Journal of Mammalogy, 90(5):1075–1082, 2009
MITOCHONDRIAL DNA PHYLOGEOGRAPHY OF BLACK
BEARS (URSUS AMERICANUS) IN CENTRAL AND SOUTHERN
NORTH AMERICA: CONSERVATION IMPLICATIONS
RONALD A. VAN DEN BUSSCHE,* JUSTIN B. LACK, DAVID P. ONORATO, LYNNE C. GARDNER-SANTANA,
BONNIE R. MCKINNEY, JONAS DELGADILLO VILLALOBOS, MICHAEL J. CHAMBERLAIN, DON WHITE, JR., AND ERIC C. HELLGREN
Department of Zoology, 430 Life Sciences West, Oklahoma State University, Stillwater, OK 74078,
USA (RAVDB, JBL, LCG)
Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Naples, FL 34104, USA (DPO)
Proyecto El Carmen, CEMEX, Avenida Independencia 901 Ote. Col. Cementos, Monterrey, Nuevo Leon,
Mexico (BRM, JV)
School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA 70803,
USA (MJC)
Arkansas Forest Resources Center, University of Arkansas, Monticello, AR 71656, USA (DW)
Cooperative Wildlife Research Laboratory, Department of Zoology, 251 Life Science II, Southern Illinois University,
Carbondale, IL 62901, USA (ECH)
Present address of LCG-S: Johns Hopkins Bloomberg School of Public Health, The W. Harry Feinstone Department of
Molecular Microbiology and Immunology, 615 N Wolfe Street, Suite E5132, Baltimore, MD 21205, USA (LCG)
The American black bear (Ursus americanus) experienced a significant range contraction during the 19th and
20th centuries due to a variety of anthropogenic factors. Although previous molecular studies of black bears
provided insight into historic and contemporary forces shaping phylogeographic patterns, none included black
bears from the central part of the species distribution. Understanding the historical aspects of the connectivity
and genetic differentiation of black bears in this region is important for proper management and conservation
programs, but this understanding is confounded by poorly documented translocation efforts and population
expansion. To address these issues, we generated mitochondrial DNA sequence data for 409 black bears from
15 populations in North America. Two sampling localities (Manitoba, Canada, and Minnesota) were source
populations for translocation into western Arkansas and Louisiana. Major conclusions from our study include:
black bears in western Arkansas were affected genetically by the translocation program; eastern Oklahoma has
been repopulated by westward expansion of bears from Arkansas with a mixture of translocated bears and
remnant individuals; black bears in Louisiana were not affected genetically by the translocation program; black
bears in western Texas and northern Mexico dispersed there from the southeastern United States; and bears in
White River National Wildlife Refuge (eastern Arkansas) share closer genetic affinities with U. a. luteolus than
they do with the widespread U. a. americanus.
Key words:
americanus
black bears, genetic structure, mitochondrial DNA, phylogeography, recolonization, translocation, Ursus
The American black bear (Ursus americanus) experienced a
significant range contraction from its widespread North
American distribution during the 19th and 20th centuries
due to anthropogenic factors such as habitat fragmentation,
* Correspondent: [email protected]
E 2009 American Society of Mammalogists
www.mammalogy.org
1075
unrestricted harvesting, and predator control (Laliberte and
Ripple 2004). This contraction resulted in many isolated
populations, particularly in the southern and southwestern
United States and northern Mexico and may have facilitated
loss of genetic variation and increased genetic differentiation
among populations. Despite this recent fragmentation, many
populations have been increasing in size since the 1980s,
especially within the southern United States (Pelton et al.
1999). Understanding historical aspects of the connectivity
and genetic differentiation among black bears from these areas
1076
JOURNAL OF MAMMALOGY
Vol. 90, No. 5
FIG. 1.—Location of 14 of the 15 populations of black bears (Ursus americanus) sampled in North America. The locality identified in Fig. 2
as ‘‘Trans-Pecos region, Texas’’ (Texas west of the Pecos River) is not mapped because specimens included in that sample did not come from a
single locality (Onorato et al. 2004).
is important for proper management and conservation
programs, but this understanding is confounded by poorly
documented translocation efforts (Smith and Clark 1994) and
population expansion (Bales et al. 2005; Onorato et al. 2004).
These types of events can have a dramatic impact on genetic
characteristics of populations due to naturally and anthropogenically induced founder events and mixture of translocated and remnant gene pools.
