A comprehensive survey carried out by the World Conservation Union (IUCN) has said that a sixth of Europe's mammal species is threatened with extinction.
Unless the trend is reversed, conservationists fear that the European Union will not be able to meet its self-imposed target of halting biodiversity loss by 2010.
Of the roughly 250 mammal species that live in Europe and western Russia, some 15 percent are classed as 'vulnerable' or worse, according to the IUCN's criteria. This means that they face a "high risk of extinction in the wild" if action is not taken, reports the Nature magazine.
The report, entitled the European Mammal Assessment and released to mark today's International Biodiversity Day, shows that European countries have their work cut out if they are to fulfil their 2010 biodiversity target, known as the Habitats Directive.
Worst affected is the handful of European mammals classed as 'critically endangered', the most serious category. The Iberian lynx, for example, is the world's most endangered big cat only an estimated 150 are thought to remain. The Arctic fox and European mink face similar plights.
This new assessment proves that many European mammals are declining at an alarming rate.
The assessment shows that the situation is even more perilous for Europe's marine mammals, of which 22 percent are classed as vulnerable or worse.
Hilton-Taylor, a conservation expert involved with the study, adds. "The situation in the tropics is even worse."
In tropical regions, which have greater numbers of species overall, an average of one in four is officially threatened, largely as a result of extensive deforestation.
Currently, some 27 percent of the mammal species surveyed are thought to be declining, meaning that more may join the ranks of those classed as threatened, whereas only eight percent are growing in number.
The main drivers of this change are habitat degradation, deforestation, pollution and excessive hunting, the report says.
But there are some success stories. The Alpine ibex, which was hunted almost to extinction during the nineteenth century, has now rebounded to number more than 30,000. And the European bison, which for much of the past century was only found in zoos, now roams in herds across much of Eastern Europe.
Conservation efforts in the European Union's newest members, such as Poland and Bulgaria, will be crucial in preventing biodiversity from sliding, Hilton-Taylor argues.
"We need a more structured monitoring system," he adds.