Temporal Changes and Prescribed-Fire Effects on
Vegetation and Small-Mammal Communities in Central
Appalachian Forest, Creek, and Field Habitats
Karen E. Francl and Christine J. Small
Southeastern Naturalist, Volume 12, Issue 1 (2013): 11–26
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2013 SOUTHEASTERN NATURALIST 12(1):11–26
Temporal Changes and Prescribed-Fire Effects on
Vegetation and Small-Mammal Communities in Central
Appalachian Forest, Creek, and Field Habitats
Karen E. Francl1,* and Christine J. Small1
Abstract - We quantified changes in vegetation and small-mammal communities over
a 3-year period in paired creek, forest, and field sites in the central Appalachian Mountains.
Prescribed burns were applied to field sites in 2008. Data were collected at all
sites during summers of 2008 (pre-burn for fields), 2009 (ca. 2–4 months post-burn for
fields), and 2010 (ca. 14–16 months post-burn for fields). In 19,640 trap-nights across 3
years, we captured 605 individuals of 14 small-mammal species. Sørenson index showed
substantial differences in mammal communities between 2008 pre-burn and 2009/2010
post-burn fields (<10% similarity for all pre- to post-burn comparisons). Creek and forest
habitats showed markedly greater year-to-year similarities (46–82%). Unlike mammals,
vegetation and habitat structure showed little change over time. Minimal changes in preand
post-burn fields suggest that field vegetation at these sites recovered rapidly after
the low-intensity surface fires. In contrast, fire appears to have had a profound effect on
small-mammal communities in fields, as documented by dramatic temporal changes in
species composition and abundance and little evidence of recovery after 16 months postburn.
As many managed fields in this region are burned on 3-year rotations, this potential
impact of prescribed fire on small-mammal communities is important. Additional studies
are needed to determine whether small-mammal populations are strongly affected by conditions
during prescribed burns (i.e., direct effects on species mortality and emigration),
or if the changes we observed reflect natural cyclical patterns (annual or multi-annual
periodicities) in these populations.
Prescribed fire is a management tool used in a variety of open and forested
habitats in the central Appalachian Mountains. Goals of prescribed fire include
reduction of surface fuels, regeneration of desirable, fire-tolerant forest species,
and maintenance of early successional habitats. Because of the historical application
of fire, many extensive oak (Quercus spp.)- and pine (Pinus spp.)-dominated
forests in the Appalachians are dependent upon fire for long-term maintenance
(Lafon and Hoss 2005).
Several short-term studies of birds (e.g., Greenberg et al. 2007) and herpetofauna
(e.g., Ford et al. 1999, Kirkland et al. 1996, Russell et al. 1999) have
examined the effects of fire in natural habitats of the central and southern
Appalachian Mountains. However, the number of studies investigating fire
effects on Appalachian small-mammal communities is limited. Ford et al.
(1999) found no marked differences in abundances of southern Appalachian
1Biology Department, Radford University, Radford, VA 24142. *Corresponding author -
12 Southeastern Naturalist Vol. 12, No. 1
small-mammal forest species due to prescribed fire, instead attributing preversus
post-fire variation to differences in slope. However, Kirkland et al.
(1996) discovered that generalist species such as Peromyscus leucopus Rafinesque
(White-footed Mouse) were less common in tracts treated with fire than
in unburned tracts. Furthermore, arvicoline rodents were noticeably absent in
burned treatments (Kirkland et al. 1996).
Before European colonization, frequent and widespread fires created
and maintained fire-tolerant vegetation types across the Appalachian region
(Abrams et al. 1997). While a range of presettlement fire regimes occurred,
dendrochronological studies of the George Washington and Jefferson National
Forests (GWJNF; western Virginia) indicate that fire in most mixed oak forest
stands occurred at ca. 3- to 9-year intervals from the mid-1600s until the 1930s
(Abrams et al. 1997, Nowacki and Abrams 2008). Today, prescribed fire is ap -
plied, in part, to reestablish these historic intervals, with goals including the
restoration of native communities and creation or maintenance of habitats suitable
to rare species (USDA Forest Service 2011). In many forested habitats,
managers follow a prescribed burn cycle of 4 to 12 years to promote forest
health and to keep fuel loads at a manageable level. For grassland habitats
managed by the US Forest Service, this burn cycle may be as little as 2 to 3
years to ensure the maintenance of an early-successional state (C. Croy, USFS,
Roanoke, VA, pers. comm.).
Despite the frequent use of prescribed fire on the GWJNF, most studies of
early-successional fire effects in the Appalachian region focus on vegetation and
abiotic properties (e.g., Christensen 1976) or on fires in late-successional habitats
(Ford et al. 1999). Indeed, no published studies of the effects of fire on small
mammals in early-successional habitats of the Appalachian Mountains could be
found in recent literature. One possible explanation for lack of studies is that
small mammals typically are not a target group by resource managers because
many species in the region are generalists that might not respond to habitat alterations
(Litvaitis 2001, Mitchell et al. 1997).
