More highlights from the latest IUCN Red List update

26 October 2012 | Article

In the most recent update of The IUCN Red List of Threatened Species™, there were both new additions and changes to the status of species already listed. Good news included the rediscovery of two frog species and the downlisting of a number of species due to conservation efforts. However, of the 65,518 species on The IUCN Red List, 20,219 are assessed as “threatened”.

Rediscovered Species

The Sri Lankan toad species Adenomus kandianus was until recently known only from one late 19th Century record, and the lack of further sightings led to this species being labelled as Extinct. However, in 2009 this species was rediscovered in cloud forest in the Peak Wilderness Sanctuary in Central Province, Sri Lanka. While it is possible that this toad has a more widespread occurrence, it is so far only known from a single site in an area of 200 m². There is a continuing decline of its natural habitat in this area due to illegal gem mining, conversion of forest to tea plantations, and pollution from a very high volume of religious pilgrimage. This species has therefore been assessed as Critically Endangered.

Holdridge’s Toad (Incilius holdridgei) was once common in appropriate habitat (with 2,765 males seen visiting two pools in an eight-day period in 1975) but in 2008 it was declared Extinct, having not been seen since 1986 despite intensive searches. This Costa Rican endemic was then rediscovered in 2009 at two nearby sites – adults, juveniles, and tadpoles were all present but extensive searching has revealed less than five adult toads, suggesting a total population of fewer than 50 adults. This species is therefore assessed as Critically Endangered. Although it has not been proven, the main cause of the population decline is thought to be chytridiomycosis, perhaps in combination with the effects of climate change.

Reassessed species

Widespread but relatively rare throughout the Indo-Pacific, the Spiny Seahorse (Hippocampus histrix), previously Data Deficient, has been reassessed as Vulnerable. A population decline of at least 30% over the last 10–15 years is suspected, and these declines are expected to continue into the future. As well as targeted fishing for the aquarium and traditional medicine trades, there are also concerns about habitat destruction and capture of seahorses as bycatch throughout the species’ range.

The Steller Sea Lion (Eumetopias jubatus) was previously assessed as Endangered, but is now Near Threatened thanks to a genuine improvement in its situation. This northern Pacific species has two subspecies, one of which experienced a dramatic and unexplained population decline between the late 1970s and 1990. This downward trend has recently started to turn around. Meanwhile, the population of the second subspecies has been steadily increasing since 1979, and so the species as a whole has only declined by 28% over the last three generations, with the population currently increasing.

Species new to The IUCN Red List

Endemic to Rotuma, a small island in Fifi, the Rotuma Forest Gecko (Lepidodactylus gardineri) is a highly arboreal species which is strongly dependent on secondary forest. Clearance of the secondary growth forest for farmland could have devastating effects on this Vulnerable species, which is not found in any protected areas.

The Arabian Horned Viper (Cerastes gasperettii) is threatened in Saudi Arabia by over-collection for venom extraction. However, it has a wide distribution, and there are no major threats to this species in the Arabian Peninsula part of its range. It is presumed to have a large population which is stable overall, and has been assessed as Least Concern.
 


variegated golden frog