Trophic rewilding: the diet of an opportunistic mesopredator

Trophic rewilding aims to restore lost ecological functions and diversity by focusing on top-down regulation through predator reintroductions. Genetic-based diet studies can provide valuable insights into trophic interactions, and the wider impacts of reintroductions and rewilding. We investigated the diet of a reintroduced mesopredator (eastern quoll, Dasyurus viverrinus) using metabarcoding of faeces. We analysed both vertebrate (12S rRNA) and invertebrate (CO1) prey species. 

Unexpectedly, we found mammals dominated eastern quoll diet (55 % relative read abundance and 73 % frequency of occurrence), likely due to persistent drought conditions and a lack of competing ground-dwelling predators. Invertebrate prey was present in at least one third of all samples across all seasons, underscoring their continued importance as a food source. 

While trophic rewilding focusses on returning ecological function, complexities and unexpected outcomes can arise in novel environments, challenging our assumptions regarding niche and trophic interactions. DNA metabarcoding proved efficient in diet analyses, supporting its use in long-term rewilding studies to understand trophic interactions over time.