Given the prevalence of prescribed fire as a management tool in our region,
and the scarcity of studies examining fire effects on early-successional small
mammals, we investigated short-term (3-year) changes in small-mammal communities
following prescribed fire in a central Appalachian early-successional
habitat. By examining capture success in pre- and post-burn fields, as well as
adjacent unburned creek and hardwood forest sites, we sought to better understand
prescribed fire effects and natural short-term variations in vegetation and
resident small-mammal communities in common habitats of the central Appalachian
Data on small-mammal community composition and capture success were
collected over a 3-year period (2008–2010) at the Caldwell Fields complex on
2013 K.E. Francl and C.J. Small 13
the GWJNF (Montgomery County, VA; 37.3370735°N, 80.3256051°W). This
site encompasses a number of habitat types, including two fields (6.35-ha Addison
Field and 1.95-ha Liatris Field) burned in late February or early March on
a 3-year rotation. Each field was bordered by an adjacent creek (Craig Creek)
and associated riparian habitat that served as a firebreak for field burns. Mature
mixed-hardwood forests occur on east- and west-facing slopes. Some portions of
the forest tracts were historically burned in a controlled manner (e.g., forest tract
south of Liatris Field burned in 2000). However, the passage of the 2009 Ridge
and Valley Act (part of HR146) set aside 1940 ha of Brush Mountain (including
both of our forest tracts) as a Wilderness Area, and precluded future use of prescribed
fire as a management tool.
Studies were conducted immediately before and in the two years after prescribed
fire in Addison and Liatris fields. This timing allowed us to examine
small-mammal and habitat trends before burning (Year 1: 2008, >2 years postfire),
at their most disturbed (Year 2: 2009, ca. 2–4 mo. post-burn), and at a
moderate level of disturbance (Year 3: 2010, 14–16 months post-burn). Creek
(at the edge of each burn unit) and forest (not burned) sites provided habitat
comparisons and allowed us to observe annual fluctuations in small-mammal
communities in the absence of fire.
At the two field and two forest sites, we established three 100-m transects
per site, each with trap stations at 5-m intervals. To reduce trap bias
(e.g., Rana 1982), we used a combination of 7.6- x 8.9- x 22.9-cm Sherman
live traps (H.B. Sherman, Inc., Tallahassee, FL) and Victor mouse snap-traps
(Model #M154, Woodstream Corp., Lititz, PA) placed in visible mammal runways,
along logs, or at the bases of shrubs within 1 m of the trapping interval.
Additionally, we used six Tomahawk traps (four size #202, two size #207;
Tomahawk Live Trap Co., Tomahawk, WI): two per 100-m transect, each separated
by at least 25 m. At the two creek sites, we established a line of traps on
one (Addison; 300-m transect) or both (Liatris; two 150-m transects) sides of
the creek, as restricted by the topography of the site. Traps were baited with
rolled oats and peanut butter (Shermans), sardines (snap traps), or canned dog
food and a variety of fruits and vegetables (Tomahawks). Although we acknowledge
that the addition of pitfall traps may have further limited trap bias
(e.g., Francl et al. 2002, Mengak and Guynn 1987), time and state permitting
limitations did not allow for the use of this additional technique.
We set traps for four consecutive nights in late May and again in early July
of 2008, 2009, and 2010. Each site contained a total of 6 Tomahawks, 60 Shermans,
and 60 snap-traps, which were checked twice daily—morning and late
afternoon. All live small mammals captured were sexed, aged (juvenile vs.
adult), measured (total length, tail length, hind foot length, ear length) to assist
with species identification, weighed, marked with an ear clip to determine recapture
rates, and released.
14 Southeastern Naturalist Vol. 12, No. 1
Some Peromyscus individuals did not clearly fall into the length categories
and visual descriptions of P. maniculatus Wagner (Deer Mouse) or P. leucopus
and were treated as Peromyscus sp. in statistical analyses (Linzey 1998). Larger
mammals (>1 kg) in Tomahawks were sexed, weighed, and released. Deceased
mammals were identified, measured, and subsequently frozen. Some have been
prepared as voucher specimens and deposited in the Radford University Department
of Biology’s natural history collection.
For statistical analyses, we converted species capture numbers to capture per
trap night as an index of relative abundance. Because preliminary analyses found
no differences in capture success between trapping bouts within a yea r (May vs.
