Movement, Seasonal Activity, and Home Range of an
Isolated Population of Glyptemys muhlenbergii, Bog Turtle,
in the Southern Appalachians
Lisa M. Smith and Robert P. Cherry
Southeastern Naturalist, Volume 15, Issue 2 (2016): 207–219
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22001166 SOUTHEASTERN NATURALIST 1V5o(2l.) :1250,7 N–2o1. 92
Movement, Seasonal Activity, and Home Range of an
Isolated Population of Glyptemys muhlenbergii, Bog Turtle,
in the Southern Appalachians
Lisa M. Smith1,*, and Robert P. Cherry1
Abstract - Glyptemys muhlenbergii (Bog Turtle) is a small, federally threatened, aquatic
turtle found only within a fragmented range in the eastern US. From 2005–2009, we studied
the movements and home ranges of 9 adult turtles during the active season in an isolated
population located in the Southern Appalachians. We used radio telemetry to locate turtles
once a day for 1 week of every month, and then once a week for the rest of the month. We
calculated average distance moved between locations for consecutive days. Movements of
Bog Turtles averaged 13.00 m/d for females and 14.51 m/d for males with no significant
difference between sexes. Movement distances were significantly shorter during the period
following emergence from and the one preceding entrance into hibernation. We used 95%
minimum convex polygon, 50% fixed-kernel density, and 95% fixed-kernel density to
calculate home-range size. Home-range size was highly variable: the 95% kernel density
estimation ranged from 0.21–2.43 ha and we detected no significant difference between
sexes. Over the entirety of our study, more than 80% of home ranges were smaller than 1.55
ha. There was no significant difference between turtle home-range size during the breeding
and post-breeding season for either sex. Our determinations of the average home-range
overlap for individual turtles tracked in multiple consecutive years indicated that turtles
remained in similar locations from year to year. Our population experienced 1 emigration—
a turtle moved out of the bog into a nearby wetland—which suggested the importance of
suitable corridors for movement and protection of additional habitat. Our results indicated
that Bog Turtles have small home-ranges and are capable of existing in small wetlands;
thus, management plans should incorporate surveys and protection of smaller wetlands that
may be easily overlooked. Suitable buffer areas surrounding wetland habitat and stream
corridors should be maintained and protected to promote connectivity to other Bog Turtle
populations and allow for successful emigration.
Introduction
The federally threatened Glyptemys muhlenbergii (Schoepff) (Bog Turtle) is
North America’s smallest aquatic turtle (Ernst et al. 1994, USFWS 1997). Bog
Turtles occur in a fragmented range, inhabiting freshwater wetlands and spring-fed
wet meadows of eastern North America. Bog Turtle populations have experienced
declines as a result of illegal collection, habitat loss, and habitat fragmentation
(Carter et al. 1999, Ernst et al. 1994, Turtle Conservation Coalition 2011). In addition
to human-caused threats, Bog Turtles are also limited by natural habitat loss
due to drying and vegetational succession in the seasonally flooded wetlands where
they occur (Chase et al. 1989, Morrow et al. 2001a).
1Blue Ridge Parkway, 5580 Shulls Mill Road, Blowing Rock, NC 28605. *Corresponding
author - Lisa.Smith.7744@gmail.com.
Manuscript Editor: John Placyk
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Various environmental factors and biological needs influence Bog Turtle movement
and habitat use. Biological needs include feeding, reproduction, basking, and
availability of refugia (Lovich et al. 1992). Efforts to meet these biological requirements
should be reflected in the turtle’s home range and movement patterns and
should be correlated with lifetime reproductive success. Environmental factors including
temperature, daily rainfall, and drought may influence movements and home
range (Feaga 2010, Pittman and Dorcas 2009). Bog Turtles must be able to meet their
biological requirements in a relatively small area because most wetlands containing
Bog Turtles are less than 2 ha in extent (Lee and Norden 1996). Typically, Bog Turtles have
small home ranges that vary from 0.05 ha to 0.178 ha in Maryland (Chase et al. 1989,
Morrow et al. 2001b) to about 1.3 ha in Pennsylvania (Ernst 1977).
Knowledge of home-range use, movement, overlap, and fidelity are critical for
understanding spatial requirements of Bog Turtles on the landscape. We examined
the spatial ecology of an isolated population of Bog Turtles in the Southern Appalachian
Mountains of western North Carolina, a region of the Bog Turtle’s range that
is understudied. The purpose of this paper is to describe the annual activity cycle
and movement patterns of Bog Turtles, as well as evaluate its home-range size,
overlap, and fidelity. We provide data on several individuals in an isolated population
over multiple years.
