| Abstrakt: |
This paper, an integration of history, ecology and zoogeography, is based on a comprehensive search for firsthand (eyewitness) information from navigators' and explorers' journals (1658-1875), colonists' accounts (1829-1889) and later settlers' records and oldtimers' recollections (1890-2006). Pertinent data for 37 conspicuous vertebrate species (10 bird, 26 mammal and 1 snake species) were collated, analysed, and integrated with more recent scientific information. Much of the information discovered in colonial records and obtained from interviews with oldtimers has been neglected by zoologists and ecologists. The original distributional limits of many of the species studied were thus clarified and redetermined. Detailed information is also provided on the history of the introduction of 14 mammal species into south-west WA, in order to assess their potential contribution to the extinction of native vertebrate species. The introduction, spread and density in bushland of commercial and livestock species does not correlate with the chronology of declines of native species. Changes in geographical distribution of species were assessed against an interpretive framework of 29 factors, and based on this analysis, a conceptual model (termed the 'fusion' model) of mammal declines and extinctions in south-west and adjacent parts of WA since European settlement is proposed. The reconstructed sequence of events commenced in the 1880s, with declines being caused by disease (10 species estimated to have become totally extinct in WA and 8 species abruptly reduced in abundance and distribution). Another 12 species subsequently reached near-extinction status, following establishment of the fox in the 1920s. Trapping of some species for their fur and accidental poisoning by rabbit baits contributed to local extinctions but were not finally decisive factors. The conceptual framework adopted, based on detailed examination of the information discovered, recognizes three tiers of relevant factors. Only one or two main factors operate at one time, with some of the remaining factors acting in a subsidiary way, and sometimes concurrently or sequentially. Dominant factors are not necessarily the same for each species. Factors usually affected species adversely. South-west WA, despite being settled by Europeans earlier than most other parts of Australia, experienced a stagnant economy, slow population growth and hence minimal clearance of the original vegetation until the 1890s. The anthropogenic factors identified as significant in the decline and depletion of the native fauna, together with an understanding of their correct sequence of operation, provide a historically appropriate conceptual model that may be applicable elsewhere in Australia. The baseline data and historical accounts provide a resource for specialists working on particular species, and include much new material relating to the pelt industry and pest control activities. 'what's past is prologue' (Shakespeare 1623, The Tempest, Act 2 Scene 1) 'The past is never dead. It's not even past' (Faulkner 1953) 'The pastness of the present and the presence of the past' (Taruskin 1988). [ABSTRACT FROM AUTHOR] |
