Multiyear monitoring of threatened iconic arboreal mammals in a mid‐elevation conservation reserve in eastern Australia

Multiyear investigations of population dynamics are fundamental to threatened species conservation. We used multiseason occupancy based on spotlight surveys to investigate dynamic occupancy of the koala and the greater glider over an 8‐year period that encompassed a severe drought in year 6. We combined our occupancy estimates with literature estimates of density to estimate the population sizes of these species within the focal conservation reserve. Both species showed substantial yearly variation in the probability of detection (koala: 0.13–0.24; greater glider: 0.12–0.36). Detection of the koala did not follow any obvious pattern. Low detection of the greater glider coincided with the drought and two subsequent years. We suggest the low detection reflected a decline in abundance. The probability of occupancy of the koala was estimated to be 0.88 (95% CI: 0.75–1.0) in year 8. Autonomous recording units were also used in year 8, enabling an independent occupancy estimate of 0.80 (0.64–0.90). We found no evidence of a drought‐induced decline in the koala. Habitat variables had a weak influence on koala occupancy probabilities. The probability of occupancy of the greater glider changed little over time, from 0.52 (95% CI: 0.24–0.81) to 0.63 (0.42–0.85) in year 8. Modeling suggested that the probability of colonization was positively influenced by the percentage cover of rainforest. Increased cover of these nonbrowse trees may reflect thermal buffering, site productivity, or soil moisture. We estimate that our study reserve is likely to contain >900 adult koalas and >2400 adult greater gliders. These are among some of the first reserve‐wide estimates for these species. Our study reserve can play an important role in the conservation of both species.

Extensive range contraction predicted under climate warming for a gliding mammal in north-eastern Australia

We used MaxEnt to model the current distribution of the yellow-bellied glider (Petaurus australis) and to predict the likely shift in the species’ future distribution under climate-warming scenarios in the Wet Tropics (WT) Bioregion in north Queensland and in the South-eastern Queensland (SEQld) Bioregion, which encompasses south-eastern Queensland and north-eastern New South Wales. Bioclimatic layers were used to generate models from 57 independent records in the WT and 428 records in SEQld. The modelled distribution of core habitat under current climate showed a good fit to the data, encompassing 91% and 88% of the records in each area, respectively. Modelling of future warming scenarios suggests that large contractions in distribution could occur in both bioregions. In the WT, 98% of core habitat is predicted to be lost under low warming (1°C increase) and 100% under high warming (2−3°C increase) by 2070. In SEQld, 80% of core habitat is predicted to be lost under low warming and 90% under high warming by 2070. These results suggest that this species is highly vulnerable to climate warming and highlight the importance of focusing conservation efforts at the bioregional scale. There is also a need to identify potential thermal refuges and ensure habitat connectivity.