overwintering in hatchling turtles: some they do, and … · 2014. 8. 26. · gibbons and nelson...

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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