Investigating the thermal ecology of the desert box turtle

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Investigating the thermal ecology of the desert
box turtle

• Emily Stinson
• 2008 REU Student
• Mentor Ian Murray
• August 14, 2008

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Desert Box TurtleTerrapene ornata luteola

• Distribution
  Southeastern Arizona
• 
  Central Southern New
  Mexico
• 
  West
  Texas
• 
  Northern
  Mexico
• Characteristics
• Terrestrial turtle with a HINGED shell
• Omnivorous (primarily insectivorous)
• Ectothermic ?Thermoregulate to avoid intolerable
  body temperatures (S.J. Converse J.A. Savidge
  2003)
• Low metabolic rate? Variable climates
  unpredictable resources (Penick et. al 2002 in
  Plummer 2004)
• Bimodal activity pattern (S.J. Converse J.A.
  Savidge 2003)

(Degenhardt Christiansen, 1974)
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Relevance of Study

• Novel Technique
• Contributes to current knowledge of the natural
  history of the species
• In AZ desert box turtle is protected under state
  law population is declining (NM status is
  unknown)
• Global Warming? increase in temperatures
  aridity may restrict species distribution
  survival
• Sevilleta National Wildlife Refuge (SNWR)
  benefits from learning about little known
  species

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Study Questions

• Can ibuttons be used to quantify the behavior
  and activity of desert box turtles?
• How does turtle activity relate to ambient
  weather conditions?
• Are there sex differences in the activity
  patterns of the desert box turtle?
• Can we begin to construct a time budget for
  desert box turtles?
• Hypothesis
• ibuttons will show the temperature dependent
  lifestyle of desert box turtles with bimodal
  peaks of activity during morning and evening

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Study Site
New Mexico SNWR
McKenzie Flats Five Points Road McKenzie North
Road
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Methods
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ibuttons
Ambient Temperature
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-40C - 85C
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Spooling Method

• Attached basic sewing bobbin (coated in Plasti
  Dip) to the carapace of turtle 172 using epoxy
• Closely monitored turtle for 10 days

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Results

• 12 total ibuttoned turtles recaptured
• 2 turtles logging data relocated
• 921 (7/12-7/26)
• 641 (7/18-7/21)
• First day disregarded
• 8 recaptures w/ ibuttons BUT werent recording
• 2 turtles found without their ibuttons
• Fallen off
• Attacked by animal

921
641
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Ambient ibutton Temperature Data

• Logging July-present
• 0cm, 30cm below ground, 30cm above ground
• 2 sites within turtles habitat vegetation and
  bare ground

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Results
37C
Maximum temperature recorded by ibutton
37C Critical maximum temperature 41 C
(Plummer et. al, 2003)
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• Consistent emergence times
• Activity period characterized by fluctuating
  temperature
• readings
• Sharp temperature decrease followed by steady
  recordings denotes
• inactive periods

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How many hours a day are desert box turtles
active?
3.4 hours ACTIVE per day 20.6 hours INACTIVE
per day
3.8 hours ACTIVE per day 20.2 hours INACTIVE
per day
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Is turtle activity dependent on the weather?
p0.06
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Does maximum daily temperature correlate to
number of hours active for turtle 921?
Pearsons r -0.53 The higher the daily
maximum temperature, the fewer number of hours
the turtle spent active
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Spool Method Results

• Turtle 172 still in burrow after 8 days
• Dug up? Found spool but NO turtle

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Discussion/Conclusion

• Tracking the daily activity of a desert box
  turtle via ibutton technology IS possible
• Desert box turtles spend the majority of their
  time in an inactive state
• Turtles are primarily active within several hours
  of sunrise (555-1000 am)
• Sometimes show burst of activity in the evening
• Can be active any time during diurnal rains
• Negative correlation between maximum temperature
  hours active
• Turtles remain active longer on rainy days
  (p.06)
• Spool Methodgood attempt at tracking turtle
  movement temperature shows potential

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Future Research

• This is an ongoing study
• 14 turtles still have ibuttons on SEV waiting to
  be captured
• No time limit on retrieving ibuttons (no
  rollover)
• Differences between individual behavior patterns
• Male vs. Female differences (i.e nesting
  behavior)
• Continue spool method and/or radio telemetry on
  turtles to improve recapture rates
• Broaden seasonal scope of data collection? expand
  outside of monsoon season

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Acknowledgments

• National Science Foundation
• 2008 REU Program
• UNM Sevilleta LTER
• US Fish and Wildlife
• Jennifer Johnson
• Ian Murray
• John DeWitt
• All the 2008 REU students interns
• Natalie Alberg, Emerson Tuttle, Dan Colman, Sam
  Markwell, CJ Jewell, Christine Waters, Sarah
  Gardner, Ashley Schafer

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References

• Converse, S.J. and Savidge, J.A. 2003. Ambient
  temperature, activity, and microhabitat use by
  ornate box turtles (Terrapene ornate ornate).
  Journal of Herpetology. 37(4) 665-670.
• Degenhardt, W.G. and Christiansen, J.L. 1974
  Distribution and habitats of turtles in New
  Mexico.The Southwest Naturalist. 19(1) 21-46
• Nieuwolt, P.M. 1996. Movement, activity, and
  microhabitat selection in the western box
  turtle, Terrapene ornate luetola, in New Mexico.
  Herpetologica. 54(4), 487-495.
• Nieuwolt-Dacanay, P.M. 1997. Reproduction in the
  western box turtle, Terrapene ornate letola.
  Copeia. 4 819-826.
• Plummer, M.V. 2004. Seasonal inactivity of the
  desert box turtle, Terrapene ornate luteola, at
  the species southwestern range limit in Arizona.
  Journal of Herpetology. 38(4) 589-593
• Plummer, M.V., Williams, B.K., Skiver, M.M., and
  Carlyle, J.C. 2003. Effects of dehydration on the
  crucial thermal maximum of the desert box turtle
  (Terrapene ornate luteola). Journal of
  Herpetology. 37(4) 747-750.
• IPCC. 2007. Climate Change 2007 Synthesis Report.
  Accessed online on June 8, 2008.
  lthttp//www.ipcc.ch/ipccreports/ar4-syr.htmgt

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Questions?
Thats All Folks