Field-site Description
We studied Bog Turtles at a 1.99-ha wetland in northwest North Carolina. The
site, classified as a Southern Appalachian Bog community (Price et al. 1994), is
characterized by winding channels of water among suspended sphagnum mats
typical of northern bogs. This high-elevation bog is located at ~1025 m asl. The
majority of the site is unforested; Scirpus cyperinus (L.) Kunth (Woolgrass),
S. expansus Fernald (Wood Bulrush), Juncus effusus L. (Common Rush), J. debilis
A. Gray (Weak Rush), Carex spp. (sedges) and Sphagnum spp. (sphagnum mosses)
are the dominant species (Price et al. 1994). The shrub zone is poorly developed.
The bog is enclosed by second-growth woodland vegetation and a dry meadow
with scattered small trees and shrubs. A stream meanders along one edge of the
bog with a side channel running along another edge of the dry meadow. Although
nearby wetlands have historically supported Bog Turtles, the next-nearest wetland
known to contain a viable population of Bog Turtles is located more than 30 km
away (R.P. Cherry, pers. observ.).
Methods
From 2005 to 2009, we fitted 9 turtles with radio transmitters and tracked them
for 1–4 y. We located turtles by trapping or by opportunistic encounters in the field.
We sexed, weighed, measured, attached the transmitters, and returned the turtles to
their capture location within 60 min. We used epoxy to attach 5.2-g, Model SB-2
transmitters (Holohil Systems, LTD, Carp, ON, Canada) to the rear of the carapace;
the overall weight of the transmitter and epoxy was less than 10% of the turtle’s
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weight. We tracked the radio-tagged turtles with a Wildlife Materials, Inc. (Carbondale,
IL) Model TRX-1000S receiver and a Yagi 3-element antenna.
We tracked turtles during the active season, usually from mid-April into October.
During 1 week each month, we attempted to track turtles to obtain data on
daily movements. We measured to the nearest meter the straight-line distance between
the consecutive daily locations. We considered all movements to be linear
and unidirectional. This sampling interval of 1 day allowed enough time for turtles
to travel the length of their home range; therefore, we considered the observations
as independent. After the week of daily tracking, we tracked turtles once a week
for the rest of the month. We analyzed turtle movements for bimodal differences in
movement by grouping measurements from the time preceding entrance to hibernation
(16 September–1 November) and the period after emergence from hibernation
(1 April–15 May), and comparing this value to movements during the warm summer
months. We also examined the effect on movement of turtle habitat, specifically
in or within 1 m of a channel. We defined channels as slow-moving, narrow,
deep, second-order streams with a stable bank. Our hypothesis was that channels
would facilitate turtle movement throughout the bog.
We used locations of the turtles during the active season following emergence
from hibernation, throughout the summer, and prior to their return into the hibernacula
to calculate home ranges. We also determined separate breeding-season
and post-breeding season ranges. We defined the breeding season as the time following
emergence until the end of June; the post-breeding season extended from 1
July to entrance into the hibernacula. We used 3 different home-range estimators:
minimum convex polygon (MCP), 50% fixed kernel density estimation (KDE),
and 95% KDE. MCP is a simple method that requires drawing the smallest convex
polygon that connects exterior locations, with no angle greater than 180° (Worton
1987). Although this method tends to overestimate home-range size because it
includes unused portions of the habitat (Worton 1987), we calculated it so that we
could compare our home-range sizes to those reported in other studies (Carter et al.
1999, Morrow et al. 2001b, Pittman and Dorcas 2009). KDE uses a nonparametric
probability density function that can better account for the non-linear-shaped outlines
of the home ranges (Worton 1989). The core area of each turtle’s home range
was reflected by the 50% KDE. We used a smoothed cross-validation bandwidth
estimator to calculate fixed-kernel estimates. We employed Geospatial Modeling
Environment (GME) version 0.7.2.1 (Beyer 2012) to determine home-range estimates.
We plotted home ranges in ESRI ArcMap 10.1 (ESRI, Redlands, CA) and
calculated the overlapping area between home ranges.
