Anuran responses to urbanization: Evaluating life history traits of Rhinella arenarum in urban wetlands

Abstract

Wetlands are unique ecological environments capable of harboring high biodiversity. However, urbanization can degrade, eliminate, or transform these habitats. Although amphibians utilize habitats created by humans in urban landscapes, few studies have investigated the influence of the habitat quality on the life history of anurans. We assessed life history traits such as snout-vent length (SVL), body condition, and reproductive investment in the South American common toad Rhinella arenarum, to determine whether urbanization is harmful or beneficial to this species. We sampled wetlands with different levels of urbanization in Río Cuarto city, Córdoba, Argentina. We recorded males with lower SVL in medium urbanized wetlands and those with the highest SVL in both low and high urbanization categories, similar to what was found for body conditions with males with low body conditions inhabiting wetlands with a medium degree of urbanization. In females, lower SVL was recorded in medium urbanization and highest SVL in high and low urbanization. It is observed that females recorded in highly urbanized wetlands have a very low body condition. The reproductive investment parameters were not significantly different, but we observed an association between a greater number of eggs and clutch size with wetlands of low urbanization. These results show a variability of responses of R. arenarum to urbanization, which could be due to phenotypic plasticity in its life history parameters, allowing it to inhabit urban areas. Continuous monitoring of the species in these wetlands is needed to determine if these biological responses are temporary or persistent.