Photo: Zoos Victoria
Researchers are hoping to increase the population of one of Australia’s most endangered frogs by helping them reach sexual maturity earlier.
The number of wild northern corroboree frogs, which are only found in cold, mountainous areas of the ACT and New South Wales, has been in sharp decline, mostly due to chytrid fungus. The fungus causes an infectious disease that is killing frogs around the world. There are only 20 of the small black and yellow striped frogs left living in the wild in the ACT and fewer than 1,000 in NSW.
The ACT government has a captive breeding program at Tidbinbilla Nature Reserve and will this month release 30 frogs into an outdoor enclosure to experience a more natural habitat. The next step will be developing a self-sustaining wild population and researchers will spend this year investigating how to give the frogs the best shot at surviving and thriving.
Lead researcher Ben Scheele from the Australian National University said they were looking at the benefits of introducing the frogs to lower elevation areas with warmer temperatures where they would grow faster, reaching sexual maturity at one or two years of age rather than three of four.
“Frogs are a cold-blooded species and their growth is really tied to temperature,” he said. “At high elevations with snow in the winter they hibernate, so they have a limited window to feed and grow each year and they take longer to grow to full adult size. At lower elevations with less or no snow, the active period throughout the year is four or five months longer.”
He said if the frogs were able to mature more quickly they would have a better chance at breeding before becoming affected by chytrid fungus, which predominantly kills adult frogs.
Northern corroboree frogs have been found in the wild at elevations of between 800m and 1,800m above sea level. It appears frogs living at lower elevations in NSW have an edge over those living up higher.
Scheele said the main reason they needed to find new sites for the frogs was that the areas where they used to live have been populated by the common eastern froglet, which has become resistant to the deadly fungus but still carries the disease.
In addition to chytrid fungus, other threats to the species include climate change, and fire and habitat disturbance.
Researchers hope they will be able to begin reintroducing the frogs to the wild in 2019 or 2020, depending on what their research yields this year.