We conducted our analyses of movement and home-range data in PROC
GLIMMIX with a negative binomial distribution in SAS Enterprise Guide 5.1
(SAS Institute Inc., Cary, NC). Our analyses incorporated differences between the
fixed effects of year (2006–2009), season, and gender, and the random effect of the
individual turtle. We grouped the influence of stream channels on movement year
and gender, and used the Mann-Whitney U-test to assess this variable. Prior to data
analysis, we removed movements resulting in emigration.
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Results
We radio-tracked 9 Bog Turtles (6 males, 3 females) for 1–4 y. The average
number of locations per turtle per year was 44.1 (range = 28–57). Movement
rates for Bog Turtles were not significantly different between sexes (F1,6.8 = 1.56,
P = 0.25) or years (F3,194.6 = 0.39, P = 0.76); males moved an average of 14.51
(± 24.04) m/d, and females moved 13.00 (± 21.00) m/d (Fig. 1). The average daily
movement for all turtles was 14.09 (± 23.22) m/d. Distances traveled in 1 d ranged
from 0–54 m. Movements during cooler months, prior to emergence and after
entrance from the hibernacula, were significantly lower than movements during
summer months (F1,338.4 = 24.50, P < 0.005); the average daily movement in the
cool months was 7.85 (± 19.28) m/d and the average daily movement in the summer
months was more than 2 times greater—16.75 (± 24.47) m/d. Activity levels
for all turtles peaked in June at an average 23.40 (± 31.76) m/d, and remained high
for July and August. Habitat, i.e., proximity to a channel, significantly affected
movement rates. Turtles located in or near a channel moved significantly farther in
a day’s time then turtles away from channels (U = 12014.5, n1 = 231, n2 = 150, P less than
0.001). The average turtle movement on land was 9.73 (± 19.71) m/d, while turtles
in or near the channel moved 16.42 (±20.76) m/d.
One turtle emigrated from the population during the study. This turtle was an
adult male that moved 0.61 km downstream and crossed a 4th-order river to a nearby
wetland not believed to contain any other Bog Turtles. After 2 weeks at his new
location, we could no longer locate the turtle. We assume that he reentered the river
and moved an unknown distance downstream.
Home-range size varied between years, though these differences were not significant
(F1,17 = 0.95, P = 0.34; Table 1). Home ranges varied in size as shown by
Figure 1. Monthly average movements (m) of Glyptemys muhlenbergii (Bog Turtles) in a
southern Appalachian wetland from 2005 to 2009 (n = 354).
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the 95% KDE values (range = 0.21–2.43 ha). Over the course of the study, more
than 80% of turtles had a home range less than 1.55 ha. There was no significant difference
between home-range size during the breeding and post-breeding season for either
sex (F1,34 = 0.78, P = 0.38). We palpated female turtles during the breeding season
and found no gravid turtles at any point during the study.
Home-range overlap was considerable and was especially apparent when we
tracked >4 turtles in a single year (Figs. 2, 3). Home-range overlap occurred both
within and between genders. During the 2007 and 2008 field seasons, we tracked
5 and 8 turtles, respectively, and the results showed considerable overlap of corehabitat
range in the central and southern areas of the bog, especially along the main
and side channels. In 2007, average 95% KDE home-range overlap was 45.41%
(± 27.65) between each pair of turtles. In 2008, when we tracked 8 turtles, 6 of those
home ranges overlapped substantially, with an average of 58.39% (± 26.71) overlap
between ranges. During 2008, two female turtles had home ranges that overlapped
Table 1. Home-range sizes (ha) of Glyptemys muhlenbergii (Bog Turtle) in a southern Appalachian
wetland calculated using average minimum convex polygon (MCP), 50% kernel density estimator
(KDE), and 95% KDE from 2005–2009.
