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2006 SOUTHEASTERN NATURALIST 5(2):191–204
Natural History of Terrapene carolina (Box Turtles)
in an Urbanized Landscape
Sarah A. Budischak1,2, Joy M. Hester1,3, Steven J. Price1,
and Michael E. Dorcas1,*
Abstract - Urbanization and other anthropogenic factors are often implicated in
turtle population declines, yet limited research on the natural history of turtles in
urban areas has been conducted. To assess the effects of urbanization and to help
develop proper conservation strategies for Terrapene c. carolina (Eastern Box
Turtles), we conducted a mark-recapture study in the vicinity of Davidson, NC, from
1999 to 2004. We made 354 turtle captures, 42 of which were recapture events. We
evaluated meristic characters, body condition, activity patterns, population structure,
and growth rates, and then examined relationships among these variables and the
amount of anthropogenically-modified habitat within 100 m of each turtle’s collection
location. Males and females had different patterns of seasonal activity and body
condition indices. Growth rates decreased with turtle age and varied between developed
and forested habitats. More turtles over the age of 20 were found in areas with
extensive forest cover than in areas that were developed. Although box turtles may
persist in urbanized landscapes and may grow more quickly there, they suffer higher
mortality in these habitats compared to forested landscapes.
Recent research suggests that reptiles are declining worldwide and these
declines are often credited to anthropogenic causes, including exploitation
and habitat alteration (Gibbons et al. 2000, Mitchell and Klemens 2000).
Urbanization and other human impacts may increase pollution levels, fragment
habitats, further the spread of disease, and introduce dangers such as
roads and household pets (Belzer and Steisslinger 1999; Dodd et al. 1989;
Kornilev et al., in press; Mitchell and Klemens 2000; Wilcove et al. 1986;
Wilcox and Murphy 1985; Williams and Parker 1987). Turtle life history
characteristics, such as delayed sexual maturity, may put them at an increased
risk and slow population recovery following declines (Klemens
2000). Effective conservation planning requires knowledge of the natural
history of the species of interest (Congdon et al. 1994). For example, studies
of the life history characteristics of Emydoidea blandingi Holbrook
(Blanding’s Turtles), Chelydra serpentina Linnaeas (Common Snapping
Turtles), and other long-lived animals have demonstrated that harvesting
such species is not sustainable (Congdon et al. 1993, 1994).
1Department of Biology, Davidson College, Davidson, NC 28035-7118. 2Current
address - Department of Fisheries and Wildlife Sciences, 100 Cheatham Hall, Virginia
Tech, Blacksburg, VA 24061-0321. 3Current address - College of Veterinary
Medicine and Biomedical Sciences, Colorado State University, 1601 Campus Delivery,
Fort Collins, CO 80523-1601. *Corresponding author - email@example.com.
192 Southeastern Naturalist Vol. 5, No. 2
Terrapene carolina carolina Stejneger and Barbour (Eastern Box
Turtles) regularly live longer than 50 years (Stickel 1978). Because
box turtles are long-lived organisms that rely on relatively high juvenile
survivorship and low adult mortality to maintain stable populations
(Congdon and Gibbons 1990, Hall et al. 1999, Klemens 2000), the full extent
of anthropogenic effects that negatively impact recruitment may not be
immediately evident (Congdon et al. 1994, Garber and Burger 1995, Hall et
al. 1999). Previous long-term studies of box turtle populations have
documented significant population size and density declines in areas experiencing
only moderate anthropogenic impacts (Schwartz and Schwartz 1974,
Stickel 1978, Williams and Parker 1987). Long-term studies of turtle natural
history and ecology in habitats undergoing various levels of anthropogenic
influence are needed to estimate the effects of urbanization on turtle populations
and to develop conservation strategies for these animals (Congdon et
al. 1993, 1994; Garber and Burger 1995; Hall et al. 1999).
