Frogs and the Ecosystem
Over the past 50 years, scientists have recorded major declines in frog populations around the world. A few species have vanished completely. Many frog die-offs are the result of local human activity, but the epidemic has also reached remote areas. Is there a global cause? Scientists continue to search for answers.
© James Harding, MSU
American toad, Bufo americanus. with throat pouch inflated
Major causes of frog declines:
- Habitat destruction
- Introduced species
- Chemical pollution
- Climate changes
- Epidemic diseases
Frogs with extra or missing legs, eyes, and toes have been found in 44 states since 1996. Possible causes include parasites, pollution, and ultraviolet radiation.
In a laboratory study in 1997, nearly half of the frog eggs exposed to ultraviolet light grew into malformed adults, while eggs with no exposure developed into normal adults.