Modelling the amphibian chytrid fungus spread by connectivity analysis: towards a national monitoring network in Italy

• Published in: Biodiversity and conservation 2021-08, Vol.30 (10), p.2807-2825
• Main Authors: Costa, Andrea, Dondero, Lorenzo, Allaria, Giorgia, Morales Sanchez, Bryan Nelson, Rosa, Giacomo, Salvidio, Sebastiano, Grasselli, Elena
• Format: Article
• Language: English
• Subjects: Amphibians; Aquatic reptiles; Batrachochytrium; Biodiversity; Biomedical and Life Sciences; Circuits; Climate Change/Climate Change Impacts; Climatic data; Connectivity; Connectivity analysis; Conservation Biology/Ecology; Diffusion; Disease; Ecology; Endangered & extinct species; Extinction (Biology); Fungi; Identification; Life Sciences; Original Paper; Pandemics; Pathogens; Permeability; Population decline; Probability theory; Protected areas; Reptiles & amphibians; Species
• ISSN: 0960-3115; 1572-9710
• DOI: 10.1007/s10531-021-02224-5

The emerging amphibian disease, Batrachochytrium dendrobatidis (Bd), is driving population declines worldwide and even species extinctions in Australia, South and Central America. In order to mitigate effects of Bd on amphibian populations, high-exposed areas should be identified at the local scale and effective conservation measures should be planned at the national level. This assessment is actually lacking in the Mediterranean basin, and in particular in Italy, one of the most relevant amphibian diversity hotspots in the entire region. In this study, we reviewed the available information on Bd in Italy, and conducted a 5-year molecular screening on 1274 individual skin swabs belonging to 18 species. Overall, we found presence of Bd in 13 species and in a total of 56 known occurrence locations for peninsular Italy and Sardinia. We used these occurrence locations and climate data to model habitat suitability of Bd for current and future climatic scenarios. We then employed electric circuit theory to model landscape permeability to the diffusion of Bd, using a resistance map. With this procedure, we were able to model, for the first time, the diffusion pathways of Bd at the landscape scale, characterising the main future pathways towards areas with a high probability of Bd occurrence. Thus, we identified six national protected areas that will become pivotal for a nationally-based strategic plan in order to monitor, mitigate and possibly contrast Bd diffusion in Italy.