Over 40% of amphibian species are threatened, urbanization being a major threat to their survival. Conservation efforts to sustain viable amphibian populations within urban spaces may play a meaningful part in protecting amphibian species. To explore the factors that influence the viability of urban amphibian population in Mediterranean environments, we used a capture-recapture analysis applied to a large dataset collected in a multi-year citizen-science program, focused on two urban Salamandra infraimmaculata populations, and to a second dataset of two Bufotes variabilis populations in an urban park and in a nearby nature reserve. Individuals of both species have individually-unique patterns of dorsal spots, allowing for noninvasive recapture identification. Using the salamander dataset, we developed a length-based age-estimation method and discovered a prolonged period of increased vulnerability throughout their first years of life, even after reaching sexual maturity, a finding with important implications for management. Additionally, the two case studies suggest that the creation of fish-containing artificial water bodies in Mediterranean habitats can have highly detrimental impacts on amphibian populations. The study uncovered population-specific information, such as unknown breeding sites and population size estimates, of conservation importance, and demonstrates the utility of citizen science in study and conservation of urban ecology.