Since the 1980s, decreases in amphibian populations, including population decline and localized mass extinctions, have been observed in locations all over the world. This type of biodiversity loss is known as one of the most critical threats to global biodiversity. The possible causes include habitat destruction and modification, diseases, 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 ongoing research.
Chytridiomycosis is an infectious disease in amphibians, caused by the chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans. Chytridiomycosis has been linked to dramatic population declines or extinctions of amphibian species in western North America, Central America, South America, eastern Australia, east Africa (Tanzania), and Dominica and Montserrat in the Caribbean. Much of the New World is also at risk of the disease arriving within the coming years. The fungus is capable of causing sporadic deaths in some amphibian populations and 100% mortality in others. No effective measure is known for control of the disease in wild populations. Various clinical signs are seen by individuals affected by the disease. A number of options are possible for controlling this disease-causing fungus, though none has proved to be feasible on a large scale. The disease has been proposed as a contributing factor to a global decline in amphibian populations that apparently has affected about 30% of the amphibian species of the world. Some research found evidence insufficient for linking chytrid fungi and chytridiomycosis to global amphibian declines, but more recent research establishes a connection and attributes the spread of the disease to its transmission through international trade routes into native ecosystems.
The mountain yellow-legged frog, also known as the southern mountain yellow-legged frog, is a species of true frog endemic to California in the United States. It occurs in the San Jacinto Mountains, San Bernardino Mountains, and San Gabriel Mountains in Southern California and the Southern Sierra Nevada. It is a federally listed endangered species, separated into two distinct population segments (DPS): a northern DPS, listed endangered in 2014, and a southern DPS that was listed endangered in 2002.
Atelopus is a large genus of Bufonidae, commonly known as harlequin frogs or toads, from Central and South America, ranging as far north as Costa Rica and as far south as Bolivia. Atelopus species are small, generally brightly colored, and diurnal. Most species are associated with mid-to-high elevation streams.
The Wyoming toad, also known commonly as Baxter's toad, is a species of toad in the family Bufonidae. The Wyoming toad is an extremely rare amphibian that exists only in captivity and within Mortenson Lake National Wildlife Refuge in Wyoming in the United States. The Wyoming toad was listed as an endangered species in 1984, and listed as extinct in the wild since 1991. As with black-footed ferrets at the Tom Thorne and Beth Williams Wildlife Research Center at Sybille in Wheatland, Wyoming, the effort to save the Wyoming toad has been a cooperative effort among state and federal agencies and private landowners. The Wyoming toad was common from the 1950s through the early 1970s, but its distribution was limited to the Laramie Basin in Albany County. The population crashed around 1975 and was extremely low by 1980. The Wyoming toad was federally listed as endangered in January 1984. To prevent extinction, a captive-breeding program began in 1989 at the Thorne Williams Unit that produced enough offspring in its first few years to supply seven zoos, and in 1998 the Saratoga National Fish Hatchery received captive-breeding stock. Nearly 46,000 offspring were produced at the Thorne Williams Unit from 1995 until 2006, when the remaining captive stock was moved to the Red Buttes Environmental Biology Laboratory south of Laramie, and then released back into the wild. Before the sharp declines occurred, this toad had been originally classified as Bufo hemiophrys baxteri, a subspecies of the Canadian toad, by Kenneth Raymond Porter in 1968.
Holdridge's toad, formerly Bufo holdridgei, is a species of toad endemic to Costa Rica. In October 2008, it was declared extinct by the International Union for Conservation of Nature in its Red List since the species had not been seen since 1987, despite years of extensive searches. However, the species was rediscovered in 2010 by a Costa Rican herpetologist and is now classified as critically endangered. It is believed that the species is most threatened by the presence of the chytrid fungus in its habitat.
Batrachochytrium dendrobatidis, also known as Bd or the amphibian chytrid fungus, is a fungus that causes the disease chytridiomycosis in amphibians.
The Panamanian golden frog, also known as Cerro Campana stubfoot toad and other names, is a species of toad endemic to Panama. Panamanian golden frogs inhabit the streams along the mountainous slopes of the Cordilleran cloud forests of west-central Panama. While the IUCN lists it as Critically Endangered, it may in fact have been extinct in the wild since 2007. Individuals have been collected for breeding in captivity in a bid to preserve the species. The alternative common name, Zetek's golden frog, and the epithet zeteki both commemorate the entomologist James Zetek.