Previous molecular studies of black bears provided insight
into historic and contemporary forces shaping phylogeographic patterns (Byun et al. 1997; Onorato et al. 2004;
Paetkau and Strobeck 1996; Stone and Cook 2000; Wooding
and Ward 1997), but none included individuals from the center
of the species distribution, such as Arkansas, Louisiana, or
Oklahoma. This portion of the range of black bears is
particularly important because it has been impacted by
anthropogenic activities (e.g., overharvest and translocation),
contains a federally threatened subspecies (Louisiana black
bear [U. a. luteolus]—Department of the Interior 1992), and
contains a native population within the White River National
Wildlife Refuge (White River NWR) in eastern Arkansas for
which the subspecific taxonomy is uncertain (Fig. 1). A recent
analysis of the subspecific status of the White River NWR
population using skull morphology led to a recommendation
that the population be considered U. americanus subspecies
indeterminate (Kennedy 2006). Black bears at White River
NWR could represent an ‘‘incipient subspecies occurring in a
historic zone of intergradation’’ between U. a. luteolus and U.
a. americanus (Kennedy 2006:27). The subspecific affinity of
black bears in the White River NWR may have conservation
implications for the region (Warrillow et al. 2001).
Populations of black bears were extirpated, or nearly
extirpated from Arkansas, Louisiana, Missouri, and Oklahoma
by the early 1900s (Smith and Clark 1994; Smith et al. 1991).
Habitat loss and increased anthropogenic activities prompted
the decline and eventual extirpation of black bears from
Oklahoma (1915) and Missouri (1931). An estimated 25–50
black bears were thought to remain in Arkansas by the 1940s,
with the majority occurring in the southeastern portion of the
state within the White River bottomland (now White River
NWR—Dellinger 1942; Holder 1951; Smith and Clark 1994).
In an attempt to restore black bears to other parts of Arkansas,
the Arkansas Game and Fish Commission translocated
approximately 250 black bears from Minnesota and Manitoba,
Canada, into Arkansas during 1958–1968 (Miller et al. 1998;
Smith and Clark 1994; Warrillow et al. 2001). Translocation
sites included the Piney Creek and White Rock Wildlife
Management Areas in the Ozark National Forest, and Muddy
Creek Wildlife Management Area in the Ouachita National
Forest (Miller et al. 1998). Thereafter, the population of black
bears in Arkansas grew rapidly (Smith and Clark 1994). By
the 1980s, the success of this translocation resulted in a
westward expansion of black bears into the Ouachita National
Forest of southeastern Oklahoma, where there currently
October 2009
VAN DEN BUSSCHE ET AL.—BLACK BEARS IN CENTRAL NORTH AMERICA
appears to be a viable and growing population (Bales et al.
2005).
From 1964 to 1967, approximately 160 black bears (U. a.
americanus) from Minnesota were released into the Tensas
and Atchafalaya river basins of eastern Louisiana (Lowery
1974). Most of these bears (approximately 130) were
translocated into the area labeled ‘‘Inland Louisiana population’’ in Fig. 1, and at the time of the translocation this area
was believed to be devoid of black bears (Triant et al. 2004).
The remaining approximately 30 individuals were released
into the Tensas River area (Fig. 1). No individuals were
released into the coastal Louisiana area (Taylor 1971). Despite
these translocations, the Louisiana black bear (U. a. luteolus)
was federally listed as threatened in 1992. All black bears in
Louisiana, southern Mississippi, and eastern Texas were
subsequently protected under this listing (Warrillow et al.
2001).
Three independent studies that examined different subsets
of the nuclear genome in different combinations of black bear
populations from Arkansas and Louisiana have added to the
controversy regarding the genetic uniqueness of populations,
subspecific affinities, and impact of the translocation projects
(Csiki et al. 2003; Miller et al. 1998; Triant et al. 2004;
Warrillow et al. 2001). Using DNA fingerprinting techniques,
Miller et al. (1998) concluded that the translocation of black
bears from Canada and Minnesota had no significant genetic
impact on populations of black bears in Arkansas or
Louisiana. Miller et al. (1998) further concluded that the
population of black bears at the White River NWR showed
greater genetic affinity to U. a. luteolus than to U. a.
americanus. This result has significant management implications under the Endangered Species Act.
Warrillow et al. (2001) examined the partitioning of genetic
variation at 7 microsatellite loci within and among 8
populations of black bears, including populations from the
Ozark and Ouachita National Forests and White River NWR
in Arkansas, the Tensas River NWR and upper and lower
Atchafalaya Basin in Louisiana, the Mobile River in southern
Alabama, and Cook County, Minnesota. Their genetic
analyses provided support for a southern coastal plain group
of black bears consisting of the White River, Tensas River,
upper and lower Atchafalaya, and Alabama populations
(Warrillow et al. 2001). Moreover, they concluded that
translocation of black bears into Arkansas and Louisiana
affected the gene pool but did not significantly alter
interpopulation relatedness. Overall, Warrillow et al. (2001),
in agreement with Miller et al. (1998), concluded that black
bears at the White River NWR are U. a. luteolus.
