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Amphibians in Danger

Around the world, amphibians (frogs, toads, salamanders) have been on the decline. There are fewer of them in fewer places.

Habitat destruction is a major factor, in particular wetland draining —in southern Ontario alone, it is estimated that 90% of wetlands have been drained since colonial times. But what is even more unsettling is that amphibian declines have also hit relatively pristine sites, including the Monteverde forests of Costa Rica, where species are becoming extinct despite the existence of a nature reserve!


More roads mean more traffic mortality, as these animals migrate from pond to pond, seeking breeding sites. Road kill reaches the millions very quickly. Even a few cars can wipe out an entire population of frogs.

Another cause is collecting— for food, medicines, bait, pets and even for teaching biology. The numbers are staggering. Acid rain alters the chemistry of lakes and ponds. Pesticides are a big problem. Frogs and their eggs are affected by higher levels of ultraviolet radiation, as we deplete the ozone layer with chemical pollution. Global climate change is another cause of amphibian decline, as droughts increase.




  So what?

Amphibians help control insect populations, and they provide food for fish, birds and mammals. More importantly, like the canaries in the coal mines of the 19th century, they are indicators of environmental health. Because they breathe through their skin, they are far more affected by pollution. Because of this, they are the subject of international monitoring.


Check out the Global Amphibian Assessment Program for more details -


Common Petrie frogs: 

  • Leopard frog
  • Green frog
  • Bullfrog.
Page updated 2015-01-17    © Friends of Petrie Island