July), we combined capture effort to focus on differences among years. Further,
because no discernible biases were discovered in preliminary analyses of temperature,
moon phase, and rainfall (monthly or annual), we did not examine these
All trapping was completed in compliance with the Radford University
Animal Care and Use Committee (Francl, #FY08-013), within the guidelines
of Virginia scientific collecting permits (Francl, # 031159 and 035794), and
with written permission from the USDA Forest Service, Eastern Divide Ranger
To characterize vegetation composition and habitat structure, we established
one 400-m2 plot at each site. Field and forest plots were 20 x 20 m;
creek plots were 10 x 40 m, with the longest plot dimension parallel to the
creek edge to maintain habitat homogeneity within the plot. All plots were
immediately adjacent to or within small-mammal trapping grids. Because plot
corners were not permanently fixed, some degree of year-to-year variation
in plot location (± 10 m) occurred at each study site. In each plot, percentage
ground area covered by each vascular plant species was estimated using
standard cover classes (<1, 1–2, 2–5, 5–10, 10–25, 25–50, 50–75, 75–100%;
VA DCR-DNH 2011). In addition, we estimated total cover per plot for bryophytes/
lichen and surface-substrate categories (bedrock, mineral soil, water,
decaying wood, leaf litter, other). Basal area and stem density were determined
for each woody species reaching or exceeding breast height (1.37 m)
in each plot. Additional plot measures included: number of snags (dead upright
trees >10 cm diameter at breast height [DBH]); number of logs (dead,
downed trees >2 m long, >10 cm diameter); light (5 replicate measures of
photosynthetically active radiation [PAR]; LI-250A quantum sensor light
meter, LI-COR, Lincoln, NE); tree canopy cover (concave spherical densiometer,
following corrected procedure of Strickler : % tree canopy cover
= [(sum of cover estimates at cardinal compass directions) x 1.5)] - 1); soil
moisture (4 replicate measures; Kel Instruments, Inc., Wyckoff, NJ); leaflitter
depth (4 replicate measures); elevation; slope steepness; and topographic
aspect. Twenty replicate range-pole measurements were taken in each plot
2013 K.E. Francl and C.J. Small 15
to calculate the Levins index of vertical diversity (Levins 1968) and total
vegetation volume (Mills et al. 1989). Composite soil samples from the Ahorizon
(upper 10 cm) were collected from each plot and used in laboratory
determinations of soil pH (glass-electrode method) and percent organic matter
(dry-ash method; Shepard et al. 1993). Habitat surveys were conducted in
early July 2008, 2009, and 2010.
Vegetation and small-mammal capture data were compared across our six
sites and three sample years using global Non-Metric Multidimensional Scaling
(NMS) ordination, with Sørenson distance (Magurran 2004, McCune and
Grace 2002). NMS ordination has been shown to perform well with ecological
data, which tend to be non-normal and contain numerous zero entries (Mc-
Cune and Grace 2002). Separate ordinations were performed for vegetation
and small-mammal data. Following ordination analysis, Pearson productmoment
correlations of habitat variables and NMS axis scores were calculated
to identify habitat conditions most strongly correlated with small-mammal
To test for changes in small-mammal and vegetation communities across sites
and years, we used blocked multi-response permutation procedure (MRPP). This
non-parametric, multivariate analysis tests for significant differences in species
composition between samples (McCune and Grace 2002). Sørenson was used as
the distance measure for consistency with NMS ordination analyses. All multivariate
analyses were conducted using PC-ORD for Windows (ver. 5.14; MjM
Software, Gleneden Beach, OR).
In 18,144 trapnights across 3 years, we trapped 605 individuals of 14 mammal
species (12 species in 2008, 9 in 2009, 9 in 2010; Table 1). Mammal trap success
by year was 4.3% in 2008, 2.7% in 2009, and 1.9% in 2010, including recaptures.
Two species of Peromyscus, White-footed Mouse (25.6% of all captures) and
Deer Mouse (24.8% of all captures), dominated captures across all years. Sigmodon
hispidus Say and Ord (Hispid Cotton Rat), captured in 2008 in Addison
Field, was a new county record (Francl and Meikle 2009).
Small-mammal communities differed markedly across habitats, particularly in
fields. In our initial sample year (2008), mammal captures in fields were ≤10%
similar to creeks or forests (Sørenson index; Table 2). Mammal captures in creek
and forest habitats showed much greater compositional similarity (>50% similarity)
in 2008 (Table 2). Ordination analysis of small-mammal captures was best fit
by a two-axis solution, based on a NMS scree plot and Monte Carlo randomization
test (P < 0.05, final stress = 26.63, final instability = 0.05, 500 iterations).
These NMS axes accounted for 84.5% of the variability in the data (Axis 1 =
16 Southeastern Naturalist Vol. 12, No. 1
Table 1. Capture metrics (captures per trapnight and species richness) for small mammals at Caldwell Fields complex, VA over a three-year study. Within
the complex, Addison and Liatris sites each included a field, an adjacent creek, and upland forest. The two field sites had prescribed burns between the
2008 and 2009 trapping efforts.
