Analysis of diet and impact of two invasive amphibian species on endemic fauna on the Island of Oahu

• Grant number: 22/00437-9
• Support Opportunities: Scholarships abroad - Research
• Start date: August 01, 2022
• End date: November 01, 2022
• Field of knowledge: Biological Sciences - Ecology
• Principal Investigator: Luis Felipe de Toledo Ramos Pereira
• Grantee: Luis Felipe de Toledo Ramos Pereira
• Host Investigator: Brenden Stephen Holland
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Hawai'i Pacific University (HPU), United States

Abstract

Invasive wildlife on islands pose major risks via competition, disease transmission and direct predation on local fauna on a global scale. Among these potential impacts, the transmission of pathogens and disruption of trophic networks are quite common. This problem can be even intensified when the island did not naturally have a taxonomic group that invaded it with several species. This is precisely the case in the Hawaiian archipelago, where no amphibian species occur naturally and at least six anuran species are now established, invasive and maintain breeding populations on multiple islands. Two of them are considered quite aggressive and successful colonizers: the North American Bullfrog (Aquarana catesbeiana) and the Cane Toad (Rhinella marina). Thus, in the present project, I propose to study in detail aspects of diet and chytrid fungus (Bd) infection in these two species. With these data, it will be possible to assess whether these species are actually feeding directly on native, endemic, or even threatened fauna, and will also allow testing of hypotheses regarding food niche displacement when species are in syntopy and dietary differences influenced by Bd infection. Such hypotheses have been rarely tested or are still novel for amphibians. The results of this project could support local conservation and management actions in Hawaii, but could also be applied in similar cases in Brazil, such as the one observed in Fernando de Noronha or other islands with invasive amphibian populations around the world. The project has the full support of Hawaii Pacific University faculty, staff and students, with whom a new collaborative line of research will be established, extending our scientific network. (AU)