EFFECTS OF FOREST DISTURBANCES ON SMALL MAMMAL COMMUNITIES
AT BANKHEAD NATIONAL FOREST OF THE CUMBERLAND PLATEAU
by
Kelvin Wendell Young
A THESIS
Submitted in partial fulfillment of the requirements
for the degree of Master of Science
in the Department of Plant and Soil Sciences
in the School of Graduate Studies
Alabama Agricultural and Mechanical University
Normal, Alabama 35762
December 2007
CERTIFICATE OF APPROVAL
Submitted by KELVIN WENDELL YOUNG in partial fulfillment of the
requirements for the degree of MASTER OF SCIENCE specializing in PLANT AND
SOIL SCIENCE.
Accepted on behalf of the Faculty of the Graduate School by the Thesis Committee:
_________________________________________
_________________________________________
_________________________________________
_________________________________________
_________________________________________ Major Advisor
______________________________________ Dean of the Graduate School
_____________________________________ Date
ii
Copyright by
KELVIN WENDELL YOUNG
2007
iii
DEDICATION
This thesis is dedicated to my mother Jo Ann Young, who passed away April
2005, and my grandmother Lovonia Young, who passed away summer 2006. I would
also like to dedicate this thesis to my family for their support and prayers.
iv
ACKNOWLEDGMENTS
I would like to thank the following for their efforts and contributions towards this
thesis: Mohamed Soumare, Heather Howell, Lisa Gardner, Wallace Dillon, Meiko
Thompson, Terrance Fletcher, Bobby Jackson, Dawn Lemke, Allison Bohlman, Jill
Wick, Bill Sutton, Ashantye’ Williams, Florence Chan, Shara Johnson, Nicole Proctor,
Cordero France, my committee members and others. I would also like to especially thank
Dr. William E. Stone for his guidance, support, and patience in helping me successfully
complete this study.
I also appreciate the efforts of the Bankhead National Forest for conducting the
treatment prescriptions in timely fashion. Special thanks go to John Creed and Allison
Cochran for their coordinating efforts with Alabama A&M University.
v
Small Mammal Community Response to Communities at Bankhead National Forest
Disturbances of the Cumberland Plateau
Kelvin W. Young, M.S., Alabama A&M University, 2007. 61 pp.
Thesis Advisor: William Stone, Ph.D.
Effects of forest thinning and prescribed burning on small mammal communities
inhabiting sixteen 25-acre (9 ha) loblolly pine stands were evaluated with a BACI
(before-after,
control-intervention)
complete
random
design.
Four
treatment
combinations (thin and burn, thin and no burn, burn and no thin, and control) were
replicated four times each in the Bankhead National Forest in northwestern Alabama.
Stands were intensively sampled for four consecutive nights using 160 baited Sherman
live traps and 8 baited medium-sized Tomahawk live traps placed in a modified
Anderson trapping web once prior to treatments and once following treatments during the
summers of 2005-2006. The following small mammals were captured: white-footed
mouse (P. leucopus), golden mouse (P. nuttali), cotton mouse (P. gossypinus), northern
short-tailed shrew (B. brevicauda), rice rat (O. palustris), raccoon (P. lotor), opossum (D.
virginiana), spotted skunk (S. putorious,), and eastern cotton-tail rabbit (S. floridanus).
White-footed mice were the most common species captured comprising 81% of the small
mammal community. A two-way ANOVA revealed that small mammal communities
were not significantly different in species diversity, richness, and abundance between
treatment stands prior to, or following, treatments. White-footed mice were significantly
(P< 0.05) more abundant during the second year, but this occurred throughout all stands
regardless of treatment type. Landscape variables (edge density, stream density, and
southern pine beetle spots) were measured in a 10-ha circle around the trapping web
location using a geographic information system (GIS) and inventory data (CISC) from
the national forest. However, linear regression of these variables failed to explain the
variation in abundance of small mammals among the sixteen stands.
Key words: small mammals, thinning, burning, forest practices
ii
TABLE OF CONTENTS
Page
CERTIFICATE OF APPROVAL ....................................................................................... ii
DEDICATION ................................................................................................................... iv
ACKNOWLEDGMENTS .................................................................................................. v
ABSTRACT .......................................................................Error! Bookmark not defined.
