An iconic mangrove tree in Western Port. Photo: Jim Worrall By Neil Daly
APART from one or two small isolated coves along the Lang Lang foreshore, the goal of restoring mangroves in sufficient numbers to arrest coastal erosion along the eastern arm of Western Port may be over.
This was the message I took away from the Western Port Biosphere Foundation's mangrove symposium, “Mangrove planting around Western Port: past experience and future potential”. Held at Grantville on 2 December 2024, it featured key speakers from the Western Port Seagrass Partnership and Deakin University’s Blue Carbon Lab.
The Bass Coast Landcare Network, Bunurong Land Council Aboriginal Corporation, The University of Melbourne and the Department of Energy, Environment and Climate Action (DEECA) were invited but did not attend. OzFish, AgPath Pty Ltd and the Corinella Foreshore Reserve Committee sent apologies. Melbourne Water was represented.
APART from one or two small isolated coves along the Lang Lang foreshore, the goal of restoring mangroves in sufficient numbers to arrest coastal erosion along the eastern arm of Western Port may be over.
This was the message I took away from the Western Port Biosphere Foundation's mangrove symposium, “Mangrove planting around Western Port: past experience and future potential”. Held at Grantville on 2 December 2024, it featured key speakers from the Western Port Seagrass Partnership and Deakin University’s Blue Carbon Lab.
The Bass Coast Landcare Network, Bunurong Land Council Aboriginal Corporation, The University of Melbourne and the Department of Energy, Environment and Climate Action (DEECA) were invited but did not attend. OzFish, AgPath Pty Ltd and the Corinella Foreshore Reserve Committee sent apologies. Melbourne Water was represented.
Stephen Brend of the Biosphere Foundation delivered the opening address to the 12 attendees.
Following this, Greg Parry from the Western Port Seagrass Partnership presented research findings detailing mangrove seedling growth and retention rates, and reviewed earlier trials using milk cartons and hard plastic tubes.
Following this, Greg Parry from the Western Port Seagrass Partnership presented research findings detailing mangrove seedling growth and retention rates, and reviewed earlier trials using milk cartons and hard plastic tubes.
The Western Port Seagrass Partnership restoration team working at Grantville. Photo: Neil Daly
Greg spoke of the continuing use of the John Eddy method (i.e. attaching a seed to a bamboo stake with an elastic band) and planting seeds and seedlings at various distances from the foreshore to establish an optimum planting area. Their current project site at Grantville is adjacent to an existing mangrove stand near Colbert Creek.
Anchoring the bamboo brush plugs. Photo: Deakin Blue Carbon Lab Sabrina Olsson, of The Regenerating Our Coast team, Deakin University, reported that using their biodegradable frames to grow mangrove seeds and seedlings had been challenging. To overcome the problem, they are now planting seedlings in higher density clusters to increase their resilience to wave action.
Of note was the trialling of a ready-made biodegradable “bamboo brush plug”. Its purpose is to capture mangrove seeds floating on the tide and settling in the sediment. The trial started in 2024 at Jam Jerrup. It will be monitored to assess its effectiveness in what at times can be a challenging tidal environment.
Jason Noonan, representing the local community, reviewed some aspects of Queensferry’s mangrove history. He also presented an overview of the project: “Mangrove Research Project: A citizen science perspective”. This project was undertaken by Jason and me at Queensferry from December 2022 to December 2023. I wrote the research project report.*
Of note was the trialling of a ready-made biodegradable “bamboo brush plug”. Its purpose is to capture mangrove seeds floating on the tide and settling in the sediment. The trial started in 2024 at Jam Jerrup. It will be monitored to assess its effectiveness in what at times can be a challenging tidal environment.
