Saving Seagrass

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Saving Seagrass


  Last updated December 4, 2017 at 4:49 pm


Seagrasses provide shelter and food to an incredibly diverse community of life, from the tiniest of marine creatures to fish, turtles, dugongs, other marine mammals and birds.

It is also estimated one hectare of seagrass can absorb 35-times as much carbon dioxide as a hectare of Amazon rainforest, as well as produce 100-thousand litres of oxygen per day.

Despite this immense value, large areas of seagrass are disappearing every year because of accumulated stressors, including human activities, most notably dredging.

A new study, led by QUT researchers in collaboration with seagrass experts at Edith Cowan and James Cook universities, has developed a way of predicting the ideal time to dredge in order to give seagrass the best and quickest chance of recovery.

Lead researcher, QUT’s Dr Paul Wu, said dredging was a source for seagrass loss and timing of dredging determines if seagrass will recover.

“This is called an ecological window,” Dr Wu said.

Dr Wu has developed an advanced statistical model to predict when dredging is least likely to damage seagrass.

“Our model can provide up to a fourfold reduction in recovery time, and up to a 35 per cent reduction in local extinction risk for seagrass species,” said Dr Wu.

“So if the seagrass can come back more quickly, or minimise the impact, that will also help everything that depends on it.”

The modelling also takes into account another very important factor – resilience.

Some areas of seagrass are stronger and healthier and can handle more stress. The modelling looks at how resistant a system is to change, how quickly it can recover, and considers the probability of extinction in local populations.

“Being able to tell the difference between a site where you can do some dredging and seagrass will come back, a site that is at its limit and you shouldn’t do any more to it, or a site that’s already dying and it doesn’t make a difference what you do to it, is very important,” said Dr Wu.

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