Like most terrestrial elements of biodiversity, amphibian diversity is severely threatened (Sala et al. 2000), and the mountain regions have been especially hard hit (Young et al. 2001). The threats to the amphibians are various; deforestation, fertilisers, pesticides, acid precipitation, low pH, increased UV radiation, emerging diseases, introduced species, climate change, chytrid fungus (Batrachochytrium dendrobatidis), hybridization, human predation etc. (e.g. Duellman 1999 cited by Galindo-Leal et al. 2003; Beebee & Griffiths 2005). A global decline in amphibians was first recognized in 1989 (e.g. Vitt et al. 1990; Wake 1991) and the situation has not improved since then. In the end of the year 1998, 124 species of amphibians were categorized as threatened; in 2010 the number had increased more than 15 times to 1898 threatened species (IUCN 2010a). This is 29 % of the total number of amphibian species described in the IUCN Red List (IUCN 2010a), more than any other category of animals.

 

Latin America harbours a highly diverse amphibian fauna representing half of the world’s total species richness (Duellman 1999 cited by Galindo-Leal et al. 2003). The amphibian declines are widespread throughout this area (Young et al. 2001). Peru harbour more than 500 species of amphibians and is regarded as a mega-diverse country (von May et al. 2008).

One of the 70 threatened and endemic amphibian species (IUCN 2010b) in Peru is the poison dart frog Excidobates mysteriosus (Marañón Poison Frog). The species is classified as endangered (EN) and the population trend is assessed to be decreasing (Icochea et al. 2010). The frogs are only known from a single location in the vicinity of the village Santa Rosa at the foothills of Cordillera del Cóndor (Cajamarca Department), north-western Peru, at around 1000 meters above sea level (m.a.s.l.) (Icochea et al. 2010).

 

The knowledge about the frog species is scarce. Twomey and Brown (2008) performed a study on E. mysteriosus and used 13 presence points for a niche model, ending up with a possible distribution between 200-1500 m.a.s.l. They concluded that the species is terrestrial or scansorial and diurnal. Lötters et al. (2007) (cited by Twomey & Brown 2008) reported the clutch size to be 8-13 eggs, which develops into free swimming tadpoles that finally metamorphs into frogs. The only published note on behaviour found is from Twomey and Brown (2008) which wrote that the frogs are hesitant to jump and tend to “walk” instead.
 

 

The utilization rate of individual bromeliads may be affected by different habitat factors (quality variables). Zotz and Thomas (1999) found that frogs were disproportionately encountered in large bromeliads. A study on the poison dart frog Dendrobates pumilio showed that increasing bromeliad density also increased the presence of adult frogs leading to more breeding, resulting in a higher presence of juveniles (Donnell 1989). In a study by de Silva et al. (2011) they found a bromeliad usage pattern, where higher presence of anuran frogs were found on bromeliads with higher sun exposure than on those who had lower sun exposure. No detailed studies have been performed on the behaviour including breeding or habitat utilization of E. mysteriosus. Crucial information for conservation of the species is therefore lacking.

 

The main aims of this paper were to study the basic ecology of E. mysteriosus, including habitat requirements, occupancy patterns, individual frog dispersal, feeding and tadpole release behaviours. This knowledge should facilitate efforts to preserve the species, including the development of guidelines for managing sites where it occurs.