Distribution, abundance and population structure of the threatened western saw-shelled turtle, Myuchelys bellii, in New South Wales, Australia
Bruce C. ChessmanCentre for Ecosystem Science, University of New South Wales, Sydney, NSW 2052, Australia, and Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia. Email: b.chessman@unsw.edu.au
Australian Journal of Zoology 63(4) 245-252 https://doi.org/10.1071/ZO15034
Submitted: 14 June 2015 Accepted: 31 August 2015 Published: 23 September 2015
Abstract
The western saw-shelled turtle is listed as threatened globally, nationally, and within the Australian state of New South Wales. Although nearly all of the geographic range of the species lies within New South Wales, little information has been available on the distribution, abundance and structure of New South Wales populations. Through a survey of 60 sites in 2012–15, I established that M. bellii is much more widely distributed in New South Wales than has previously been recognised, comprising four disjunct populations, including two in the New South Wales portion of the Border Rivers basin. It occurs mainly in larger, cooler rivers upstream of barriers to dispersal of the Macquarie turtle, Emydura macquarii macquarii. Although M. bellii is locally abundant, its populations are greatly dominated by large adults and recruitment appears to be low. Eye abnormalities are common in some populations but do not necessarily impair body condition or preclude long-term survival. The species is threatened by competition with E. macquarii, which appears to be expanding its range through translocation by humans, and possibly by predation, disease and drought. Long-term monitoring of M. bellii is needed to assess population trends and responses to threats, and active management to restrict the further spread of E. macquarii is probably required to ensure the persistence of M. bellii throughout its current range.
References
Buffington, J. M., Lisle, T. E., Woodsmith, R. D., and Hilton, S. (2002). Controls on the size and occurrence of pools in coarse-grained forest rivers. River Research and Applications 18, 507–531.| Controls on the size and occurrence of pools in coarse-grained forest rivers.Crossref | GoogleScholarGoogle Scholar |
Buhlmann, K. A., Akre, T. S. B., Iverson, J. B., Karapatakis, D., Mittermeier, R. A., Georges, A., Rhodin, A. G. J., van Dijk, P. P., and Gibbons, J. W. (2009). A global analysis of tortoise and freshwater turtle distributions with identification of priority conservation areas. Chelonian Conservation and Biology 8, 116–149.
| A global analysis of tortoise and freshwater turtle distributions with identification of priority conservation areas.Crossref | GoogleScholarGoogle Scholar |
Chessman, B. C. (1978). Ecological studies of freshwater turtles in south-eastern Australia. Ph.D. Thesis, Monash University, Melbourne.
Cogger, H. (2014). ‘Reptiles and Amphibians of Australia.’ (CSIRO Publishing: Melbourne.)
Fielder, D. P. (2012). Seasonal and diel dive performance and behavioral ecology of the bimodally respiring freshwater turtle Myuchelys bellii of eastern Australia. Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology 198, 129–143.
| Seasonal and diel dive performance and behavioral ecology of the bimodally respiring freshwater turtle Myuchelys bellii of eastern Australia.Crossref | GoogleScholarGoogle Scholar | 22045114PubMed |
Fielder, D., Vernes, K., Alacs, E., and Georges, A. (2012). Mitochondrial gene variation among Australian freshwater turtles (genus Myuchelys), with special reference to the endangered M. bellii. Endangered Species Research 17, 63–71.
| Mitochondrial gene variation among Australian freshwater turtles (genus Myuchelys), with special reference to the endangered M. bellii.Crossref | GoogleScholarGoogle Scholar |
Fielder, D. P., Limpus, D. J., and Limpus, C. J. (2014). Reproduction and population ecology of the vulnerable western sawshelled turtle, Myuchelys bellii, in the Murray–Darling Basin, Australia. Australian Journal of Zoology 62, 463–476.
| Reproduction and population ecology of the vulnerable western sawshelled turtle, Myuchelys bellii, in the Murray–Darling Basin, Australia.Crossref | GoogleScholarGoogle Scholar |
Georges, A., and Thomson, S. (2010). Diversity of Australasian freshwater turtles, with an annotated synonymy and keys to species. Zootaxa 2496, 1–37.
