Where has seagrass in Western Port been lost, and which of these areas are most suitable for attempting seagrass restoration? What are the most appropriate methodologies for restoration? These are the main questions we’ve been trying to answer over the past two years.
Seagrass mapping in Western Port
A team of scientists from Deakin’s EcoGenetics, Blue Carbon Lab, and Melbourne Water have recently finished conducting bay-wide habitat classifications of Western Port. Researchers, led my PhD candidate Oliver Dalby, collected images of the seafloor at 172 sites across Western Port to identify the spatial arrangement of seafloor habitats present.
Imagery collected will be integrated into a remote sensing pipeline that will combine satellite images and statistical models to create up to date maps of where important blue carbon ecosystems, such as seagrasses, exist. These can then form the basis for future monitoring and seagrass restoration assessments.
Seagrass restoration trials
In September 2019, a team led by PhD candidate Yi Mei Tan started testing five different methodologies at three locations around Western Port. These included:
- Shoots tied to nails
- Shoots tied to metal frames
- Shoots weaved into hessian mat
- Seagrass cores
- Seagrass seeds
A total of 11,250 shoots, 450 seagrass cores, and 4500 seagrass seeds were transplanted!
These transplants were initially monitored regularly until COVID-19 restrictions were imposed. The team has since been able to return to two of the three locations, and will be marking the transplants’ “one-year anniversary” soon!
While some of the techniques have not fared very well, growth and long-term survival have been noted in others, which is encouraging for the overall program. The transplants will continue to be monitored and the experimental trial further developed this year to include different combinations/arrangements of our current methodology to improve survival.
Local communities joined seed collection!
The transplanting of seagrass seeds -a technique we trialled in 2019- will used gain this field season (on a larger scale!). Seed-based restoration is generally considered to be less labour-intensive compared to shoot-based restoration, and to cause less damage to donor meadows. Furthermore, the use of seeds can potentially result in greater genetic diversity, leading to higher resilience and survival. The collection of seeds is also simple, making it the perfect opportunity for us to involve members of the public!
In February 2020, the team partnered with VRFish and held a community flower picking day at Woolley’s Beach Reserve. Despite the cold, drizzly morning, the turn out was good and with the help of these lovely people, we currently have 10 times as many seeds compared to our first collection in 2019! The team hopes to plan more community flower picking events in the future, so stay tuned as these will happen around February each year.
For more updates about our our seagrass restoration research, please visit Zosteration Facebook page