Demographic and Life-History Responses of Rhinella arenarum to Road-Associated Environments

The global decline of amphibians is linked to habitat loss, with urbanization and roads as major threats. Roads fragment habitats and introduce stressors like pollution, temperature changes, and non-native predators. Despite growing awareness, studies in Latin America are scarce. In this study, we examined life-history traits of Rhinella arenarum from four sites in central Argentina that differ in urbanization intensity near roads. We analyzed snout-vent length (SVL), age, growth, size at maturity, and longevity in reproductive individuals. Sexual size dimorphism was present across sites, with females consistently larger than males. Moderate variation in SVL and age structure was observed among populations, with smaller and generally younger individuals in sites with medium-to-high urbanization. In contrast, individuals from the least disturbed site tended to show broader age ranges and greater longevity. Growth rates were also slower in the most urbanized site. While differences were moderate and sample sizes limited, these patterns suggest that urban-associated factors may influence demographic traits in R. arenarum. These findings contribute to our understanding of how human-altered environments might affect amphibian populations and highlight the need to distinguish between natural geographic variation and anthropogenic impacts on amphibian populations.