Slow and unsteady: growth of the Australian eastern long-necked turtle near the southern end of its natural range

Abstract. Knowledge of growth rates and maturation times of freshwater turtles is important in assessing population viability. I analysed growth of Australian eastern long-necked turtles (Chelodina longicollis) from individual capture–recapture records spanning periods of up to 17 years for a population in Gippsland, Victoria, close to the high-latitude end of the species’ natural range. Juvenile growth was rapid and similar among individuals but adult growth was usually slow, highly variable among individuals and erratic within individuals over time. In addition, asymptotic body lengths were disparate among individuals for both males and females. Von Bertalanffy growth models fitted separately to males plus unsexed juveniles and females plus unsexed juveniles performed better than logistic models but tended to underestimate growth rates for very small and very large turtles and overestimate growth for medium-sized individuals. Sexual maturity was estimated to be achieved at 10 years in males and 16 years in females, which is late compared with most estimates for other populations of C. longicollis and for other turtle species in south-eastern Australia. The high variability of individual growth in this population makes age estimation from body size unreliable beyond the first few years of life.

[1]  D. Stokeld,et al.  Terrestrial habitat and individual fitness increase survival of a freshwater turtle in an urban landscape , 2018, Urban Ecosystems.

[2]  R. Spencer,et al.  Critically evaluating best management practices for preventing freshwater turtle extinctions , 2017, Conservation biology : the journal of the Society for Conservation Biology.

[3]  B. Chessman Freshwater turtle hatchlings that stay in the nest: strategists or prisoners? , 2017, Australian Journal of Zoology.

[4]  A. Georges,et al.  Responses of an Australian freshwater turtle to drought‐flood cycles along a natural to urban gradient , 2017 .

[5]  H. Welsh,et al.  Changes across a Decade in Size, Growth, and Body Condition of Western Pond Turtle (Actinemys marmorata) Populations on Free-flowing and Regulated Forks of the Trinity River in Northwest California , 2015, Copeia.

[6]  R. Kendrick,et al.  Growth Rate and an Evaluation of Age Estimation for the Endangered Big-Headed Turtle (Platysternon megacephalum) in China , 2015 .

[7]  R. van der Ree,et al.  Factors influencing occurrence of a freshwater turtle in an urban landscape: a resilient species? , 2014, Wildlife Research.

[8]  A. Rhodin,et al.  Turtles of the World, 7th Edition: Annotated Checklist of Taxonomy, Synonymy, Distribution with Maps, and Conservation Status. , 2014 .

[9]  M. Ryan Human impacts on the long-necked turtle Chelodina longicollis (Shaw 1794) in peri-urban Sydney , 2014 .

[10]  R. Brooks,et al.  Application of hierarchical biphasic growth models to long-term data for snapping turtles , 2013 .

[11]  J. Gibbons,et al.  Indeterminate growth in long-lived freshwater turtles as a component of individual fitness , 2012, Evolutionary Ecology.

[12]  A. Georges,et al.  Suburbs: Dangers or Drought Refugia for Freshwater Turtle Populations? , 2011 .

[13]  B. Chessman Declines of freshwater turtles associated with climatic drying in Australia’s Murray–Darling Basin , 2011 .

[14]  A. Georges,et al.  Chelodina longicollis (Shaw 1794) – Eastern Long-Necked Turtle, Common Long-Necked Turtle, Common Snake-Necked Turtle , 2009 .

[15]  A. Georges,et al.  Terrestrial activity, movements and spatial ecology of an Australian freshwater turtle, Chelodina longicollis, in a temporally dynamic wetland system , 2008 .

[16]  A. Georges,et al.  Maintenance of variable responses for coping with wetland drying in freshwater turtles. , 2008, Ecology.

[17]  A. Rhodin,et al.  Turtles of the World: Annotated Checklist of Taxonomy and Synonymy , 2008 .

[18]  R. Spencer,et al.  Experimental Analysis of the Impact of Foxes on Freshwater Turtle Populations , 2005 .

[19]  R. Spencer Growth patterns of two widely distributed freshwater turtles and a comparison of common methods used to estimate age , 2002 .

[20]  K. Lue,et al.  Growth Patterns of the Yellow-Margined Box Turtle (Cuora flavomarginata) in Northern Taiwan , 2002 .

[21]  D. Judge THE ECOLOGY OF THE POLYTYPIC FRESHWATER TURTLE SPECIES, Emydura macquarii macquarii. , 2001 .

[22]  J. L. Gittleman,et al.  Predicting extinction risk in declining species , 2000, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[23]  J. Litzgus,et al.  Growth in a cold environment: body size and sexual maturity in a northern population of spotted turtles, Clemmys guttata , 1998 .

[24]  A. Dalem Demography and movement patterns of a population of eastern snake-necked turtles, Chelodina longicollis (Shaw, 1794) , 1998 .

[25]  J. Arendt,et al.  Adaptive Intrinsic Growth Rates: An Integration Across Taxa , 1997, The Quarterly Review of Biology.

[26]  P. Hartfield,et al.  Population Size and Growth in the Turtle Graptemys oculifera , 1995 .

[27]  R. Shine,et al.  Patterns of survival, growth and maturation in turtles , 1995 .

[28]  J. L. Greene,et al.  Temporal variation in growth and age at maturity of male painted turtles, Chrysemys picta , 1993 .

[29]  Gregory P. Brown,et al.  Body size, age distribution, and reproduction in a northern population of wood turtles (Clemmys insculpta) , 1992 .

[30]  A. Georges,et al.  Habitat utilization and its relationship to growth and reproduction of the eastern long-necked turtle, Chelodina longicollis (Testudinata: Chelidae), from Australia , 1990 .

[31]  M. Obbard,et al.  The Influence of Growth Rate on Age and Body Size at Maturity in Female Snapping Turtles (Chelydra serpentina) , 1989 .

[32]  B. Chessman Habitat Preferences of Fresh-Water Turtles in the Murray Valley, Victoria and New-South-Wales , 1988 .

[33]  P. Stott USE OF GROWTH RINGS TO DETERMINE AGE IN THE FRESHWATER TORTOISE CHELODINA-LONGICOLLIS A CAUTIONARY NOTE , 1988 .

[34]  B. Chessman Evaporative Water Loss from Three South-Eastern Australian Species of Freshwater Turtle , 1984 .

[35]  G. M. Thornhill Comparative Reproduction of the Turtle, Chrysemys scripta elegans, in Heated and Natural Lakes , 1982 .

[36]  T. Schoener,et al.  Estimating and Interpreting Body-size Growth in Some Anolis Lizards , 1978 .

[37]  H. Wilbur A Growth Model for the Turtle Chrysemys picta , 1975 .

[38]  J. Gibbons REPRODUCTIVE DYNAMICS OF A TURTLE (PSEUDEMYS SCRIPTA) POPULATION IN A RESERVOIR RECEIVING HEATED EFFLUENT FROM A NUCLEAR REACTOR. , 1970 .

[39]  Fabens Aj,et al.  Properties and fitting of the Von Bertalanffy growth curve. , 1965 .

[40]  A. J. Fabens,et al.  Properties and fitting of the Von Bertalanffy growth curve. , 1965, Growth.

[41]  D. Tinkle Geographic Variation in Reproduction, Size, Sex Ratio and Maturity of Sternothaerus Odoratus (Testudinata: Chelydridae) , 1961 .

[42]  J. M. Legler A simple and inexpensive device for trapping aquatic turtles , 1960 .

[43]  M. David,et al.  Long-term Ecological Studies on a Population of Painted Turtles , Chrysemys picta , on Long Island , New York , 2022 .