All could disappear in future decades because global efforts to protect them are inadequate, the scientists believe.
Although 11.5 percent of the Earth\'s surface is a protected zone, conservationists have discovered huge gaps in coverage that could lead to the extinction of unique species of mammals, birds, amphibians, turtle and tortoises.
\"This study demonstrates that the global protected area is far from complete,\" Ana Rodrigues, a research fellow at Conservation International in Washington, D.C, said in an interview.
Most of the coverage gaps are in the world\'s tropical belt - mainly islands and mountain areas in central America, the Caribbean, eastern and western Africa, India, Myanmar and the Pacific region.
Nearly 150 threatened mammal species, 411 types of amphibians, 232 bird species and 12 turtle and tortoise species live in unprotected areas.
\"Conservation in these areas needs to be a global project,\" said Rodrigues.
QUALITY NOT QUANTITY
In the most comprehensive analysis of its kind, Rodrigues and her colleagues used a global database on protected areas and the latest information on threatened species gathered by thousands of scientists at dozens of institutions to pinpoint the gaps in coverage.
The analysis, which is reported in the science journal Nature, included 11,633 different species.
\"We overlapped one with the other and we are just looking at species which completely fall through the cracks. This is an underestimate of the species that need more protection. These are species which are not protected anywhere,\" she said.
The global conservation strategy, with a 10 percent target for global coverage by 2000, was formulated at the 1992 World Parks Congress.
The target has been exceeded but conservationists believe the analysis provided evidence that more protected areas are needed in areas with the most biodiversity.
\"Protecting more than 10 percent of the planet\'s land surface is a major conservation achievement,\" said Gustavo Fonseca, executive vice president of CI.
\"But this study proves that no matter how appealing arbitrary percentage targets might be from a political standpoint, we should focus on those places with the greatest concentrations of threatened and endemic species,\" he added in a statement.
Without more protection, the 100 known Caerulean Paradise-flycatcher birds found only on Indonesia\'s Sangihe Island or the 150 yellow-eared parrots in Colombia could vanish.