In this study, we evaluated data from a 6-year mark-recapture study of
Eastern Box Turtles in the vicinity of Davidson College, Davidson, NC. We
examined meristic characters, body condition, activity patterns, population
structure, and growth rates, and then examined the relationships between
these variables and the amount of anthropogenically-modified habitat near
each turtle’s collection location. Our study provides information on box
turtle natural history in the eastern United States and increases understanding
of the potential impacts of urbanization.
We studied box turtles in the western Piedmont of North Carolina, within
Mecklenburg, Iredell, Rowan, and Cabarrus Counties. Our study area, which
is approximately 20 km north of Charlotte, NC, has undergone rapid urban
growth and large-scale changes in land use, including a significant decrease
in the amount of forested land, during the last 30 years (Griffith et al. 2003).
A large fraction of turtles collected for this study were from the Davidson
College Ecological Preserve (DCEP) and local residential areas (Hester et
al., in press). The DCEP is an approximately 89-ha area of mostly forested,
protected land adjoining the Davidson College campus and it accounted for
35% of the total captures.
A box turtle mark-recapture study was initiated at Davidson College
in May 1999. The final date of data collection for this study was 1 September
2004. Students and faculty of Davidson College and members of
the surrounding communities accounted for a large portion of our
collection effort (Hester et al., in press). All box turtles were captured
opportunistically and taken to the Davidson College Herpetology Laboratory
to be marked and measured.
2006 S.A. Budischak, J.M. Hester, S.J. Price, and M.E. Dorcas 193
We marked the turtles by filing three notches in their marginal scutes,
corresponding to an alphabetical coding system (Gibbons 1968, Sexton
1959). We determined gender on the basis of coloration intensity, tail length,
plastron concavity, and carapace depth (Palmer and Braswell 1995).
Juveniles included all animals whose gender could not be determined morphologically
(most turtles under age 6, carapace length [CL] aprox. 33–82
mm). We approximated the age of each turtle by counting the lines of
arrested growth of carapace scutes, although the validity of this technique
has been questioned (Wilson et al. 2003). A second researcher verified each
count of arrested growth lines, and both researchers agreed upon a degreeof-
confidence integer ranking between 0 and 3, with 3 representing relatively
high confidence in the accuracy of their count (Sexton 1959). This
age-confidence scale was used because growth rings on older turtles can be
difficult to count due to wear and other factors (Dodd 2001, Stickel 1978).
We used a top-loading balance to determine the mass of each turtle to the
nearest 0.1 g. To rehydrate potentially dehydrated turtles, all turtles were
placed in a container with approximately 3 cm of water for at least 3 hours
before weighing. We measured shell dimensions, including straight-line carapace
length, straight-line plastron length, maximum shell width, and maximum
shell depth, to the nearest 1 mm with calipers. If the front hinged flap was
angled or closed, the plastron length was measured as the sum of the lengths of
the two plates. We recorded additional comments, and digital images of each
turtle were taken to aid in recapture identification and to document physical
condition. We returned each turtle to its collection site, typically within 2 days
of collection, and recorded the geographic coordinates (UTM, NAD 83) for the
location (± 3 m) using a Garmin Handheld GPS unit or online topographic maps
and aerial photographs taken in 2002 (1 pixel = 0.5 m).
We used all available data, but our records for each turtle were not always
complete. For example, we have no mass data for turtles when only an empty
carapace was collected. Thus sample sizes vary among analyses and reflect
these missing data. An experiment-wide significance level was set at α = 0.05.
We examined correlations between carapace length and other size and age
measurements for males, females, and juveniles using linear regression. Mass
was log transformed before this analysis. We also compared meristic characters
between males and females using one-tailed t-tests. Age distributions
were tested for gender differences using one-tailed t-tests and included only
the age at first capture for recaptured turtles.
