Once we are gone and millions of years have elapsed to destroy all record of our existence will some future newly evolved intelligent species become puzzled over what caused the planet Earth's 6th major extinction event? Or will they decide the absence of evidence for an asteroid strike or volcano could only mean a smart super predator was at work? Habitat loss and species extinction characterize our era.

Governments must act urgently to halt loss of habitats and invading species that are posing major threats to biodiversity and causing species extinctions across Australia, New Zealand and the Pacific Islands, according to a landmark new study.

Published in the international journal Conservation Biology, the report is the first comprehensive review of more than 24,000 scientific publications related to conservation in the Oceanic region. Compiled by a team of 14 scientists, it reveals a sorry and worsening picture of habitat destruction and species loss. It also describes the deficiencies of and opportunities for governmental action to lessen this mounting regional and global problem.

"Earth is experiencing its sixth great extinction event and the new report reveals that this threat is advancing on six major fronts," says the report's lead author, Professor Richard Kingsford of the University of New South Wales.

Well, we are historical in our impact. Gotta give us that. Way to go us.

On oceanic islands the biggest extinction cause is invasive species brought (accidentally or intentionally) from other parts of the world.

• Loss and degradation of habitat is the largest single threat to land species, including 80 percent of threatened species.
• More than 1,200 bird species have become extinct in the Pacific islands and archipelagos.
• In Australia agriculture has modified or destroyed about 50 percent of woodland and forest ecosystems, and about 70 percent of remaining forests are ecologically degraded from logging.
• Invasive species, particularly vertebrates and vascular plants, have devastated terrestrial species of the Pacific Islands and caused 75 percent of all terrestrial vertebrate extinctions on oceanic islands.
• More than 2,500 invasive plants have colonized New Zealand and Australia – representing about 11 percent of native plant species.
• Many invasive weeds, vertebrate pests, and fishes were introduced by government, agriculturalists, horticulturalists and hunters.

I'm thinking we need to systematically collect DNA samples so that some of the species could be reintroduced once we die off and space aliens uncover a specially constructed highly durable DNA sample storage facility. Think we could design a DNA storage vault underground that could last 100,00 years? Otherwise the losses will be considerable.

• Nearly 17,000 of the world's 45,000 assessed species are threatened with extinction (38 percent). Of these, 3,246 are in the highest category of threat, Critically Endangered, 4,770 are Endangered and 8,912 are Vulnerable to extinction.
• Nearly 5,500 animal species are known to be threatened with extinction and at least 1,141 of the 5,487 known mammal species are threatened worldwide.
• In 2008, nearly 450 mammals were listed as Endangered, including the Tasmanian Devil (Sarcophilus harrisii), after the global population declined by more than 60 percent in the last 10 years.
• Scientists have catalogued relatively little about the rest of the world's fauna: only 5 percent of fish, 6 percent of reptiles, and 7 percent of amphibians have been evaluated. Of those studied, at least 750 fish species, 290 reptiles, and 150 amphibians are at risk.
• The average extinction rate is now some 1,000 to 10,000 times faster than the rate that prevailed over the past 60 million years.

Extinctions might end up being our most enduring legacy. Just about everything else we've created won't last very long.