Csiki et al. (2003) examined the partitioning of genetic
variation at 5 microsatellite loci within and among black bears
from Ozark, Ouachita, and White River in Arkansas, inland
and coastal Louisiana, and Minnesota. In contrast to the
conclusions of Miller et al. (1998) and Warrillow et al. (2001),
Csiki et al. (2003) concluded that populations of black bears
from the Ozark and Ouachita mountains of Arkansas and the
inland population of Louisiana were similar in levels of
1077
genetic diversity and allele frequencies to populations from
Minnesota, suggesting that these populations are derived from
descendents of translocated bears. Furthermore, Csiki et al.
(2003) concluded that black bears from White River NWR and
coastal regions of Louisiana represent isolated fragments of a
single North American black bear population and that black
bears from the White River NWR are genetically more distinct
from all other black bear populations than are the federally
protected bears from Louisiana.
These previous molecular studies of black bears provide
insight into the partitioning of genetic variation within and
among populations, but the slowly evolving nuclear markers
used in these studies are less likely to track phylogeographic
patterns as efficiently as do rapidly evolving mitochondrial
loci. The mitochondrial genome is maternally inherited and
therefore has an effective population size one-fourth that of
the nuclear genome. This characteristic, coupled with the lack
of genetic recombination, means that species characterized by
male dispersal should have a greater percentage of the total
genetic variation at mitochondrial loci partitioned among,
rather than within, populations, leading to more readily
observable phylogeographic patterns. Therefore, our objectives were to evaluate the genetic characteristics of black bears
in Arkansas, Louisiana, and Oklahoma based on mitochondrial
DNA (mtDNA) sequence variation and to interpret these
results in light of a broader phylogeographic study by
including black bears from Manitoba and Minnesota (the
source populations for reintroductions of black bears into
Arkansas and Louisiana), New Mexico, western Texas, and
Mexico. Specifically we attempted to address the following
questions: What impact did the translocation of black bears
from Manitoba and Minnesota have on the genetic characteristics of black bears in western Arkansas and Louisiana? What
are the genetic characteristics of the Ouachita Mountain
populations of black bears in southwestern Arkansas and
southeastern Oklahoma? What are the mtDNA affinities of
black bears at White River NWR and black bears from
Louisiana? and What is the comparative strength of mtDNA
links between populations of black bears in western Texas and
northern Mexico with populations in either New Mexico or the
eastern United States.
MATERIALS AND METHODS
We obtained samples of black bears from 15 geographic
areas (Fig. 1). As part of a previous study, black bears were
captured between May 2001 and October 2002 in the Kiamichi
and Choctaw districts of the Ouachita National Forest, LeFlore
County, Oklahoma (Bales et al. 2005). Samples of ear cartilage
were collected from 86 individuals using 6-mm disposable
biopsy punches, stored in 5 ml of lysis buffer, and total cellular
DNA was extracted following the method of Longmire et al.
(1997). We also received samples of DNA from individuals
representing the Ozark (n 5 11), Ouachita (n 5 28), and White
River NWR (n 5 18) populations in Arkansas; an inland region
(n 5 16), southern coastal region (n 5 20), and Tensas River
1078
Vol. 90, No. 5
JOURNAL OF MAMMALOGY
TABLE 1.—Distribution of mitochondrial DNA (mtDNA) haplotypes, measures of haplotype (h) and nucleotide (p) diversity, and standard
errors (SEs) for populations of black bears (Ursus americanus). Collection localities are mapped in Fig. 1.
No. individuals with indicated mtDNA haplotype
Collection locality
A
Manitoba, Canada
Cook County, Minnesota
White River National Wildlife Refuge,
Arkansas
Ozark Mountains, Arkansas
Ouachita Mountains, Arkansas
Ouachita Mountains, Oklahoma
Inland Louisiana
Tensas River, Louisiana
Coastal Louisiana
Big Bend National Park, Texas
26
Black Gap Wildlife Management
Area, Texas
Trans-Pecos region, Texas
1
Mogollon Mountains, New Mexico
Serranias del Burro, Mexico
12
Sierra del Carmen, Mexico
4
B
C
D
E
5
5
F
G
H
2
5
18
1
11
1
16
7
17
5
9
3
I
J
K
3
3
1
L
1
4
14
4
6
3
80
23
3
1
1
25
4
48
31
Area (n 5 30) of Louisiana; Cook County, Minnesota (n 5 10);
and Manitoba, Canada (n 5 20). Finally, we obtained 29 black
bear samples from a concurrent demographic study underway in
the Sierra del Carmen of Coahuila, Mexico. We downloaded
from GenBank sequences of haplotypes A–E (GenBank
accession numbers AY334363–AY334367) defined from black
bears collected in northern Mexico (Serranias del Burro and
Sierra del Carmen), Texas (Big Bend National Park, Black Gap
Wildlife Management Area, and the Trans-Pecos region), and
the Mogollon Mountains of New Mexico (Onorato et al. 2004).