To examine age-specific growth rates, we grouped turtles into four 5-
year age groups. These groupings serve to minimize the effects of inaccurate
growth ring counts and assume that one ring was added each year (Wilson et
al. 2003). Because of the difficulty associated with estimating the age of
older turtles by counting marginal scute rings (Dodd 2001, Stickel 1978), all
turtles > 20-yr old were classified in one age group termed “older.” We
examined our ability to confidently estimate the age of a turtle relative to
that turtle’s age group using a chi-square test. For each 5-year group, we
analyzed the relationship between age and carapace length using linear
194 Southeastern Naturalist Vol. 5, No. 2
regression. The slope of each age group’s regression line was calculated to
estimate a growth rate for that group. To test if the growth rates differed
from zero we determined if zero was within the 95% confidence intervals of
the growth rate of each group.
To assess the condition of the turtles, we calculated the residuals of a
linear regression with mass because mass does not scale 1:1 with size (i.e.,
larger turtles weigh more per unit of carapace length than smaller turtles;
Shine et al. 2002). This method allowed us to compare individual turtle
masses to the average mass for their size. We treated this condition index as
the dependent variable and collection month as the independent variable for
months with at least 4 captures (May through October) to study seasonal
variation in condition. We used separate single-factor analyses of variance
to determine if condition varied seasonally for males or for females. Tukey-
Kramer tests were conducted separately for each sex to determine if
condition differed among individual months. We used two-factor analysis of
variance to compare the monthly condition distributions of males and females.
We conducted additional Tukey-Kramer tests to test for significant
condition differences between the sexes for individual months.
Capture locations were plotted using a Geographical Information System
(ArcGIS ver. 8.3, ESRI, Redlands, CA). We added 100-m circular buffers
around each location and visually estimated the relative amounts of developed,
open field, and forested land within the buffer to the nearest 10% using
aerial photographs taken in 2002 (1 pixel = 0.5 m). Since locations were
classified based on local cover type, we could not distinguish between
clusters of suburban trees and expanses of forest. Because forest is the
preferred habitat of box turtles (Dodd 2001) and forest coverage has decreased
significantly in the vicinity of Davidson during the last 30 years
(Griffith et al. 2003), we examined the relationship between percent forest
and condition (by gender) and age using linear regression. By classifying
turtles into two groups (those from > 50% forest and those from < 50%
forest), we determined if turtle size (carapace length) differed by amount of
forest for each age group using two-tailed t-tests with a modified alpha value
due to multiple comparisons (adjusted α = 0.05/4 = 0.0125). Additionally,
we examined the influence of forested habitat on age-specific growth rates
by calculating the slopes of the relationship between turtles’ ages and carapace
lengths for each 5-year age group. Since we only had one age-specific
growth rate for each habitat type (low or high forest cover), we could not
perform any statistical analysis to compare the growth rates (i.e., our df = 0).
Meristic and population characteristics
From May of 1999 until September 2004, we collected 365 turtles, 342 of
which were alive. Forty-three turtles were recaptured, five of which were
captured three times over the 6-year period. We captured slightly more
females than males and few juveniles (Table 1). Approximately one-third of
2006 S.A. Budischak, J.M. Hester, S.J. Price, and M.E. Dorcas 195
the total captures were found on the DCEP. Males had significantly longer
carapaces (t = 6.15, df = 328, p < 0.01), shallower shell depths (t = 3.59, df =
320, p < 0.01), and shorter plastrons (t = 14.7, df = 327, p < 0.01) than
females , but both sexes had similar shell widths (t = 0.03, df = 324, p = 0.49)
and masses (t = 0.11, df = 311, p = 0.46; Table 2). The carapace lengths of
the largest male, largest female, and smallest juvenile captured alive in this
study were 145 mm, 142 mm, and 26.8 mm, respectively. In general, carapace
length and other body measures were positively correlated in adults (R2
ranged from 0.57 to 0.92) and were highly positively correlated for juveniles
(most R2 > 0.92; Table 3). Because carapace length was highly correlated
with other shell dimension measurements in adults, it was used as a measurement
of overall turtle size in all subsequent analyses.
