The amphibians of the Circeo National Park, central Italy: distribution and aquatic habitat use

Amphibians usually show pronounced variety in habitat use at different periods, selecting only part of the habitats available from their home range depending on the specific stage of the life cycle (larval, juvenile, adult) and the phenological phase (terrestrial, aquatic). The authors investigated the distribution and aquatic habitat use of seven species of amphibians occurring in Circeo National Park, central Italy. Aquatic habitats were inspected fortnightly in diurnal and nocturnal surveys from September 2009 to August 2010. Amphibians were found in 15 water bodies (three artificial and 12 natural) that differed in terms of hydro-morphology (size, depth, bottom substrate, turbidity), vegetation (aquatic, riparian and surrounding), and location (near lakes and riparian areas, fields or wooded areas). Analysis of the individuals detected was done to assess the reliability of presence/absence data and a PCA was performed for reducing dimensionality and decreasing redundancy of the environmental covariate data set. Logistic regression analysis produced significant habitat models for the anuran species (Bufo bufo, Bufotes balearicus, Hyla intermedia, two collectively evaluated Pelophylax taxa [lessonae and esculentus] and Rana dalmatina), whereas for both urodelan species (Lissotriton vulgaris and Triturus carnifex) it was not possible to derive statistically significant models. It is discussed how faunistic and ecological data appropriately analyzed could provide practical instruments for the amphibian conservation at a local scale by identifying priority species and biotopes that deserve strict management.