LIST OF ABBREVIATIONS .............................................................................................. i
LIST OF TABLES ............................................................................................................... i
LIST OF FIGURES ............................................................................................................. i
CHAPTER 1 ....................................................................................................................... 1
INTRODUCTION .............................................................................................................. 1
CHAPTER 2 ....................................................................................................................... 1
LITERATURE REVIEW ................................................................................................... 1
BACKGROUND ON BIOLOGY OF TARGET SPECIES ............................................... 1
CHAPTER 3 ..................................................................................................................... 13
MATERIALS AND METHODS ...................................................................................... 13
CHAPTER 4 ..................................................................................................................... 27
RESULTS AND DISCUSSION ....................................................................................... 27
CHAPTER 5 ..................................................................................................................... 41
CONCLUSION AND RECOMMENDATIONS ............................................................. 41
BIBLIOGRAPHY ............................................................................................................. 43
LIST OF ABBREVIATIONS
AAMU- Alabama A&M University
ANOVA- Analysis of Variance
BACI- Before and After, Control and Intervention
BNF- Bankhead National Forest
CISC- Continuous Inventory of Stand Conditions
CREST- Center for Research Excellence in Science and Technology
CWD- Coarse Woody Debris
GIS –Geographical Information System
NSF- National Science Foundation
SPB- Southern Pine Beetle
SPSS- Statistical Package for the Social Sciences
SMZ- Streamside Management Zone
US- United States
USDA- United States Department of Agriculture
LIST OF TABLES
Table
Page
1. Treatments applied to study stands in the Bankhead National Forest. ................. Error!
Bookmark not defined.
2. Experimental design with four replicates of each treatment and four control stands.
Prescribed burns were conducted (December – February) and thinning (March –
September). ..................................................................Error! Bookmark not defined.
3. Small mammal species list and number of captures for each year. A total of 83
mammals were captured for both years (2005-2006). White-footed mice had the
highest number of individuals captured. ..................................................................... 29
4. a.) Two-way ANOVA results for small mammal abundance 2005-2006 which
indicated no significance for the (treatment X year) interaction (P≥0.05). b.) Twoway ANOVA results for white-footed mice abundance only which indicated no
significance for the (treatment X year) interaction (P≥0.05). There is some
significance between (year) and (treatment) (P≤0.05). .............................................. 31
5. a.) Two-way ANOVA results for species richness which indicated no significance
(P≥0.05). b.) Two-way ANOVA results on (Shannon-Weiner) diversity also
indicated no significance (P≥0.05). ............................................................................ 32
LIST OF FIGURES
Figures
Page
1. Map of the Bankhead National Forest located mainly in Lawrence and Winston
counties. Thirty-six long-term study stands are distributed throughout the northern
portion of the forest. .................................................................................................... 14
2. Map of Bankhead National Forest with Mammal Trapping Webs Locations
(symbolized in red) labeled by long-term block and treatment designations.
........................................................................................................................................... 16
3. Modified trapping design (Anderson et al., 1983). The trapping web consisted of
eight lines of 20 Sherman live traps spaced 3 meters apart and a Tomahawk live trap
on the end of each line. Lines radiated out from a central point oriented toward North,
NE, East, SE, South, SW, West, and NW directions.
........................................................................................................................................... 20
4. Example of the trapping web across the landscape with the 10-ha circle. B1T2 was
one of a few stands that contained a stream within the 10-ha circle........................... 23
5. a.) Total stream distance for each stand measured within the 10-ha circle. Only three
stands contained streams within the 10-ha circular plot. b.) Illustration of stream
distance being measured using the ruler tool in ArcMap. .......................................... 24
6. a) Total edge distance for each stand measured within the 10-ha circle. b.) Illustration
of edge distance being measured using the ruler tool in ArcMap. Adjacent forest
cover types usually consisted of Oak (Quercus) species. ........................................... 25
7. a.) Total number of Southern Pine Beetle (SPB) points located within a 10-ha circle
centered on the small mammal trapping web for each study stand. b.) Illustration of
a SPB point located within the 10-ha circle for a control stand over-layed on GIS land
cover data. ................................................................................................................... 26
8. Small mammal abundance for 2005-2006. Pre-treatment data indicated that some
stands already contained high numbers of small mammals prior to treatment
applications. Mammal numbers increased post treatment in most stands, especially in
treatments that were thinned. ...................................................................................... 30
9. a.) Illustration of regression analyses results with trend line. There was a slight
increase of edge and small mammal abundance pre treatment but not significant. b.)
There was no relationship between edge and small mammal captures post treatment.
