Vulnerability of a small population of an arboreal mammal to landscape change associated with a new motorway and drought

Small populations are vulnerable to extinction due to extrinsic factors such as increasing levels of habitat disturbance and isolation, as well as environmental variation. We investigated the response of a small population of a nationally threatened Australian arboreal mammal, the yellow-bellied glider (Petaurus australis; 560 g), to the construction of a new motorway, which increased the isolation of this population. We contrasted the small population with two larger populations in conservation reserves in the broader region. We conducted surveys in 6 of 10 years at 92 sites across the three forest areas to describe changes in population occupancy. A severe drought occurred in year 6 of our study. The probability of occupancy in year 1 was lower (0.22) in the small population compared to the larger reserve populations (0.52). The drought had a profound influence on all populations, with lower detection leading into the drought, before detection recovered to pre-drought levels in the re..., , # Data from: Vulnerability of a small population of an arboreal mammal to landscape change associated with a new motorway and drought

Dataset DOI: [10.5061/dryad.jwstqjqnk](10.5061/dryad.jwstqjqnk)

## Description of the data and file structure

Spotlight survey data - We conducted surveys three times in each of six years over 10 years: 2014, 2016, 2018, 2019, 2021, 2023. Spotlight surveys were conducted along a 200-m-long transect over 20 minutes. Spotlighting was used because it is a general survey technique for nocturnal arboreal mammals in Australia. Spotlighting was conducted by a single person who walked at a slow speed (600 m per h) and illuminated the forest on both sides of a transect using a flashlight torch (producing 350 or 600 lumens). Any arboreal mammals seen or heard calling were recorded. At the halfway mark, four recorded calls of the yellow-bellied glider and the powerful owl (*Ninox strenua*) were broadcast from a portable speaker, loud enough for yellow-bellied gli...,