 Since the 1980s , decreases in amphibian populations , including population crashes and mass localized extinctions , have been spotted from locations all over the world . These declines are known as one of the most critical threats to global biodiversity , and several causes are believed to be involved , including disease , habitat destruction and modification , exploitation , pollution , pesticide use , introduced species , and ultraviolet @-@ B radiation ( UV @-@ B ) . However , many of the causes of amphibian declines are still poorly understood , and the topic is currently a subject of much ongoing research . Calculations based on extinction rates suggest that the current extinction rate of amphibians could be 211 times greater than the background extinction rate and the estimate goes up to 25 @,@ 000 – 45 @,@ 000 times if endangered species are also included in the computation . 
