Environmentalists and community advocates have helped develop a plan to promote the regeneration of a deteriorating mangrove forest at St Kilda, in Adelaide's north.
- Environmentalists have launched a strategy to restore damaged mangroves at St Kilda
- The mangroves were killed by hypersaline which leaked from neighbouring salt ponds
- Latest monitoring of the site shows salinity levels are reducing
A community vision and strategic plan was launched in response to the dieback of mangroves and salt marsh at St Kilda.
The widespread damage to the mangrove forest was caused when a salt mining company filled dried out gypsum ponds at the nearby Dry Creek salt fields with hypersaline water in September 2020.
Almost 10 hectares of mangroves are now considered completely dead, along with 35 hectares of salt marsh, as a result of the pollution.
Environmental consultant Peri Coleman said the release of a strategy to restore the site is a significant milestone to the local community, who have been advocating for action for years.
"The community vision gives us a really good indication of what lots of people from different organisations, what their ideal for this area would be, and that helps to inform us as we move forward."
The document states that the removal of the salt that was deposited in the ponds is a "priority" to prevent ongoing impacts.
It outlines seven management zones across the overall site with detailed actions proposed for each area.
"They were broken up into naturally formed zones that reflect things like the salinity in the old ponds and the types of habitat that occurs around the old pond in that area," Ms Coleman said.
"Some areas are going to be more easily adjusted, modified, rehabilitated than other areas.
"So the types of decisions that we need to make about each zone are informed by those things about it."
Positive signs don't reduce threat
Ecologist Alice Jones said soil samples taken during recent monitoring at the site revealed slow signs of recovery.
"In the past some of the soil salinities had been up at over 10 times saltwater salinity which is very saline and almost all plants will not tolerate that," Ms Jones said.
Ms Jones said while the reduction in salinity is an improvement, there has still been little re-growth in the damaged zones.
She said the persistence of brine in the ponds is leading to repeated crystallisation in summer months and leakage during winter months, causing continuous impacts on the ecosystem.
"We do need to be aware that although we're seeing positive signs in terms of recovery, there's still a huge risk that we'll see the exact same thing happen again if we don't address the real issue which is the leaking of hypersaline water from the adjacent ponds."
Strategy to guide long-term solutions
Environment Minister Susan Close said the report would be "incredibly useful" to guide the environmental principles behind the state government's long-term plan to rejuvenate the ecosystem.
"We do need to do what we can to restore what was lost here and then we also need to have a good plan for the future of the entire site," Ms Close said.
"We need to make sure that we keep the salt levels down, constant monitoring is part of that, and then we will see the re-growth start to occur."
Ms Close said while the state government is committed to continue monitoring the area, fixing the problem will require a collaborative approach.
"We've got lots of players here, we've got the government, we've also got the city council but importantly we've got a private owner… so we need to work with them on what the future is and how we can all contribute to a future that helps development but looks after the environment."