Creek Field Forest
Location/Order Family Scientific name 2008 2009 2010 2008 2009 2010 2008 2009 2010
Didelphimorphia Didelphidae Didelphis virginiana 0.001 0.002 - - - - - 0.002 -
Insectivora Soricidae Blarina brevicauda - 0.002 0.004 0.004 0.002 0.004 - 0.002 0.001
Insectivora Soricidae Cryptotis parva - - - 0.003 - - - - -
Rodentia Cricetidae Microtus pennsylvanicus - - - 0.095 0.002 0.001 - - -
Rodentia Cricetidae Peromyscus leucopus 0.022 0.017 0.012 0.002 0.001 - 0.012 0.006 0.002
Rodentia Cricetidae Permyscus maniculatus 0.010 0.015 0.023 0.004 - - 0.004 0.007 0.003
Rodentia Cricetidae Peromyscus sp. 0.015 0.003 0.002 0.001 - - 0.002 0.002 0.001
Rodentia Cricetidae Sigmodon hispidus - - - 0.006 - - - - -
Rodentia Cricetidae Synaptomys cooperi - 0.001 - 0.013 - - - - -
Rodentia Sciuridae Glaucomys volans - - - - - - - - 0.001
Rodentia Sciuridae Tamias striatus 0.001 - - - 0.001 - - - -
Rodentia Cricetidae Zapus hudsonius - 0.002 - - 0.005 - - - -
Carnivora Mephitidae Mephitis mephitis - - - - - 0.002 - - -
Carnivora Procyonidae Procyon lotor - 0.001 - - - - - - -
Lagomorpha Leporidae Sylvilagus floridanus - - - 0.001 - - - - -
Species richness 4 7 3 8 5 3 2 4 4
Didelphimorphia Didelphidae Didelphis virginiana - - - - - - 0.001 - -
Insectivora Soricidae Blarina brevicauda - 0.003 - 0.001 - - - 0.001 0.002
Insectivora Soricidae Cryptotis parva - - - - - - - - -
Rodentia Cricetidae Microtus pennsylvanicus - - - 0.039 0.002 0.002 - - -
Rodentia Cricetidae Peromyscus leucopus 0.020 0.017 0.011 0.001 0.006 - 0.013 0.009 0.004
Rodentia Cricetidae Permyscus maniculatus 0.008 0.022 0.023 0.002 0.003 - 0.005 0.013 0.007
Rodentia Cricetidae Peromyscus sp. 0.008 0.005 0.002 - - - 0.012 0.003 0.004
Rodentia Cricetidae Sigmodon hispidus - - - - - - - - -
Rodentia Cricetidae Synaptomys cooperi - - - - - - - - -
Rodentia Sciuridae Glaucomys volans - - - - - - - - -
Rodentia Sciuridae Tamias striatus - - 0.001 - 0.001 - 0.002 0.004 0.003
Rodentia Cricetidae Zapus hudsonius 0.001 - - 0.002 0.001 0.001 - - -
Carnivora Mephitidae Mephitis mephitis - - - - - - - - -
Carnivora Procyonidae Procyon lotor 0.001 0.001 - - - - - 0.001 -
Lagomorpha Leporidae Sylvilagus floridanus - - - - - 0.001 - - -
Species richness 4 4 3 5 5 3 4 5 4
2013 K.E. Francl and C.J. Small 17
Table 2. Sørenson similarity (%) for small-mammal captures at Addison (AD) and Liatris (LI) field, creek, and forest sites throughout the three-year study
period. Underlined values are discussed in text. (See Methods f or complete description of sampling design.)
2008 2009 2010
AD LI AD LI AD LI
Field Creek Forest Field Creek Forest Field Creek Forest Field Creek Forest Field Creek Forest Field Creek Forest
AD Field 100.0 8.3 9.9 49.4 8.7 9.1 7.0 12.0 12.6 9.9 11.7 10.4 7.2 13.3 10.0 4.4 8.9 12.5
AD Creek 100.0 53.0 6.7 83.7 77.2 6.6 67.7 46.6 31.9 66.2 58.0 0.0 53.7 20.8 0.0 56.2 46.0
AD Forest 100.0 10.0 62.4 70.3 6.9 58.8 66.2 58.2 54.4 62.7 0.0 60.5 46.3 0.0 62.7 54.5
LI Field 100.0 10.0 8.1 21.8 14.1 13.2 21.1 9.1 10.9 7.8 9.8 15.6 12.0 7.7 13.0
LI Creek 100.0 73.5 8.2 74.2 51.3 38.1 72.1 61.1 0.0 56.0 25.3 4.6 56.3 50.4
LI Forest 100.0 9.1 58.4 55.3 43.4 57.1 60.8 0.0 52.2 29.2 0.0 55.2 58.3
AD Field 100.0 18.5 20.0 41.7 10.2 14.3 33.3 11.5 21.1 40.0 8.3 25.8
AD Creek 100.0 61.3 35.7 83.5 73.0 8.0 73.8 27.5 4.3 70.0 50.8
AD Forest 100.0 56.3 50.7 64.0 15.4 56.7 51.9 0.0 53.6 76.9
LI Field 100.0 29.5 45.5 10.0 33.3 47.6 35.3 40.0 48.5
LI Creek 100.0 68.4 10.9 87.6 25.0 0.0 82.4 50.0
LI Forest 100.0 5.3 69.4 35.9 0.0 73.5 70.6
AD Field 100.0 16.7 13.3 18.2 0.0 14.8
AD Creek 100.0 28.6 0.0 92.3 49.2
AD Forest 100.0 0.0 26.7 50.0
LI Field 100.0 0.0 0.0
LI Creek 100.0 49.1
LI Forest 100.0
18 Southeastern Naturalist Vol. 12, No. 1
39.4%, Axis 2 = 45.1%). Again, mammal captures in field sites appeared most
distinct, separating out low on NMS Axes 1 and 2 (Fig. 1A) and negatively correlated
with light availability (Axis 1 r = -0.73, Axis 2 r = -0.66). Captures in
2013 K.E. Francl and C.J. Small 19
forest and creek sites showed much greater similarity and were arranged high
on NMS Axes 1 and 2. These were positively correlated with tree canopy cover
(Axis 1 r = 0.75, Axis 2 r = 0.70) and shrub cover (Axis 1 r = 0.47, Axis 2 r =
0.65). Soil moisture also was positively correlated with Axis 1 (r = 0.64).
