Buckmaster A.J.,University of Canberra |
Osborne W.S.,University of Canberra |
Pacific Conservation Biology
Urban development can alter species composition and diversity within an area through biotic homogenization, the introduction of exotic species, and localized extinctions of native species. In this study we examined the composition and diversity of small terrestrial mammals within nature reserves surrounded by urban landscapes and compared this with previous surveys of these reserves and nearby non-urban reserves with similar vegetative and geomorphological characteristics. A combination of live trapping and indirect detection techniques was employed in eight reserves in the Australian Capital Territory and surrounding New South Wales to determine current species composition. Compared with previous studies and the non-urban reserves, the urban reserves appear to have lost two-thirds of their native terrestrial small mammal species in the past 26 years. Exotic species were present in all urban reserves, but were only associated with areas characterized by human-induced disturbance in non-urban reserves. Possible causes of this disparity in native species diversity between urban and non-urban reserves are discussed. Source
Austin J.J.,University of Adelaide |
Olivier L.,University of Adelaide |
Nankervis D.,University of Tasmania |
Brown W.E.,Parks |
And 3 more authors.
Australian Journal of Zoology
Twenty di- to pentanucleotide microsatellites are reported for the wedge-tailed eagle (Aquila audax), a large raptor from Australia, Tasmania, and New Guinea. These loci were tested for variation among 49 individuals. All loci are polymorphic with 2-14 alleles per locus, and observed heterozygosities ranged between 0.021 and 0.898. Genotype frequencies for all loci did not differ significantly from Hardy-Weinberg equilibrium and there was no evidence of linkage disequilibrium. These markers will be used to assess population structure and conservation genetics of this species, focusing on population differentiation and gene flow between Tasmanian and mainland populations and conservation genetics of the endangered Tasmanian population. © CSIRO 2014. Source
Ramsey D.S.L.,Arthur Rylah Institute for Environmental Research |
Ramsey D.S.L.,University of Adelaide |
Macdonald A.J.,University of Canberra |
Quasim S.,University of Canberra |
And 2 more authors.
Journal of Applied Ecology
Polymerase chain reaction (PCR) diagnostic tests are increasingly applied to the identification of wildlife. Yet rigorous verification is rare and the estimation of test accuracy (the probability that true positive and true negative samples are correctly identified - test sensitivity and specificity, respectively), particularly in combination with sequencing, is uncommon. This is important because PCR-based tests are prone to contamination in sampling and the laboratory. Here, we use an experimental case-control approach to estimate the sensitivity and specificity of a sequential PCR-based wildlife detection test used to identify incursions of red foxes into Tasmania from predator faeces (scats). Our results show that the sensitivity of the fox test is high (∼94%) for the PCR-based test on its own, but this decreases to ∼84% when combined with the DNA sequencing step. In contrast, the specificity increases from ∼96% in the PCR-only test to 99·6% after inclusion of the DNA sequencing step. The intense public scrutiny of the fox eradication programme in Tasmania has undoubtedly influenced the application of a sequential PCR test that maximizes specificity at the expense of sensitivity and so increases the risk that scats containing fox DNA would not be detected. This could lead to the establishment of foxes in Tasmania as a consequence. Synthesis and applications. Importantly, the estimation of the sensitivity and specificity of sequential tests enables decisions about the risk associated with mistaken identification (i.e. false negatives vs. false positives) to be quantified for decision-makers. The cost of false-negative errors should be balanced against the costs of false-positive errors, which could include the expenditure incurred in the application of unnecessary management actions were foxes not in fact present. Understanding the risks and costs associated with both false-negative and false-positive errors is therefore a key component to the decision-making process for the management of the Tasmanian fox incursion. © 2015 British Ecological Society. Source
Burridge C.P.,University of Tasmania |
Brown W.E.,Parks |
Wadley J.,University of Adelaide |
Nankervis D.L.,University of Tasmania |
And 6 more authors.
Proceedings of the Royal Society B: Biological Sciences
Populations on continental islands are often distinguishable from mainland conspecifics with respect to body size, appearance, behaviour or life history, and this is often congruent with genetic patterns. It is commonly assumed that such differences developed following the complete isolation of populations by sea-level rise following the Last Glacial Maximum (LGM). However, population divergence may predate the LGM, or marine dispersal and colonization of islands may have occurred more recently; in both cases, populations may have also diverged despite ongoing gene flow. Here, we test these alternative hypotheses for the divergence between wedge-tailed eagles from mainland Australia (Aquila audax audax) and the threatened Tasmanian subspecies (Aquila audax fleayi), based on variation at 20 microsatellite loci and mtDNA. Coalescent analyses indicate that population divergence appreciably postdates the severance of terrestrial habitat continuity and occurred without any subsequent gene flow. We infer a recent colonization of Tasmania by marine dispersal and cannot discount founder effects as the cause of differences in body size and life history. We call into question the general assumption of post-LGM marine transgression as the initiator of divergence of terrestrial lineages on continental islands and adjacent mainland, and highlight the range of alternative scenarios that should be considered. © 2013 The Author(s) Published by the Royal Society. All rights reserved. Source
Swan King Editions Llc and Parks | Date: 2005-04-28
Books featuring artwork.