Predation Pressure of Invasive Marsh Frogs: A Threat to Native Amphibians?

Anurans have been introduced in many parts of the world and often become invasive over large geographic areas. Although predation is involved declines invaded amphibian populations, there a lack quantitative assessments evaluating potential risk posed to native species. This particularly true for Pelophylax water frogs, which western Europe, but no studies date examined their on other amphibians range. Predation by marsh frogs (Pelophylax ridibundus) was assessed stomach flushing once month four months 21 ponds southern France. Nine percent stomachs contained amphibians. Seasonality major determinant consumption. effect mediated body size, with largest invaders ingesting bigger natives, such as tree frogs. These results show that represent threat through ability forage at adult stage. The also indicate numbers are predated. More broadly, fact site- time-specific highlights need repeated samplings across habitats key periods clear understanding impact invaders.