Turtle # n Sex MCP 50% KDE 95% KDE
2005
1.0 33 female 0.69 0.38 1.54
2006
0.9 33 male 0.98 0.59 2.43
1.0 30 female 1.16 0.21 1.53
1.1 28 male 0.45 0.18 0.89
Average 30 0.86 (± 0.37) 0.32 (± 0.23) 1.62 (± 0.77)
2007
0.6 50 male 0.61 0.18 0.91
0.7 57 male 0.16 0.03 0.21
0.9 54 male 1.30 0.29 1.45
1.0 40 female 1.24 0.22 1.47
1.1 56 male 0.55 0.07 0.48
Average 51 0.77 (± 0.49) 0.16 (± 0.11) 0.90 (± 0.57)
2008
0.5 34 male 0.62 0.60 0.46
0.6 42 male 0.49 0.17 0.82
0.7 22 male 0.28 0.04 0.33
0.9 55 male 0.78 0.35 1.53
1.0 41 female 0.73 0.12 0.75
1.1 54 male 2.45 0.21 1.62
1.5 41 female 0.31 0.12 0.54
2.0 30 female 0.78 0.23 1.03
Average 40 0.81 (± 0.69) 0.23 (± 0.18) 0.89 (± 0.48)
2009
0.9 39 male 1.14 0.37 2.00
1.7 25 male 0.30 0.18 0.84
Average 32 0.72 (± 0.60) 0.27 (± 0.13) 1.4 (± 0.82)
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entirely with a male turtle’s home range. The male turtle had a large home-range
during this year; the following year he emigrated from the population. Also in 2008,
another male turtle’s home range overlapped entirely with 2 other turtles, 1 male
and 1 female. Our values likely underestimate the degree of overlap between home
Figure 2. Overlapping core home-ranges calculated using 95% kernel density estimator
(KDE) of Glyptemys muhlenbergii (Bog Turtle) in a southern Appalachian wetland in 2007.
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ranges because we did not track every turtle in the population at any one time. Our
extensive trapping efforts confirmed the presence of 16 Bog Turtles in the study
population, and we believe that these turtles likely represent the majority of the
remaining adult population at the site.
Figure 3. Overlapping core home-ranges calculated using 95% kernel density estimator
(KDE) of Glyptemys muhlenbergii (Bog Turtle) in a southern Appalachian wetland in 2008.
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We evaluated home-range fidelity for 5 turtles monitored in multiple consecutive
years (Table 2). According to the 50% and 95% kernel density estimates, the
percent of overlapping home range of individual turtles between years was highly
variable. The average core-range overlap was 28.85% (± 23.89), and the average
95% KDE overlap was 46.19% (± 18.77). The percent home-range overlap ranged
from 0.85% to 59.30% for the core-habitat areas, and from 4.43% to 68.97% for
the overall home range. Although we removed emigration movement prior to the
home-range calculation, the male turtle that emigrated had a very low percentage
of home-range overlap between 2007 and 2008. This finding is likely a result of
numerous small movements out of the main bog prior to leaving the population,
which resulted in much of his home range occurring outside of traditional habitat.
Discussion
Bog Turtles in our study exhibited higher daily movement rates than turtles in
other studies (Lovich et al. 1992, Morrow et al. 2001b). Turtles in the piedmont
of North Carolina traveled an average of 2.1 m/d (males), and 1.1 m/d (females)
(Lovich et al. 1992), while turtles in Maryland moved an average of 3.4 m/d and
3.1 m/d for males and females, respectively (Morrow et al. 2001b). Turtles in
our population moved considerably farther, averaging 14.5 m/d and 13.0 m/d
for males and females, respectively. Carter et al. (2000) reported similar rates of
movement in southwestern Virginia, where average movements were 16 m/d for
males and 17 m/d for females. Feaga (2010) reported much larger daily movement
rates of 38.4–49.9 m/d, but their study also used multiple locations a day taken at
short intervals. We located turtles at 1-d intervals, whereas other studies sampled
at longer or irregular intervals and did not include the distance moved per day in
their original study design (Carter et al. 2000, Lovich et al. 1992, Morrow et al.
2001b). It is difficult to compare the results of various studies because each one
used a different method to assess Bog Turtle movement rate. However, all movement-
rate calculations are subject to bias because movement is rarely linear and
Table 2. Percent overlap of home range (ha) using 50% kernel density estimator (KDE), and 95%
KDE of 5 Glyptemys muhlenbergii (Bog Turtle ) tracked in consecutive years in a southern Appalachian
wetland from 2005 to 2009.
% Overlap
Turtle # Year 1 Year 2 50% KDE 95% KDE
0.6 2007 2008 59.30 60.34
0.7 2007 2008 50.80 37.23
0.9 2006 2007 3.56 55.22
0.9 2007 2008 19.47 68.97
0.9 2008 2009 0.85 49.34
1.0 2005 2006 44.41 63.49
1.0 2006 2007 52.41 50.43
1.0 2007 2008 46.80 39.52
1.1 2006 2007 5.30 32.94
1.1 2007 2008 5.56 4.43
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actual movement rates may be much higher than estimates reflect (Carter et al.
2000, Chase et al. 1989).
