Unlike the last one, which finished off the dinosaurs some 65 million years ago, this one is not caused by a wandering asteroid or comet, super-volcano or other natural phenomenon. It is caused by us. Dr Tim Flannery. As the sixth mass extinction progresses, the thylacine disappeared from the continent, about 3000 years ago, leaving only the Tasmanian tiger population still co-existing with the early Aborigines. Since European colonization on Tasmania in 1803, the 'tiger' was exhaustively shot or trapped by sheep farmers paranoid of the marsupial predator. Whole-scale extermination was encouraged by private and state bounties, and lucrative rewards from international museums and zoos. Competition with feral dogs and diseases among the remaining, weakened populations, all contributed to its demise. The last confirmed record of a wild tiger came from a farmer who killed the animal in 1930.

Six years later, the thylacine was finally granted legal protection. This came far too late. In the same year - on September 7, 1936 - the last surviving Tasmanian tiger on Earth died in Hobart’s Beaumaris Zoo after 12 years of captivity. The thylacine was gone merely 131 years after the first European encountered it. , in commemoration of this tragic loss. More recently, in 1981, the Southern Gastric Brooding Frog of South-East Queensland also became extinct. In the second half of the 20th century, Queensland cleared more land than in the preceding 150 years. The female of this species had for milleniums an ingenious way of ensuring the survival of its offspring. It swallowed its tadpoles, stopped producing digestive acids temporarily and brooded the tadpoles inside its stomach. In less than two months, little froglets emerged as the female regurgitated.

Despite such a reproductive marvel, and the apparent healthy stream habitats of the Conondale and Blackall Ranges north of Brisbane where the species once thrived, it has vanished. Its close relative, the northern gastric brooding frog in Eungella National Park, followed suit soon after. It took years before scientists concluded that chytrid fungus caused the demise of the gastric brooding frogs, decline of several other frog species in the Wet Tropics, and indeed havoc in many other amphibians worldwide. The introduction of the fungus into Australia is likely a result of poor quarantine procedures associated with the exotic amphibian pet trade. Another introduced disease of national significance is the Phytophthora root rot, caused by the soil fungus Phytophthora cinnamomi. Imported unknowingly with citrus trees from Asia, the fungus has caused 'dieback' of many native plants and affected natural ecosystems as well as agricultural crops. Australians probably have more stories to tell than most other nations when it comes to introduced pests, many of which were initially considered 'super-heroes', 'magic fixers', or simply brought in as hunting targets, new food sources or familiar companions.

While the prolific rabbit, toxic cane toad and cunning fox have stolen the spotlight, countless other animals and plants have been introduced, deliberately or not, causing irreversible damage to our fragile environment and wildlife. Predation by red foxes and feral cats, competition with native species and land degradation by feral rabbits, pigs and goats, are all listed as Key Threatening Processes under the federal government’s EPBC Act. Of the 28,000 plant species (ornamentals, pasture grasses, horticultural species) that arrived with early Europeans, 2800 have become problem weeds. Each year, management of weeds and feral animals and agricultural losses accounts for more than $4.7 billion. Interestingly, native species out of their natural ranges can also become pests. Examples include the tropical cadaghi (a eucalypt) and the umbrella tree. Both have become weeds in populated areas on the east coast. The latter, with its abundant seeds, is out-competing native species, even in national parks and reserves.

Native fauna and flora need habitat. Yet, in the second half of the 20th century, Queensland cleared more land than in the preceding 150 years. Under the federal and state government’s Brigalow Scheme, three million hectares of native bushland were cleared, using bulldozers and metal chains strung between powerful tractors. Furthermore, a report commissioned by WWF-Australia outlined that Queensland’s clearing rate between 1997 and 1999 was estimated at around 446,000 hectares per year, a rate equivalent to one hundred football fields every hour, according to Dr Nicola Markus of Bush Heritage Australia. Despite stricter clearing regulations in recent years, land clearing has continued on a smaller yet devastating scale, especially in SE Queensland. To many native wildlife, the combined impacts of loss of food, shelter and territory, habitat loss or fragmentation, the spread of weeds, fire, susceptibility to diseases and increased mortality to road traffic, dogs and cats, have become too much to cope with.

