Species diversity and distribution of amphibians and reptiles in Sardinia, Italy

Although distribution databases are a dynamic tool, continuously updated, it is important to take "snapshots" of the species distribution over time to promptly identify potential conservation issues. With this work, we provide an update of the distribution of amphibians and reptiles in Sardinia and satellite islands. Data derive from both direct field observations (carried out since 2005 until July 2022) and literature, accounting for over 7000 records: 1416 records of 11 species of amphibians and 5600 records of 18 species of reptiles. Distribution maps (on 10 × 10 km UTM grid) of 29 species are provided in supplementary materials as well as the updated list of the amphibians and reptiles occurring in the circum-Sardinian islands. Most of the meshes were characterized by the presence of 1-3 amphibian species (73%) and 6-8 or 9-11 reptile species (32% with 6-8 species, 30% with 9-11 species). Species abundance was favoured by environmental heterogeneity, and mostly varied in relation to elevation range and edge density

Which processes are behind the relationship between species abundance and environmental suitability? Monte Albo cave salamander as model species

Species can show a strong variation of local abundance across their ranges. Recent analyses suggested that variation in abundance can be related to environmental suitability, as the highest abundances are often observed in populations living in the most suitable areas. However, there is limited information on the mechanisms through which variation in environmental suitability determines abundance. We analyzed populations of the microendemic Monte Albo cave salamander Hydromantes (Speleomantes) flavus Stefani, 1969 (Plethodontidae), and tested several hypotheses on potential relationships linking environmental suitability to population parameters. For multiple populations across the whole species range, we assessed suitability using species distribution models and measured density, activity level, food intake, and body condition index. In high-suitability sites, the density of salamanders was up to 30 times higher than in the least suitable ones. Variation in activity levels and population performance can explain such variation of abundance. In high-suitability sites, salamanders were active close to the surface and showed a low frequency of empty stomachs. Furthermore, when taking into account seasonal variation, body condition was better in the most suitable sites. Our results show that the strong relationship between environmental suitability and population abundance can be mediated by the variation of parameters strongly linked to individual performance and fitness. Furthermore, we highlighted the potential use of cave animals as model species to answer macroecological questions

Measures of intact prey items

Data related maximum size of intact prey recognized from Hydromantes stomach contents