Mammal species differed considerably in their habitat preferences. Across all
years, Peromyscus species showed similar habitat preferences, based on NMS
ordination results (Fig. 1B). Deer Mice (Axis 1 r = 0.61, Axis 2 r = 0.38) and Whitefooted
Mice (Axis 1 r = 0.76, Axis 2 r = 0.50) were positively correlated with Axes 1
and 2, indicating greater capture success at creek sites. We captured Tamias striatus
L. (Eastern Chipmunk) only in forests (Axis 1 r = 0.21, Axis 2 r = 0.26). Didelphis
virginiana Kerr (Virginia Opossum; Axis 1 r = 0.28, Axis 2 r = 0.28) and Procyon
lotor L. (Raccoon; Axis 1 r = 0.41, Axis 2 r = 0.25) were captured at both forest
and creek sites (Fig. 1B). Microtus pennsylvanicus Ord (Meadow Vole; Axis 1 r =
-0.72), Sylvilagus floridanus J.A. Allen (Eastern Cottontail; Axis 1 r = -0.58), and
Zapus hudsonius Zimmermann (Meadow Jumping Mouse; Axis 1 r = -0.54) all
were negatively correlated with Axes 1 and 2, with higher capture success in fields.
Blarina brevicauda Say (Northern Short-tailed Shrew; Axis 1 r = -0.15, Axis 2 r =
-0.22) was ubiquitous across habitat types.
In examining year-to-year variations in mammal communities, we found
that fields showed considerable declines in small-mammal captures over time,
whereas capture rates in creeks and forests were relatively constant (Table 1).
Results of MRPP analysis emphasized this marked change in field mammals
over time (within group distance = 272.4–654.4) and lesser changes in creek
(134.5–152.8) and forest (75.9–108.0) habitats (Table 3). Sørenson values for
fields were extremely low across years, especially when comparing 2008 (preburn)
mammal communities to post-burn years (all 7–21% similarity; Table 2).
Two species (Hispid Cotton Rat and Least Shrew [Cryptotis parva Say]) were
Figure 1 (opposite page). NMS ordination of small-mammal capture data at Liatris
(LI) and Addison (AD) study sites (field = FI, creek = CK, forest = FO). Each site was
sampled in 2008, 2009, 2010. A) Vectors indicate the strength and direction of Pearson
product-moment correlations between plots and habitat variables. Vectors: trees = mean
relative basal area and density; canopy = tree canopy cover; topographic position = visual
characterization of topography position (1 = crest, 2 = upper slope, 3 = middle slope,
4 = lower slope, 5 = toe slope, 6 = floodplain or level bottom, 7 = basin or depression;
categories follow VA DCR-DNH ). (See Table 4 and text for remaining variable
definitions and field methods.) B) Locations of species maxima on the ordination, based
on abundance at each study site and sample year. Species abbreviations: BLBR= Blarina
brevicauda, CRPA= Cryptotis parva, DIVI= Didelphis virginiana, GLVO= Glaucomys
volans L. (Southern Flying Squirrel), MEME= Mephitis mephitis Schreber (Striped
Skunk), MIPE= Microtus pennsylvanicus, PEsp= Peromyscus leucopus/maniculatus
(unknown), PELE= Peromyscus leucopus, PEMA= Peromyscus maniculatus, PRLO=
Procyon lotor, SIHI= Sigmodon hispidus, SYCO= Synaptomys cooperi Baird (Southern
Bog Lemming), SYFL= Sylvilagus floridanus, TAST= Tamias striatus, ZAHU= Zapus
hudsonius. C) Vectors connect annual observations for each study site, illustrating magnitude
and direction of change in mammal communities from 2008 to 2010.
20 Southeastern Naturalist Vol. 12, No. 1
captured solely in Addison Field in 2008. Although similarity remained relatively
low, field mammals showed much greater similarity in 2009 vs. 2010 post-burn
samples (33–35% similarity), (Table 2). Ordination analysis also emphasized the
dramatic compositional shift in pre- to post-burn mammals (2008 vs. 2009 and
2010 fields; Fig. 1C). In contrast, forest (46–71% similarity) and creek (53–82%
similarity) sites showed relatively little change in mammal captures across our
three years of sampling (Table 2, Fig. 1C).
Unlike small-mammal communities, vegetation showed little change over
time, regardless of habitat type. Our three habitat types were widely separated
on the vegetation ordination (two-axis solution, final stress = 5.68, final instability
= less than 0.00001, 59 iterations), indicating marked compositional differences,
particularly in fields. However, within-habitat variation was minimal (Fig. 2).
Each habitat/study site showed tight clustering of 2008, 2009, 2010 samples,
indicating little year-to-year variation. Most compositional variation was explained
by ordination Axis 2 (65.6%). Axis 2 was positively correlated with
Figure 2. NMS ordination of vegetation data at Liatris (LI) and Addison (AD) study sites
(field = FI, creek = CK, forest = FO). Each site was sampled in 2008, 2009, and 2010.
Vectors connect annual observations for each study site, illustrating magnitude and direction
of vegetation change from 2008 to 2010. (See text for complete description of habitat
variables and sampling methodology).
2013 K.E. Francl and C.J. Small 21
light (r = 0.77) and herbaceous cover (r = 0.66), which reached greatest abundance
in fields, and negatively correlated with tree cover (r = -0.85), shrub (r =
-0.69) cover, and density of logs (r = -0.81) and snags (r = -0.80), factors greatest
in our tree-dominated creek and forest sites. Axis 1 accounted for 22.3% of
the variation in vegetation data and was strongly correlated with moisture (r =
0.94; greatest in creek sites).
