Saltmarsh profiling continuing on Eyre Peninsula

SURVEY: A saltmarsh community at Acraman Creek. Research is being undertaken on saltmarshes across Eyre Peninsula. Photo: Eyre Peninsula Landscape Board
SURVEY: A saltmarsh community at Acraman Creek. Research is being undertaken on saltmarshes across Eyre Peninsula. Photo: Eyre Peninsula Landscape Board

The profiling of saltmarsh communities across Eyre Peninsula is providing scientists with a better understanding of species within the saltmarsh and changes to sites over time.

Saltmarsh profiling is taking place at 11 sites across the region, with the latest profile survey completed at Acraman Creek - near Smoky Bay - as part of a baseline data comparison of the condition of sites.

The profiling is nearing the halfway mark with Acraman Creek the fifth profile survey to be completed as part of the Saltmarsh Threat Abatement and Recovery Project, supported by Eyre Peninsula Landscape Board (EPLB) through the federal government's National Landcare Program.

EPLB staff were joined in the field by Adelaide University scientists, local surveyors, Far West Coast rangers and staff from the Department for Environment and Water's Coast and Marine branch.

They worked together to collect information, including vegetation type, vegetation height and density, land height, evidence of animal presence and any signs of disturbance.

EPLB landscape officer Alex Fraser said it was great to work alongside and learn from a range of people with knowledge about saltmarsh.

"Saltmarshes are a critically important vegetation community we have on Eyre Peninsula," he said.

"Many are supporting early stages of marine species and provide important feeding areas for many shorebirds.

"These surveys are really important to help us to manage the more than 3000 kilometres of saltmarsh coastline across the Eyre Peninsula."

Results from the surveys undertaken so far are being analysed, with early indications revealing some sites have changed little in about 25 years since they were previously surveyed, while others are showing more significant changes.

During the field work, Adelaide University researcher Dr Alice Jones and PhD student Sophie Russell collected soil cores from different types of saltmarsh vegetation communities at different heights along the profile.

Blue carbon stocks in coastal ecosystems at Acraman Creek, as well as Davenport Creek, are also being assessed.

Blue carbon is the organic carbon stored in the plants and soils of coastal ecosystems such as saltmarshes, seagrasses and mangroves.

These ecosystems can capture more carbon than forests on land, storing it for up to thousands of years which prevents it being released to the atmosphere as carbon dioxide.

It also means coastal ecosystem conservation and restoration are nature-based options for reducing climate change through decreasing the amount of carbon dioxide in the atmosphere.

Dr Jones said the study of Eyre Peninsula saltmarsh sites was shedding new light on the influence of vegetation types and saltmarsh on carbon stock in South Australia.

"It highlights that different environmental conditions affect soil blue carbon stocks, causing variability within sites and between sites," she said.

Carbon analysis is currently being undertaken on the sediment samples and will investigate the influence of tides, sea level, vegetation type and disturbance on carbon storage in saltmarshes.

The results from the western Eyre Peninsula sites will add to the results from 181 sediment core samples taken at Mount Young, Franklin Harbour and Tumby Bay sites last year.

Results from the three eastern Eyre Peninsula sites showed sediment organic carbon stocks were highest in mangroves, followed by intertidal saltmarsh and then supratidal saltmarsh.

In addition, there was some variability between sites, with Franklin Harbour having greater organic carbon stocks than the other sites.

A final report for all sediment sample sites will be undertaken once the western Eyre Peninsula sediment analysis is complete.