Hence, the monitoring program needed to meet multiple requirements, in addition to
being an accurate, cost effective, and repeatable approach, so that management and
monitoring agencies could implement it on a regular basis using their staff and
resources.
Due to the extensive area covered by Moreton Bay, mapping the extent and density
of L. majuscula on a daily or weekly basis could not be done using standard field
survey techniques (e.g. video transects, diver transects, or diver quadrats). Remotely
sensed data from airborne or satellite imaging systems provided an alternative for
synoptic coverage and could be used to map the location and density of L. majuscula to
a depth of 3m in clear water (Roelfsema, 2001, 2002). Maps of L. majuscula collected
over time could then be examined to assess bloom dynamics and potential controlling
factors. A procedure to map L. majuscula in the Eastern region of Moreton Bay was
developed from field-spectrometry of key substrate types, radiative transfer modelling
to assess water depth effects on the ability to discriminate Lyngbya, and field data to
verify the results of image based mapping (Roelfsema, 2001, 2002). The result of this
work was a mapping program for use with Landsat TM/ETM+ data that could be used
to map L. majuscula in areas of clear water < 3m deep. The mapping approach relied on
coincident field survey data to train an image classification. A geometrically registered
and dark-pixel corrected Landsat TM/ETM+ image was required, with the aid of field
survey to map the location of L. majuscula. This work was implemented as a joint
monitoring program, combining local field expertise of Marine Park authorities
(Queensland Parks and Wildlife Service), with remote sensing capabilities of a research
group at the University of Queensland. The aim of the program was to provide regular
baseline maps, integrating field and image based approaches to present L. majuscula
density and distribution in one section of Moreton Bay, Eastern Banks.
6.2.4 Inclusion of Community Information with the Field and Image Based Mapping
Program
Community groups (e.g. oyster lease owners, seagrass watch groups) in Moreton
Bay were informed about the characteristics of L. majuscula via websites, handouts,
and public presentations. In each form of communication explicit instructions were
provided on how information on bloom sightings (e.g. percent cover, colour, location)
was to be recorded and then submitted to Queensland Parks and Wildlife Service
(QPWS) for analysis.
A field-monitoring program was developed to provide a repeatable GPS based
field survey to improve on an earlier QPWS subjective and non-geolocated survey
technique. Boat driven survey tracks were first located over the sections of the Bay to
be monitored, taking into account the most recent bloom locations and expected
changes. Data were then collected at regular spatial and temporal intervals along these
tracks. Data collected included: GPS coordinates for each sample point; substrate type;
visual estimate of substrate percent cover; and digital images captured for those sites
with L. majuscula present. The digital images were used to confirm the field estimation
of % L. majuscula cover, and to provide archival information. The collected
information was then processed in a GIS to produce quantitative field maps of
L. majuscula distribution.
Field data collection activities were scheduled to coincide with overpasses of the
Landsat TM/ETM+ sensors. This enabled the use of field data for both calibration and
validation purposes. Depending on the severity of the bloom, the field and image
242
Phinn, Joyce, Scarth and Roelfsema
6.2.3 Remote Sensing for Mapping L. majuscula
being an accurate, cost effective, and repeatable approach, so that management and
monitoring agencies could implement it on a regular basis using their staff and
resources.
Due to the extensive area covered by Moreton Bay, mapping the extent and density
of L. majuscula on a daily or weekly basis could not be done using standard field
survey techniques (e.g. video transects, diver transects, or diver quadrats). Remotely
sensed data from airborne or satellite imaging systems provided an alternative for
synoptic coverage and could be used to map the location and density of L. majuscula to
a depth of 3m in clear water (Roelfsema, 2001, 2002). Maps of L. majuscula collected
over time could then be examined to assess bloom dynamics and potential controlling
factors. A procedure to map L. majuscula in the Eastern region of Moreton Bay was
developed from field-spectrometry of key substrate types, radiative transfer modelling
to assess water depth effects on the ability to discriminate Lyngbya, and field data to
verify the results of image based mapping (Roelfsema, 2001, 2002). The result of this
work was a mapping program for use with Landsat TM/ETM+ data that could be used
to map L. majuscula in areas of clear water < 3m deep. The mapping approach relied on
coincident field survey data to train an image classification. A geometrically registered
and dark-pixel corrected Landsat TM/ETM+ image was required, with the aid of field
survey to map the location of L. majuscula. This work was implemented as a joint
monitoring program, combining local field expertise of Marine Park authorities
(Queensland Parks and Wildlife Service), with remote sensing capabilities of a research
group at the University of Queensland. The aim of the program was to provide regular
baseline maps, integrating field and image based approaches to present L. majuscula
density and distribution in one section of Moreton Bay, Eastern Banks.
6.2.4 Inclusion of Community Information with the Field and Image Based Mapping
Program
Community groups (e.g. oyster lease owners, seagrass watch groups) in Moreton
Bay were informed about the characteristics of L. majuscula via websites, handouts,
and public presentations. In each form of communication explicit instructions were
provided on how information on bloom sightings (e.g. percent cover, colour, location)
was to be recorded and then submitted to Queensland Parks and Wildlife Service
(QPWS) for analysis.
A field-monitoring program was developed to provide a repeatable GPS based
field survey to improve on an earlier QPWS subjective and non-geolocated survey
technique. Boat driven survey tracks were first located over the sections of the Bay to
be monitored, taking into account the most recent bloom locations and expected
changes. Data were then collected at regular spatial and temporal intervals along these
tracks. Data collected included: GPS coordinates for each sample point; substrate type;
visual estimate of substrate percent cover; and digital images captured for those sites
with L. majuscula present. The digital images were used to confirm the field estimation
of % L. majuscula cover, and to provide archival information. The collected
information was then processed in a GIS to produce quantitative field maps of
L. majuscula distribution.
Field data collection activities were scheduled to coincide with overpasses of the
Landsat TM/ETM+ sensors. This enabled the use of field data for both calibration and
validation purposes. Depending on the severity of the bloom, the field and image
242
Phinn, Joyce, Scarth and Roelfsema
6.2.3 Remote Sensing for Mapping L. majuscula