Approximately 555 base pairs (bp) of the mitochondrial
genome covering the 39 end of cytochrome b and 59 end of the
D-loop were amplified by polymerase chain reaction and
sequenced following the methods described in Onorato et al.
(2004). The computer program AssemblyLIGN 1.0.9 (Oxford
Molecular Group PLC 1998) was used to assemble contiguous, overlapping fragments for each individual. A multiple
sequence alignment of all individuals was obtained using
CLUSTAL X software (Thompson et al. 1997), and the
resulting multiple alignment was imported into the computer
program MacClade (Maddison and Maddison 2000) for visual
inspection and to identify unique haplotypes using the
REDUNDANT TAXA option. The computer program TCS
(version 1.21—Clement et al. 2001) was used to generate an
unrooted haplotype genealogy following the algorithm of
Templeton et al. (1992), with ambiguities in the genealogy
resolved following Crandall and Templeton (1993) and
Crandall et al. (1994). An analysis of molecular variance
(AMOVA), estimates of haplotype (h) and nucleotide (p)
diversity, and population comparisons (pairwise wST) were
calculated using ARLEQUIN software (version 3.0—Excoffier et al. 2005). The pattern of interpopulation genetic
differentiation based on Slatkin’s linearized FST was summarized in a neighbor-joining tree using MEGA 4.0 (Tamura et
al. 2007). For all analyses, insertion–deletion events (indels)
1
M
n
h
SE
p
SE
1
20
10
0.858
0.711
0.042
0.118
0.006
0.005
0.003
0.003
18
11
28
86
16
30
20
31
0.000
0.618
0.606
0.134
0.000
0.370
0.268
0.280
0.000
0.104
0.051
0.049
0.000
0.084
0.013
0.090
0.000
0.008
0.005
0.001
0.000
0.001
0.001
0.001
0.000
0.005
0.003
0.001
0.000
0.001
0.001
0.001
9
6
29
60
35
0.000
0.786
0.246
0.325
0.239
0.000
0.113
0.094
0.062
0.092
0.000
0.003
0.001
0.001
0.001
0.000
0.002
0.001
0.001
0.001
were treated as a 5th character state and transition and
transversion substitutions were weighted equally.
RESULTS
Alignment of approximately 555 bp of the mitochondrial
genome from 409 black bears resulted in 14 variable positions
and 13 haplotypes (Table 1). Of the 14 variable positions, 10
are transition substitutions, 1 is a transversion substitution, and
the remaining 3 are indels. Using the computer program TCS,
we produced a haplotype network in which the 95%
confidence limit to connection was 10 steps (Fig. 2). Within
this haplotype network are 2 loops revealing alternative paths.
We believe the connection between haplotypes B and D, the 2
geographically most widespread haplotypes, is the most
parsimonious explanation for the evolutionary history of these
haplotypes. We reject the path connecting haplotypes A and I
via 3 missing haplotypes based on the observation that
haplotype I was restricted to 3 individuals from Manitoba,
whereas haplotype A was detected only in individuals from
Texas and Mexico (Table 1). Similarly, we reject the
connection between haplotypes C and E because haplotype
C was detected in 23 individuals from the Tensas River basin
in Louisiana, 3 individuals from coastal Louisiana, and 1
individual from the Trans-Pecos region of Texas, whereas
haplotype E was detected in individuals from Manitoba,
Minnesota, and 3 mountain ranges (Ozark, Ouachita, and
Mogollon; Table 1).
Haplotypes F–M are new haplotypes detected in this study
(GenBank accession numbers FJ619652–FJ619659). Haplotype
diversity was high (h . 0.7) for Manitoba, Minnesota, and
Trans-Pecos, intermediate for the Ozark and Ouachita (Arkansas) populations, and low (h , 0.4) for all other populations
examined. Nucleotide diversity was low for all populations
sampled (Table 1). The AMOVA revealed a high level of
October 2009
VAN DEN BUSSCHE ET AL.—BLACK BEARS IN CENTRAL NORTH AMERICA
FIG. 2.—Unrooted haplotype network developed using maximum
parsimony and the computer program TCS (Clement et al. 2001).
