Invasive species and habitat loss our biggest biodiversity threats

Date:  December 10, 2018

Source:  University of Queensland

Invasive species and habitat loss are the biggest threats to Australian biodiversity, according to new research by the Threatened Species Recovery Hub in partnership with The University of Queensland.

Lead researcher Stephen Kearney from UQ's School of Earth and Environmental Sciences said Australia was rich in unique biodiversity, but has had a poor track record since European settlement.

"Australia is one of only 17 'megadiverse' countries globally, with more than 12 per cent of the world's vertebrate species -- more than four out of five of our species are found nowhere else on Earth," Mr Kearney said.

"The country has recorded 90 extinctions since European settlement -- 36 plants, 27 mammals, 22 birds, four frogs and an earthworm, and extinction rates per decade are not improving.

"One of the major causes of Australia's ongoing extinction crisis is our insufficient response to threats to our biodiversity.

"To support improvements in this area we have reviewed the major threats facing over 1500 species listed as Critically Endangered, Endangered or Vulnerable under Australian environmental law.

The top factors impacting Australia's threatened species are invasive species, which affect 82 per cent of our threatened species, and changes in habitat, which affect 74 per cent of species.

"Invasive species include pest animals, plants and diseases, while changes to habitat include things like altered fire patterns and degradation from human activities," Mr Kearney said.

"Around the world the top two impacts on threatened species are habitat loss and change due to agriculture, closely followed by overexploitation activities, such as hunting or timber harvesting.

"Overexploitation threatens around three quarters of imperilled species globally, but only about one quarter of Australian species.

"The large impact of invasive species sets Australia apart from the global trend.

Continued  

Growing Threats to Biodiversity ‘Arks’ - via Herp Digest

NEW YORK (July 25, 2012) Press Release WCS—Many of the world’s tropical protected areas are struggling to sustain their biodiversity, according to a study published today in Nature by more than 200 scientists from around the world.

Professor William Laurance, from James Cook University in Cairns, Australia, and the Smithsonian Tropical Research Institute in Panama, said: “These reserves are like arks for biodiversity. But some of the arks are in danger of sinking, even though they are our best hope to sustain tropical forests and their amazing biodiversity in perpetuity.”

Laurance and his team—including several contributors from the Wildlife Conservation Society—studied more than 30 different categories of species—from trees and butterflies to primates and large predators—within protected areas across the tropical Americas, Africa and Asia-Pacific.

They estimated how these groups had changed in numbers over the past two to three decades, while identifying environmental changes that might threaten the reserves.

Laurance said their conclusion was that while most reserves were helping to protect their forests, about half were struggling to sustain their original biodiversity.

“The scariest thing about our findings is just how widespread the declines of species are in the suffering reserves,” said Carolina Useche of the Humboldt Institute in Colombia. “It’s not just a few groups that are hurting, but an alarmingly wide array of species.”

These included big predators and other large-bodied animals, many primates, old-growth trees, and stream-dwelling fish and amphibians, among others.

The researchers found that reserves that were suffering most were those that were poorly protected and suffered encroachment from illegal colonists, hunters and loggers.

“Maintaining high quality buffer zones seems to be as essential to preserving park biodiversity as maintaining the parks themselves, so the moral is clear—protect the forests and the wildlife both inside and outside the reserves or risk losing them,” said Dr. Fiona Maisels of the Wildlife Conservation Society. “Park staff who patrol these wild places are critical for conserving the biodiversity they contain.”

Dr. Kadiri Serge Bobo of the University of Dschang in Cameroon, Africa, emphasized the growing external threats to tropical protected areas. “Eighty-five percent of the reserves we studied lost some nearby forest cover over the past two to three decades,” said Bobo. “But only two percent saw an increase in surrounding forest.”

Deforestation is advancing rapidly in tropical nations and most reserves are losing some or all of their surrounding forest.

The team found many nature reserves acted like mirrors—partially reflecting the threats and changes in their surrounding landscapes.

“For example, if a park has a lot of fires and illegal mining around it, those same threats can also penetrate inside it, to some degree,” Useche said.

The bottom line, the researchers say, is that a better job needs to be done in protecting the protected areas—and that means fighting both their internal and external threats, and building support for protected areas among local communities. Such efforts will help ensure protected areas are more resilient to future threats such as climate change.

“We have no choice,” said Laurance. “Tropical forests are the biologically richest real estate on the planet, and a lot of that biodiversity will vanish without good protected areas.”

CONTACT: JOHN DELANEY—WCS: (1-718-220-3275; jdelaney@wcs.org)

STEPHEN SAUTNER—WCS: (1-718-220 3682; ssautner@wcs.org)

WILLIAM LAURANCE—Lead Author, James Cook University

(61-7-4038-1518; bill.laurance@jcu.edu.au)