2013 NORTHEASTERN NATURALIST 20(3):493–497
Effects of Prescribed Fire on the Eastern Box Turtle
(Terrapene carolina carolina)
Christopher A.F. Howey1,* and Willem M. Roosenburg1
Abstract - While conducting an on-going project investigating the effects of prescribed
fire on reptile communities, 31 Terrapene carolina carolina (Eastern Box Turtle) were
captured in burned and unburned study sites; some with extensive injuries that were
likely caused by a recent prescribed burn. In order to determine if the disturbance had
any negative effects on the turtles, we recorded morphometrics, mass, sex, and injuries
for each one captured. Twenty percent of box turtles in the burned area exhibited injuries
caused by the fire. Turtles in burned sites were similar in length but weighed significantly
less (df = 1, F = 5.255, P = 0.0329) and had a poorer body-condition index than turtles in
unburned sites. Additionally, one injured box turtle was encountered 32 times in a burned
site. On average, this individual moved 22.5 m/day within a 3.77 ha home range. Over
the course of 1 year, the turtle grew 1.3 mm and gained 27 g. The injuries to the carapace
of this individual never fully healed during that year, and the scutes did not grow back;
however, regeneration of the carapace may require a longer period of time. These scant
data suggest that Eastern Box Turtles may not respond favorably to prescribed fire, and
indicate that additional studies are needed to increase knowledge of the effects of prescribed
fire on this species.
Introduction
Prescribed burning has become a popular tool in forestry management used to
create a more open, early successional habitat; however, it is unclear how most
reptiles respond to this landscape disturbance. Terrapene spp. (box turtles) reportedly
suffer high rates of mortality and/or extensive injuries as a result of the
direct effects of fire (Allard 1949, Babbitt and Babbitt 1951, Bigham et al. 1964,
Dolbeer 1969). Due to the slow movements of box turtles and their tendency to
take shelter in leaf litter, box turtles may not be able to avoid a fire as it passes
through the landscape. If box turtles survive the fire, they are sometimes left with
extensive injuries that may lead to the partial or complete loss of the epidermal
layer (scutes) of the shell (Babbitt and Babbitt 1951, Rose 1986). Regeneration of
the scutes has been documented in a few instances (Rose 1986), but it is unclear
if this phenomenon is common, how these animals will cope with the changed
landscape, and if the health of the animal will improve or deteriorate in these
altered environments.
Methods
Terrapene carolina carolina L. (Eastern Box Turtle) were captured in burned
and unburned sites between 2010 and 2011 as part of a larger study. The burned
1Ohio Center for Ecology and Evolutionary Studies, Department of Biological Sciences,
Ohio University, Athens, OH 45701. *Corresponding author - chris.howey@gmail.com.
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sites had been recently subjected to a prescribed fire (September 2010), and were
located in the Franklin Burn Unit at Land-Between-the-Lakes National Recreational
Area, KY. Morphometrics, mass, sex, and the presence of injuries were
recorded for each captured turtle. Additionally, each captured turtle was uniquely
marked (Cagle 1939) prior to its release.
One severely injured, adult male Eastern Box Turtle was recaptured multiple
times over the course of a year in a burn site (Fig. 1). Upon each encounter with
the turtle, GPS coordinates, morphometrics, mass, and condition of the injuries
to the carapace were recorded. These data were used to determine if there was a
change in morphometrics, mass, or condition of injuries over the course of the
year. GPS coordinates were analyzed with Home Range Tools 1.0 extension in
ArcGIS 9.3 (Rodgers et al. 2007) to determine movement rates and home-range
size based on a 95% Kernal estimate.
Results and Discussion
In total, 31 Eastern Box Turtles were captured in burned and unburned study
sites—20 turtles in burned sites and 11 in unburned sites. All turtles captured in
Figure 1. Eastern Box Turtle with injuries from a prescribed fire. The front vertebral
(denoted by “V” ) and right and left pleural scutes (denoted by “P”) are discolored and
weakly attached to the carapace. All other vertebral and pleural scutes have fallen off of
the carapace. Marginal scutes (surrounding the perimeter of the carapace) and plastron
appear to be unaffected.
