The Dry Creek salt field in the vicinity of the St Kilda mangroves is a complex 30 kilometre, 4000 hectare site which encompasses the Adelaide International Bird Sanctuary and the Adelaide Dolphin Sanctuary.
This area provides important feeding and roosting habitat for migratory and resident shorebirds, is recognised as a wetland of national significance and is part of the East Asian-Australasian Flyway Site.
It contains Temperate Saltmarsh, which is listed as a threatened ecological community under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The salt field areas to the south also form part of the Barker Inlet-St Kilda Aquatic Reserve.
The South Australian government shares the communities concern about the mangrove dieback at St Kilda in the vicinity of the Dry Creek salt field.
Approximately 10 hectares of mangroves and 35 hectares of intertidal saltmarsh at St Kilda within the Adelaide International Bird Sanctuary National Park – Winaityinaityi Pangkara (AIBS) have been affected.
Experts from the Department for Energy and Mining (DEM), the Department for Environment and Water (DEW), the Environment Protection Authority (EPA) and the University of Adelaide, along with external consultants, are collaborating to:
- stop further impact
- promote conditions for recovery of the affected areas
- establish long-term environmental stability for the mangrove and wider ecosystem.
This includes accurately defining the areas of impact and using more precise high-resolution imagery sources.
DEW is working closely with DEM and the EPA to understand this complex issue.
A project team is undertaking scientific investigations to understand why the dieback has occurred, how any further impact can be stopped, how recovery of the ecosystem can be supported, and how to ensure the health of the local coastal environment into the future.
18 March 2021: Mapping work continues
DEW is currently investigating and mapping areas of dead or impacted mangroves and saltmarsh across the extent of the saltfields, with a particular focus on those areas that have already been identified as impacted (immediately south of St Kilda).
We have commissioned new high resolution, and multi-spectral aerial imagery to be acquired in autumn that will be analysed to identify dead vegetation and vegetation that is under stress.
In parallel, we will be conducting on-ground assessments of vegetation condition, in partnership with the EPA and DEM, to validate analysis of this imagery. Results of mapping and assessments will become available in May 2021.
16 March 2021: Discussions from restoration workshop
A joint DEW and Salisbury Council Workshop was held in the first week of March with attendees from state and local government, the local community and academia.
Discussions centred around important issues in the rehabilitation process for areas of mangrove, saltmarsh and riparian species impacted around St Kilda and Little Para River including measures to get conditions to a point where natural regeneration of the can occur.
The workshop discussed impacts across the ecosystem and for a range of plant species and how other species like birds, crabs and spiders are also affected.
The group workshopped potential actions that could be taken to increase the rate of regeneration e.g. algal inoculation, harvesting and spreading mangrove propagules, and propagating some of the more difficult salt marsh species that take a long time to re-establish.
A full report from the workshop will be made available in the coming weeks.
25 Feb 2021: Restoration workshop
Together with the Salisbury Council, DEW is hosting a workshop to discuss and develop plans for the restoration of the areas impacted around St Kilda. While it is expected that the environment will recover itself once the conditions are right, there are activities that can be undertaken to assist and fast track the natural recovery.
The workshop includes expertise from the community, universities, council and government.
The workshop will discuss options and develop a planned approach to the restoration and monitoring including community involvement where appropriate.
17 Feb 2021: Mapping work underway
DEW is currently leading the development of methods to map and monitor the condition of the affected vegetation in the area.
Historic and new remote sensing data from satellites, planes and drones is being used in conjunction with ground level information to map dead and impacted vegetation and to monitor any further changes in their condition.
These analyses will be used to inform the community and stakeholders on the extent of the impact to the mangroves and saltmarsh habitats adjacent to the ponds.
On-ground assessment of vegetation impacts has been undertaken and will be repeated over time as required.
DEM is the lead regulator and regulates the salt fields site under the Mining Act 1971. The DEM website has up-to-date information on the current activities underway.
The WaterConnect web portal provides access to the latest information about South Australia's water resources, providing users with direct access to water-related publications and data. Groundwater level and salinity information from the St Kilda mangroves piezometer network is available via the portal. Download instructions on how to access this specific information.