A coral collapse off Queensland in the first half of last century has heightened concerns about the effects of coastal development on the Great Barrier Reef.
Australian scientists have been studying the collapse, around the Palm Islands off Townsville between 1920 and 1955.
Cores taken through the coral reef at Pelorus Island show a healthy community of branching Acropora corals flourished for centuries before European settlement of the area.
That was despite frequent floods and cyclone events.
But between 1920 and 1955, the branching Acropora failed to recover.
The collapse coincided with wide-spread land clearing for grazing and agriculture, which took place in the nearby Burdekin River catchment in the late 19th Century.
That clearing caused an increase in the amount of mud and nutrients into the Great Barrier Reef lagoon, says the study's lead author Dr George Roff, from the ARC Centre of Excellence for Coral Reef Studies at the University of Queensland.
"Corals have always died from natural events such as floods and cyclones, but historically have shown rapid recovery following disturbance," Dr Roff says.
"Our results suggest that the chronic influence of European settlement on the Queensland coastline may have reduced the coral's ability to bounce back from these natural disturbances."
The researchers said they found no similar collapse at any time in the previous 1700 years, pointing to increased sediment and nutrient loading from land clearing as a cause.
They said the findings add weight to evidence that human activity is implicated in the recent loss of up to half of the corals on the Great Barrier Reef.
At two sites the Acropora corals vanished completely, while at a third, there was a marked shift in coral species from Acropora to Pavona, which the researchers say parallels similar observations of human impacts in the Caribbean.
"On a global scale, our results are consistent with a recent report from the Caribbean region, where land use changes prior to 1960 were implicated in a significant decline in Acropora corals in near-shore reefs," the researchers found.
They said the research highlighted the very strong link between land-based activities and the reef's future and the importance of controlling run-off.
In a June report, the United Nation's environmental arm UNESCO said coastal development was one of the most pressing threats to the Great Barrier Reef.
It's due to decide next year of the reef should be listed as a World Heritage site in danger.