BirdLife Tasmania said the 28 Tasmanian devils released on the nearly 45 square miles of Maria Island between 2012 and 2013 grew to an estimated 100 by 2016, the Guardian reported. The 3,000 breeding little penguins that were on the island a decade ago have entirely disappeared since the introduction of the carnivorous marsupials, according to BirdLife Tasmania.
Eric Woehler, a researcher for the group, told the BBC that losing 3,000 penguins from an island that serves as a national park and refuge for birds is a "major blow," yet a predictable one based on research of human intervention in nature.
"Every time humans have deliberately or accidentally introduced mammals to oceanic islands, there's always been the same outcome . . . a catastrophic impact on one or more bird species," he told the Guardian.
The erasure of the little penguins from Maria Island marks another disturbing turn in wildlife populations for the nation. In recent months, Australia has seen mice devastate agricultural lands and spiders cover towns with webs.
The Tasmanian devils were originally shipped to the island through a collaboration between the Australian and Tasmanian governments to protect them from devil facial tumor disease, a transmissible cancer spread through biting that causes the appearance of tumors on the face or inside the mouth.
The disease led the population of the endangered species to dwindle from 140,000 to 20,000 since the illness was first seen by scientists around the mid-1990s, according to National Geographic.
A paper published in December in the journal Science found that spread of the disease has appeared to slow but suggested that scientists should be careful when making decisions to increase the population.
The slowing spread of the infection and the growing numbers of Tasmanian devils have come with an increased threat to other species, a prediction nearly a decade old.
A 2011 Tasmanian Department of Primary Industries, Parks, Water and Environment report anticipated that the devils' predatory tendencies would lead to negative consequences for penguin and shearwater bird populations, the Guardian reported.
Last year, researchers found that shearwater colonies continued to decrease over the years and reached zero occupancy within four years of the introduction of the devils. Researchers for the study published in Biological Conservation, a peer-reviewed journal, also noted that "conservation translocations of endangered predators must consider trade-offs between their protection and potential impacts on non-threatened native prey species."
A Tasmanian government spokesperson told foreign media outlets that its joint effort with the Australian government, the Save the Tasmanian Devil Program, will continue to adapt its programs along with science and priorities, the Guardian reported. The spokesperson also noted that Maria Island remains important for restoring and maintaining the devil population in Tasmania.
The devils have had a "catastrophic ecological impact on the bird fauna on Maria Island," Woehler told the Guardian, suggesting the population could be moved as numbers for the species continue to climb in other parts of the country, he told the Guardian.
While the little penguins are no longer on Maria Island, populations can be found in other parts of Australia. Phillip Island on Australia's southern coast is home to the country's largest colony of little penguins, with over 32,000 breeding penguins found on the Summerland Peninsula, according to the Penguin Foundation.
Published : June 21, 2021
By : The Washington Post · Lateshia Beachum