Table 3. Multi-response permutation procedure (MRPP) analysis of changes in small-mammal and
vegetation communities from 2008 to 2010 at Addison and Liatris study sites. Values represent average
within-group Euclidean distance. Mammals were trapped along three 100-m transects at each
site, with trap stations at 5-m intervals, using a combination of Sherman live traps and Victor mouse
snap-traps. Vegetation data were collected in one 400-m2 plot adjacent to or within small-mammal
trapping grids in each habitat. (See Methods section for a complete description of sampling design.)
Field Creek Forest
Addison Liatris Addison Liatris Addison Liatris
Small mammals 654.4 272.4 152.8 134.5 75.9 108.0
Vegetation 2.5 3.7 15.4 9.2 11.8 9.3
Table 4. Habitat variables measured in one 400-m2 plot adjacent to or within small-mammal trapping
grids at Addison and Liatris study sites. Values represent means ± standard error of 2008,
2009, and 2010 data. Only variables significantly correlated with NMS ordination of small-mammal
captures (Fig. 1) shown. See text for variable definitions a nd field methods.
Field Creek Forest
Addison Liatris Addison Liatris Addison Liatris
Tree basal area (m2/400-m2 plot) 0.00 0.00 1.06 0.91 0.79 0.70
(0.00) (0.00) (0.20) (0.44) (0.08) (0.05)
Tree density (stems/400-m2 plot) 0.00 1.33 168.00 18.67 125.67 98.33
(0.00) (1.33) (59.01) (6.69) (7.80) (26.03)
Tree canopy cover (%) 0.50 4.40 96.07 86.73 73.97 81.83
(0.50) (4.40) (1.97) (5.87) (15.78) (6.85)
Shrub cover (%) 2.17 5.50 13.83 14.00 22.00 43.33
(0.67) (0.58) (2.33) (1.32) (1.89) (5.67)
Herbaceous cover (%) 100.00 100.00 85.67 100.00 34.83 33.67
(0.00) (0.00) (7.84) (0.00) (5.25) (3.83)
Light (μmol/sec/m2) 1027.78 1203.39 19.00 66.43 37.97 204.35
(93.34) (81.13) (4.40) (13.28) (3.50) (276.85)
Soil moisture (%) 37.67 40.40 32.92 36.32 14.17 7.75
(5.63) (7.52) (6.36) (7.83) (5.56) (3.06)
Snag density (#/plot) 0.00 0.00 1.00 0.67 3.67 4.00
(0.00) (0.00) (0.58) (0.33) (1.20) (0.00)
Log density (#/plot) 0.00 0.33 2.33 2.33 9.67 6.67
(0.00) (0.33) (0.88) (0.88) (1.20) (2.03)
22 Southeastern Naturalist Vol. 12, No. 1
Results of MRPP analyses emphasized the lack of vegetation change over
time (MRPP within group distance = 2.5–15.4), as compared to small mammal
communities (Table 3). This stability was expected in forest and creek habitats,
as these are dominated by long-lived trees and thus maintain relatively constant
composition and structure. These sites were heavily wooded with high tree density,
basal area, and canopy cover (Table 4). Forests generally had greater density
of snags and logs; creeks had higher herbaceous cover (comparable to fields).
Field habitats remained open, with high light, dense herbaceous cover, and few
trees or shrubs (Table 4). Snags and downed logs were virtually absent. However,
given the 2008 prescribed burns and pronounced changes in field mammals over
time, the lack of temporal change in field vegetation (average within-group distance
= 2.5–3.7; Table 3) was a strong contrast.
Perhaps the most notable finding at the Caldwell Fields complex was the stark
difference in fire response by mammal and vegetation communities. Whereas
mammals exhibited precipitous declines in capture success and species richness,
vegetation showed markedly little change over our three-year study. Both ordination
(Fig. 1) and MRPP (Table 2) analyses highlighted the dramatic changes
in small-mammal communities over time (within-group distance for small mammals,
all habitat types = 233.0 ± 88.6). These temporal changes were particularly
pronounced in field sites (463.4 ± 191.0). In contrast, we found relative stability
of vegetation and habitat structure at each site (within-group distance for all
vegetation types = 8.7 ± 2.0). Least compositional change was observed in field
sites, despite prescribed burns (Table 2, Fig. 2). As our field sites were dominated
by a mixture of early-successional species, including many fire-tolerant perennial
grasses and forbs, it is not surprising that field vegetation recovered quickly after
prescribed fires. As in other eastern North American natural areas where fire is
used to maintain open grassland conditions and control invasion of woody plants
(e.g., Christensen 1976), fire appeared to have little detrimental effect on herbaceous
plants at our site.
Based on other studies, we predicted highest small-mammal capture rates
in fields prior to burning, lowest immediately after burning, and recovery to
near pre-burn levels within 1–2 years. Due to the absence of fire, we expected
considerably less year-to-year variation in adjacent creek and forest sites. The
mammalian species richness declines that we observed in the short-term were
similar to a Utah study of Artemisia tridentata Nutt. (Big Sagebrush ) community.