Letters represent the haplotypes listed in Table 1. Black circles
indicate missing haplotypes. The 2 ambiguous loops (indicated by
dashed lines) were resolved using the protocols of Crandall and
Templeton (1993) and Crandall et al. (1994).
genetic structuring, with 67.32% of the genetic variation
partitioned among populations, and pairwise wST revealed that
67 of the 105 values were significantly different from 0
(Table 2). A neighbor-joining tree based on Slatkin’s linearized
FST-values revealed 2 clusters of populations, a mostly northern
cluster containing populations from Manitoba, Minnesota, the
Ouachita and Ozark mountains of Arkansas, and the Mogollon
Mountains of New Mexico, and a southern cluster containing
samples from eastern Oklahoma, southeastern Arkansas,
Louisiana, western Texas, and Mexico (Fig. 3).
DISCUSSION
It is undisputed that black bears were translocated from
Manitoba and Minnesota into the Ouachita and Ozark
mountains of Arkansas and from Minnesota into the inland
and Tensas regions of Louisiana. However, based on nuclear
microsatellite loci, the impact of these translocations on the
genetic characteristics of these populations has been unclear
(Csiki et al. 2003; Miller et al. 1998; Warrillow et al. 2001).
Examination of our data does not support the conclusion of
Miller et al. (1998) that the introduction of northern black
bears had no genetic impact on populations of the central
United States. Not only are all pairwise comparisons of wST
between source (Manitoba and Minnesota) and recipient
populations in Arkansas nonsignificant (Table 2), these
1079
populations share haplotype E (Table 1). Haplotype E was
previously detected only in black bears from New Mexico
(Onorato et al. 2004), yet our study reveals that this haplotype
is also found in black bears from Manitoba, Minnesota, the
Ozark Mountains of Arkansas, and Ouachita Mountains of
both Arkansas and Oklahoma. Because haplotype E was not
found in any samples we examined from the White River
NWR (an area not receiving translocated individuals),
Louisiana, Texas, or Mexico, the most parsimonious explanation for the presence of this haplotype in the Ouachita and
Ozark mountains is that it represents a genetic signature of the
reintroduction program from Manitoba and Minnesota into
Arkansas and subsequent spread into southeastern Oklahoma.
Further support for our contention that black bear
populations in the Ouachita and Ozark mountains were
influenced by reintroductions comes from the genetic
characteristics of the population of black bears at the White
River NWR. All 18 black bears examined from the White
River NWR possess the predominant (in terms of absolute
numbers and geographic distribution) haplotype B (Table 1),
and this population is significantly differentiated from
populations in the Ouachita and Ozark mountains as well as
Manitoba and Minnesota (Table 2; Fig. 3). This pattern of
differentiation is in direct contrast to the pattern of minimal
genetic differentiation among populations of black bears from
White River NWR, Louisiana (except the Tensas River
population), Mexico, and Texas (except the Big Bend
population [Table 2; Fig. 3]).
It is believed that by about 1915, black bears were
extirpated from eastern Oklahoma (McCarley 1961). Translocation of northern black bears to Arkansas eventually led to
range expansion west along the ridges of the Ouachita
Mountains into southeastern Oklahoma (Bales et al. 2005).
We anticipated that such an expansion would result in minor
genetic differentiation between black bears in the Ouachita
Mountains of Arkansas and Oklahoma, but our analysis
revealed significant differentiation between these 2 populations (Table 2). The Oklahoma population shares haplotypes
B and E with populations from the Ozark and Ouachita
mountains of Arkansas, haplotype H with the Ozark
population, and haplotype F with black bears from the
Ouachita Mountains of Arkansas (Table 1). According to
our network (Fig. 2), haplotype F gave rise to haplotype H,
which is found only in black bears from Oklahoma and the
Ozark Mountains of Arkansas (Table 1). Based on the
relationship among haplotypes (Fig. 2) and the geographic
distribution of haplotypes (Table 1), it is possible that
haplotypes F and H are characteristic of remnant resident
populations in western Arkansas and eastern Oklahoma that
avoided extermination during the early 1900s. We propose
that the population in the Oklahoma Ouachitas represents a
mixture of black bears from the Ozark and Ouachita
mountains of Arkansas influenced by both the translocation
process and genetic characteristics of a remnant population.
The populations in western Arkansas appear to retain the
genetic signature of the translocations from Manitoba and
1080
JOURNAL OF MAMMALOGY
Vol. 90, No. 5
TABLE 2.—Genetic differentiation for all comparisons of black bears (Ursus americanus) examined in this study. Statistically significant
values (P , 0.0005 with Bonferroni correction) are denoted by an asterisk. The solid box in the upper left corner denotes the lack of statistically
significant genetic differentiation among the source populations in Canada and Minnesota and reintroductions in Arkansas. The dashed box
highlights the lack of statistically significant genetic differentiation among several populations in eastern Arkansas, Louisiana, Texas, and
Mexico. Collection localities are mapped in Fig. 1.
