Providing artificial shelter for the endangered bridled nailtail wallaby may be one key to increasing its numbers in the wild, according to a University of Queensland study.
Zoology Department PhD student Diana Fisher recently won the $500 first prize at the Royal Society of Queensland's Stan Colliver Memorial Meeting for her research paper on the wallaby's survival, behaviour and breeding strategies.
Parasitology Department PhD student Alistair Dove won the $300 second prize for his paper on feral fish infesting Australia's waterways.
Research papers were presented in the fields of botany, geology and zoology by Queensland's best postgraduate students from four universities at the September meeting commemorating the renowned amateur field naturalist.
Mr Colliver (1908-1991) was a scientific officer with the University's Geology Department from 1948 with his chief interest being rocks, minerals, fossils and mollusc shells. He also attended classes in chemistry, zoology and botany at the University.
A fossil-toothed whale, Mammilodon colliveri, was named after him after he discovered the lower jaw of the creature near Geelong in 1939 as is Cralopa colliveri, a minute land mollusc he discovered in wet forest land of the Gippsland Lakes region.
He donated his collection of around 400,000 mollusc shells and 5000 geological specimens to the Queensland Museum and his books to the Society. The meeting was sponsored by both organisations as well as the Queensland Museum Association and the Queensland Naturalists' Club.
Ms Fisher radio-tracked, marked and spotlighted wallabies to determine their day and night-time behaviour and studied their shelter, food, predators and diseases.
Her research found wallabies were forced to be independent at a very young age, their mothers leaving them hiding in vegetation during the day. A lack of cover due to drought or overgrazing by stock or other wallaby species meant both young and adult wallabies became easy prey for feral cats and dingoes, she said.
Ms Fisher found providing artificial cover such as hollow logs may help wallaby populations to recover through their rapid breeding abilities.
She said retaining enough shelter in combination with predator control would help to maintain wallaby populations especially in drought years.
Mr Dove found feral fish may have an advantage over native fish in their reduced parasite loads. Feral fish currently pose a grave threat to native fish, crowding them out of Australian waterways. Australia has only about 200 fish species with 20 of these introduced or feral.
The fish have been introduced by humans and include aquarium fish flushed down the toilet by their owners - Mr Dove estimates that around half of Australia's feral species have been introduced in this way.
'The situation has become so serious that during the recent National River Survey, researchers calculated that 10,000 feral fish would have to be caught before one native fish was discovered,' Mr Dove said.
'The three main ways introduced fish destroy native populations is through predation, out-competing them for food and passing on diseases including parasites. These parasites include many species of worm, protozoans and crustaceans.'
Mr Dove has so far tested about 40 fish species for parasitic infection with a third of these introduced fish species. He is surveying coastal and alpine rivers from Bundaberg to Echuca in Victoria and the Murray-Darling Basin.
He said the introduced fish species not only have far fewer parasite species than native fish, they can also pass them on to susceptible native fish populations.
'Carp for example introduced a tapeworm which now also infects native fish. The worm can reproduce only inside carp. However, while it's relatively harmless to them, it sickens and possibly kills native fish,' Mr Dove said.
His research helps explain the carp's competitive advantage over native fish and consequent success in filling Australian waterways.
For more information, contact Ms Fisher (telephone 07 3365 2491 ) and Mr Dove (telephone 07 3365 6979)