..................................................................................................................................... 36
10. a.) Illustration of regression analyses results with trend line. Stream density seemed
to have a negative effect on small mammal captures. There was also a negative
relationship for post treatment as well. Few stands contained a stream within the 10ha circle making the correlation difficult to decipher. ................................................ 37
11. a.) There was a negative relationship of mammal numbers and Southern Pine Beetle
points pre-treatment. b.) There was a negative relationship post treatment as well.
Only one stand contained a SPB point within the 10-ha circular plot making this
correlation difficult to analyze. ................................................................................... 38
ii
CHAPTER 1
INTRODUCTION
Small mammals are some of the most numerous and diverse groups in the
taxonomic class Mammalia. Rodentia is the most diverse taxonomic order of mammals
and includes all rodents (Vaughan, 1972). The second most diverse order of small
mammals is Chiroptera and includes all bat families. Another order of small mammals
that is not as diverse as the two previously mentioned is Lagomorpha. Lagomorpha
includes rabbits, which are also important members of terrestrial communities and are
world wide in distribution (Vaughan, 1972).
Small mammals are beneficial to forest regeneration as agents of seed distribution
and scarification, distribution of mycorrihzal spores, and plant cross-pollination (Smith
and Aldous, 1947; Pank, 1974; Gullion, 2003). Some insectivorous small mammals aid
in forest health by consuming forest insect pests, which reduces threats of insect
infestations (Hanski, 1987). Small mammals can be used as biodiversity measures due to
their relative abundance and ecosystem roles (Entwistle and Stephenson, 2000; Lomolino
and Perault, 2000).
There are numerous small mammal species found throughout the Cumberland
Plateau region of northwestern Alabama. Some expected species are: white-footed mouse
(Peromyscus leucopus), golden mouse (Peromyscus nuttalli), short-tailed shrew
1
(Blarina brevicauda), eastern wood rat (Neotoma floridana), striped skunk (Mephitis
mephitis), opossum (Didelphis marsupialis), raccoon (Procyon lotor), eastern gray
squirrel (Sciurus carolinensis), eastern fox squirrel (Sciurus niger), eastern chipmunk
(Tamia striatus), eastern cotton-tail rabbit (Sylvilagus floridanus) and several more small
to medium sized mammals (Mirarchi et al., 2004); (Mengak and Guynn, 2003).
Forest management practices such as thinning, burning and clear-cutting, modify
forest vegetation, composition and structure. These disturbances alter small mammal
habitat by removing under-story plants and food, such as seeds and insects. The effects
of forest practices on small mammal communities are directly related to modifications of
vegetation and food sources (USDA Forest Service, 1981).
Forest management practices such as thinning and burning have some negative
and positive effects on wildlife in general. Both practices are disturbances that cause
changes in the ecosystem. Different species of wildlife are affected differently by these
disturbances. Thinning a dense pine stand may negatively affect certain species due to an
increase in ground temperature and decrease in humidity (Dickson, 1981). The sprouting
of herbaceous cover after a thin produces habitat and food for several other species.
Burning may have the same relationship depending on the severity of the burn and
frequency. Burning can negatively affect small mammal communities by the removal of
coarse woody debris (CWD), which serves as cover for animals such as rabbits, squirrels
and mice. Forest management may also affect predator-prey interactions among
mammals. Modifications in cover type and structure can limit prey species abundance
and therefore cause a decrease in predator numbers. Burning and thinning both cause
2
alterations to the forest that may result in changes in small mammal abundance and
diversity (Baker and Hunter, 2002).
Prescribed or controlled burning is the practice of using regulated fires to reduce
or eliminate the unincorporated organic matter of the forest floor or low, undesirable
vegetation (Smith et al., 1997). Burning is conducted under conditions such that the size
and intensity of the fires is no greater than necessary to achieve the purpose of the burn.
Burning is used as a tool to achieve timber production, reduction of fire hazard (fuel
reduction), wildlife management, and improving grazing areas. (Fahnestock, 1973;
Chandler et al., 1983). Thinning is the cultural adjustment of numbers and arrangements
so that the stand and the individual tree in the stand will grow in a more economical.
would otherwise be the case. Thinning is used as a means for forest stand density control
and is the most well established method of forest management operations (Sharpe et al.,
1976). Thinning can improve wildlife habitat by changing the structure and composition
of a stand. The change in composition and structure could also negatively affect some
wildlife species. Essentially thinning affects wildlife directly and indirectly. Thinning an
overstocked pine stand is beneficial to species such as bats, because it makes the stand
more navigable (USDA Forest Service, 2003). The combination of thinning and burning
improves herbaceous cover, provides food, and creates more room for browsing (USDA
Forest Service, 2003).
