overwintering in hatchling turtles: some they do, and … · 2014. 8. 26. · gibbons and nelson...
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OVERWINTERING IN HATCHLING TURTLES:
SOME THEY DO, AND SOME THEY DON'T,
AND SOME YOU JUST CAN'T TELL
Turtle Stewardship and Management Workshop
Toronto Zoo
March 17March 17March 17March 17----19, 200819, 200819, 200819, 2008
“Hatchling turtles of most
temperate region species are
presumed to emerge from the nest
in the fall (Ernst and Barbour 1972).
Actual dates of hatchling
emergence, however, are well-
known for only a few species.”
from Gibbons and Nelson, 1978. Evolution.
Gibbons and Nelson 1978
Chrysemys picta – Indiana, New York, Michigan, Minnesota, Nova ScotiaGraptemys geographica – Indiana, MinnesotaTrachemys scripta – IllinoisClemmys guttata – OhioChelydra serpentina – Ontario, Nova Scotia
Delayed Emergence in Hatchling Turtles
But…
Delayed Emergence in Hatchling Turtles
Malaclemys terrapin – North CarolinaChinemys reevsii – JapanChelodina expansa – AustrailiaGopherus agassizi – CaliforniaTrachemys scripta – Pamama
Ellenton Bay, a Carolina bay on the Savannah River Site (SRS) in South Carolina, is an isolated wetland for which herpetofaunal records have been kept for 38 years.
Study Location – Ellenton Bay
• Savannah River Site, Aiken Co., SC
• 10-ha Carolina bay• Currently fishless
• Isolated
• Previous research
• Diverse assemblage of reptiles and amphibians
Methods – Drift Fence•Drift fence completely
encircling Ellenton Bay
• ~1 mi long; 40-cm high
• 242 – 19L (5 gal) pitfall traps
• Traps checked at least once daily for 10 yr.
• All turtles measured and marked
FRESHWATER TURTLE HABITATS
dry yeardry year
wet yearwet year_ _ _ _ _ _ _
TERRESTRIAL DRIFT FENCE
Hatchling Emergence in South Carolina
0%
20%
40%
60%
80%
100%
Pseudemys
floridana
(n=133)
Deirochelys
reticularia
(n=392)
Trachemys
scripta
(n=305)
Kinosternon
subrubrum
(n=867)
Sternotherus
odoratus
(n=59)
Chelydra
serpentina
(n=158)
% E
merg
ing
in
Seaso
n
Spring
Fall
Hatchling Emergence after Rain -- South Carolina
0%
20%
40%
60%
80%
100%
0 1 2 to 5 6+
Days relative to rain
% o
f d
ay
s w
ith
ca
ptu
res
Effects of Delayed Emergence
Chrysemys picta in Michigan
[data from Justin Congdon]
0%
20%
40%
60%
80%
100%
Spring Fall
% E
me
rgin
g in
Se
as
on
0%
10%
20%
30%
40%
Fall Spring
Season released
% R
ec
ap
ture
d
Natural Nests Field Experiment
n = 300 n = 200
Life History of the Chicken Turtle
(Deirochelys reticularia)
Kurt A. Buhlmann
Justin D. Congdon
J. Whitfield Gibbons
Judith L. Greene
Turtle Nesting in South Carolina
0
20
40
60
80
100
J F M A M J J A S O N D
Month
Ne
sti
ng
Fe
ma
les
D. reticularia
Other species
HATCHLINGS
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