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Abstract:From observations conducted in a suburban property in Perth, Western Australia, over 22 years, it appears that a single pet cat may have exterminated a population (est. 40-50 animals) of the lizard Ctenotus fallens over two years, but with the greatest impact in just the first few months. C. fallens did not begin to recolonise the site until six years after the cat had moved away. The observations support the hypothesis that extinctions of wildlife in suburbia following the introduction of cats can be swift. They also suggest that C. fallens is a suitable species for reintroduction experiments into suburban Perth, comparing the success of reintroductions at sites where cats are confined with those where cats roam freely.

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Patchy resource distribution can cluster predator activity around areas of the highest productivity in ecosystems. For the endangered Western Spiny-tailed Skink (Egernia stokesii badia) in Western Australia, the log piles that they permanently inhabit in an otherwise patchy, arid landscape, represent a potentially reliable, high abundance food source for predators. Not only are encounter rates by potential predators of E. s. badia likely to be influenced by vegetation structure at the microhabitat scale but also E. s. badia occurs in a region where mine sites and associated infrastructure, such as landfill sites, likely concentrate generalist predators (e.g. Feral Cats and corvids). We assessed the influence of the presence of coarse woody debris (CWD) and distance to the landfill on predator behaviour towards E. s. badia through plasticine model experiments, unbounded point count bird surveys and camera trapping. We found that CWD inhabited by E. s. badia attracted a greater relative activity of corvids compared with uninhabited CWD, or control sites without CWD. The relative activity of corvids and predatory birds combined increased with decreasing distance from the landfill. Preferential hunting by corvids at CWD inhabited by E. s. badia compared to both uninhabited CWD and open sites suggests that inhabited CWD may be targeted by generalist predators in the region, and that adaptive management may be required for species conservation around active mining areas.

A central principle of threatened species management is the requirement for detailed understanding of species habitat requirements. Difficult terrain or cryptic behaviour can, however, make the study of habitat or microhabitat requirements difficult, calling for innovative data collection techniques. We used high-resolution terrestrial LiDAR imaging to develop three-dimensional models of log piles, quantifying the structural characteristics linked with occupancy of an endangered cryptic reptile, the western spiny-tailed skink (Egernia stokesii badia). Inhabited log piles were generally taller with smaller entrance hollows and a wider main log, had more high-hanging branches, fewer low-hanging branches, more mid- and understorey cover, and lower maximum canopy height. Significant characteristics linked with occupancy were longer log piles, an average of three logs, less canopy cover, and the presence of overhanging vegetation, likely relating to colony segregation, thermoregulatory requirements, and foraging opportunities. In addition to optimising translocation site selection, understanding microhabitat specificity of E. s. badia will help inform a range of management objectives, such as targeted monitoring and invasive predator control. There are also diverse opportunities for the application of this technology to a wide variety of future ecological studies and wildlife management initiatives pertaining to a range of cryptic, understudied taxa.