Age distributions of both males and females were skewed towards older
ages, with the number of turtles > 20 yrs exceeding that of all single-year age
groups (Fig. 1). Older turtles were significantly more difficult to age with a
high degree of confidence (χ2 = 46.6, df = 8, 326, p < 0.0001), and no turtles of
Table 1. Capture data for T. carolina (Eastern Box Turtles) in the Piedmont of North Carolina
from May 1999 to September 2004. Empty carapace shells account for most of the turtles of
Captures Recaptures Total individuals
Male 134 9 125
Female 204 34 170
Juvenile 16 0 16
Unknown 11 - 11
Total 365 43 322
Table 2. Meristic data, by sex, for all living and dead Eastern Box Turtles (T. carolina)
collected in the vicinity of Davidson, NC. Data are presented as means ± 1 SE. Sample sizes are
given below each mean. Asterisks (*) indicate a significant difference between males and
females determined by one-tailed t-tests ( α = 0.05).
CL* (mm) PL* (mm) Width (mm) Depth* (mm) Mass (g) Age* (yr)
Females 119.2 ± 0.8 118.5 ± 0.8 100.0 ± 4.1 61.8 ± 0.5 363.2 ± 7.0 16.5 ± 0.3
198 198 196 195 189 193
Males 126.2 ± 0.7 100.0 ± 1.0 99.9 ± 1.0 59.1 ± 0.5 362.2 ± 5.8 17.5 ± 0.4
132 131 130 127 124 124
Juveniles 54.6 ± 4.5 52.4 ± 4.6 47.1 ± 3.5 26.8 ± 2.1 35.7 ± 6.8 2.9 ± 0.5
16 16 16 16 16 16
Table 3. Correlation coefficients (r2) of linear regressions of carapace length and other meristic
measurements from Eastern Box Turtles collected near Davidson, NC.
Females Males Juveniles
Age 0.40 0.55 1.00
Plastron length 0.92 0.91 1.00
Carapace width 0.90 0.76 1.00
Shell depth 0.79 0.57 0.92
Log(mass) 0.76 0.67 0.97
196 Southeastern Naturalist Vol. 5, No. 2
the two youngest age groups received the lowest confidence rating (Fig. 2).
Relatively more females of intermediate ages (15–18) were found than males
of the same ages. Average age of males was significantly higher than that of
females (t = 1.97, df = 315, p = 0.02). Turtles showed age-specific growth
rates with relatively rapid growth from ages 0–4 yr (2.78 mm/yr) and from 5–9
yr (2.26 mm/yr, Fig. 3). After age ten, the mean growth rate decreased to 0.63
mm/yr and slowed even further after age 15 (0.05 mm/yr; Fig. 3).
Activity and condition
The active season for box turtles in the Davidson area began in April and
continued through October, although a few individuals were active in
March, November, and December. From May through October, male and
female turtles exhibited different seasonal patterns of captures (χ2 = 21.0, df
= 5, p < 0.01; Fig. 4). A significantly larger fraction of females than males
Figure 1. Ages
of female (A)
and male (B)
age at first capture
Figure 2. The
for 5-year age
spans show the
2006 S.A. Budischak, J.M. Hester, S.J. Price, and M.E. Dorcas 197
were collected in June (χ2 = 4.34, df = 1, p = 0.04). The trend towards malebiased
captures in August approached significance (χ2 = 3.10, df = 1, p =
0.08), and a significantly larger fraction of males than females was collected
in September (X2 = 9.81, df = 1, p < 0.01).
