Understanding the Age of Extinction
We are living through a biodiversity crisis, or what scientists are calling the ‘sixth mass extinction’, as around 1 million species face extinction, many within decades.
May 7th 2021
Australia is renowned for its spectacular and iconic wildlife, from cute and seemingly cuddly marsupials like koalas and kangaroos, to the fearsome venomous snakes and ravenous crocodiles showcased by Steve Irwin. However, Australia’s biodiversity extends far beyond these species we commonly associate with the continent, and is comprised of an incredible array of plant and animal species, many of which are endemic.
Regrettably, human activity, namely habitat destruction and exotic species introduction, have been tremendously detrimental to Australia’s wild species. By some accounts, Australia has had one of the highest rates of extinction on the planet, with 83 plant and 43 animal native species having become extinct there in the modern era.
Many more species are imperiled, and either have a declining population, or are inherently vulnerable due to a small population size or limited range. The Australian government lists over 500 species that are either extinct, endangered, or vulnerable. Of the extant species, 75 species are listed as Critically Endangered, meaning that they are teetering on the brink of extinction.
Here is a selection of lesser-known examples of critically endangered Australian wildlife, which are dependent on ongoing conservation efforts for their survival:
Orange-bellied parrot: This magnificent parrot species boasts an impressive multi-colored plumage, complete with blue and green wings, a yellow body, and you guessed it – an orange belly. The species is one of three migratory parrot species, breeding in eucalyptus forests of southwest Tasmania, and then moving to overwintering salt marsh habitats in southeast Australia. The species has exhibited a significant range contraction, and was once found from Sydney to Adelaide outside the breeding season. Today, the wild population numbers only less than 50 individuals, but breeding programs have yielded a captive population of over 300 birds. Habitat restoration and predator control programs to assist the species recovery in the wild are underway.
Gilbert’s potoroo: The world’s most endangered marsupial, this member of the family Potoroidea (the “rat-kangaroos”), has an extremely narrow range, limited to the sandy shrublands of the Mount Gardner headland at Two Peoples Bay in Western Australia. This species has a gourmet diet largely comprised of the fruiting bodies of underground fungi (“truffles”), but also includes berries, seed-pods, and insects. The species, thought to be extinct until rediscovery in 1994, exists in a population limited to about 40 individuals at Mount Gardner. However, between 2005 and 2007, ten individuals were translocated to nieghbouring Bald Island, which now supports about 60 additional individuals. Subsequent efforts established a semi-captive fenced population at Waychinicup National Park.
Leadbeater’s possum: This primitive possum species, representing the only living member of its genus, inhabits ash and snow gum forests in the Central Highlights of Victoria, located northeast of Melbourne. The species was thought to be extinct for almost a century, until its rediscovery in 1961. Its nocturnal lifestyle, agility, and occupation of the upper canopy of mature forests make it a difficult species to detect and study. It is colonial, as it forms family groups, which sleep together in a canopy nest site.
The leadbeater’s possum is the subject of the longest running longitude study of a wild species, which was started by David Lindenmayer, a professor at the Australian National University in 1983. The species has a narrow habitat requirement that complicates its conservation – it prefers mid-aged forests, many of which have recently burned in wild fires. The wild population is estimated around 1,500 individuals, and ongoing conservation efforts, including habitat monitoring and the installation of artificial nest boxes, are central to the maintenance of this species.
Southern corroboree frog: This frog species exhibits an aposematic black and yellow coloration, making it look very similar to new world poison dart frogs. It is indeed poisonous, but unlike poison dart frogs which attain their poison from their dietary sources, it produces its own poisonous alkaloid, the only known vertebrate to do so (along with the related northern corroboree). This frog inhabits subalpine woodland and tall heath habitats of the southern tablelands along the New South Wales and Victorian border. It faces an array of threats, including habitat modification, ozone depletion, feral animals, and drought, which have reduced its population to below 200 individuals. Captive breeding and habitat restoration efforts are underway to help conserve this species.
Lord Howe Island phasmid – What’s a phasmid, you say? Well, it’s a bug. A big bug. This species of stick insect inhabits the Lord Howe Island Group, a group of 28 islands located approximately 550 km to the east of mainland Australia. This species was particularly hard hit by the introduction and establishment of predatory black rats, and it was thought to have gone extinct in 1920. However, in 1964, a team of climbers discovered evidence of a remnant population on Balls’ Pyramid, a jagged volcanic stack that juts out from the Pacific Ocean. It was not until 2001 however that a team of entomologists identified the population, numbered at just 16 individuals, which was located around a single shrub. Two pairs were collected, and a captive population has been established.
These five species represent just a narrow selection of the many incredible and fascinating imperiled wildlife species. The survival and recovery of these species are dependent on converted conservation efforts by passionate professionals and volunteers alike.
By WorkingAbroad Blog Writer Sean Feagan
Photo by JJ Harrison from Wikimedia