The influences of prey, predators and habitat variables on drought-affected forest preference in a Darling Range endemic skink

Smithies, Sean (2016) The influences of prey, predators and habitat variables on drought-affected forest preference in a Darling Range endemic skink. Honours thesis, Murdoch University.

Abstract

Large-scale canopy collapse occurred within the northern jarrah (Eucalyptus marginata) forest of southwest WA following a record hot and dry year/summer in 2010/11. The forest die-off had noted effects on the reptile communities. The endemic lizard Ctenotus delli (Scincidae) was recorded more frequently within drought-affected sites compared with adjacent apparently healthy intact regions. The present study investigated possible drivers for this apparent preference, quantifying: 1) leaf litter invertebrate assemblages and termite activity (prey influence); 2) predatory bird assemblages (predator influence); and 3) the effect of black and white disruptive markings on concealment of skinks in leaf litter (primary antipredatory response) between drought-affected and healthy sites. Leaf litter invertebrate assemblages did not differ across drought-affected and healthy sites, however, predatory bird assemblages varied significantly between drought-affected and healthy sites (P = 0.009) with greater numbers of predatory birds observed within healthy sites. Plasticine models of three variations (side-striped, back-striped, and plain) placed among various leaf litter densities revealed that side-striped models were attacked less severely (P =0.039) than back-striped models, although there were no differences in the total numbers of attacks recorded. Therefore, side-stripes (as found on C. delli) did not minimise detection but may increase survivorship. Further implementation of invertebrate trapping coupled with behavioural studies in avian predators across drought-affected and healthy sites may conclusively determine the selective pressures behind drought-affected site preferences of C. delli.

Item Type:	Thesis (Honours)
Murdoch Affiliation(s):	School of Veterinary and Life Sciences
Supervisor(s):	Fleming, Trish, Bateman, Bill, Hardy, Giles and Dundas, Shannon
URI:	http://researchrepository.murdoch.edu.au/id/eprint/34323

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