The Threats Facing Amphibians

Written by Chris Bednarski

Amphibians all over the world are affected by several factors causing alarming declines in populations. The most concerning issue currently is Batrachochytrium dendrobatidis more commonly known as chytrid or Bd. Bd is an aquatic epizootic(an epidemic of a disease event in nonhuman animals) fungus which causes a disease known as chytridiomycosis. This fungus attaches itself to the skin of an amphibian restricting proper intake of oxygen and osmoregulation, which are two very important duties of amphibian skin. In 1998 the first case of chytrid was documented in Australia, and then in 2004 Dr. Karen Lips documented chytrid in Central America. Dr. Lips noted that populations decline very rapidly, sometimes over just a few weeks! This fungus occurs on every continent where amphibians occur and has caused catastrophic declines or extinctions of almost 200 species of amphibians, even in pristine habitat in just about 30 years.

A species which you may see on exhibit in the Reptile and Amphibian House, the Panamanian Golden Frog, is now a functionally extinct species in its native range. This is due primarily to the chytrid fungus. This fungus much like every other living organism has a “breeding season”, if temperatures are too hot or too cold it lies dormant, but when the temperatures are just right like where the Panamanian Golden Frogs live the fungus multiplies and spreads non-stop. This doesn’t allow for amphibian populations to “hop” back and therefore wipes out an entire species in some cases, in less than a year. Several theories of where this fungus originated, how it has spread so rapidly, and how to control it have been discussed but to date no solid answers have been found.

Other factors, which include pollution of soil and waterways due to pesticides used on lawns and gardens and the improper disposal of batteries, habitat loss for palm oil plantations, paper manufacturing or even wooden chop sticks, global warming, and over collection for the food and pet trade, also play a significant role in amphibian declines worldwide. Many scientists, researchers and biologists agree that amphibians may be the next mass extinction since the dinosaurs some 65 million years ago.