Frog-predator interactions in Aotearoa New Zealand: observations and two case studies using molecular and visual gut-content analyses

Interactions between endemic frogs and introduced predators in Aotearoa New Zealand are important to document for consideration in species management. Predation has emerged as a formidable threat to the survival of native frog populations in Aotearoa, with most research focusing on predation by Rattus species. Here we collate unpublished observations of mortality events or predator interactions in introduced and endemic frog species. At Mahakirau Forest Estate (Coromandel, North Island) and Whareorino Conservation Area (King Country, Central North Island), molecular and visual gut-content analyses were also used to assess frog consumption by ferrets (Mustela furo), stoats (Mustela erminea) and feral pigs (Sus scrofa). These unpublished observations and case studies document intensive predation events by feral pigs, rats, stoats, and ferrets on native frogs. In addition, weka (Gallirallus australis) and cats (Felis catus) have been observed preying on introduced Litoria species, with the potential to also prey on native frogs where they co-exist. These observations raise concerns for threatened frog populations and emphasise the importance of targeted management programmes.