Coffs Harbour, Australia
Coffs Harbour, Australia

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Brazill-Boast J.,Macquarie University | Brazill-Boast J.,Ecosystems and Threatened Species Unit | Griffith S.C.,Macquarie University | Pryke S.R.,Macquarie University | Pryke S.R.,Australian National University
Evolutionary Ecology | Year: 2013

Understanding genetic colour polymorphism has proved a major challenge, both in terms of the underlying genetic mechanisms and the evolutionarily forces maintaining such genetic variation. In this context, genetic differences in aggression or competitive-related traits may covary with the expression of alternative phenotypes, and affect the evolutionary stability and maintenance of colour polymorphisms. Genetic red and black head-colour morphs of the Gouldian finch (Erythrura gouldiae) co-occur in temporally and geographically stable frequencies in sympatric populations. Gouldian finches are obligate cavity-nesters with highly specific preferences for nest-site morphometry that directly affect reproductive success. Because intra- and interspecific competition for high quality nest-sites is prevalent, and fitness is directly related to nest-site quality, we investigated the relative access (and consequences for reproductive success) of alternative morphs to this critical limiting resource in the wild. Red males defended higher quality nest-sites, and overcame greater levels of nest-site competition against conspecifics and superior heterospecific competitors than black males. Red-headed males also produced more fledglings (especially with red-headed females) than black-headed males, independent of nest-site quality. Finally, the independent (positive) effect of nest-site quality on reproductive success was confirmed. Such competitive asymmetries are important to relative selection among coexisting morphs, and are likely to contribute to the maintenance of alternative sympatric colour-morphs in wild populations. © 2013 Springer Science+Business Media Dordrecht.

Andren M.,Ecosystems and Threatened Species Unit | Cameron M.A.,Ecosystems and Threatened Species Unit
Australian Zoologist | Year: 2014

The Black Grass-dart Butterfly Ocybadistes knightorum has a highly restricted distribution along the New South Wales north coast and is listed as an Endangered species in the State. Recent surveys have dramatically increased the known distribution of the species, warranting a reassessment of its conservation status. Fine-scale mapping of the entire known habitat of the species enabled a detailed assessment to be conducted that was commensurate with the small size of the butterfly and the fine-grained environmental data available. We evaluate the status of O. knightorum against IUCN Criteria B (Geographic Range).The butterfly was found to have an extent of occurrence of 312 km2 and an area of occupancy of 76 km2, at three locations. A detailed digital elevation model was used to demonstrate the likelihood of continued decline due largely to sea-level rise induced by climate change. An estimated 85% of the current habitat of O. knightorum will become unsuitably saline by 2100 according to the best currently available sea-level rise prediction. Weed invasion and anthropogenic disturbance are also serious threats, contributing to continued decline in some areas. Adopting a precautionary approach, we assess the species as Endangered under IUCN criteria.

Andren M.,Ecosystems and Threatened Species Unit | Milledge D.,Landmark Ecological Services | Scotts D.,Wildlife Matters | Smith J.,Ecosystems and Threatened Species Unit
Australian Zoologist | Year: 2013

The Long-nosed Potoroo Potorous tridactylus tridactylus has declined substantially on the far north coast of New South Wales. In this study, the known and potential habitat of the Long-nosed Potoroo on the coastal sandplain in the region is mapped in detail for the first time. A total of 3,613 ha of potential habitat is distributed in 10 areas from 24 ha to 1,423 ha in size. Heathy Scribbly Gum Eucalyptus signata woodland was considered to be particularly significant habitat in the region. While there is evidence that eight of the areas mapped once supported potoroos, their presence has only been confirmed in four of them since 2000.Targeted survey at known sites where the Long-nosed Potoroo has not been recently confirmed is urgently required, as well as a thorough reassessment of its conservation status in the region. Ecological research into threats and food preferences, and implementation of targeted conservation management actions is also needed.

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