The IUCN Red List update 2020-3 is now online! This update is a huge accomplishment for the Amphibian Red List Authority (ARLA) as a record number of 1,333 amphibian assessments was published, an historical update in the history of the ARLA. This comes with some sad news, as three species are now listed as Extinct (EX) and a total of 99 species are in a higher threat category than in the past, 32 of which are uplistings due to genuine worsening of threats. Not everything is gloomy, however. The genuine improvement of 16 species in Mesoamerica gives us hope that some amphibians are showing resilience. Habitat loss and degradation, chytridiomycosis and climate change remain the main factors of declines.
Newly declared EX frogs:
Chiriqui harlequin toad (Atelopus chiriquiensis), changed from CR(PE) to EX. (Costa Rica & Panama)
This once abundant toad has not been recorded since 1996, and extensive searches in the appropriate habitat, during the appropriate season and within the known range, have failed to locate this species. Its disappearance has been attributed, at least in part, to chytridiomycosis-related declines.
Wizened harlequin toad (Atelopus senex), changed from CR to EX. (Costa Rica)
This formerly common species has not been recorded since 1986, and extensive searches in the appropriate habitat, during the appropriate season and within the known range, have failed to locate this species. Its disappearance has been attributed, at least in part, to chytridiomycosis-related declines. Climate change or the synergistic effects of multiple factors cannot be ruled out as playing a role.
Craugastor myllomyllon (no common name), changed from DD to EX. (Guatemala)
This species is known from only a single female specimen collected in 1978. Numerous surveys between 1998 and 2019 have been unsuccessful in finding any other individuals, whereas other related species have been observed. The cause of its disappearance is unknown but we know that the habitat at the only known site has been destroyed by agriculture. Chytrid may have played a role, as it has affected many other robber frogs, but we just don’t know for sure.
Genuine improvements (Possible recovery from Batrachochytrium dendrobatidis (Bd)-related declines and/or habitat protection)
Oaxaca treefrog (Sarcohyla celata), changed from Critically Endangered to Near Threatened. (Mexico)
This species is apparently recovering from a severe population decline and has recently been recorded at several sites. Its continued survival is entirely dependent on the protection and rigorous management provided by local communities. The municipality of Santiago Comaltepec has assigned a conservation area for La Esperanza where an area of cloud forest is protected and no agriculture or logging activities can take place. Without this level of protection, it is very likely that the species’ habitat would be degraded and fragmented resulting in major population declines, and would likely warrant an immediate uplisting.
American cinchona plantation treefrog (Isthmohyla rivularis)
This Mesoamerican tree frog species seemingly disappeared from most of its range in the 1980s probably as a result of infection with the chytrid fungus. In 2007, a population was rediscovered and as of 2019, the species has been recently recorded in five localities in Costa Rica, which suggests that it is beginning to rebound from the edge of extinction. However, this species remains rare and the surviving population is considered to be relatively small, so even though it may be recovering it’s still facing all sorts of pressures including habitat loss and disease.
Adler’s mottled treefrog (Sarcohyla thorectes)
This Mexican tree frog species experienced a dramatic decline in the 1980s, probably due to chytridiomycosis, and had not been seen for around 30 years until a surviving population was found in 2007. From 2012-2019, it continued to be common within its small range and it seems that it avoided extinction (at least for now)!