Specie relitte dell’Appennino centro-meridionale: un approccio integrato per la conservazione degli elementi faunistici di origine glaciale.

Glacial relict species occurring at the rear edge of their distribution represent natural laboratories for understanding extinction dynamics under rapid environmental change. This thesis focuses on the conservation of isolated populations of the Alpine newt (Mesotriton alpestris) in the Central and Southern Apennines, with particular emphasis on the subspecies M. a. apuanus and M. a. inexpectatus. These populations are characterized by extreme isolation, low detectability, and exposure to multiple interacting stressors, including habitat alteration, invasive species, emerging pathogens, and climate change. The research adopts an integrated, multi-level approach combining field ecology, spatial modelling, disease screening, behavioural ecology, and applied conservation actions. Long-term field surveys, including visual encounter surveys, dip-netting, and capture–mark–recapture based on photo-identification, were conducted to assess population status and detectability patterns. Results revealed extremely low and temporally inconsistent detection rates in central Apennine populations, suggesting demographic fragility rather than methodological limitations. To identify current and future suitable habitats, Species Distribution Models (SDMs) were developed using a weighted modelling framework, incorporating climatic, topographic, and land-use predictors. These models were coupled with connectivity analyses to delineate functional ecological networks and identify priority areas for conservation interventions. The results highlight a contraction of suitable habitats under future climate scenarios and the critical role of habitat connectivity in maintaining population persistence. Health assessments focused on the detection of chytrid pathogens (Bd), revealing the presence of infection in some populations and emphasizing the need to incorporate disease surveillance into conservation planning. In parallel, behavioural experiments demonstrated species-specific responses to visual stimuli, providing a basis for improving sampling efficiency in low-density populations. Applied conservation actions were implemented through a captive breeding program for the Calabrian lineage (M. a. inexpectatus), followed by a soft-release strategy in restored and historically occupied sites. This intervention, conducted under IUCN guidelines, represents one of the first integrated attempts to combine ex situ and in situ conservation for this taxon. Early outcomes support the feasibility of reinforcement actions even in contexts where threats, such as invasive fish, are not yet fully mitigated. Overall, this thesis demonstrates that passive monitoring is insufficient for the conservation of rear-edge amphibian populations. Instead, it supports a shift toward active, adaptive, and integrated management frameworks that combine ecological data, spatial planning, and direct intervention. The approach developed here provides a transferable model for the conservation of other glacial relict species facing similar ecological and climatic constraints.