Conservation status of mammals and birds in southwestern Australian forests. I. Is there evidence of direct links between forestry practices and species decline and extinction?

Abstract

Sixteen mammal species and 22 bird species whose distributions extended into southwestern Australian forests before European settlement have been listed as threatened at some time in Commonwealth legislation, State legislation, or action plans of Environment Australia or its predecessors. Confident assessment of the causes of conservation status is hampered by poor base-line data, few studies of putative impacts and a preponderance of circumstantial or anecdotal rather than experimental evidence. However, introduced foxes were Implicated In the current conservation status of 62% of the mammal species recognized, while 44% of them were negatively impacted by feral cats, 44% by agricultural clearing and 44% by changed fire regimes. Forestry practices were impllcated in the conservation status of only one mammal species. For the bird species recognized, changed fire regimes had the greatest negative impact (45% affected), agricultural clearing affected 41%, draining of wetlands affected 32% and grazing by livestock affected 22%. Forestry practices were not directly implicated in the conservation status of any bird species. While these results suggest that forestry has had minimal direct impact on the mammals and birds of the forests, the conclusion should be treated cautiously because of the poor data. While awaiting a rigorous evaluation, we argue for a strong precautionary approach to forestry in the region. With proper forest management and sound sylvicultural [sic] treatment there is no reason why there should not be built up on the wreckage of the once splendid forests of Western Australia tended forests which will yield for all time 100 cubic feet of timber per acre per year. Lane-Poole (1920). There are many reasons why Australian environmentalists would like to end logging in native forests. The preservation of wilderness, aesthetics, an almost religious identification with old growth forests and the conservation of forest wildlife figure importantly in environmental efforts to restrict logging. Wilderness and a personal identification with trees and undisturbed forests are fundamentally incompatible with logging. Recher (1996).

Regulation of domestic cat ownership to protect urban wildlife: a justification based on the precautionary principle

“…evidence suggests that they may suppress prey populations (see Dickman 1996;Dell 1998 andRisbey 2000 for full reviews). However, numerous authors have argued that demonstrating that feral cats prey on native species is not proof of an impact on prey populations and that experimental evidence from manipulation of predator densities is required (Bomford et al 1995;Dickman 1996;Risbey et al 1999).…”

The impact of cats and foxes on the small vertebrate fauna of Heirisson Prong, Western Australia. II. A field experiment

“…With no similar evidence for cats (Felis catus), the case against cats is more contentious. Claims regarding the impact of feral cats have been based on anecdotal (Finlayson 1961;Spencer 1990;Horsup and Evans 1993;Smith et al 1994) and historical evidence (Dickman et al 1993;Smith and Quin 1996;Calver and Dell 1998;Short 1999). As a consequence, experimental studies have been recommended to determine the response of prey species to the removal of cats (Dickman 1996a(Dickman , 1996b.…”