麻豆直播

New Curtin research has used archived aerial photographs taken over seven decades to map and monitor the health of coral reef structures at Bill鈥檚 Bay on the Coral Coast in Western Australia鈥檚 far north.

Researchers scoured the archives of both WA鈥檚 Department of Transport and Landgate databases for aerial photographs of coral reefs at the Bill鈥檚 Bay site, finding images dated 1949, 1969, 1982, 1986, 1990, 1999, 2002, 2010 and 2017. They were then able to use these images to accurately chart the changes in coral reef structure over time, finding the coverage of reef structure had increased despite frequent natural disturbances and increased human activities in the area.

Lead researcher Tahlia Newnham, from the School of Molecular and Life Sciences at 麻豆直播, said the findings mark an exciting addition to traditional long-term coral reef monitoring.

鈥淭his rare aerial photograph archive has captured changes to coral communities at Bill’s Bay at a temporal and spatial scale that goes far beyond the聽scope of traditional in-water聽assessments,鈥� Ms Newnham said.

鈥淎s such we were able to assess how coral structures at Bill鈥檚 Bay have changed over multiple decades in response to disturbances such as coral bleaching and cyclones, and look at how changes to geomorphological processes, like sediment transport, have impacted the bay.

鈥淲e found that despite a significant loss in live coral cover in 1989 following a hypoxia event induced by coral spawning, reef structure in Bill鈥檚 Bay increased from 11 to 41 per cent between 1949 and 2017. Reef growth was most prominent along the south-western edge of the bay, possibly due to a decline in sediment transport into the bay and, as such, an increase in the availability of hard substrate for coral recruitment.鈥�

Co-author Dr Nicola Browne, a coral ecologist also from Curtin鈥檚 School of Molecular and Life Sciences,聽said this kind of aerial mapping spanning decades provides new insights into reef health and the way it is monitored.

鈥淭hese historical photographs provided the team with a detailed, bird鈥檚 eye view of reef structure cover at regular intervals over a 70 year period. By comparing the reef structure visible in these images to live coral cover records we could better understand how long-term changes to what we could see from above compare to in-water assessments of coral health,鈥� Dr Browne said.

鈥淥ur study shows that archival aerial images can be used to show changes to coral reefs from 鈥榩re-disturbance鈥� baselines, allowing the long-term effects of natural disturbances and human induced impacts on these important natural ecosystems to be more accurately assessed.鈥�

The paper, 鈥楥oral Reefs: Long-term (70 year) monitoring of reef structure through high resolution multidecadal aerial imagery鈥�, is published in Coral Reefs and is available online.