Chytrid fungus infection related to unusual mortalities of Salamandra salamandra and Bufo bufo in the Penalara Natural Park, Spain

Chytridiomycosis is a fatal disease associated with amphibian population declines and extinctions worldwide. In a protected area in central Spain, the Penalara Natural Park, the disease almost extirpated the population of Alytes obstetricans over only a few years, but did not apparently affect other amphibians. We present new observations documenting the occurrence of the disease in other species. In 2001-2003 we collected over 400 larvae or recently metamorphosed individuals of Salamandra salamandra and also several dead individuals of Bufo bufo. The analysis of the skin of post-metamorphic specimens revealed the presence of chytrid sporangia and discharge tubes in both species. According to measures of larval abundances in 1999 and 2003 the population of S. salamandra has suffered a marked decline but no significant trend was observed for B. bufo. We discuss the possible role of chytridiomycosis in the decline of S. salamandra and comment on the differential susceptibility exhibited by various species in the amphibian community at Penalara.