The Majorcan Midwife Toad (Alytes muletensis), also known as Balearic Midwife Toad, is endemic to the Balearic Islands. Since Roman times, when this species was introduced, its distribution has been restricted to remote streams in the Tramontana Mountains. Following a successful plan to reintroduce the species, everything seemed to be improving until we discovered the fungus Batrachochytrium dendrobatidis in a few stocks in 2004.
In order to save the affected populations and prevent the disease from spreading throughout the island of Majorca, we have been monitoring infection and mitigation actions closely with the Ministry of the Environment of the Balearic Islands.
Infected populations are found in small streams which flow over limestone rock which after torrential rains of autumn hold water year round in small isolated pools. These environments, although difficult to access, have allowed us to test pioneering methods of disinfection. In a first attempt to completely dry the affected ponds we moved all larvae that occupied them by helicopter to a centre for treatment with fungicides. This was not entirely effective so in further disinfection attempts we applied the antifungal medication in the field.
These actions were successful and in subsequent years, we found that the pools remained free of fungus. Unfortunately, a small pool has been re-infected, so this week we returned to Majorca to try to clean it.
Together with the Ministry of Environment we will continue detailed monitoring of populations of the Majorcan Midwife Toad and if necessary, continue with efforts to eradicate the fungus on the island.
Experience in Majorca shows that, contrary to what was thought, it is possible to eliminate the fungus in the environment. This is the first step of this project and we will try to eradicate the fungus in the permanent lakes of the Guadarrama Mountains.