Scientists first began to notice a decline in the numbers of amphibians, especially frogs, about almost thirty years ago.
Since then it’s become obvious that something is very wrong – entire populations and even species of frogs seem to be disappearing, even from apparently pristine areas. The Global Amphibian Assessment that was released in 2004 found that almost one third (32%) of the amphibians were of conservation concern. Amphibians were the most threatened vertebrate group in the world, compared to even birds (12%) and mammals (23%) which had a lower proportion of threatened species.
Scientists now think that the frogs’ declines are not caused by any single factor but by a complex of causes, including habitat loss, pollution, ozone layer depletion (increased UV), and disease. It is distressing because all these factors have to do with human activities. Even the diseases may have been spread by the introduction of exotic species to different ecosystems by people. It is important for us to learn more about these declines and to do our best to try to reverse them.