Bilbies are endangered and superficially rabbit-like marsupials. New research shows they can help regenerate the Australian environment.
Credit: Wikimedia
SYDNEY: Foraging bilbies and bettongs play a role in conserving Australia's desert plantlife, whereas rabbits contribute to its destruction, according to new research.
The findings show that bilbies (Macrotis lagotis) and bettongs (bettongia lesueur), which are both superficially rabbit-like marsupials, can help green the landscape in arid areas by creating pockets of nutrient-rich soil. This allows greater numbers of plants to thrive.
Rabbits (Oryctolagus cuniculus) forage in a similar way, but their method of digging was found to have a negative impact on the plant community.
Benefit to the whole ecosystem
"The reintroduction of a species doesn't just have a beneficial impact on that species, but also a beneficial effect on the environment" said researcher behind the study, Alex James, an ecologist with the University of New South Wales in Sydney.
Bilbies, bettongs and rabbits all build burrows, thrive in dry conditions and dig small foraging pits. The similarity ends there, however. Rabbits are placental mammals and an invasive European species, whilst bilbies and bettongs are an Australian native marsupials.
Rabbits are herbivores, eating grasses and young plants, whilst bilbies and bettongs are omnivores, feeding on underground insects, seeds and fungi. Their foraging pits are also different: bilby and bettong pits are about 10 to 20 cm deep and wide, whilst rabbit pits are shallower.
Desert reserve
Once common, bettongs are now extinct on mainland Australia, whilst bilbies have suffered an 80% reduction in range due to introduced predators such as foxes and cats. Conservation programs have focussed on reintroducing them to fenced fox-, cat- and rabbit-free nature reserves.
To learn more about the environmental impact of these species, James and co-worker David Eldridge, turned to a fenced bilby and bettong reintroduction program run by conservation group Arid Recovery in the South Australian desert.
They analysed plant growth in and around 450 pits, comparing those dug by the native animals on the reserve side of the fence to those dug by rabbit on the outside. They also compared both types of pits to undisturbed soil, measuring the number of seedlings per square metre and the concentration of nutrients in the soil.
