Gentile Francesco Ficetola and Fiorenza De Bernardi
Gentile Francesco Ficetola, Roberta Pennati and Raoul Manenti
Underground environments are increasingly recognised as important habitats for the distribution of certain amphibians. However, very few analyses tested whether amphibians occur randomly in underground environments, or they select cavities with specific environmental features. We assessed the distribution of the cave salamander Hydromantes (Speleomantes) strinatii in an area of NW Italy during summer, and analysed relationships between salamander distribution and multiple cave features, considering parameters describing both the biotic and the abiotic environment. Using visual encounter surveys, species’ detection probability was high, indicating that this technique provides reliable information on distribution. Salamanders were associated to caves with cold and humid microclimate, presence of wet walls, and hosting large numbers of Meta spiders. The association with less luminous caves was close to significance. Distribution data were not affected by spatial autocorrelation, suggesting that cave features are more important than the proximity to other occupied caves in determining the pattern of occupancy. Caves are heterogeneous environments: cave salamanders are strongly related to the features of underground environments. Food availability and abiotic features are major determinants of suitability for cave salamanders. Inter-correlation among biotic and abiotic cave features makes it complex identifying the role of factors determining species distribution, but quantitative analyses and PCA help to unravel the cave habitat requirements for amphibians.
Raoul Manenti, Fiorenza De Bernardi and Gentile Francesco Ficetola
Understanding the relationship between environmental features and species distribution is a key step for successful habitat conservation. In semiaquatic amphibians, the features of both breeding sites and the surrounding upland habitat can play important roles. We evaluated the relative role of (1) stream morphology, (2) biotic features of water, and (3) composition of landscape surrounding wetlands, for the distribution of the fire salamander, Salamandra salamandra. We determined the presence of larvae in 132 localities, and we used an information-theoretic approach to build species distribution models. We then used variance partitioning to evaluate the relative importance of environmental variables. A model including both stream and landscape features explained a large proportion of variation. Larvae were associated to heterogeneous and shallow streams, with scarce periphyton, rich macrobenthos communities characteristic of oligotrophic water, and surrounded by woodlands. Variance partitioning showed that stream morphology was the parameter with the largest independent effect, but most of variation was explained by the combined effect of multiple variables, suggesting a strong interplay among biotic and abiotic features in determining species distribution. The complementation between multiple elements, such as wetlands and landscape features, can be the key of a correct understanding of distribution of semi-aquatic amphibians.
Neftali Sillero, João Campos, Anna Bonardi, Claudia Corti, Raymond Creemers, Pierre-Andre Crochet, Jelka Crnobrnja Isailović, Mathieu Denoël, Gentile Francesco Ficetola, João Gonçalves, Sergei Kuzmin, Petros Lymberakis, Philip de Pous, Ariel Rodríguez, Roberto Sindaco, Jeroen Speybroeck, Bert Toxopeus, David R. Vieites and Miguel Vences
A precise knowledge of the spatial distribution of taxa is essential for decision-making processes in land management and biodiversity conservation, both for present and under future global change scenarios. This is a key base for several scientific disciplines (e.g. macro-ecology, biogeography, evolutionary biology, spatial planning, or environmental impact assessment) that rely on species distribution maps. An atlas summarizing the distribution of European amphibians and reptiles with 50 × 50 km resolution maps based on ca. 85 000 grid records was published by the Societas Europaea Herpetologica (SEH) in 1997. Since then, more detailed species distribution maps covering large parts of Europe became available, while taxonomic progress has led to a plethora of taxonomic changes including new species descriptions. To account for these progresses, we compiled information from different data sources: published in books and websites, ongoing national atlases, personal data kindly provided to the SEH, the 1997 European Atlas, and the Global Biodiversity Information Facility (GBIF). Databases were homogenised, deleting all information except species names and coordinates, projected to the same coordinate system (WGS84) and transformed into a 50 × 50 km grid. The newly compiled database comprises more than 384 000 grid and locality records distributed across 40 countries. We calculated species richness maps as well as maps of Corrected Weighted Endemism and defined species distribution types (i.e. groups of species with similar distribution patterns) by hierarchical cluster analysis using Jaccard’s index as association measure. Our analysis serves as a preliminary step towards an interactive, dynamic and online distributed database system (NA2RE system) of the current spatial distribution of European amphibians and reptiles. The NA2RE system will serve as well to monitor potential temporal changes in their distributions. Grid maps of all species are made available along with this paper as a tool for decision-making and conservation-related studies and actions. We also identify taxonomic and geographic gaps of knowledge that need to be filled, and we highlight the need to add temporal and altitudinal data for all records, to allow tracking potential species distribution changes as well as detailed modelling of the impacts of land use and climate change on European amphibians and reptiles.