Sniffing out weeds in Western Port

A collaborative and creative effort between Melbourne Water and key partners such as Parks Victoria has succeeded in controlling the invasive weed, Spartina in Western Port estuaries and coastal wetlands. The novel use of boats, helicopters and even a trained sniffer dog were all deployed to achieve an environmental win for the fish, shoreline birds and native vegetation that call Western Port's wetlands home.

Western Port contains one of the largest expanses of saltmarsh in Victoria, as well as the world's most southern extent of Grey Mangroves (Avicennia marina). The presence of invasive weeds poses a threat to the rich biodiversity of this environment.

Melbourne Water have worked collaboratively with Parks Victoria and the Department of Environment, Land, Water and Planning (DELWP) since 2016 towards eradicating an invasive grass species, Spartina (Spartina anglica), from Western Port. After years of hard work, promising signs towards eradication are evident.

"While Spartina anglica, or Common Cordgrass, was once used to facilitate coastal stabilisation, this invasive species outcompetes native vegetation such as saltmarsh and leads to the loss of feeding habitat for a range of estuarine birds and animals. Not only is the loss of biodiversity an environmental blow, but this can also have economic ramifications for commercial fishing and tourism industries. "

There is a legal obligation to control this species to protect the biodiversity of the region. Since 1982, a large portion of Western Port was designated as a wetland of international importance under the Ramsar Convention on Wetlands of International Importance, particularly for its provision of habitat for a range of migratory birds. Additionally, Westernport is celebrated as an UNESCO Biosphere Reserve, being one of 5 natural areas in Australia to be a part of this Intergovernmental Scientific Program set up to improve the relationship between people and their environments. The wetlands of Westernport are also recognised as an area of ecological significance nationally under the Environmental Protection and Biodiversity Conservation Act 1994.

“Western Port has nine critical components and processes: wetland bathymetry, geomorphology and sedimentation, seagrass, mangrove and saltmarsh, significant flora species, waterbirds, marine invertebrates, fish, and significant fauna species. It also has 10 critical services: commercial port; commercial fishing; recreational fishing; passive recreation; spiritual and inspirational; biodiversity—wetland type/habitat availability; biodiversity—high diversity of waterbird species; distinct or unique wetland species—seagrass, mangrove and saltmarsh communities; threatened wetland species, habitats and ecosystems; and priority wetland species and ecosystems.”

Kellogg Brown, Ecological Character Description of Western Port Ramsar Wetland.

Melbourne Water's Waterways and Catchment Operations team has been working with Parks Victoria, Ecology Australia, and Birdlife Australia for several years to develop and implement new, effective methods to target Spartina.

Early in the eradication program the areas of invasive Spartina existed over significant areas of the Inlets and the Bass River Estuary. Early intervention techniques included the safe and novel use of a grass herbicide applied applied to intertidal areas via a targeted snorkel sprayer used from a helicopter. Conditions had to be just right in order for controls to be effective. After more than 10 years of intervention, this weed species now occurs so sparsely across the wetland areas of Westernport that we not rely on the specially trained nose of Melbourne Water's very own sniffer dog- Raasay for ongoing control.

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Now that the expansion of Spartina in the region is being controlled, native vegetation has been able to re-establish across the inter-tidal zone, including ecologically significant species of seagrass, mangrove, and saltmarsh plants, as well as other species found across mudflats and rocky reefs. These environments support over 115 species of migratory and waterbirds, a range of threatened and vulnerable species, and a large diversity of fish.

However, we're not out of the woods yet. Even a small amount of Spartina missed in the area or spread into the area from nearby properties can rapidly regrow and spread across the region. To truly eradicate Spartina, ongoing monitoring and targeted outbreak control will continue through this program, and also requires vigilance form landholders, residents, and visitors to Westernport.

“When it comes to the success of this project, we really are going to rely on the land holders – and that includes the private and the public land holders. We want to work together with them so that we can get the ultimate goal of this project, which is eradication.”

Alanna Wright, Melbourne Water.

WATCH - Spartina Management in the Westernport Catchment