Gone walkabout? Movement of the eastern long-necked turtle
Chelodina longicollis
from farm dams
in northwest peri-urban Sydney (Australia)
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MICHELLE RYAN and SHELLEY BURGIN*
College of Health and Science, University of Western Sydney, Locked Bag 1797,
South Penrith Distribution Centre, New South Wales, Australia
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Abstract
Many freshwater turtle species maintain site fidelity. Short term
studies (1-4 years) of the eastern long-necked turtle Chelodina
longicollis have shown that turtles moved among water bodies, but
some were later recaptured at the dam of initial capture. No long-term
studies have been undertaken to determine if site fidelity is
maintained. In this paper we re-visited farm dams, initially surveyed a
decade previously, and sampled turtles to determine the extent to which
C. longicollis maintained site fidelity. Only 11.9% (n=572) of
turtles were recaptured. We then expanded the search (from 1 km to 2 km
radius of core of original survey site) for marked individuals, and
found one marked individual among 179 additional captures. Overall <10%
of turtles netted in 2006 were captured in 1995-1996. The sex ratio of
recaptured animals after one decade did not differ significantly (1:1
sex ratio). Based on the growth of carapace length, annual growth rate
varied between 0-0.84 cm year–1. Population structure in
1995-1996 and 2006 was similar, which indicated that the change was not
due to loss of aged individuals and recruitment of young, but to an
overall turnover of individuals. We concluded that C. longicollis
turtles do not maintain site fidelity over extended periods. Although
shown to navigate accurately during fine weather, C. longicollis
turtles frequently move during inclement weather and we suggest that
they become disoriented due to a lack of environmental queues, and thus
take up residence in ‘new’ wetlands.
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