity to
shipping lanes, and inflow from rivers are only a few examples of the threats to reefs in
this region. The accompanying report states that although there is widespread
knowledge of the reef degradation in this region, specific information for local reefs
was typically minimal prior to the Reefs at Risk project. The Reefs at Risk in Southeast
Asia project was intended to address this information deficit through an extensive data
compilation effort (Burke et al., 2002).
Reefs at Risk in the Caribbean is the most recent WRI publication regarding reefs
and threats to reef health (Burke et al., 2004). The available georeferenced datasets
incorporate vector and raster data, including but not limited to, reef locations, threats
from anthropogenic activities, river mouths, bathymetry, ports, oil/gas wells, airports
marine protected areas, population densities, soil type, dive centers, and watershed
boundaries. Following the integration and analysis of these datasets, there were several
important trends and patterns which emerged. First, there is a clear decline in marine
protected area effectiveness. There has been a tremendous increase in tourism and
development in areas adjacent to coral reefs. Currently, there are more than 285 MPAs
in the Caribbean, but the protection provided by those MPAs is not consistent
throughout the Caribbean. According to Burke et al. (2004) only 6% of MPAs were
successfully managed. Threats to reef survival can include disease, increase in ocean
temperature, fishing pressure, increased tourism, sedimentation, and pollution. The
datasets provided by Burke et al. (2004) provide an excellent source of data for further
reef research and future data integration.
4. Data Integration Issues
Combining datasets of different data format, scales (temporal, spectral, spatial),
and geometric rectification can yield a more clear and sophisticated analyses of any
ecosystem. Data integration can also introduce error or uncertain results. There are
general integration issues, and there are uncertainty issues that belong solely to imagery
or data from acquired for an aquatic environment. The most basic type of uncertainty
arises from data acquisition error in terms of geometric aspects (scale, projection,
illumination geometry), data acquisition method per different sensor system (SAR, TM,
LIDAR), platform stability (aerial versus orbital), ground control corrections, and
atmospheric conditions (Lunetta et al., 1991). Merging datasets with inherent errors in
the data structure or geometry can lead to unreliable results.
Difficulties unique to aquatic environments include lack of reliable ground control
points and the rapid change in ocean, lake, and freshwater ecosystems. First, if imagery
does not contain an identifiable set of ground control reference points, accurate
georectification cannot occur. This situation is not only true in underwater areas, it also
occurs due to tidal changes, particularly in marsh areas. Second, a water-based
environment changes at a much faster rate than a land-based environment. Substantial
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Gebelein
at high risk of destruction (Burke, 1998). This dataset and report were completed due
to the efforts of many collaborators, including WRI, the World Conservation
Monitoring Centre (WCMC), the International Center for Living Aquatic Resources
Management (ICLARM), and the United Nations Environment Programme (UNEP).
Since the Global dataset indicated that the greatest risk to reefs was found in
Southeast Asia, this led to the second Reefs at Risk dataset specific to this region. This
dataset was completed in 2002 by Burke et al. (2000), and is also a georeferenced (GIS)
point database with reefs categorized by threats. Overfishing, tourism, increased
fishing pressure, proximity to cities, coral disease, land cover type, proximity to
shipping lanes, and inflow from rivers are only a few examples of the threats to reefs in
this region. The accompanying report states that although there is widespread
knowledge of the reef degradation in this region, specific information for local reefs
was typically minimal prior to the Reefs at Risk project. The Reefs at Risk in Southeast
Asia project was intended to address this information deficit through an extensive data
compilation effort (Burke et al., 2002).
Reefs at Risk in the Caribbean is the most recent WRI publication regarding reefs
and threats to reef health (Burke et al., 2004). The available georeferenced datasets
incorporate vector and raster data, including but not limited to, reef locations, threats
from anthropogenic activities, river mouths, bathymetry, ports, oil/gas wells, airports
marine protected areas, population densities, soil type, dive centers, and watershed
boundaries. Following the integration and analysis of these datasets, there were several
important trends and patterns which emerged. First, there is a clear decline in marine
protected area effectiveness. There has been a tremendous increase in tourism and
development in areas adjacent to coral reefs. Currently, there are more than 285 MPAs
in the Caribbean, but the protection provided by those MPAs is not consistent
throughout the Caribbean. According to Burke et al. (2004) only 6% of MPAs were
successfully managed. Threats to reef survival can include disease, increase in ocean
temperature, fishing pressure, increased tourism, sedimentation, and pollution. The
datasets provided by Burke et al. (2004) provide an excellent source of data for further
reef research and future data integration.
4. Data Integration Issues
Combining datasets of different data format, scales (temporal, spectral, spatial),
and geometric rectification can yield a more clear and sophisticated analyses of any
ecosystem. Data integration can also introduce error or uncertain results. There are
general integration issues, and there are uncertainty issues that belong solely to imagery
or data from acquired for an aquatic environment. The most basic type of uncertainty
arises from data acquisition error in terms of geometric aspects (scale, projection,
illumination geometry), data acquisition method per different sensor system (SAR, TM,
LIDAR), platform stability (aerial versus orbital), ground control corrections, and
atmospheric conditions (Lunetta et al., 1991). Merging datasets with inherent errors in
the data structure or geometry can lead to unreliable results.
Difficulties unique to aquatic environments include lack of reliable ground control
points and the rapid change in ocean, lake, and freshwater ecosystems. First, if imagery
does not contain an identifiable set of ground control reference points, accurate
georectification cannot occur. This situation is not only true in underwater areas, it also
occurs due to tidal changes, particularly in marsh areas. Second, a water-based
environment changes at a much faster rate than a land-based environment. Substantial
192
Gebelein