Ground Parrots and fire in east Gippsland, Victoria: habitat occupancy modelling from automated sound recordings

摘要

The peak-and-decline in the density of eastern populations of Ground Parrot (Pezoporus wallicus) with increasing time since fire is one of the best-documented post-fire responses of any Australian animal. However, existing studies have typically shown this relationship within a set of sites highly likely to be occupied by Ground Parrots, rather than demonstrating that fire history affects whether a site is occupied. This paper describes a landscape-scale, targeted survey of Ground Parrots at 80 heathland sites between Marlo and Mallacoota, Victoria. Selection of sites was stratified by combinations of time since fire and modelled predictions of the distribution of Ground Parrots. All sites were sampled 10 times in late 2013 using automated sound recorders, and a subset of 23 sites had at least one traditional, observer-based physical survey. Both time since fire and the species-distribution model were significantly associated with the probability of Ground Parrots occupying a site. The most parsimonious occupancy model was applied to two earlier datasets from the study area, and provided indirect evidence for an inferred decline in Ground Parrot occupancy in recent decades. Landscape modelling of the expected total area occupied by Ground Parrots between 1979 and 2013 suggested a strong peak would have occurred in the late 1990s; suitability of habitat over much of the landscape is now declining. Finally, given that many Australian fauna species are responsive to fire, this study shows that assumptions behind the management of such species can be tested efficiently by combining legacy datasets and literature with contemporary data collection and modelling methods.