Sun 30 Dec
2018,
They are
more commonly associated with parks and lawns, but sprinklers are now also
lining a beach in south-east Queensland in a world-first trial to keep turtle
nests cool and reduce heat-related deaths of the animals.
Rather than
keeping grass green and lush, the "artificial rain" created by
sprinklers at the renowned turtle rookery Mon Repos, near Bundaberg, has the
job of lowering the sand temperature.
Mon Repos is
the most important breeding site in the South Pacific for the endangered
loggerhead turtle, and has the largest concentration of nesting marine turtles
on eastern Australia's mainland.
Every year,
from November to March, marine turtles nest and hatch on Mon Repos' beaches.
But in the
past two seasons, heatwaves have elevated sand temperatures above 29 degrees
Celsius — the ideal temperature for baby turtles to hatch from eggs buried in
the sand.
Hotter sand,
fewer turtles, more females
Dr Col
Limpus, chief scientist with the Queensland Department of Environment and
Science's threatened species unit, said the hotter sand had halved the rate of
turtle eggs hatching.
"The
last two summers we've had heatwaves and with the heatwaves, elevated sand
temperatures causing the death of eggs and hatchlings," Dr Limpus said.
"Sand
temperatures at the nest depth ... are getting above 32 degrees and that's
getting into the level where we start to have failure of hatchlings.
"Not
necessarily just [at] this beach, but [at] other beaches … instead of getting
80 per cent hatchling production we're looking at about 40 per cent, so they
can be quite significant changes.
"The
sand temperatures we're measuring these days are much higher than the
temperatures we had when we started this work 50 years ago."
Hotter sand
also has a secondary effect: the hatchlings are more likely to be female.
"The
temperature of the nest also determines the sex of the hatchlings, and when you
get hot nests, all you're going to get is females," Dr Limpus said.
"We run
the risk of not getting enough male hatchlings. We want to bring temperatures
down, so that we get a mix of male and female hatchlings.”
Artificial
rain
A series of
five sprinklers has been set up along the beach to create different amounts of "artificial
rain" each night throughout the nesting season, Dr Limpus said.
"The
control [sprinkler] station doesn't have any artificial rain.
"Then
we have four sprinkler systems giving us artificial rain: one giving one hour
of rain a night, the second one giving two hours of rain, the third one three
hours of rain, the fourth one four hours of rain.”
By measuring
the sprinkler water and how hot the sand is underneath, researchers are testing
whether they can control the temperature of the sand.
"Hopefully
we're going to come up with an equation which would tell us how much rain
[would] bring temperatures down to any particular level," Dr Limpus said.
"Once
we have that, we'll be able to provide advice to the park management so that in
the future, if they wanted to be cooling beaches in the event of a heatwave,
they'll have a recipe for how to go about it.”
The
sprinklers could be another option in addition to shade cloths, which have been
trialled in the past.
Battle for
survival
The odds of
survival are already stacked against the baby turtles.
It is thought
only one in 1,000 of the hatchlings survive to maturity. For loggerheads, that
is 30 years of age.
Hotter
temperatures mean fewer baby turtles even reach the stage of hatching from
their eggs and with more heatwaves forecast, researchers say time is of the
essence.
"The
Bureau of Meteorology is predicting another heatwave this summer so we're
trying to look forward to find solutions that we could use in the future … to
cool the sand in the event of excessive heatwaves," Dr Limpus said.
"The
predictions are that it's going to get hotter in decades to come, so now is the
time to look for options, not in the future when we have a major problem.”
If the trial
is successful, sprinklers will be installed at other turtle nesting sites in
Queensland.
Future
generations
Turtles have
helped put the Bundaberg region on the map.
Thousands of
visitors make the night-time journey to Mon Repos each season to see the
animals come to shore to lay their eggs, and in the following months, to
witness the hatchlings make their way down the sand to the sea.
Bundaberg
Tourism Board chairman Ross Peddlesden said the tourism industry supported any
measure that would help preserve the turtle population for future generations.
"To be
able to see conservation in action, to be able to see these marvelous animals
breeding and hatching, all of those things are important," he said.
It is a
sentiment shared by local Carmel Coney.
"It's
the first I've heard of it [the trial] but it sounds good," Ms Coney said.
"It
[the rookery] is very important. I want it to be here for my grandson. I'm
looking forward to seeing the results of the trial.”
Posts