Bog Turtles rely on wetland habitat; thus, differences in movement rates could
be explained by the size of the wetland available in each study. The study by Lovich
et al. (1992) took place in a 0.3-ha wetland, while the Morrow et al. (2001b)
study took place on several wetlands smaller than 1 ha. The bog in our sampling
area was just under 2 ha. Geographic, environmental, and habitat differences may
also affect movement rates due to differences in weather, flora, and channelization
(Carter et al. 2000, Feaga 2010). For example, aestivation or emigration may result
in decreases or increases, respectively, in movement rates during periods of drought
(Ernest and Barbour 1989, Feaga 2010). Therefore, short-term studies might not
reveal accurate home-range sizes if conditions are abnormal during study years.
The importance of channels for facilitating movement within the home range was
demonstrated by the significantly higher movement rates of turtles in or near the
channel than turtles on land. Pittman and Dorcas (2009) also found that although
turtles preferred soft mud and standing water, they frequently traveled to stream
habitat, even when water levels in the wetland were high. Feaga (2010) also found
that large movements were more likely to occur when turtles were near a stream,
although this was often a result of drought conditions causing turtles to move into
favorable habitat.
Consistent with the findings reported by others, turtles in our study did not experience
different rates of movement based on gender (Carter et al. 2000, Chase
et al. 1989, Feaga 2010, Morrow et al. 2001b). Similar movement rates between
males and females is unexpected because the “reproductive strategies hypothesis”
proposes that, to increase mating success, males tend to be more active and travel
greater distances than females during the breeding season (Gibbons et al. 1990,
Morreale et al. 1984). The need to travel long distances to find mates may be reduced
by the considerable home-range overlap between individual turtles. This
hypothesis also suggests that gravid females will travel larger distances to find
suitable nesting areas; however, we documented no gravid turtles during the course
of our study. Lovich et al. (1992) found that males moved almost twice as far as
females during 1-d periods, which supports the reproductive strategies hypothesis.
It is possible that the data from Lovich et al. (1992) are limited by an extremely
small sample size (n = 5) and the unequal time interval between relocations.
Bimodal activity in Bog Turtles has been reported in earlier studies (Ernst and
Barbour 1989, Nemuras 1967). Patterns of bimodal activity show an increase in
activity after emerging from hibernation in the spring and prior to entering the
hibernacula in the fall, with depressed activity levels during summer when turtles
often burrow in the mud or undergo aestivation to escape the hot, dry conditions.
On the contrary, Morrow et al. (2001b) did not detect any significant signs of bimodal
activity. Bog Turtles in our population experienced the opposite pattern of
bimodal activity, with an increase of movement during the warm summer months.
This activity pattern may be more common because Bog Turtles are thought to
require higher temperatures to initiate activity than other turtle species (Ernst and
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Barbour 1989). Geographic differences between studies, such as the high elevation
of our study site—which may result in cooler summer temperatures—may explain
differences in activity patterns between studies.
Home-range size for adult Bog Turtles in our study was larger than those
reported by most researchers. Other studies reported average home ranges of
0.03–0.18 ha (Carter et al. 1999, Chase et al. 1989, Morrow et al. 2001b, Pittman
and Dorcas 2009). In our study, home-range size was variable between years, but
our combined average over the course of the study was 0.79 ha using MCP and
1.10 ha using 95% KDE. Two studies reported larger home ranges than ours, one
in Pennsylvania with an average home range of 1.33 ha for males and 1.26 ha for
females (Ernst 1977), and one in southwestern Virginia with an average range of
4.7 ha for males and 3.3 ha for females (Feaga 2010); both used MCP for their
calculations. Bog Turtles rely on wetland habitat and rarely leave it; thus, it is
probable that like their movement rates, home-range size is affected by the size
of the wetland itself, accounting for some of the variation between studies (Chase
et al. 1989, Morrow et al. 2001b, Pittman and Dorcas 2009). The differences in
home-range size between studies may also be affected by environmental conditions,
e.g., a dry year vs. a wet year, presence or absence of a beaver dam and
pond, quality of the habitat, geographical differences in habitat characteristics,
and/or estimation technique (Carter 1999, Morrow et al. 2001b).
