Establishment and potential spread of the introduced spotted-thighed frog, Litoria cyclorhyncha (Ranoidea cyclorhynchus), in South Australia

ABSTRACT Litoria cyclorhyncha is a hylid frog native to southwest Western Australia (WA). It was first recorded in South Australia (SA) in 2000 and has established a breeding population in Streaky Bay on the western Eyre Peninsula since at least 2011. L. cyclorhyncha is a relatively large predatory frog that presents a potential threat to fauna and ecosystem processes in SA and eastern Australia. This study examines the invasion history and current and potential future distributions of this frog using historical records, field surveys and species distribution modelling (SDM). The historical records in SA suggest human-assisted dispersal through transport networks. Field surveys throughout the Eyre Peninsula during 2016–2017 detected three native species of frogs but no additional breeding populations of L. cyclorhyncha outside of Streaky Bay. Within Streaky Bay, frog abundance appears to be concentrated around permanent water bodies, but the species is also well established in urban habitats. SDM suggests that suitable environmental conditions exist for L. cyclorhyncha in southern and eastern Australia. This, and the frog’s ability to disperse over long distances, suggests considerable potential for the species to become invasive. As L. cyclorhyncha has potential to significantly impact biodiversity and ecosystems, management strategies are urgently needed.