Minnesota. This explains the juxtaposition of these populations in the neighbor-joining tree (Fig. 3).
Our results for the populations of black bears in Louisiana
suggest that the genetic characteristics of these populations
have been minimally affected by the translocations (Fig. 3).
The source population for black bears translocated to
Louisiana was Cook County, Minnesota, and our samples
from this population were characterized by individuals
possessing haplotypes B, D, E, and L. Of these haplotypes,
only haplotype B was detected in Louisiana black bears.
However, haplotype B appears to be an ancestral haplotype
and thus does not allow determination of the impact of the
translocation program on Louisiana black bear populations.
Additionally, we noted a lack of significant genetic differentiation among populations from Louisiana (except Tensas),
White River NWR, Texas (except Big Bend), and Mexico,
coupled with highly significant levels of genetic differentiation between these populations and those in Oklahoma,
Manitoba, and Minnesota (Table 2; Fig. 3). Populations of
black bears in White River NWR, coastal Louisiana, Texas,
and Mexico did not receive individuals translocated from
Manitoba or Minnesota, which may explain the clustering of
these taxa in the neighbor-joining tree (Fig. 3). Previous
studies of the influence of translocations on black bears in
Arkansas and Louisiana (Csiki et al. 2003; Miller et al. 1998;
Warrillow et al. 2001) provided conflicting and inconclusive
results, probably because they sampled different combinations
of Arkansas and Louisiana populations, assessed genetic
variation at nuclear versus mitochondrial loci, and assumed
that the genetic implications of the introductions were the
same for all of Arkansas and Louisiana.
Warrillow et al. (2001) concluded that black bears at the
White River NWR were most closely related to the Louisiana
black bear (U. a. luteolus), whereas Csiki et al. (2003)
concluded that black bears from White River NWR and
coastal Louisiana represent isolated fragments of a single
North American population of black bears. Consistent with the
findings of Warrillow et al. (2001), our mtDNA analysis
revealed a lack of statistically significant genetic differentiation between White River NWR and inland and coastal
populations of Louisiana black bears.
Relationships among our study populations based on
analysis of mtDNA suggest that black bears expanded toward
the southwestern United States from 2 directions; they
October 2009
VAN DEN BUSSCHE ET AL.—BLACK BEARS IN CENTRAL NORTH AMERICA
1081
FIG. 3.—Unrooted neighbor-joining tree based on Slatkin’s linearized FST-values depicting relationships among the 15 populations of black
bears (Ursus americanus) mapped in Fig. 1.
expanded southward along the Continental Divide into New
Mexico, and they moved westward from Louisiana into Texas
and Mexico. The genetic link between the New Mexico and
Manitoba populations, the close genetic association of black
bears from Louisiana and those from Texas and Mexico, and
the disparate haplotype signatures of New Mexico versus
Texas and Mexican black bears (Fig. 3; Onorato et al. 2004)
support this scenario. In addition, patterns of Pleistocene treecover expansion and current extent (Williams 2002) provided
the appropriate ecological pathways for black bear colonization in these directions.
Haplotype B is the predominant haplotype we detected,
occurring in all populations except samples from Manitoba and
the Mogollon Mountains of New Mexico. Based on our network
(Fig. 2), haplotype B gave rise to haplotypes A and C, both of
which are found only in the southern United States and northern
Mexico (Table 1). Populations of black bears from White River
NWR, Louisiana, Texas, and Mexico are characterized by
haplotypes A, B, and C, thus the most parsimonious explanation
for the recolonization of this portion of the range of black bears
is the movement of black bears into this region from the east
rather than colonization from New Mexico. Although we did
not have samples of black bears from localities further to the
east, we suspect that the limited number of historical barriers to
gene flow in this region would result in the identification of
haplotypes A–C, which would characterize typical eastern
lineages of black bears (Wooding and Ward 1997). Tests of our
phylogeographic hypotheses await mtDNA analysis of a
comprehensive sampling of black bears in the eastern United
States, Canada, and the Rocky Mountain states.
Development of proper management plans for black bears
requires understanding of past and present levels of population
connectedness. In their phylogenetic survey of black bears
from the southwestern United States and northern Mexico,
Onorato et al. (2004) concluded that the endemic qualities of
haplotypes A, B, and C to the Mexico–Texas region may have
conservation implications for southwestern bears. Inclusion of
mtDNA data from other southeastern populations, especially
fragmented habitats in Alabama and Florida, should complete
the phylogeographic description of black bears in their
southern range.
We reiterate that examination of our mtDNA data indicates
that the translocation of black bears from Manitoba and
Minnesota affected genetic characteristics of black bears at the
sites of reintroduction in western Arkansas, but not Louisiana.
