Habitat utilisation by small mammals in a coastal heathland exhibiting symptoms of Phytophthora cinnamomi infestation

摘要

Phytophthora cinnamomi is a soil-inhabiting ‘water mould’nfrom the Class Oomycete that is pathogenic to many nativenplant species in Australia (Environment Australia 2002). Itnmainly affects woody perennial species, the most susceptiblenfamilies being Proteaceae, Fabaceae, Dillenaceae and Epa-ncridaceae (Weste and Marks 1987; Podger and Brown 1989;nWills 1993; Weste 1994; Shearer and Dillon 1995), whilenmany herbaceous perennials, annuals and geophytes survivenor are resistant to infection. P. cinnamomi has been shown tonalter plant species abundance and richness, as well as thenstructure of vegetation in sclerophyllous vegetation through-nout Australia (Weste 1974, 1980; Podger and Brown 1989;nWills 1993; Shearer and Dillon 1996; McDougall et al. 2002;nWeste et al. 2002). The pathogen has been identified as an‘key threatening process’ in the Australian environmentn(Environment Australia 2002). The threatening process is thenlethal epidemic of ‘Phytophthora dieback’ that occurs whenna combination of plant species susceptibility, presence of thenfungal pathogen and vulnerability due to favourable environ-nments leads to a major disruption of plant community struc-nture, the extinction of populations of some flora species andna reduction in primary productivity within affected eco-nsystems. If these changes in vegetation alter important com-nponents of faunal habitat, consequential effects on endemicnfauna such as change in abundance and species richnessnwould be expected. The decrease in species richness, loss ofnplant species and litter fall associated with dieback diseasenhave been predicted to impact on fauna through direct andnindirect loss of food resources, and the loss of protectivencover, shelter or nest sites (Wilson et al. 1994; Laidlawn1997). Conversely, increases in resistant plant species maynprovide increased food resources for specialist herbivoresnsuch as the swamp rat (Rattus lutreolus) (Wilson et al. 1994).