Consistent with some other studies (Carter et al. 1999, Morrow et al. 2001b), we
found no significant difference in home-range size between the sexes, while other
studies detected a difference (Chase at al. 1989, Feaga 2010, Pittman and Dorcas
2009). The absence in our data of significant differences between male and female
turtle movements and home ranges during the breeding season may be a result of
overlapping home ranges. Bog Turtles experience considerable home-range overlap,
and it is possible that it is not necessary for male turtles to travel large distances
to encounter potential mates. The overlap of home ranges within and between sexes
might also indicate a lack of territoriality. Morrow et al. (2001b) reported similar
home-range sizes and considerable overlap within and between sexes. On the contrary,
Chase et al. (1989) reported home-range overlap, but still found significant
differences between home-range sizes of the sexes. Conflicting results on differences
in home-range sizes between genders is common and may be influenced by
the small sample sizes available within small populations.
Home-range size and location of turtles monitored in multiple years was
highly variable. Home-range size almost doubled between consecutive years for
1 turtle and stayed constant for another. The variable nature of home-range size
in Bog Turtles may be indicative of changes in environmental conditions. Morrow
et al. (2001b) noted a decrease in home-range size as a result of hotter and
dryer conditions. Carter et al. (1999) detected no significant change of homerange
size between years, but found a change in home-range locations. Changes
in home-range location may be a response to temporal changes in wetland habitat,
allowing turtles to follow favorable conditions and adapt to a changing environment
(Carter et al. 1999).
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In our study, 1 adult turtle emigrated out of the population. Prior to this movement,
he had a consistently small home range, less than 1.0 ha. In July 2008, the
turtle spent 10 d about 100 m outside the wetland before encountering a large river
and returning to the wetland. The next month he moved about 0.6 km to a new
wetland where he remained for 2 wks before presumably moving further downstream
and out of our detection range. Other studies have reported migration of
adults (Carter et al. 2000, Morrow et al. 2001b, Pittman and Dorcas 2009). Most
other turtles moved between neighboring wetlands, only to return to the original
wetland at a later time (Carter et al. 2000, Morrow et al. 2001b). Emigration and
migration usually occur when hatchlings leave the nesting area or depart from an
unsuitable habitat (Lovich et al. 1992). Long-distance movements by adults in
unaltered habitat indicate that there is some other cause that may result in longdistance
movements (Carter et al. 2000). That these movements occur demonstrates
the importance of maintaining suitable buffer areas and travel corridors for turtles
(Morrow et al. 2001b). On a landscape with limited habitat destruction and fragmentation,
turtles are able to move between populations in search of favorable
conditions or mates. Overall, the known occurrence of large-scale movements in
our population was low—we detected only 1 turtle moving to a different wetland
in the 5-y project. However, we did not recapture several of the turtles in 2 or more
years, and it is possible that they too may have left the wetland.
Bog Turtles have small home-ranges and are capable of existing in small wetlands.
The smallest home range in our population was 0.21 ha, indicating that
management plans should incorporate surveys and protection of smaller wetlands
that may be easily overlooked. Bog Turtle movement rates and home ranges in
our study area were similar between sexes, seasons, and years. These findings
indicate a regular, constant, and continuous use of bog habitat. Home-range locations
shifted between years, possibly allowing turtles to follow ideal habitat
conditions that may change with variation in weather or changes in floral composition
over time. Buffer areas around the primary habitat should be protected to
allow for this fluctuation. Although Bog Turtle home ranges and movements tend
to be restricted to wetland habitat, the documented use of neighboring habitat and
waterways to emigrate out of a population demonstrates the importance of maintaining
the surrounding habitat to promote connectivity in the face of an often
increasingly fragmented or degraded habitat.
Acknowledgments
We thank Friends of the Blue Ridge Parkway for funding our work, and J. Beane, G.
Graeter, D. Herman, E. Leone, B. Teague, T. Thorpe, B. Tyron, and L. Williams for their
support and technical advice. We appreciate assistance in the field from S. Adair, L. Barnes,
J. Barbee, D. Bauer, K. Bauer, S. Gamble, S. Chelf, K. Cherry-Leigh, C. Fisher, J. Gilliam,
M. Hall, C. Henson, K. Lawn, K. McDonald, J. McMann, M. Mullen, D. O’Neill, H.
Newton, A. Paoletta, C. Phillips, J. Pope, S. Price, A. Renfranz, R. Sturgill, C. Trivette, J.
Weaver, K. White, and C. Williams.
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Literature Cited
Beyer, H.L. 2012. Geospatial Modeling Environment version 0.7.2.1. Available online at
http://www.spatialecology.com/gme. Accessed 1 April 2015.