One possible explanation for this difference is related to how
each translocation program was conducted. Over a 10-year
period, the Arkansas Game and Fish Commission moved
approximately 250 black bears from Manitoba and Minnesota
to Arkansas. In contrast, the Louisiana program was smaller
(only about 160 individuals) and of shorter duration (3 years).
Thus, the sustained importation of about 25 bears per year over a
10-year period might allow bears to assimilate better into the
resident population than would importation of a larger number
of bears (.50) per year over a shorter (3-year) period of time.
Finally, black bears from inland and coastal Louisiana and
those from White River NWR, Arkansas, and Louisiana are
genetically indistinguishable based on our data and belong to a
southern clade of black bears that is highly differentiated from
the northern clade (Fig. 3). Thus, our results are consistent
with the conclusion of Warrillow et al. (2001) that black bears
in White River NWR share closer genetic affinities with U. a.
luteolus than they do the widespread U. a. americanus.
ACKNOWLEDGMENTS
We thank D. Rhoades for supplying DNA samples of black bears
from Arkansas, Louisiana, Manitoba, and Minnesota. H. Hristienko
provided tissue samples of black bears trapped in Manitoba. Special
thanks are extended to S. Blochowiak, C. Weigert, and N. Lang for
sequencing some of the samples. We also extend our sincerest
appreciation to the numerous field crews from a variety of black bear
projects who expended a great deal of time and effort collecting these
samples. Finally, we thank the 3 anonymous reviewers and the
Associate Editor, whose comments and criticisms of previous
versions greatly improved this manuscript. Sample collection in
Oklahoma was supported by the Federal Aid, Wildlife Restoration
Act under Project W-147-R of the Oklahoma Department of Wildlife
Conservation and Oklahoma State University administered by D.
1082
JOURNAL OF MAMMALOGY
Leslie, Jr., and the Oklahoma Cooperative Fish and Wildlife Research
Unit (Oklahoma State University, Oklahoma Department of Wildlife
Conservation, United States Geological Survey, and Wildlife
Management Institute). Procedures for handling animals were
approved by the Institutional Animal Care and Use Committee at
Oklahoma State University (protocol AS0131). This study was
supported, in part, by grants from the National Science Foundation
(DEB 06-10844 to RAVDB) and the National Park Service
(Intermountain Region International Conservation Programs Office
to DPO and BRM).
LITERATURE CITED
BALES, S. L., E. C. HELLGREN, AND D. M. LESLIE, JR. 2005. Dynamics
of a recolonizing population of black bears in the Ouachita
Mountains of Oklahoma. Wildlife Society Bulletin 33:1342–1351.
BYUN, S. A., B. F. KOOP, AND T. E. REIMCHEN. 1997. North American
black bear mtDNA phylogeography: implications for morphology
and the Haida Gwaii glacial refugium controversy. Evolution
51:1647–1653.
CLEMENT, M., D. POSADA, AND K. A. CRANDALL. 2001. TCS: a
computer program to estimate gene genealogies. Molecular
Ecology 9:1657–1659.
CRANDALL, K. A., AND A. R. TEMPLETON. 1993. Empirical tests of some
predictions from coalescent theory with applications to intraspecific phylogeny reconstruction. Genetics 134:959–969.
CRANDALL, K. A., A. R. TEMPLETON, AND C. F. SING. 1994.
Intraspecific phylogenetics: problems and solutions. Pp. 273–297
in Phylogeny reconstruction (R. W. L. Scotland, D. J. Siebert, and
D. M. Williams, eds.). Clarendon Press, Oxford, United Kingdom.
CSIKI, I., ET AL. 2003. Genetic variation in black bears in Arkansas and
Louisiana using microsatellite DNA markers. Journal of Mammalogy 84:691–701.
DELLINGER, S. C. 1942. Conservation of wild animal life in Arkansas.
Pp. 289–350 in Arkansas’ natural resources—their conservation
and use (R. Roberts, G. C. Branner, and M. R. Owens, eds.).
Democrat Printing and Lithographing Co., Little Rock, Arkansas.
DEPARTMENT OF THE INTERIOR. 1992. Endangered and threatened
wildlife and plants: threatened status for the Louisiana black bear
and related rules. Federal Register 57:588–595.
EXCOFFIER, L., G. LAVAL, AND S. SCHNEIDER. 2005. Arlequin ver. 3.0:
an integrated software package for population genetics data
analysis. Evolutionary Bioinformatics Online 1:47–50.
HOLDER, T. H. 1951. A survey of Arkansas game. Arkansas Game and
Fish Commission, Little Rock.
KENNEDY, M. L. 2006. An assessment of the subspecific taxonomy of
black bears (Ursus americanus) at the White River National
Wildlife Refuge, Arkansas. Final report. United States Fish and
Wildlife Service, Jackson, Mississippi.
