New Zealand Frogs: Leiopelmatidae

According to the World Conservation Union (IUCN), all four species in this family are in danger. The most at-risk species is Archey's frog, listed as Critically Endangered, which means that it faces an extremely high risk of extinction in the wild. They were once much more common, but when scientists counted them in 1996 and again in 2002, they found that their numbers fell by 80 percent: four out of every five frogs had disappeared. In one population, the number of frogs went from 433 individuals to just 53. The cause of the drop was probably disease, possibly caused by a fungus. Scientists first became aware of the fungus, called chytrid (KIH-trid) fungus, in Australia and Central America in 1998 and have since blamed it for the declines of many frog species. They think an introduced species, called the Australian bell frog, brought the fungus to New Zealand and passed it on to Archey's frog in about 1998. The fungus is still a problem. When the fungus infects one of these frogs, it has trouble moving and soon becomes paralyzed.

The IUCN considers Hamilton's frog to be Endangered, which means that it faces a very high risk of extinction in the wild. The remaining two species, Maud Island and Hochstetter's frogs, are Vulnerable and face a high risk of extinction in the wild. The major threats to these species are introduced predators, including rats and ermines, which are in the weasel family, and the lizard-like tuataras. In some cases, conservationists are trying to build barriers around the frogs' habitats so the predators cannot reach them. In addition, scientists are keeping a watchful eye on these three species to see if the chytrid fungus eventually affects them, too.