McGee (1982) found that small-mammal species richness declined
slightly post-fire but returned to pre-burn levels after three years. In this Utah
study, however, total mammalian abundance significantly increased in the first
two years post-burn, partly because of a dramatic increase in captures (presumably
also an increase in abundance) of Deer Mice, a species also present in our
study. Studies in Midwestern tallgrass prairies and western grassland systems
also reported generally high survival rates for Deer Mice and White-footed
Mice following fire, and increased abundance during the next growing season
2013 K.E. Francl and C.J. Small 23
relative to pre-burn and unburned sites. Population increases were attributed to
their rapid colonization ability and reduced litter depth and increased food supplies
for Peromyscus spp. after fire (Kaufman et al. 1990, Sullivan 1995). In our
study, however, both Deer Mice and White-footed Mice were uncommon in the
field sites across all years, and both populations appeared stable and abundant
in the creek and forest sites.
Both forest sites showed declines in mammal capture success from 2009 to
2010, but these declines were of lesser magnitude than in our fields and were
not evident from 2008 to 2009. In addition, year-to-year variation in mammal
composition (based on Euclidean distance) was minimal in creek and especially
forest sites, as compared to fields (Table 3). However, it is possible that our
trapping techniques (lack of pitfall traps) underestimated soricid community’s
response to fire.
We cannot eliminate the possibility that mammalian communities varied not
only because of the prescribed fire, but also because of natural cyclical patterns.
Other studies have shown that Deer Mice, White-footed Mice, and Hispid Cotton
Rats all exhibit annual or multi-annual periodicities (Brady and Slade 2004,
Langley and Shure 1988, Rehmeier et al. 2005). Despite our preliminary analyses
indicating that yearly or monthly rainfall was not correlated with capture success,
unmeasured climatological metrics may have altered resource availability (e.g.,
food, nesting sites) for small mammals (Langley and Shure 1988, Rehmeier et
al. 2005). However, if the observed variations were linked to climate patterns
and natural population cycles, we should expect comparable declines at our forest
and (potentially) creek sites. All of our habitats showed marked changes in
mammal captures over time, yet none were as dramatic as our field sites. It is
important to note, however, that eastern forests typically show little response to
small-scale moisture variations (Small and McCarthy 2002). High canopy cover
and moisture availability at our creek sites would contribute greatly to droughtresilience.
Our forest sites, on the other hand, were significantly drier than other
habitats (Table 4), dominated by relatively drought-tolerant oak- and heathdominated
Our study provides evidence that small-mammal communities in central Appalachian
grasslands are responding to prescribed fire in the short-term, while
habitat conditions remain remarkably unchanged. Lack of variati on in field vegetation
from pre- to post-burn years suggests that plant species in these habitats
are tolerant of low-intensity surface fire. In contrast, the small-mammal communities
of Caldwell Fields complex showed marked change, without recovery
16 months post-burn (despite little change in habitat structure). As many managed
fields in this region are burned on 3-year rotations, this potential impact of
prescribed fire on small-mammal communities is important. Additional studies
are needed to determine whether small-mammal populations show pronounced
response to conditions occurring during prescribed burns (i.e., direct effects on
species mortality and emigration), or if the changes we observed reflect natural
cyclical patterns (annual or multi-annual periodicities) in these populations, as
reported for selected small-mammal populations in other regions .
24 Southeastern Naturalist Vol. 12, No. 1
Due to the brevity of our project, the long-term implications still are unknown.
We suggest that surveys like these be expanded to investigate the
effects on mammals in other burned grasslands on the George Washington
and Jefferson National Forests. A larger-scale small-mammal surveying effort
would allow investigators to capture multiple fields at different stages of postfire
succession. The time between burns also could be investigated as a factor
in small-mammal recovery.
Because of the failure for small-mammal communities to recover 16 months
post-burn, we suggest that care be taken in burning early-successional habitats.
It is likely that an additional year between burns (4-year rotation) at Caldwell
Fields could allow for sufficient recovery time for small-mammal populations,
yet still maintain an early-successional habitat. In cases where previous smallmammal
surveys have revealed the presence of rare species or species of concern,
the details (season, frequency) of the burn should be planned with this species’
natural history characteristics in mind.
We thank C. Croy, S. Croy, and J. Overcash of the USDA Forest Service for
assistance with site selection and GIS mapping components. We also thank numerous
student technicians who assisted with field work and lab analyses: M. Baisey,
R.C. Bland, M. Brennan, E. Burnett, T. Canniff, K. Creange, S. Demeo, C. Faidley,
G. Good, J. Lucas, D. Mathews, D. Meikle, B. Meyer, A. Noble, M.A. Patton, and K.
Urban. This work was supported by two Radford University Faculty Summe r Scholarships
in 2008 and 2010.
Abrams, M.D., D.A. Orwig, and M.J. Dockry. 1997. Dendroecology and successional
status of two contrasting old-growth oak forests in the Blue Ridge Mountains, USA.
Canadian Journal of Forest Research 27(7):994–1002.
Brady, M.J., and N.A. Slade. 2004. Long-term dynamics of a grassland rodent community.
Journal of Mammalogy 85(3):552–561.
Christensen, N.L. 1976. Short-term effects of mowing and burning on soil nutrients
in Big Meadows, Shenandoah National Park. Journal of Range Management
Ford, W.M., M.A. Menzel, D.W. McGill, J. Laerm, and T.S. McCay. 1999. Effects of a
community restoration fire on small mammals and herpetofauna in the southern Appalachians.