Atelopus varius, the Costa Rican variable harlequin toad or clown frog, is a small Neotropical true toad from the family Bufonidae. Once ranging from Costa Rica to Panama, A. varius is now listed as critically endangered and has been reduced to a single remnant population near Quepos, Costa Rica, and has only relict populations in western Panama. Recent variation in air temperature, precipitation, stream flow patterns, and the subsequent spread of a pathogenic chytrid fungus linked to global climate change have been the leading cause of decline for A. varius. A. zeteki has been considered a subspecies of A. varius, but is now generally considered a separate species.
The starry night harlequin toad is a species of toad in the family Bufonidae endemic to the Sierra Nevada de Santa Marta, Colombia. Its natural habitats are sub-Andean and Andean forests, sub-páramo and páramo at 2,000–3,500 m (6,600–11,500 ft) above sea level. It is named after its unique coloration, being largely black with white spots.
Atelopus balios, the Rio Pescado stubfoot toad, is a species of toad in the family Bufonidae. It is endemic to southwestern Ecuador, with records from Pacific lowlands in Azuay, Cañar, and Guayas Provinces. It is a rare species that was already suspected to be extinct, but a single specimen was discovered in 2011 by a team from Conservation International during a hunt for missing amphibians. The decline in amphibian populations is well documented. The Atelopus balios is Critically Endangered as a result of the widespread amphibian Chytridiomycosis fungus that has decimated other amphibian populations. There are only 10 known findings of the tadpole, Atelopus balios.
The Guajira stubfoot toad or Carrikeri harlequin frog is a species of toad in the family Bufonidae. It is about 5 cm (2.0 in) long and typically black, though some populations have orange coloration. This species is endemic to the Sierra Nevada de Santa Marta mountain range of northern Colombia. It is critically endangered because of the chytrid fungus, Batrachochytrium dendrobatidis, and habitat destruction due to agriculture. The species had not been seen from 1994 until it was rediscovered in early 2008.
Atelopus glyphus, the Pirri harlequin frog or Pirri Range stubfoot toad, is a species of toad in the family Bufonidae found in Colombia and Panama within the Northwestern Andean montane forests. Its natural habitats are subtropical or tropical moist montane forests and rivers.
Atelopus limosus, the limosa harlequin frog is an endangered species of toad in the family Bufonidae endemic to Panama. Its natural habitats are stream banks in tropical moist lowland forests and rivers of the Chagres watershed in central Panama.
The cross toad, hourglass toad or slender-legged toad is a species of toad in the family Bufonidae. It is found in Indonesia, Malaysia, Thailand, and possibly Brunei and the outskirts of Singapore. Its natural habitat is subtropical to tropical moist lowland forest and subtropical to tropical moist montane forest, typically near creeks and rivers. It is threatened by habitat loss as well as the spread of chytrid fungus.
The Copan brook frog is a species of frog in the family Hylidae found in northeastern Guatemala and northwestern Honduras, specifically in the Sierra del Merendón, Sierra de Omoa, Sierra de Caral, and Sierra Espíritu Santo ranges. The colouring of this species is very distinctive and the specific name soralia comes from the resemblance of its markings to the vegetative structures on some crustose lichens.
The green-eyed treefrog is a species of Australasian treefrog in the subfamily Pelodryadinae that occurs in the Wet Tropics of Australia.
The Kroombit tinker frog, also sometimes referred to as Pleione's torrent frog, is a species of frog in the family Myobatrachidae. It is endemic to Central Queensland in Australia. It lives among rocks and leaf litter near small flowing streams.
The Javan ferret-badger is a mustelid endemic to Java and Bali, Indonesia. It is listed as Least Concern on the IUCN Red List and occurs from at least 260 to 2,230 m elevation in or close to forested areas.
The golden toad is an extinct species of true toad that was once abundant in a small, high-altitude region of about 4 square kilometres (1.5 sq mi) in an area north of the city of Monteverde, Costa Rica. It was endemic to elfin cloud forest. Also called the Monte Verde toad, Alajuela toad and orange toad, it is commonly considered the "poster child" for the amphibian decline crisis. This toad was first described in 1966 by herpetologist Jay Savage. The last sighting of a single male golden toad was on 15 May 1989, and it has since been classified as extinct by the International Union for Conservation of Nature (IUCN).
