Occupancy of an urban-sensitive specialist: the role of habitat availability and fire on the urban edge

Context Urban-sensitive species face a heightened risk of extinction in bushland remnants on the urban edge. Understanding the habitat factors that influence their occupancy is essential for effective conservation management in peri-urban landscapes. Aims This study aimed to identify the key landscape and habitat factors influencing the occupancy of the eastern pygmy possum (Cercartetus nanus), as an urban-sensitive species, in peri-urban northern Sydney. Methods We used occupancy modelling to examine the relationships between occupancy and environmental covariates, on the locality (home range) and landscape scales. Surveys were conducted in peri-urban bushland remnants using nest boxes over a 7-year period. Key results Detection probability peaked in autumn at 0.49 (s.e. 0.05) per visit, coinciding with the flowering of key foraging resources, and was lowest in summer at 0.27 (s.e. 0.06). The occupancy estimate under median conditions was 50%, indicating widespread occupancy by this threatened species in the peri-urban study area. Occupancy was positively associated with the extent of remnant native vegetation in the landscape (potentially a surrogate for connectivity) and an increasing proportion of the landscape that had burnt. When native vegetation comprised at least 50% of a 500 m buffer (~40 ha), occupancy probability was ≥70%. Occupancy was ≥70% when at least 50% of the native vegetation (500 m buffer) had been burnt in the 30 years prior to survey. Conclusions These findings highlight the need for management actions that enhance both the extent and quality of native vegetation around known populations, particularly with key foraging resources. Fire management, particularly for prescribed burns, will be important for the species; however, further research is required to determine optimal fire intervals and intensities. Implications Effective habitat management, including increasing native vegetation cover and appropriate fire management practices, is crucial for the long-term survival of the eastern pygmy possum in peri-urban areas. Further research is needed to determine optimal fire intervals and intensities for conservation efforts.