Abstract: In small, artificial freshwater ecosystems, climate-driven shifts in amphibian breeding phenology can trigger catastrophic recruitment failures by altering predator-prey temporal dynamics. We document a case of 100% larval mortality in a Rana temporaria cohort within an artificial stone fountain (6 m²) in the Italian Prealps (Caslino d’Erba, Como), monitored daily for 6 years. In spring 2026, a 15-day delay in oviposition shifted tadpole hatching into the peak energetic demand window of overwintering macroinvertebrate predators (Aeshna sp. and Dytiscus sp.), resulting in total cohort collapse within 29 days from peak density. Unlike the anurans, Salamandra salamandra larvae avoided total extinction due to their strictly benthic, thigmotactic behavior and early cutaneous chemical deterrence. Additionally, a post-breeding adult male was found dead displaying a locked post-mortem amplexus reflex, likely sustained by late-season hormonal peaks and subsequent opportunistic macroinvertebrate attacks following tadpole depletion. This long-term monitoring underscores the extreme vulnerability of artificial micro-wetlands to minimal climatic and temporal fluctuations.
Publication Date: 2026-06-14