The Herpetological Journal

pp.49-56

Authors: Miguel Vences , Pedro Galan , Antonio Palanca , David R. Vieites , Sandra Ni Eto And Jorge Rey

Abstract: Habitat use and activity was studied in a common frog (Rana temporaria) population at an altitude of 2200 m in the Circo de Piedrafita, Spain, was studied during July 1998. Adult and juvenile frogs clearly selected moist microhabitats, and avoided dry substrates such as pasture and rocks. Marshes and puddles were the preferred microhabitat of both adults and juveniles; the shore and the water body itself of a larger pond were selected by adults but much less so by juveniles. Regular surveys over seven days indicated that adults showed both diurnal and nocturnal activity, whereas juveniles were more strictly diurnal. The percentage of adults observed at night in the pond was negatively correlated with the minimum air temperature. The rather aquatic habits and diurnal activity patterns appear to differ from low-altitude populations of R. temporaria. They are discussed as adaptations to the lack of humid substrates (forest leaf litter) at high altitudes, and to the extreme and unpredictable climatic conditions (low nocturnal temperatures, and sudden rapid temperature decreases at night) in montane environments.

Keywords: frog, Spain, Pyrenees, alpine environments, activity, microhabitat