Previsione della distribuzione di anfibi a partire da un ridotto numero di segnalazioni. Un esempio di proiezione semplificata dalla scala locale a quella regionale

In conservation biology species distribution and status are key information in the process of identifying conservation priorities at different levels (local, national or continental). Critical issues in determining species distribution consist in a low number of records collected in a very limited area. Aim of this work was to assess the possibility of obtaining accurate potential distributions of amphibians via iterative presence data refinement, starting from a small numbers of occurrences at local scale. To meet this need, we generate potential distribution models implementing the occurrences of four amphibian species distributed mainly in lowland areas: two widespread anurans (Rana dalmatina, Hyla intermedia) and two urodeles relatively less common (Triturus carnifex and Lissotriton vulgaris meridionalis) in the area of "La Mandria" Regional Park. We used presence-only data to fit MaxEnt models: this approach is particularly suitable with not systematic information, common situation in the case of rare species. The internal validation of models has yielded positive results for all four species of amphibians, as confirmed especially for the two anurans by performing external validation with the data reported in the herpetological Atlas of Piedmont and Valle d'Aosta. Our work has therefore shown the usefulness of this methodological approach for projecting the distribution on a regional scale using local presence information.