There are many reasons why amphibians are such good indicators of changes in the environment. Amphibians breathe through their skin, so they are much more directly affected by changes to the chemistry of air and water associated with pollution (including loss of ozone layer in upper atmosphere).
Amphibians are also sensitive to fungi and diseases which can infect them through their skin. They also require aquatic habitats for reproduction. This means the are directly affected by changing water levels and qualities, due to changes in weather, climate, and human uses.
Because of their complex life cycles amphibians often have to move between habitats. This makes them sensitive to changes in the specific habitats that they need for food and shelter as well as all the places they travel through to get to their perferred habitats. Disturbances due to roads, trails, traffic, fires, logging and other thinkgs can affect the ability of amphibian species to survive even in the most remote areas.
Follow the links to the right to find out more about amphibian monitoring and conservation.