Motorways, drought and wildfire: do they shape trajectories of arboreal mammal populations in eastern Australia?

Abstract

Motorways have the potential to create barriers to the movement of wildlife, increase mortality and cause edge effects, producing declines in abundance in nearby habitat. We investigated the response of six nocturnal arboreal mammal species to the construction of a new motorway in eastern Australia: five gliding species (three small, 500 g) and one generalist non-gliding species (4 kg). The two large gliding species are listed nationally as threatened. We employed dynamic occupancy modelling using repeat surveys at 75 sites over an 8-year period, beginning one year before motorway construction commenced. We predicted that if species were adversely affected by the motorway, then the probability of occupancy and/or detection should decline at sites near ( 0.5) across all years suggesting there was no influence due to the motorway. The probability of occupancy and detection in the large gliding species declined across the eight years. These findings support the hypothesis that differences in life history (slow vs. fast) among the gliding mammals influence their response to disturbances (landscape change, drought, wildfire). This suggests a much longer period to assess recovery is needed for species with a slow life history.

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