Enhancing sand dunes for turtle nesting on Bribie Island
The Woorim Beach Dune Rehabilitation Project is enhancing the area for turtle nesting by reducing dune erosion and artificial light spill through weed control and revegetation.
Healthy Land & Water and Moreton Bay Regional Council are supporting the Bribie Island Environment Protection Association (BIEPA) and Barung Landcare to deliver the project, which is also being supported by an impressive group of passionate local volunteers. Bribie Island lies within the internationally recognised Moreton Bay Ramsar Wetland, one of the important feeding and nesting grounds for marine turtles along the east coast of Australia.
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The recent dune planting day saw BIEPA, Barung Landcare, the Woorim Bushcare Group, and Moreton Bay Regional Council plant 2300 new shrubs, trees, and groundcover seedlings with help from a group of local community volunteers.
Hungry wallabies ate their way through over 1000 seedlings last year, making the mass replanting even more necessary. A number of measures to deter macropod grazing are now being trialled.
Healthy dune systems will provide a safe and stable nesting habitat for the internationally endangered loggerhead turtles.
2020/2021 turtle season a great hatching success
Bribie Island has a 90% successful hatching rate, but the most recent turtle season on Bribie Island had its ups and downs, which according to BIEPA President Diane Oxenford, was mirrored in other South East Queensland turtle nesting rookeries.
“We aren’t only facing this issue here on Bribie,” says Diane.
“Marine turtles all around the world are listed as endangered, some critically. The South Pacific Ocean loggerhead turtles are a genetic stock in real trouble.”
“It is important to protect every nest laid in Bribie Island’s dunes to ensure the survival of the species.”
Incredibly, the first nest of the season contained 113 eggs, 112 of which hatched successfully. However, some nests were swept away due to a combination of high tides and high seas.
In the 2019 – 2020 nesting season, the Bribie Island Turtle Trackers (BITT) recorded 51 visits along 10km of the 35km stretch of Bribie Island’s eastern foreshore. Unfortunately, 25 of these identified visits were U-turns where the turtles’ nesting attempts were abandoned.
Turtles are often disturbed, or they “decide” the location is not suitable and they return to the sea. They may try again on the same or the following night, but if their nesting attempts are thwarted too many times, they will dump that clutch of eggs at sea.
As a result of erosion, turtles are not always able to climb the dunes and instead lay their eggs on the beach at the base of the dunes. This is a vulnerable location for the nest, as they can be swamped or swept away by the tides or destroyed by vehicles driving over them.
The BITT relocated all except one of the vulnerable nests, and in one instance Diane relocated 144 eggs 500 metres up the beach to a safer site in the dunes. 133 of these eggs successfully hatched.
Bribie Island’s accredited turtle trackers are obliged to attend one week each year at Mon Repos Conservation Research Park, volunteering and being instructed by Dr Col Limpus AO and his team on the latest methods of turtle nesting care and protection.
“Relocating nests needs to be done very carefully, as it can only be done during certain times of incubation and the orientation of the eggs must be exactly the same as when laid.”
It is estimated that Loggerhead turtles return to their natal beaches every three to seven years and lay between three and five nests over a period of approximately six weeks.
All to do with the health of the dunes
Without healthy dunes, there will be no nesting habitat for visiting marine turtles.
Improving the health of the dunes will provide a more stable habitat for nesting turtles. Building the height of the native vegetation will help prevent artificial light from spilling onto the beach which can confuse the hatchlings as they head toward the light when they emerge.
This ongoing project is critical for preserving turtle populations here in Australia, and across the world.
This project is supported by Healthy Land & Water through funding from the Australian Government’s National Landcare Program and Moreton Bay Regional Council.
This project is delivered in partnership with the Bribie Island Environment Protection Association (BIEPA), Barung Landcare, and the Woorim Bushcare Group.