AbstractsBiology & Animal Science

Edge effects on small skinks : their prey, predators and competitors in peri-urban remnants in north-western Sydney

by Lynette P. Anderson

Institution: University of Western Sydney
Degree: PhD
Year: 0
Keywords: skinks; New South Wales; effect of habitat modification on; lizards; predation
Record ID: 1053763
Full text PDF: http://handle.uws.edu.au:8081/1959.7/11785


This study focused on the interactions between small skinks and their major predators/competitors (birds) and prey (arthropods) in core and edge areas of small, long established remnant Cumberland Plain woodlands of Richmond, New South Wales, Australia. Eight study sites were selected (4 edge and 4 core) within the peri-urban environment to compare the abundance and diversity of small skinks, birds and arthropods. Of the three taxa, only arthropods maintained a similar abundance and diversity between edge and core areas. Birds and skinks were either in lower numbers in the perimeter areas (skinks), or were interior/perimeter specialists (birds). Arthropod diversity and abundance of preferred skink prey, was also examined. It was concluded that the distribution of arthropod prey was similar between core and edge areas, and therefore, was not considered to have an influence on small skinks’ ability to inhabit edges. However, large, aggressive/noisy birds (including skink and small bird predators) dominated edge areas. Those birds encountered in the edge foraged in a variety of niches, such as on the ground or they swooped from vantage points. This, coupled with other anti competitor behaviour (e.g. noise, aggression, flocking), placed these birds in proximity to skinks in the edge areas. However, as most of these birds were also predators of skinks, it was concluded that the evidence supported a predator/prey relationship in the perimeter area, rather than a competitive one. This was supported by predation rates on skinks, using decoys. Birds preyed on small skink in greater numbers in the perimeter of woodland remnants than in their interior. This predation pressure was sustained throughout the year. It was concluded that predation and/or displacement of skinks and small birds resulted in lower numbers being observed in edge compared to core areas. This study demonstrated that old, small remnants not continually exposed to major disturbances (e.g. logging, agricultural practices) can re-establish stability in terms of environmental conditions. However, a stable environment or a single taxonomic group does not necessarily predict the response individual taxa will have to edge habitats and that this can alter the interactions between dependent groups such as prey/predator or competitors. . Doctor of Philosophy (PhD)