Hubert, W. A., and Kozel, S. J. (1993). Quantitiative relations of physical habitat features to channel slope and discharge in unaltered mountain streams. Journal of Freshwater Ecology 8, 177–183.
| Quantitiative relations of physical habitat features to channel slope and discharge in unaltered mountain streams.Crossref | GoogleScholarGoogle Scholar |
Ihlow, F., Dambach, J., Engler, J. O., Flecks, M., Hartmann, T., Nekum, S., Rajaei, H., and Rödder, D. (2012). On the brink of extinction? How climate change may affect global chelonian species richness and distribution. Global Change Biology 18, 1520–1530.
| On the brink of extinction? How climate change may affect global chelonian species richness and distribution.Crossref | GoogleScholarGoogle Scholar |
IUCN (2012). ‘IUCN Red List Categories and Criteria. Version 3.1.’ 2nd edn. (International Union for Conservation of Nature: Gland, Switzerland.)
Judge, D. (2001). The ecology of the polytypic freshwater turtle species, Emydura macquarii macquarii. M.Appl.Sc. Thesis, University of Canberra.
Klemens, M. W. (2000). ‘Turtle Conservation.’ (Smithsonian Institution Press: Washington, DC.)
Ream, C., and Ream, R. (1966). The influence of sampling methods on the estimation of population structure in painted turtles. American Midland Naturalist 75, 325–338.
| The influence of sampling methods on the estimation of population structure in painted turtles.Crossref | GoogleScholarGoogle Scholar |
Spencer, R.-J. (2002). Growth patterns of two widely distributed freshwater turtles and a comparison of common methods used to estimate age. Australian Journal of Zoology 50, 477–490.
| Growth patterns of two widely distributed freshwater turtles and a comparison of common methods used to estimate age.Crossref | GoogleScholarGoogle Scholar |
Spencer, R.-J., Georges, A., Lim, D., Welsh, M., and Reid, A. M. (2014). The risk of inter-specific competition in Australian short-necked turtles. Ecological Research 29, 767–777.
| The risk of inter-specific competition in Australian short-necked turtles.Crossref | GoogleScholarGoogle Scholar |
Stein, J. L., Hutchinson, M. F., and Stein, J. A. (2014). A new stream and nested catchment framework for Australia. Hydrology and Earth System Sciences 18, 1917–1933.
| A new stream and nested catchment framework for Australia.Crossref | GoogleScholarGoogle Scholar |
Thompson, M. B. (1983). The physiology and ecology of the eggs of the pleurodiran tortoise Emydura macquarii (Gray), 1831. Ph.D. Thesis, University of Adelaide.
Turtle Conservation Fund (2002). ‘A Global Action Plan for Conservation of Tortoises and Freshwater Turtles. Strategy and Funding Prospectus 2002–2007.’ (Conservation International and Chelonian Research Foundation: Washington, DC.)
van Dijk, P. P., Iverson, J. B., Rhodin, A. G. J., Shaffer, H. B., and Bour, R. (2014). Turtles of the world,: annotated checklist of taxonomy, synonymy, distribution with maps, and conservation status. 7th edn. Chelonian Research Monographs 5, 329–479.
Wanders, N., and Wada, Y. (2015). Human and climate impacts on the 21st century hydrological drought. Journal of Hydrology 526, 208–220.
| Human and climate impacts on the 21st century hydrological drought.Crossref | GoogleScholarGoogle Scholar |
Webb, B. W., Clack, P. D., and Walling, D. E. (2003). Water–air temperature relationships in a Devon river system and the role of flow. Hydrological Processes 17, 3069–3084.
| Water–air temperature relationships in a Devon river system and the role of flow.Crossref | GoogleScholarGoogle Scholar |
Zhao, T., and Dai, A. (2015). The magnitude and causes of global drought changes in the twenty-first century under a low–moderate emissions scenario. Journal of Climate 28, 4490–4512.
| The magnitude and causes of global drought changes in the twenty-first century under a low–moderate emissions scenario.Crossref | GoogleScholarGoogle Scholar |
