Abstract
Many endangered species worldwide are found in remnant populations, often within fragmented landscapes. However, when possible, an understanding of the natural extent of population structure and dispersal behaviour of threatened species would assist in their conservation and management. The brush-tailed rock-wallaby (Petrogale penicillata), a once abundant and widespread rock-wallaby species across southeastern Australia, has become nearly extinct across much of the southern part of its range. However, the northern part of the species’ range still sustains many small colonies closely distributed across suitable habitat, providing a rare opportunity to investigate the natural population dynamics of a listed threatened species. We used 12 microsatellite markers to investigate genetic diversity, population structure and gene flow among brush-tailed rock-wallaby colonies within and among two valley regions with continuous habitat in southeast Queensland. We documented high and significant levels of population genetic structure between rock-wallaby colonies embedded in continuous escarpment habitat and forest. We found a strong and significant pattern of isolation-by-distance among colonies indicating restricted gene flow over a small geographic scale ( <10 km) and conclude that gene flow is more likely limited by intrinsic factors rather than environmental factors. In addition, we provide evidence that genetic diversity was significantly lower in colonies located in a more isolated valley region compared to colonies located in a valley region surrounded by continuous habitat. These findings shed light on the processes that have resulted in the endangered status of rock-wallaby species in Australia and they have strong implications for the conservation and management of both the remaining ‘connected’8 brush-tailed rock-wallaby colonies in the northern parts of the species’8 range and the remnant endangered populations in the south.
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Acknowledgements
We thank all the private land owners for access to their properties and we are indebted to D. Sigg, J. Carter, K. Carter, R. Laws, N. Wynd, T. Barnes and numerous volunteers for help with trap** and field work over the course of this study. We are grateful to Queensland Parks and Wildlife Service and the Toowoomba City Council, including R. Laws, G. Maags, G. Lundi-Jenkins, P. Johnson, R. Hobson, M. Ready and N. Hyslop for in-kind support and samples. In particular, we wish to thank J. Rayner for help with fieldwork and for his local knowledge of rock-wallabies. We are indebted to the School of Integrative Biology Molecular Zoology and Gene Flow Labs for help with the molecular work, and D. Sigg, J. Nicholls, W. Telfer, P. Macqueen and two anonymous reviewers for constructive criticisms on earlier drafts of this manuscript. This study was approved by the University of Queensland Animal Ethics Committee and the Queensland Parks and Wildlife Service (Scientific Purposes Permit # W4/002560/00/SAA). This research was funded by the Australian Research Council, the National Geographic Society, the Norman Wettenhall Foundation, the University of Queensland and the Australian Commonwealth.
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Hazlitt, S.L., Goldizen, A.W. & Eldridge, M.D.B. Significant patterns of population genetic structure and limited gene flow in a threatened macropodid marsupial despite continuous habitat in southeast Queensland, Australia. Conserv Genet 7, 675–689 (2006). https://doi.org/10.1007/s10592-005-9101-x
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DOI: https://doi.org/10.1007/s10592-005-9101-x