Influence of landscape features on the distribution of the vulnerable frog species Mixophyes iteratus in the Tweed Valley, northern New South Wales, Australia

Context Knowing more about the influence of landscape features on occurrence or abundance may aid in conservation management of the vulnerable frog species Mixophyes iteratus in Australia. Aims We aimed to understand how M. iteratus is influenced by landscape features and fill in the knowledge gap on species distribution within the Tweed Valley landscape of northern New South Wales. Methods The species was sampled at 40 stream-based transects spread across the Tweed Valley during three breeding seasons, from 2019 to 2022. Occupancy analysis and general additive models were used to investigate the relationship between landscape features and frog occurrence and maximum frog count, respectively. Landscape variables included elevation, proportion of vegetation cover, stream morphology, and distance to conservation reserves. Key results Mixophyes iteratus distribution was concentrated in the western half of the Tweed Valley, over a range of landscape features. Landscape features did not strongly affect distribution at specific scales or in general. There was some spatial clustering of maximum frog count, especially in large, forested areas in the south and south-west of the Tweed Valley. Detection rate was higher in this study when compared to a previous study with shorter transects. Conclusions Modelling suggests that M. iteratus occurred over a broad distribution within the western half of the Tweed Valley before broad scale clearing occurred. Species occurrence is wider than previously thought; however, population strongholds appear to be within large tracts of forest. Implications Species conservation that is informed by small scale habitat selection would be enhanced by knowledge of landscape scale distribution.