Female turtle condition varied among months (ANOVA: F = 2.42, df = 5,
148, p = 0.04), although monthly condition did not differ seasonally for
males (ANOVA: F = 0.48, df = 5,105, p = 0.79; Fig. 5). Collection month
(F = 1.36, df = 5,5, p = 0.24), sex (F = 0.58, df = 1,1, p = 0.45), and the
combined effect of month and sex (2-way ANOVA: F = 0.71, df = 5, 253, p =
0.62) had no detectable effects on turtle condition. Neither the condition of
males nor females differed significantly between any two consecutive
months (t-tests, adjusted α = 0.05 / 5 pairs = 0.01, all p’s > 0.01). Condition
did not differ significantly between males and females for any individual
month (t-tests, adjusted α = 0.05 / 6 pairs = 0.008, all p’s > 0.008).
Figure 3. Agespecific
rates for box
turtles in the
Carolina, as determined
c a r a p a c e
lengths (mm) in
relation to age
at first capture.
best-fit lines for
spans were added to depict the decreasing growth rate of older turtles.
Figure 4. Monthly
variation in the
sex ratio of captures
using χ2 tests (α
198 Southeastern Naturalist Vol. 5, No. 2
Impacts of urbanization
Turtle age and percent of forest cover for males or females were not highly
correlated (R2 = 0.03 and 0.08, respectively). However, older turtles tended to
be found more often in highly forested areas (Fig. 6). Approximately 54% of
the turtles > 20 years old were collected in areas with 90–100% forest cover
within a 100-m radius of their capture location. Areas with greater than 90%
forest cover also accounted for the largest fraction of turtles in the 15–19 yr
age group (34%). Mean carapace lengths for all four age groups did not differ
between low and high forest cover areas (t-tests, p values > 0.0125; Fig. 7).
Growth rates, however, varied by age and amount of forest cover (Fig. 8). We
detected no effect of the amount of forested habitat on the body condition of
male (R2 < 0.01) or female (R2 < 0.01) box turtles.
Figure 6. The percent
of box turtles
in 5-yr age groupings
captured in locations
amounts of forest
cover was determined
estimating the percent
100 m of each
turtle’s capture location
Figure 5. Monthly
variation in condition,
the residual of the
mass to carapace
length ratio, for female
(A) and male
(B) box turtles.
Sample sizes are indicated
± one standard
2006 S.A. Budischak, J.M. Hester, S.J. Price, and M.E. Dorcas 199
This study provides information about the sex ratio, age distribution,
condition indices, and activity patterns of the Davidson, NC, Eastern Box
Turtle population. These data can be used as a baseline for comparison with
future results of this ongoing study to monitor this population. In this region,
box turtles seem to be persisting even in highly developed areas, although
we suspect that their life-spans, growth, and population density may be
negatively affected by urbanization.
Figure 8. Differences
of box turtles
and high (60–
c o v e r a g e .
slope of linear
r e g r e s s i o n
lines fitted to
length data for 5-year age groups. Numbers below age groups indicate (0–50%
forest, 60–100% forest) sample sizes used to calculate the growth rate. The growth rate ±
one standard error is shown for each 5-year age group.
(mm) for 5-
c a r a p a c e
not differ significantly
forest cover for any age group. Numbers below age groups indicate (0–50% forest,
60–100% forest) sample sizes. Vertical bars show ± one standard error.
200 Southeastern Naturalist Vol. 5, No. 2
Meristic and population characteristics
Size and age distributions for box turtles in this population were similar to
those reported in other box turtle studies (Stickel 1950, Stickel and Bunck
1989, Stuart and Miller 1987). Minor differences among studies may be
partially due to the difficulty of accurately aging turtles, the use of different
sampling methods, and different systems of classifying juvenile and slowgrowing,
older turtles. In our study, as turtles grew and matured, correlations
between age and meristic characters decreased, indicating increased variability
among individuals. The lower correlation coefficients between carapace
length and mass could be due to differences in hydration and stomach content.
The decrease in growth rate that we documented as turtles aged was consistent
with Stickel and Bunck (1989), who found that Eastern Box Turtle growth
rates neared zero by age 16. Similar decreases in growth rates with age have
been documented for T. c. triunguis Agassiz (Three-toed Box Turtles;
Schwartz 2000) and additional turtle species including Chrysemys picta
Schneider (Painted Turtles; Gibbons 1968). We found no differences in
growth rates between males and females. However, other studies that tracked
individual turtles over time found that male box turtles grew at a faster rate
than female box turtles (Stickel and Bunck 1989).