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2013 Northeastern Naturalist Vol. 20, No. 3
unburned sites were uninjured; however, 20% of turtles captured in burned sites
exhibited injuries that were presumably caused by fire. Injuries mostly consisted
of damaged or missing pleural and vertebral scutes (Fig. 1); these scutes would
be the most vulnerable if the animal were buried in the leaf litter at the time of
the fire. Mean carapace length was 127.1 mm and 130.4 mm for uninjured and
injured turtles respectively; however, mean mass was greater for uninjured compared
to injured turtles (405.8 and 385.5 g, respectively). All turtles in burned
sites (injured and uninjured) had a significantly lower body mass (mean = 373.3
g) than those found in unburned areas (mean = 448.0 g) when carapace length
was used as a covariate (df = 1, F = 5.255, P = 0.0329). In addition to the lower
body mass, turtles that were found in burned sites also had a lower body condition
index (Fig. 2), which may suggest poorer health of these animals. It is
possible that the warmer ground temperatures and higher total radiation of the
burn sites (C.A.F. Howey, unpubl. data) led to greater body water loss; and thus,
lower body mass for turtles in burned areas. Additionally, the loss of the outer
dermal layer of the shell (i.e., scutes) may exaggerate this loss of body water and
lead to a lower mass and poorer body condition. Degraded habitat may also contribute
to a diminished body condition, but data on habitat use was not recorded
for box turtles during this project. We hope that the scant data presented here may
Figure 2. Body condition index of Eastern Box Turtles is determined by the residuals
from the mean (regression line). Black squares denote turtles from burn sites. Gray circles
denote turtles from unburned sites.
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2013 Northeastern Naturalist Vol. 20, No. 3
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spur future work examining the effect of such injuries and the effect of a changed
landscape on the Eastern Box Turtle. It appears that surviving a prescribed burn
is only the first challenge for Eastern Box Turtles; maintaining a healthy body
condition may also be difficult in these disturbed landscapes.
One severely injured, adult male Eastern Box Turtle was encountered 32 times
between 30 May 2011 and 8 June 2012. Over the course of the year, the turtle
grew 1.3 mm and gained 27 g. The state of the injuries did not change over the
year; scutes that were missing did not grow back, and scutes that were severely
damaged still appeared damaged after one year (Fig. 1). Shell regeneration has
been reported for box turtles (Rose 1986); however, this phenomenon may require
more than one year. Over the course of the year, the turtle moved on average
22.5 m per day with a maximum movement of 60.8 m per day. The home range
for the turtle was 3.77 ha, and over the course of the year the turtle was never
found outside of a small valley. Although we did not record habitat characteristics
associated with the valley, greater amounts of canopy cover and understory
vegetation were observed in this area compared to surrounding habitat in the
burned landscape. In comparison to other Eastern Box Turtle studies, the home
range of this individual was equal to or smaller than previously reported home
ranges (Hester et al. 2008, Madden 1975, Wilson 2001), but movement rates were
less than the mean for turtles that occupy undisturbed, forested landscapes (40
m/day; Strang 1983). Interestingly, Iglay et al. (2007) found lower movement
rates for Eastern Box Turtles in habitat disturbed by fragmentation, which were
comparable to the movement rates for the individual in this study. It is possible
that the lower movement rate for the injured turtle is the result of reducedquality
habitat rather than the result of its injuries, but this is purely speculation.
Given these data, further work regarding the habitat use of Eastern Box Turtles
in burned and unburned landscapes is warranted. If box turtles can survive the
direct effects of prescribed fire, it is unclear if this altered landscape will provide
favorable habitat characteristics for the species, how habitat changes will affect
movement rates and home-range sizes, and ultimately energetic expenditures and
fitness of Eastern Box Turtles.
Acknowledgments
This study was conducted in compliance with state (SC1211012) and federal
(LBL10165) permits. The research was supported by funding from the National Fire Plan
through the US Forest Service’s Northern Research Station (10-CR-11242302-056). All
interactions with animals were approved under the Ohio University IACUC L09-08. We
thank M. Dickinson for assistance with this project and with obtaining funding for this
project. I thank A. Schneider, E. Stulik, R. Everett, N. Becker, B. Johnson, and K. Heckler
for assistance with data collection.
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