A growing number of creatures could disappear from the earth, with one-fifth of all vertebrates and as many as a third of all sharks and rays now facing the threat of extinction, according to a new survey assessing nearly 26,000 species across the globe.

In addition, forces such as habitat destruction, over-exploitation and invasive competitors move 52 species a category closer to extinction each year, according to the research, published online Tuesday by the journal Science. At the same time, the findings demonstrate that these losses would be at least 20 percent higher without conservation efforts now underway.

‘We know what we need to do,’ said Andrew Rosenberg, senior vice president for science and knowledge at the advocacy group Conservation International and one of the paper’s co-authors. ‘We need to focus on protected areas, both terrestrial and marine.’

The survey, conducted by 174 researchers from 38 countries, came as delegates from around the world are meeting in Nagoya, Japan, to debate conservation goals for the coming decade.

The researchers analyzed the International Union for Conservation of Nature’s ‘Red List’ – a periodic accounting that classifies mammals, birds, amphibians, reptiles and fish along a spectrum depending on how imperiled they are.

While many industrialized countries have […]