Carter, S.L., C.A. Haas, and J.C. Mitchell. 1999. Home range and habitat selection of Bog
Turtles in Southwestern Virginia. Journal of Wildlife Management 63:853–860.
Carter, S.L., C.A. Haas, and J.C. Mitchell. 2000. Movements and activity of Bog Turtles
(Clemmys muhlenbergii) in Southwestern Virginia. Journal of Herpetology 34:75–80.
Chase, J.D., K.R. Dixon, J.E. Gates, D. Jacobs, and G.J. Taylor. 1989. Habitat characteristics
and population size and home range of the Bog Turtle, Clemmys muhlenbergii, in
Maryland. Journal of Herpetology 23:356–362.
Ernst, C.H. 1977. Biological notes on the Bog Turtle Clemmys muhlenbergii. Herpetologica
33:241–246.
Ernst, C.H., and R.W. Barbour. 1989. Turtles of the World. Smithsonian Institution Press,
Washington, DC. 313 pp.
Ernst, C.H., R.W. Barbour, and J.E. Lovich. 1994. Turtles of the United States and Canada.
Johns Hopkins University Press, Baltimore, MD. 840 pp.
Feaga, J.B. 2010. Wetland hydrology and soil as components of Virginia Bog Turtle
(Glyptemys muhlenbergii) habitat. Ph.D. Dissertation. Virginia Polytechnic Institute and
State University, Blacksburg, VA.
Gibbons, J.W., J.L. Greene, and J.D. Congdon. 1990. Temporal and spatial movement patterns
of sliders and other turtles. Pp. 201–215, In J.W. Gibbons (Ed.). Life History and
Ecology of the Slider Turtle. Smithsonian Institution Press, Washington, DC. 384 pp.
Lee, D.S., and A.W. Norden. 1996. The distribution, ecology, and conservation needs of
Bog Turtles, with special emphasis on Maryland. Maryland Naturalist 40:7–46.
Lovich, J.E., D.W. Herman, and K.M. Fahey. 1992. Seasonal activity and movements of
Bog Turtles (Clemmys muhlenbergii) in North Carolina. Copeia 4:1107–1111.
Morreale, S.J., J.W. Gibbons, and J.D. Congdon. 1984. Significance of activity and movement
in the Yellow-bellied Slider Turtle (Pseudemys scripta). Canadian Journal of Zoology
62:1038–1042.
Morrow, J.L., J.H. Howard, S.A. Smith, and D.K. Poppel. 2001a. Habitat selection and
habitat use by the Bog Turtle (Clemmys muhlenbergii) in Maryland. Journal of Herpetology
35:545–552.
Morrow, J.L., J.H. Howard, S.A. Smith, and D.K. Poppel. 2001b. Home range and movements
of the Bog Turtle (Clemmys muhlenbergii) in Maryland. Journal of Herpetology
35:68–73.
Nemuras, K.T. 1967. Notes on the natural history of Clemmys muhlenbergii. Bulletin of the
Maryland Herpetological Society 3:80–96.
Pittman, S.E., and M.E. Dorcas. 2009. Movements, habitat use, and thermal ecology of an
isolated population of Bog Turtles (Glyptemys muhlenbergii). Copeia 2009:781–790.
Price, A., M.P. Schafale, and I. Smith. 1994. Julian Price Wetlands Natural Area. North
Carolina Natural Heritage Program, Division of Parks and Recreation, North Carolina
Department of Environment, Health, and Natural Resources, Raleigh, NC.
Turtle Conservation Coalition. 2011. Turtles in trouble: The world’s 25+ most endangered
tortoises and freshwater turtles. International Union for Conservation of Nature (IUCN),
SSC (Species Survival Commission), Tortoise and Freshwater Turtle Specialist Group.
IUCN, Gland, Switzerland. Available online at http://cmsdata.iucn.org. Accessed 10
April 2015.
Southeastern Naturalist
219
L.M. Smith, and R.P. Cherry
2016 Vol. 15, No. 2
United States Fish and Wildlife Service (USFWS). 1997. Final rule to list the northern
population of the Bog Turtle as threatened and the southern population as threatened due
to similarity of appearance. Fed. Reg. 62:59605-69623.1006638.
Worton, B.J. 1987. A review of models of home range for animal movement. Ecological
Modeling 38:277–298.
Worton, B.J. 1989. Kernel methods for estimating the utilization distribution in home-range
studies. Ecology 7:164–168.