Jason Noonan, representing the local community, reviewed some aspects of Queensferry’s mangrove history. He also presented an overview of the project: “Mangrove Research Project: A citizen science perspective”. This project was undertaken by Jason and me at Queensferry from December 2022 to December 2023. I wrote the research project report.*
Transplanting biodegradable pots containing multiple seedlings. Photo: Neil Daly
Some highlights of the Noonan Daly research project include: growing multiple mangrove seeds in biodegradable pots placed within a mangrove stand (a natural nursery) to seedling stage; transplanting the pots containing the seedlings to the intertidal zone; sampling intertidal sediment for chemical analysis; and suggesting marine scientists involve horticulturalists in mangrove propagation. It has 31 recommendations.
Mangroves and mud can be fun. Photo: Western PortBiosphere Foundation
As if by good planning and the need to move on from the statistical data, Lucy Kyriacou raised our spirits when she addressed some highlights of the Biodiversity Foundation’s Biodiversity in Schools Program. In particular, the work Lucy is undertaking with students from St Mary’s Primary School in planting and learning about the role mangroves play in protecting Western Port’s foreshore was well received.
The day concluded with a plenary session dealing with future potential and unanswered questions and a short walk to the Grantville foreshore to visit the Western Port Seagrass Partnership test site. In summary, there was a view that there is a need for an overarching plan founded on using modern data collection technology and practical field work.
When I first proposed the symposium in A chance encounter of the seedling kind and in a following article The mangrove challenge, I said its outcome needed to be a fully costed mangrove planting program based on specific goals that were measureable, objective, achievable, relevant and timely.
On reflection, perhaps I was asking too much of this symposium for to the best of my knowledge, this was the first time these key stakeholders had sat at the same table to address the mangrove conundrum.
This alone was probably a good outcome. However, there was no call to meet again or engage the other stakeholders. This was disappointing for there are still issues to be settled. These include:
The day concluded with a plenary session dealing with future potential and unanswered questions and a short walk to the Grantville foreshore to visit the Western Port Seagrass Partnership test site. In summary, there was a view that there is a need for an overarching plan founded on using modern data collection technology and practical field work.
When I first proposed the symposium in A chance encounter of the seedling kind and in a following article The mangrove challenge, I said its outcome needed to be a fully costed mangrove planting program based on specific goals that were measureable, objective, achievable, relevant and timely.
On reflection, perhaps I was asking too much of this symposium for to the best of my knowledge, this was the first time these key stakeholders had sat at the same table to address the mangrove conundrum.
This alone was probably a good outcome. However, there was no call to meet again or engage the other stakeholders. This was disappointing for there are still issues to be settled. These include:
- Given the many mangrove planting activities that have taken place over the last 20 years or so along Western Port’s eastern foreshore, should DEECA be asked to audit the situation and present an environment impact assessment of this work?
- In exposed areas, wave action is taking its toll on the mangrove seeds and seedlings being planted. From season to season, the mangrove retention rate is less than 2%. Is the solution a series of steel cages filled with shells and rocks 100 metres offshore?
- How much longer can the key players keep experimenting with small-scale mangrove projects? Until there is a large-scale approach, there is no means of determining if mangroves are the solution to arresting erosion along the eastern arm of Western Port.
- Knowing that the mangrove attrition rate is lower in sheltered areas, should the emphasis now turn to growing mangroves in these environments thus increasing Western Port’s carbon capture potential? This is also a way to successfully involve the community in meaningful mangrove planting activities.
- Has the “Nature-based Coastal Defences” project at Grantville, Jam Jerrup and Lang Lang lived up to expectations? If not, is it time to remove the concrete pods?
- Has the time come to forego the mangrove dream and concentrate on encouraging and developing saltmarsh and wetland environments along the low-lying areas of Western Port’s eastern foreshore?
- Who should take control of the situation? There appears to be no accountability and the next generation deserves better than just inheriting the current grant-driven piecemeal approach.
- Will the predicted sea level rise of 0.8m by 2100 negate the efforts to rectify the environmental problems confronting Western Port’s shoreline communities?
It’s time to table a fully costed practical solution.
* The views expressed in this article are in no way designed to promote the Noonan Daly research project.
* The views expressed in this article are in no way designed to promote the Noonan Daly research project.