ESR 36:269-278 (2018)  -  DOI: https://doi.org/10.3354/esr00906

Trophic ecology of the Endangered Darwin’s frog inferred by stable isotopes

Blanca E. Molina-Burgos1,2,*, Andrés Valenzuela-Sánchez2,3,4, Mario Alvarado-Rybak1,2, Sebastián Klarian2,5,6, Claudio Soto-Azat2,3,*

1Programa de Doctorado en Medicina de la Conservación, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370251, Chile
2Centro de Investigación para la Sustentabilidad, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370251, Chile
3ONG Ranita de Darwin, Santiago 8330240, Chile
4Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Avda. Rector Eduardo Morales s/n, Edificio Pugín, Valdivia 5090000, Chile
5Centro de Investigacion Marina Quintay, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Viña del Mar 2531015, Chile
6Laboratorio de Analisis Isotopico, Universidad Andres Bello, Viña del Mar 2531015, Chile

ABSTRACT: Darwin’s frogs Rhinoderma spp. are the only known mouth-brooding frogs on Earth. The southern Darwin’s frog, R. darwinii, is found in the temperate forests of southern South America, is listed as Endangered and could be the only extant representative of this genus. Based on stomach contents, invertebrate prey availability and stable isotope analysis, we determined for the first time trophic ecological parameters for this species. Our results showed that R. darwinii is a generalist sit-and-wait predator and a secondary consumer, with a trophic position of 2.9. Carbon and nitrogen isotope composition indicated that herbivore invertebrates are their main prey, detected in 68.1% of their assimilated food. The most consumed prey included mosquitoes, flies, crickets, grasshoppers and ants. Detritivore and carnivore invertebrates were also ingested, but in lower proportions. Our results contribute to a better understanding of the feeding habits of this fully terrestrial amphibian and provide the first insight into their role linking low forest trophic positions with intermediate predators. We provide valuable biological information for in situ and ex situ conservation which can be used when developing habitat protection, reintroduction and captive breeding programmes. As revealed here, stable isotope analysis is a valuable tool to study the trophic ecology of highly endangered and cryptic species.


KEY WORDS: Amphibian · Chile · Conservation · Feeding ecology · Rhinoderma darwinii


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Cite this article as: Molina-Burgos BE, Valenzuela-Sánchez A, Alvarado-Rybak M, Klarian S, Soto-Azat C (2018) Trophic ecology of the Endangered Darwin’s frog inferred by stable isotopes. Endang Species Res 36:269-278. https://doi.org/10.3354/esr00906

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