A quarter of the world’s mammals are threatened with extinction, an international survey showed on Monday, and the destruction of habitats and hunting are the major causes.

The report, the most comprehensive to date by 1,700 researchers, showed populations of half of all 5,487 species of mammals were in decline. Mammals range in size from blue whales to Thailand’s insect-sized bumblebee bat.

More than half of all frogs, toads and newts living in Europe could be driven to extinction within 40 years as climate change, diseases and habitat destruction take their toll, scientists warned last night.

The majority of the most threatened species live in Mediterranean regions, which are expected to become warmer and drier. Island species, such as the Mallorcan midwife toad and Sardinian brook newt, are especially at risk because they are unable to move to cooler climates.

The earth will warm about 2.4° C (4.3° F) above pre-industrial levels even under extremely conservative greenhouse-gas emission scenarios and under the assumption that efforts to clean up particulate pollution continue to be successful, according to a new analysis by a pair of researchers at Scripps Institution of Oceanography at UC San Diego.

That amount of warming falls within what the world’s leading climate change authority recently set as the threshold range of temperature increase that would lead to widespread loss of biodiversity, deglaciation and other adverse consequences in nature. The researchers, writing in the online edition of the Proceedings of the National Academy of Sciences, argue that coping with these circumstances will require “transformational research for guiding the path of future energy consumption.”

Parts of the Endangered Species Act, which has protected nature in the United States for 3 1/2 decades, soon may be extinct. The new regulations, which do not require Congress’ approval, would reduce the numbers of mandatory, independent reviews government scientists have been performing for 35 years, according to a draft first obtained and reported by The Associated Press.

About half the world’s apes, monkeys, and other types of primates are in danger of extinction, according to a new study that predicts a bleak future for many of humankind’s closest relatives.

Primates are falling prey to intense hunting and rapidly losing their habitats to deforestation, the study released Monday said.