Abstract Amphibians play an important role in linking aquatic and terrestrial ecosystems through nutrient cycling, energy flow, and bioturbation. In this study, we investigated the isotopic niches of three tropical frog species (Polypedates megacephalus, Microhyla mukhlesuri, and Microhyla ninhthuanensis) inhabiting temporary ponds in southern Vietnam, constructing an ontogenetic snapshot using stable isotope analysis of carbon (δ13C) and nitrogen (δ15N). We examined ontogenetic changes in isotopic signatures and dietary sources across species, comparing tadpoles and adult frogs. Our results revealed distinct isotopic niche partitioning among syntopic tadpole species within a shared pond. Microhyla ninhthuanensis (neustonic feeder) occupied the most specialized niche, whereas P. megacephalus (opportunistic omnivore) and M. mukhlesuri (nektonic suspension feeder) exhibited broader, more variable isotopic niches. Notably, M. ninhthuanensis tadpoles exhibited the closest isotopic match to conspecific adults, suggesting dependence on terrestrially derived carbon sources throughout ontogeny. Distinct isotopic niches were identified for M. mukhlesuri, both in different ponds and among various cohorts within the same pond. The observed trophic differentiation among tadpoles of the three species with different feeding modes appears to facilitate their stable coexistence in shared pond habitats by minimizing resource competition.
Stepanov et al. (Tue,) studied this question.