Anna Vidot, ABC News 3 Feb 10;
Tasmania's low lying protected shorelines are showing signs of recent and accelerating erosion, most likely caused by rising seas.
Scientists say there is evidence sea levels around the island state have risen 14 centimetres over the past 100 years.
They're taking a closer look at one section of the coastline to establish just how much damage that's caused, and how fast the decline has been.
The project is being conducted by the Cradle Coast Natural Resource Management group and scientists from the University of Tasmania's Centre for Spatial Information Science, to look at the potential effect of rising sea levels on the north west coast of Tasmania into the future.
The project will focus on how the effects of rising seas on biodiversity will in turn affect the community of Circular Head.
As part of the project, the University's coastal geomorphologist Chris Sharples and his team walked the length of the coast from the north west tip of the island, eastwards past Smithton.
He says they saw plenty of evidence that rising seas are most likely already causing significant and rapid erosion along half that section of coast.
"We do see evidence in this area of effects on the shorelines which are consistent with what you would expect from sea level rise.
"We're seeing mature trees that would have germinated tens of metres inland now being undermined by erosion," he says.
"There are some shorelines that have been naturally eroding for thousands of years, but these saltmarsh shorelines that we're talking about, under a stable sea level they would be stable.
"But they're not stable here; they're changing at what is quite obviously a rapid rate."
The retreating saltmarsh is bad news for the biodiversity of this area of north west Tasmanian coast, as well for the communities and industries in the area.
The aquaculture industry, for example, relies on clear and clean waters that will be lose its quality as the saltmarsh disappears.
"I think it will have a definite impact on fisheries and it will make the waters more murky," says Tasmania University researcher Vishnu Prahalad, who's looking at vegetation changes along the coast.
"There's also increased risk of coastal erosion without the saltmarshes.
"Saltmarshes baffle [disperse and slow down] the waves and protect the hinterland from coastal erosion, and if there are no saltmarshes that will definitely increase the risk of coastal erosion."
"These environments are providing valuable services to land owners adjacent to the coast and to aquaculturalists who are seeking to have good quality water, to recreational and commercial fishers in the area" says project leader, Dr Richard Mount from the University of Tasmania.
"What we're hoping is that we can identify what [those services or benefits] are and then add that into the understanding that people have of their area and assist them of the management of what they're doing."
