A crisis is looming in the diversity of life on Earth and an international panel of experts is needed to tackle the problem, leading biologists say.

Like the UN's panel on climate change, a biodiversity group could provide authoritative advice to governments, say the experts from 13 countries.

"Virtually all aspects of biodiversity are in steep decline and a large number of populations and species are likely to become extinct this century," they wrote in a commentary appearing in Thursday's issue of the journal Nature.

"Despite this evidence, biodiversity is still consistently undervalued and given inadequate weight in both private and public decisions. There is an urgent need to bridge the gap between science and policy," biology Prof. Michel Loreau of McGill University in Montreal and co-author Alfred Oteng-Yeboah of the Council for Scientific and Industrial Research in Accra, Ghana, said.

Biodiversity is more complex than issues such as the stratospheric ozone hole or even global climate change, since it spans genetic, species and ecosystem levels, cannot be measured by a simple indicator and needs to be managed locally, they note.

Previous biodiversity conventions weren't formally linked to and funded by governments. That support is needed to ensure scientific information leads to action at national and global levels, they said.

A related study in the same issue by Neil Rooney of the University of Guelph and colleagues surveyed ecosystems including Chesapeake Bay off the eastern United States, the Alaskan tundra, a European pine forest and a Dutch experimental farm.

The researchers concluded predators at the top of the food chain who feed on a range of species from lower levels are needed for stability in the ecosystem.