Forest Ecology and Management 114:233–243.
Francl K.E., and D.E. Meikle. 2009. A range extension of the Hispid Cotton Rat, Sigmodon
hispidus, in Virginia. Banisteria 33:54–55.
Francl, K.E., W.M. Ford, and S.B. Castleberry. 2002. Relative efficiency of three
small-mammal traps in central Appalachian wetlands. Georgia Journal of Science
Greenberg C.H., A.L. Tomcho, J.D. Lanham, T.A. Waldrop, J. Tomcho, R.J. Phillips,
and D. Simon. 2007. Short-term effects of fire and other fuel-reduction treatments on
breeding birds in a southern Appalachian upland hardwood forest. Journal of Wildlife
2013 K.E. Francl and C.J. Small 25
Kaufman D.W., E.J. Finck, and G.A. Kaufman. 1990. Small mammals and grassland
fires. Pp. 46–80, In S. Collins and S.L. Collins (Eds.). Fire in North American Tallgrass
Prairies. University of Oklahoma Press, Norman, OK. 188 p p.
Kirkland, G.L., Jr., H.W. Snoddy, and T.L. Amsler. 1996. Impact of fire on small mammals
and amphibians in a central Appalachian deciduous forest. American Midland
Lafon, C.W., and J.A. Hoss. 2005. The contemporary fire regime of the central Appalachian
Mountains and its relation to climate. Physical Geography 26(2):126–146.
Langley, A.K., Jr., and D.J. Shure. 1988. The impact of climatic extremes on Cotton Rat
(Sigmodon hispidus) populations. American Midland Naturalist 120(1):136–143.
Levins, R. 1968. Evolution in Changing Environments: Some Theoretical Explorations.
Monographs in Population Biology, No. 2. Princeton University Press,
Linzey, D.W. 1998. Mammals of Virginia. University of Tennessee Press, Knoxville, TN.
Litvaitis, J.A. 2001. Importance of early-successional habitats to mammals in eastern
forests. Wildlife Society Bulletin 29(2):466–473.
Magurran, A. 2004. Measuring Biological Diversity. Blackwell Publishing, Oxford, UK.
McCune, B., and J.B. Grace. 2002. Analysis of ecological communities. MjM Software
Design, Gleneden Beach, OR.
McGee, J.M. 1982. Small-mammal populations in an unburned and early fire successional
sagebrush community. Journal of Range Management 35(2):177–180.
Mengak, M.T., and D.C. Guynn, Jr. 1987. Pitfalls and snap traps for sampling small mammals
and herpetofauna. American Midland Naturalist 118:284–288.
Mills, G.S., J.B. Dunning, and J.M. Bates. 1989. Effects of urbanization on breeding-bird
community structure in southwestern desert habitats. Condor 91: 416–428.
Mitchell, J.C., S.C. Rinehart, J.F. Pagels, K.A. Buhlmann, and C.A. Pague. 1997. Factors
influencing amphibian and small-mammal assemblages in central Appalachian
forests. Forest Ecology and Management 96:65–76.
Nowacki, G.J., and M.D. Abrams. 2008. The demise of fire and “mesophication” of forests
in the eastern United States. BioScience 58(2):123–138.
Rana, B.D. 1982. Relative efficiency of two small-mammal traps. Acta Ecologica
Rehmeier, R.L., G.A. Kaufman, D.W. Kaufman, and B.R. McMillan. 2005. Long-term
study of abundance of the Hispid Cotton Rat in native tallgrass prairie. Journal of
Russell, K.R., D.H. Van Lear, and D.C. Guynn, Jr. 1999. Prescribed fire effects on
herpetofauna: Review and management implications. Wildlife Society Bulletin
Shepard, M.L., C. Tarnocai, and D.H. Thibault. 1993. Chemical properties of organic
soils. Pp. 423–497, In M.R. Carter (Ed.). Soil Sampling and Methods of Analysis.
Canadian Society of Soil Science, Lewis Publishers, Ann Arbor, MI. 823 pp.
Small, C.J., and B.C. McCarthy. 2002. Spatial and temporal variation in the response of
understory vegetation to disturbance in a central Appalachian oak forest. Bulletin of
the Torrey Botanical Society 129:155–162.
Strickler, G.S. 1959. Use of the densiometer to estimate density of forest canopy on
permanent sample plots. PNW Note PNW-180, USDA Forest Service, Portland,
OR. 5 pp.
26 Southeastern Naturalist Vol. 12, No. 1
Sullivan, J. 1995. Peromyscus maniculatus. In Fire effects information system [Online].
USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
Available online at http://www.fs.fed.us/database/feis/. Accessed 1 December 2011.
USDA Forest Service. 2011. Draft revised land and resource management plan: George
Washington National Forest. [Online]. Available online at https://fs.usda.gov/wps/
ull&ss=110808&position=Not Yet Determined.Html&ttype=detail&pname=George
Washington. Accessed 1 December 2011.
Virginia Department of Conservation and Recreation, Division of Natural Heritage (VA
DCR-DNH). 2011. Virginia DCR-DNH vegetation plot data collection form. Revision
2011-04-06 KDP. Richmond, VA. Available online at http://www.dcr.virginia.gov/
natural_heritage/nchome.shtml. Accessed 26 November 2011.