Male turtles had longer carapaces and shorter plastrons than females, which
is consistent with the pattern of sexual dimorphism noted in other Eastern Box
Turtle populations (Brown 1971, Dodd 1997, Palmer and Braswell 1995,
Stickel and Bunck 1989). Although males were longer than females, we did not
detect any difference in mass between males and females, which also agrees
with previous research (Dodd 1997, Stickel and Bunck 1989).
The box turtle population near Davidson, NC appears to be composed
of mostly adult turtles, a trend common to most other box turtle populations
that have been studied (Brown 1974, Schwartz and Schwartz 1974,
Stickel 1950). However, juvenile turtles were likely underrepresented in
our study because they are notoriously difficult to find (Langtimm et al.
1996, Stickel and Bunck 1989, Stickel 1950). The abundance of adult
turtles is not surprising because turtles are long-lived and rely on a lifehistory
strategy of high adult survival (Congdon and Gibbons 1990, Hall et
al. 1999, Klemens 2000).
Contrary to previous research (Dodd 1997, Hall et al. 1999, Henry 2003),
we collected more females than males. This could be due in part to uneven
sampling effort and the seasonal activity differences between genders. We
did, however, find fewer females over 20 years old than males, suggesting
that the survival of adult females may be lower than males. Hall et al. (1999)
suggested that the movement patterns and habitat selection (e.g., nesting in
fields) of females may make them more vulnerable to the effects of urbanization
such as being killed by lawn mowers and vehicles.
Activity and condition
Turtles are more likely to be encountered when they are active, assuming
detection probabilities and sampling effort are constant throughout the
2006 S.A. Budischak, J.M. Hester, S.J. Price, and M.E. Dorcas 201
year. Although we cannot justify these assumptions, we cautiously interpret
seasonal variation in capture frequency to reflect variation in activity
levels (Ford and Moll 2003). The primary active season for box turtles in
North Carolina is reported to be May through August (Palmer and Braswell
1995). Our data indicate that a considerable amount of activity also occurs
during September and October. We found that female turtles were more
active during the earlier part of the active season, a pattern corroborated by
radio-telemetric studies (J. Hester, unpubl. data) and that males were more
active during the early fall. Females of other turtle species—e.g.,
Sternotherus odoratus Latreille in Sonnini and Latrielle (Common Musk
Turtle)—have been shown to be active earlier in the year than males,
possibly allowing females to accumulate energy reserves in preparation for
producing eggs (Ford and Moll 2003). Dodd et. al (1994) detected no
seasonal differences in activities between male and female box turtles,
suggesting that regional differences in climate or resource availability may
affect activity patterns.
Box turtles utilize overlapping home ranges to find mates and commonly
undertake forays in search of females during the mating seasons (Dodd 2001).
Box turtles have been reported to mate during the entire active season (Palmer
and Braswell 1995, Williams and Parker 1987), but most mating events have
been reported in the spring (Allard 1935, Dodd 2001, Legler 1960, Minton
1972, Palmer and Braswell 1995). A second mating season in the fall apparently
occurs in some localities (Dodd 2001, Legler 1960, Minton 1972). The
fall peak in male activity we documented suggests that early fall may be the
primary mating season for box turtles in our area.
The seasonal variation in condition we documented is likely due to the
reproductive condition and corresponding activity patterns of these animals.
Female box turtles in North Carolina typically lay their eggs in June
and July (Allard 1935, Palmer and Braswell 1995), which coincides with
the dramatic decrease in female condition we observed between June and
August for the Davidson population. The decrease we observed in male
body condition during the fall, although not statistically significant, corresponds
to the time when males were most active (Ford and Moll 2003,
Legler 1960) and is likely due to energy expenditure during mate-searching
activity. Other studies have shown that males reduce feeding during courtship
(Rosenberger 1936), which may contribute to their lower condition
during the fall mating season.
