This research was funded by a Lizard Island Reef Research Foundation Critical Grant from the Charles Warman Foundation to Dr Maria Dornelas (University of St Andrews, Scotland) and Assoc Prof Joshua Madin (University of Hawaii). Previous field campaigns were also supported by an Ian Potter Foundation Doctoral Fellowship to Dr Damaris Torres-Pulliza and Dr Viviana Brambilla. The data collected during this research were pivotal for the development of a Consolidator grant application to The European Research Council awarded to Dr Dornelas (€2 million – CoralINT – GA101044975), which will continue surveying these sites until 2027.
Matthew-James Bennett mapping corals at North Point, Lizard Island. The photo was taken by Dr L. Vail, Australian Museums’ Lizard Island Research Station
The reefs at Lizard Island were seriously damaged by cyclones and marine heatwaves for four summers in a row (2014-2017). Are the corals recovering and how do we know?
The Lizard Island Reef Research Foundation funded a Critical Grant to quantify changes in coral reefs surrounding Lizard Island from 2019 to 2022.
Reef corals at Lizard Island have been mapped since the early 2000s using traditional techniques and were at a historically low abundance and diversity following a sequence of disturbances: cyclone Nathan in 2014, cyclone Ita in 2015, and marine heatwaves causing mass bleaching in 2016 and 2017.
Twenty one sites around Lizard Island have been mapped since 2016 using 3D mapping. The data gathered by the mapping project includes 3D maps, temperature, pinpointing and identifying corals, and coral recruitment.
To create the 3D maps, approximately 3000 photographs were taken in short succession, while swimming in a spiral from the central location of the site. 3D dense clouds, digital elevation models (DEM) and georeferenced orthomosaics were constructed from each set of photos, using the Agisoft Metashape software.
Temperature was recorded using data loggers which were deployed at study sites and data downloaded annually for storage.
Cher Chow (2024 Ian Potter Foundation Doctoral Fellow) mapping corals at North Point, Lizard Island. The photo was taken by Dr L. Vail, Australian Museums’ Lizard Island Research Station
Photomosaics of the corals were printed on waterproof paper, and annotated in situ with the location and species identification of each coral colony. Each year the colonies of corals were mapped using geographic coordinates (obtained using QGIS) and classed as alive or dead. Newly established colonies were added with their species identification.
Recruitment of ‘baby’ corals (known as coral spat) from the plankton to the reef is difficult to detect because the coral spat are less than 1mm across. Biologists study recruitment by placing surfaces such as terracotta tiles on the reef which are then collected after a spawning event and examined under the microscope. Terracotta tiles were deployed at each site prior to the mass spawning event in November and recovered in January,
During this project from 2018 – 2022, the reefs around Lizard island underwent a remarkable recovery, although sites differed in their pace of recovery. Specifically, within the over 2,300 m2 total reef area surveyed, the number of colonies increased from 7,580 in 2018 to 38,027 in November 2022.
In the same time period the number of species documented increased from 220 to 307. The number of colonies per site increased from 360 on average in 2018 to 1810 in 2022.
In parallel with increasing abundance and diversity, coral cover also increased during this period, with corals being barely visible on the photomosaics in 2019, but occupying almost half the area in November 2022. Future reports will document the decline in coral cover in subsequent summers.
Recruitment rates underpinned much of the variation in recovery across sites, with some sites doubling in abundance and others increasing by 10%. Recruitment rates continued to increase during the study period.
Long term monitoring is critical in understanding the condition of the reef and the effects of disturbance. The Lizard Island Research Station and the Lizard Island Reef Research Foundation have supported long term monitoring at Lizard Island. When monitoring commenced in the early 2000s nobody guessed that four disastrous summers in a row would make this data so important.
By Dr Penny Berents, Senior Fellow, Australian Museum Research Institute
Trustee, Lizard Island Reef Research Foundation
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