A case in point: " - Redland City Council. According to the Australian Koala Foundation, some 25,000 koalas have died from disease, dog attacks, cars and, increasingly, starvation in the past decade in South-East Queensland. Despite such grim findings and strong recommendations from the local council, numerous environmental groups and researchers, the koala (in particular the SE Queensland population) remains unlisted on the EPBC Act. Without national level protection, the many isolated populations of this iconic Australian species, and ultimately the species itself, will be doomed. Indeed, the 6th mass extinction has taken its toll on tens of thousands of species worldwide and is, with each passing year, growing in intensity. In Australia, the EPBC Act lists 426 threatened fauna species: 55 Extinct, one Extinct in the wild, 36 Critically Endangered, 134 Endangered, 197 Vulnerable and 3 Conservation dependent.

Alarmingly, 1324 species of plants and 46 ecological communities are also considered threatened and warrant protection. Marine species are not immune, either. Dugong, whales, turtles, sharks, fishes, even corals are now Endangered or Critically Endangered - globally. As populations decline, risks from isolation, inbreeding, diseases, habitat degradation, catastrophes, climate change and other impacts increase. Species become increasingly trapped in an 'extinction vortex' from which there is no escape. Ironically, the listing of a species on the EPBC Act does not necessarily mean that they are safe from harm’s way. A few examples still found in South-East Queensland include the Northern Quoll, Grey-headed Flying-fox, False Water Rat, Coxen’s Fig Parrot, Regent Honeyeater, Black-breasted Button-quail, Wallum Sedge Frog, Mary River Turtle, Australian Lungfish, Humpback Whale, Grey Nurse Shark, Orange Roughy and four marine turtles.

The State government’s proposed Traveston Crossing Dam on the Mary River alone, if approved, would further endanger some 20 already threatened species. The proposal has been described as environmentally, hydrologically and socially irresponsible by a wide range of international, national and regional organisations, scientists and individuals. The recent approval of the Gorgon Gas Project on Barrow Island off WA, despite being home to many threatened species, raises further questions about the agendas of governments, both national and state. So is there hope? From the achievements of some 2009 Australian Museum Eureka prize winners, the answer has got to be 'yes'. Notably, Dr Conrad Hoskin came to fame with the discovery of seven new reptiles in tropical Queensland, and with his colleagues, rediscovery of a frog species that was thought to be extinct.

Dr Hoskin also discovered a new frog and shed light on how new species might evolve rapidly. Evolve they must, with global warming threatening every corner of the globe. Is it not our moral obligation to protect at least some of what is left of the natural ecosystems and their services for future generations? Functioning ecosystems, with the species and genetic diversity they nurture, will provide the essential ingredients and opportunities for adaptation to change. Perhaps more heartwarming is the announcement of the Eureka People’s Choice Award to Dr Katherine Belov. She revealed how the lack of genetic diversity among the dwindling populations of the Tasmanian Devil has caused the current cancer 'plague', and is on the way to finding the gene needed to reverse the situation.

Perhaps Australians’ hearts are still with our 'natural treasures' – who would want to see the 'devil' go the same way as the 'tiger’ – appearing only as a symbol of loss or on beer bottles? Loading

- Value every native tree, shrub and grass – grow local natives and spare a second thought before you cut a tree down.

- Learn more about your local native species and the environment. Share this knowledge with friends, colleagues and students.

- Spend time in nature with your kids and grandkids. Encourage them to explore and discover.

- Join or support the work of conservation groups.

- Vote for politicians with clear environmental advocacy, and not climate change sceptics.

- Phone or write to politicians to voice your environmental concerns.

- Write to the media to show your support for environmental causes.

- Sign up your property as Nature Refuge or Land for Wildlife if it is eligible.

- Be a responsible pet owner, or better still, a wildlife carer instead.

- Live more sustainably – reduce your carbon / ecological footprint. The theme for this year's Threatened Species Week is "On-line to Recovery”. To find out more and to take part in activities held across the state during the week, The theme for this year's Threatened Species Week is "On-line to Recovery”. To find out more and to take part in activities held across the state during the week, click here