LALIBERTE, A. S., AND W. J. RIBBLE. 2004. Range contractions of North
American carnivores and ungulates. BioScience 54:123–138.
LONGMIRE, J. L., M. MALTBIE, AND R. J. BAKER. 1997. Use of ‘‘lysis
buffer’’ in DNA isolation and its implications for museum
collections. Occasional Papers, The Museum, Texas Tech
University 163:1–3.
LOWERY, G. H., JR. 1974. The mammals of Louisiana and its adjacent
waters. Louisiana State University Press, Baton Rouge.
MADDISON, D. R., AND W. P. MADDISON. 2000. MacClade 4: analysis of
phylogeny and character evolution. Sinauer Associates, Inc.,
Publishers, Sunderland, Massachusetts.
Vol. 90, No. 5
MCCARLEY, H. 1961. New locality records for some Oklahoma
mammals. Southwestern Naturalist 6:108–109.
MILLER, D. A., E. M. HALLERMAN, M. R. VAUGHAN, AND J. W.
KASBOHM. 1998. Genetic variation in black bear populations from
Louisiana and Arkansas: examining the potential influence of
reintroductions from Minnesota. Ursus 10:335–341.
ONORATO, D. P., E. C. HELLGREN, R. A. VAN DEN BUSSCHE, AND D. L.
DOAN-CRIDER. 2004. Phylogeographic patterns within a metapopulation of black bears (Ursus americanus) in the American
southwest. Journal of Mammalogy 85:140–147.
OXFORD MOLECULAR GROUP PLC. 1998. AssemblyLIGN 1.0.9. Oxford
Molecular Group PLC, Oxford, United Kingdom.
PAETKAU, D., AND C. STROBECK. 1996. Mitochondrial DNA and the
phylogeography of Newfoundland black bears. Canadian Journal
of Zoology 74:192–196.
PELTON, M. R., ET AL. 1999. American black bear conservation action
plan. Pp. 144–156 in Bears: status survey and conservation action
plan (C. Servheen, S. Herrero, and B. Peyton, eds.). IUCN/SSC
Bear Specialist Group, Gland, Switzerland.
SMITH, K. G., AND J. D. CLARK. 1994. Black bears in Arkansas:
characteristics of a successful translocation. Journal of Mammalogy 75:309–320.
SMITH, K. G., J. D. CLARK, AND P. S. GIBSON. 1991. History of black
bears in Arkansas: over-exploitation, near elimination and
successful reintroduction. Eastern Workshop on Black Bear
Research and Management 10:5–13.
STONE, K. D., AND J. A. COOK. 2000. Phylogeography of black bears
(Ursus americanus) of the Pacific Northwest. Canadian Journal of
Zoology 78:1218–1223.
TAMURA, K., J. DUDLEY, M. NEI, AND S. KUMAR. 2007. MEGA4:
molecular evolutionary genetics analysis (MEGA) software,
version 4.0. Molecular Biology and Evolution 24:1596–1599.
TAYLOR, D. F. 1971. A radio-telemetry study of the black bear
(Euarctos americanus) with notes on its history and present status in
Louisiana. M.S. thesis, Louisiana State University, Baton Rouge.
TEMPLETON, A. R., K. A. CRANDALL, AND C. F. SING. 1992. A cladistic
analysis of phenotypic associations with haplotypes inferred from
restriction endonuclease mapping and DNA sequence data. III.
Cladogram estimation. Genetics 132:619–633.
THOMPSON, J. D., T. J. GIBBONS, F. PLEWNIAK, F. JEAN-MOUGIN, AND D.
G. HIGGINS. 1997. The CLUSTAL X Windows interface: flexible
strategies for multiple sequence alignment aided by quality
analysis tools. Nucleic Acids Research 25:4876–4882.
TRIANT, D. A., R. M. PACE III, AND M. STINE. 2004. Abundance,
genetic diversity, and conservation of Louisiana black bears (Ursus
americanus luteolus) as detected through noninvasive sampling.
Conservation Genetics 5:647–659.
WARRILLOW, J., M. CULVER, E. HALLERMAN, AND M. VAUGHAN. 2001.
Subspecific affinity of black bears in the White River National
Wildlife Refuge. Journal of Heredity 92:226–233.
WILLIAMS, J. W. 2002. Variations in tree cover in North America
since the last glacial maximum. Global and Planetary Change
35:1–23.
WOODING, S., AND R. WARD. 1997. Phylogeography and Pleistocene
evolution in the North American black bear. Molecular Biology
and Evolution 14:1096–1105.
Submitted 28 August 2008. Accepted 24 February 2009.
Associate Editor was Mark S. Hafner.