Factors influencing the breeding habitat use by amphibians in the alpine area of the Retezat National Park (Romania)

Abstract

Factors influencing the breeding habitat use by amphibians in the alpine area of the Retezat National Park (Romania)We analyzed the distribution of amphibians according to the characteristics of breeding ponds in the alpine areas of the Retezat National Park. We inventoried 50 aquatic habitats between 1920 and 2260 m a.s.l. Three amphibian species are present at high altitudes:Rana temporaria, Bufo bufoandMesotriton alpestris. They were found in 70% of the aquatic habitats, but only 48% were used as spawning sites. Human impacts and predators were the most influential variables explaining the occurrence ofR. temporaria, whereas location and pond adjacent terrain were important forM. alpestris. Moderate grazing had a positive effect by maintaining low vegetation or providing nutrients input in the oligotrophic aquatic habitats.