Nagoya, Japan: One fifth of the world`s vertebrates are threatened with extinction but conservation efforts are having an impact in slowing their demise, scientists said in a study published Wednesday.
The study reported that the main reason for the "alarming" decline in the world`s mammals, birds, amphibians, reptiles and fish was the destruction of their natural habitats.
Tropical Southeast Asia, where rainforests are being destroyed and human populations are booming, is of particular concern, according to the study released by the International Union for the Conservation of Nature (IUCN).
"Global patterns of rising extinction risk are most marked in Southeast Asia, where agricultural expansion, logging and hunting are the primary forces behind accelerating extinction rates," a summary of the study said.
The document, by 174 scientists around the world, was described as the first time the rate of decline among vertebrate species had been quantified on a global scale.
It was based on research into 25,000 species on the IUCN`s "Red List" of threatened species.
The IUCN released the findings on the sidelines of a United Nations summit being held in the Japanese city of Nagoya to try to map out a plan to save the world`s rapidly diminishing biodiversity.
The IUCN said last year the world was experiencing its sixth mass extinction in history, the last one being 65 million years ago when dinosaurs were wiped off the planet.
However, the study said species loss and decline would have been 20 percent worse in the absence of conservation efforts to protect those under threat.
"The critical point from our analysis is the role that conservation plays in slowing species losses," said Andrew Rosenberg, senior vice-president for science and knowledge at Conservation International and an author on the paper.
"That means we can do something about this global problem by taking concerted action at local, national and regional scales."
Some of the conservation strategies the study highlighted as being beneficial were captive breeding programmes, legislation to limit hunting, establishing protected areas and efforts to remove invasive alien species.
The report highlighted dozens of species to have taken steps away from extinction due to conservation efforts, among them the humpback whale, whose numbers have grown thanks to legislation banning commercial whaling.
It also said three species that were extinct in the wild had been returned to nature -- the California Condor and the black-footed ferret in the United States, as well as a horse in Mongolia.
The document said conservation efforts had been particularly successful at combating invasive alien species on islands.
The Magpie-robin in the Seychelles had increased from fewer than 15 birds in 1965 to 180 in 2006 amid efforts to control introduced predators such as rats.