British researchers said geographical areas with high numbers of endangered species from one group don't necessarily have high numbers from others.

The study by Imperial College has broad implications for conservation groups and their decisions about where to concentrate their dollars, scientists said. Previously these decisions were based on the assumption that one area, or hotspot, with a high number of an endangered species meant that other species were endangered as well.

In the decades-long study, researchers created a comprehensive worldwide map of all species of mammals, birds and amphibians, the London university said. Researchers divided the planet into grids and all non-plant life was counted combining existing data.

Researchers could see the differences between reality and assumptions about "the global biodiversity of endangered species," said researcher Ian Owens.

Different factors affect mammals, birds and amphibians differently, which could explain the discrepancy in geographical hotspots, Owens said. For example, endangered bird species may be at risk because their habitats are being destroyed, but other species could be in danger because of disease.

"It's really important not to assume that there are simply a number of hotspots ... where everything living there is endangered," Owen said.

Copyright 2006 by United Press International