Western Palearctic Water Frogs’ (Pelophylax esculentus complex) Body Condition in Mixed Population Systems in Serbia Follow Levels of Habitat Suitability

Body condition is an important indicator in many ecological studies since it is expected that individuals and populations perform better in habitats more suitable for species. A wide range of metrics have been proposed as condition indices. In this study, we estimated the phenotypic condition of water frog species using the residual condition index. The study was carried out in three localities adjacent to nature preserves in South Banat, Serbia and with different levels of preserved natural features and anthropogenic pressure. Selected localities are typical habitats of water frogs with two parental and their hemiclonal hybrid species present. The localities were scored for suitability of the aquatic and terrestrial habitats. Statistical significance of residual condition index patterns from a multiway ANOVA was obtained for locality but not for species and sex. The lowest condition index was observed in frogs sampled from a locality maintained by human activity and with the lowest habitat suitability. Furthermore, the highest body condition index was obtained on the locality with the highest habitat suitability. One of the parental species, P. ridibundus had the highest overall body condition index while the hybrid species (P. esculentus) had the lowest. None of the three species from the complex had the highest body condition in all three localities, nor the worst.