Re-introduction of the Mallorcan midwife toad, Mallorca, Spain

The Mallorcan midwife toad (Alytes muletensis, Sanchíz & Alcover, 1977) or

ferreret was first described in the 1970s as Baleaphryne muletensis from upper

Pleistocene fossils, and was considered extinct. The discovery of live tadpoles in

1980 led to further research which confirmed the species as extant and endemic

to Mallorca (Mayol & Alcover, 1981). Subfossils suggest that the species was

once widespread across the island, but today it is confined to a few gorges within

the Serra de Tramuntana mountains in the north-west part of the island. There

are currently about 34 populations within the mountains and adjacent areas (16

original wild populations plus 18 re-introductions). These are largely isolated from

each other by physiographic barriers, but there is little evidence of any inbreeding

depression. Re-introduction of captive bred toads started in 1989 and it is

estimated that about 25% of the wild toads stem from captive bred stock. The

successful re-introduction program contributed to the downgrading of the species

from ‘Critically Endangered’ to ‘Vulnerable’ in the Global Amphibian Assessment

of 2004. There is little evidence that wild populations are continuing to decline, but

the recent discovery of chytridiomycosis in four populations gives cause for

concern.