Josh visits a pocket of urban bushland in Perth’s north to find out how the reintroduction of a little known (but very industrious!) marsupial is helping to regenerate the plant community. Craigie bushland, a reserve of remnant vegetation in Perth’s north, is a major conservation area containing a number of vulnerable plant communities across its’ 56 hectares. Josh meets with Dr Leonie Valentine, a researcher at the University of Western Australia who regularly uses the reserve for her research, who explains the importance of this space. “It’s a good quality site, containing Banksia woodlands which is a threatened ecological community”.
Dr Valentine explains “Some of the species in the reserve are Banksia attenuata, Banksia menziesii, Banksia prionotes. There’s Jarrah, Marri and tuart. You’ll see Xanthorrhoea, and there’s a herbaceously rich ground layer, so you’re seeing things like Hibbertia and donkey orchids. It’s quite rich in terms of flora”.
But it’s some recent arrivals to the reserve that are having the biggest impact on the plant communities and the wider ecosystem. In 2010 a predator-proof fence was installed around a large part of the reserve. “At the time it was unprecedented” Dr. Valentine says. “The reserve is surrounded by suburbs, so that means foxes and cats, but this fence has made it predator proof”. The fence allowed for some new residents to move in, Perth’s very own species of bandicoot - the quenda! “Up until 2018 quenda were considered a subspecies of southern brown bandicoot, and then a paper was published on a molecular study that recognised them as their own species. So it’s an endemic species; the name quenda is the noongar name”.
“They’ve been put into a good quality reserve, by good quality it has a good quality understory of plants, and these plants are providing a dense cover. They like to use the understory skirts of Balga (Xanthorrhoea preissii) as a refuge”. Now that the quendas are in the reserve, they’re already having a big impact. Leonie says “quenda have very long, sharp claws and they’re known for their digging and fossicking habits. What we’ve found is they’re digging up a lot of the soil and really changing the micro-habitat in the reserve”.
“Each quenda turns over 4 tonnes of earth per year, and a quenda only weighs 800 grams”. This is why Leonie describes these little gardeners as “ecosystem engineers”. “A quenda will dig up to 45 soil pits per nights, and even more in sandy soils, so they’re moving soil around, they’re bringing it up through the layers… breaking soil crusts”.
So what’s the impact of all this digging on the plants? To find out, Leonie and fellow researchers set up exclusion plots; areas of the reserve where quendas could and couldn’t go in, to observe the difference. “They’re digging so much it’s changing the amount of leaf cover…visually it’s very different”. “Putting that soil on top of the litter means it’s good for decomposition, it’s happening quicker. There’s higher amounts of microbial activity, and changed nutrient composition; different levels of phosphorous”.
Curious about the impact of these little diggers on seed germination, Leonie and fellow researchers devised an experiment. They took soil from a dig, and a control soil sample, and seeded both with tuart seed. “The result was the tuart grew 2-3 times faster in the soil from the quenda dig. We think it’s creating an environment for better leaf breakdown and contributing more nutrients to the soil”.
Ultimately Leonie sees the value of this project in big-picture terms. “We’ve decelerated a lot of processes by removing quendas, and perhaps reintroduction has brought them back up to speed”.
Leonie’s research is part of the Threatened Species Recovery Hub of the Australian Government’s National Environmental Science Program.
Watch Gardening Australia on ABC iview:
SUBSCRIBE:
About Gardening Australia:
Gardening Australia is an ABC TV program providing gardening know-how and inspiration. Presented by Australia's leading horticultural experts, Gardening Australia is a valuable resource to all gardeners through the television program, the magazine, books, DVDs and extensive online content.
Connect with other Gardening Australia fans:
Like Gardening Australia on Facebook:
Follow Gardening Australia on Instagram:
Visit the Gardening Australia website:
This is an official Australian Broadcasting Corporation YouTube channel.
********
Contributions may be removed if they violate ABC's Online Conditions of Use (Section 3).
0 Comments