Impacts of urbanization
Our results indicate that although box turtle populations can persist in
developed areas, they may have higher adult survivorship in forested areas, or
at least in areas with a high proportion of tree cover. Decreased survivorship
for turtles in urban environments near Davidson may be due to several factors,
including habitat degradation, pollution, increases in the number of
anthropogenically-subsidized predators, and mortality due to automobile traffic
(Belzer and Steisslinger 1999, Dodd et al. 1989, Mitchell and Klemens
202 Southeastern Naturalist Vol. 5, No. 2
2000, Stickel 1978, Wilcove et al. 1986, Wilcox and Murphy 1985, Williams
and Parker 1987). Adult Eastern Box Turtles may be especially susceptible to
road mortality. A study in Alabama showed that box turtles accounted for 85%
of the turtles killed on a series of roads (Dodd et al. 1989).
Growth patterns of turtles from highly-forested areas and areas with low
forest cover show different trends. First, although the difference was not
statistically significant, turtles of ages 0–4 from forested areas tended to be
larger than those from areas with less forest. Turtles in areas with less forest,
however, showed higher initial growth rates than those from areas with greater
than 50% forest cover. Lastly, growth in turtles from forested areas slowed to
almost zero mm per yr for the 10–14 yr old age group, whereas turtles from 10–
14 yrs old from the less forested areas continued to grow until approximately
age 15. All turtles reached similar sizes by ages 15–20, suggesting that turtles in
forested areas may reach their adult size sooner. Eastern Box Turtles are
opportunistic omnivores, so turtles in less forested areas, such as in suburban
neighborhoods, may benefit from food sources, such as gardens and dumpsters,
not available to those in more natural habitats (Dodd 2001; M. Dorcas, pers.
observ.). Turtles inhabiting forested habitats reach adult size earlier than those
in areas with < 50% forest cover, which may allow them to mate earlier and/or
provide the safety benefits of adult turtle size (Dodd 2001).
For long-lived species with characteristically low adult mortality, decreased
adult survivorship or delayed maturity may lead to long-term population
declines (Congdon and Gibbons 1990, Hall et al. 1999, Klemens 2000).
Road networks and urbanized areas in the western Piedmont of North Carolina
and in many other regions of the eastern United States are increasing rapidly
(Griffith et al. 2003). Urbanization is suspected to decrease juvenile recruitment
and adult life-span, but long-term effects may not be immediately evident
due to the secrecy of juveniles, delayed sexual maturity, and longevity of adults
(Congdon and Gibbons 1990, Congdon et al. 1993, Garber and Burger 1995).
Lower population densities are also suspected in urban areas and may have
reproductive consequences for species, like box turtles, that rely on chance
encounters for breeding (Belzer and Steisslinger 1999, Stickel 1950). Although
the Davidson box turtle population appears to be persisting despite increasing
levels of urbanization, more long-term data are needed to truly assess the health
of populations of this and other long-lived species.
We would like to thank members of the Davidson College Herpetology Lab and
the local citizen scientists for assistance in the collection and processing of turtles.
We thank Pat Peroni for assistance with statistical analysis. J.D. Willson, Kristine
Grayson, I. Lehr Brisbin, Jr., Joseph C. Mitchell, and one anonymous reviewer
provided comments on the manuscript. This research was supported by Duke Power
and a National Science Foundation grant (DEB – 0347326) to M.E. Dorcas. Manuscript
perparation was aided by the Environmental Remediation Sciences Division of
the Office of Biological and Environmental Research, US Department of Energy,
through Financial Assistance Award number DE-FC09-96SR18546 to the University
of Georgia Research Foundation.
2006 S.A. Budischak, J.M. Hester, S.J. Price, and M.E. Dorcas 203
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