An opportunity to study the small mammals response to forest disturbance
became possible in 2004, when the USDA Forest Service and Alabama A&M University
(with support from the National Science Foundation) collaborated on studying changes in
soils, vegetation, fauna, and human dimensions brought about by the Forest Health and
3
Restoration Project on the Bankhead National Forest (BNF). The purpose of the Forest
Health and Restoration Project is to improve and maintain overall forest health, restore
native upland hardwood forests and pine-oak woodlands, provide forest communities and
plant and animal habitats that are uncommon on other lands in the Cumberland Plateau
(USDA Forest Service, 2003). In order to accomplish this the USDA Forest Service staff
in the Bankhead National Forest plan to treat over 18,000 acres of loblolly pine stands
devastated over the past ten years by the Southern Pine Beetle (SPB). BNF staff plan to
thin out and control burn the pines stands which were planted over 25 years ago to restore
abandoned cutover farmlands. Studies of the changes will take advantage of the BNF
staffs’ commitment to set aside and follow prescribed treatments of some of the stands.
The overall experimental design for this project consists of a randomized complete block
design. Thirty-six study plots, nine treatments replicated in each of the four blocks, are
spread throughout the BNF.
The fauna subproject has undertaken studies of avian, arthropod, and small
mammal communities. One of the objectives of this subproject is to determine forest
disturbance effects on small mammal species richness, relative abundance, and diversity.
Statement of the Problem
Currently, the BNF does not have a list of small mammals. There have
been no research studies on the BNF that evaluate the effects of forest practices on small
mammal communities. Most small mammal studies in the southern region occur in the
deciduous forest of the Appalachians, in the Alabama coastal plain, and the Ouachita
Mountains of Arkansas. Very few of these studies have explicitly identified landscape
4
variables influencing small mammal populations. There is little or no research in the most
southern tip of the Appalachian Mountains which lie in North Alabama.
Objectives
The objectives of this study were to: 1) evaluate thinning and burning effects on
small mammal abundance, species richness, and diversity; 2) identify the relationship
between landscape variables and small mammal populations; 3) implement a small
mammal species list for the BNF. Two hypotheses are tested:
Null Hypothesis 1. Thinning and burning have no significant affect on small mammal
abundance, diversity, and richness.
Null Hypothesis 2. Landscape variables have no significant affect on small mammal
populations.
5
CHAPTER 2
LITERATURE REVIEW
Background on Biology of Target Species
White-footed Mouse (Peromyscus leucopus)
The white-footed mouse is 88-114 millimeters from head to body (length of body
excluding tail) and its tail is approximately 57-101 millimeters long. Body mass ranges
from 14-32 grams. The pelage is as short tan or reddish-brown with a distinct white
belly. The feet have white fur and it has large black eyes that protrude from its head. The
white-footed mouse is described as ubiquitous and can live in a variety of habitats such as
wooded or brushy habitats that provide canopy cover (Hoffmeister, 1989). It feeds on
seeds, nuts, and sometimes insects. During winter, this animal caches seeds and nuts in a
den. The range of the white-footed mouse starts east of the continental divide with the
exception of parts of the southwest and the northwest. The range covers the plains, the
midwest, northeast, and the southeast with the exception of Florida. The home range of
the white-footed mouse is about ½ -1½ acres. It lives 2-3 years in the wild and up to five
years in captivity (Burt and Grossenheider, 1980). Mengak and Guynn (2003) found that
white-footed mice are associated with sparse ground cover and a thin over-story of young
pine.
1
Northern Short-tailed Shrew (Blarina brevicauda)
The short-tailed shrew is about 76-101 millimeters from head to body and its tail
can be 19-25 millimeters long. Its approximate body weight ranges from 11-22 grams.
The pelage is described as lead and has no external ears and the eyes are extremely small.
Short-tailed shrews are diurnal mammals and are somewhat ubiquitous. They can make
their home on the ground, in dry leaves, grass, logs, stumps, rocks, and other debris. The
short-tailed shrew has a home range of about ½ - 1 acre. The life span of this mammal is
1-2 years. It thrives in habitats of all states just east of the Continental Divide including
the Midwest, Southeast, Central plains, northeast and southern portions of Canada (Burt
and Grossenheider, 1980). For an insectivore of its size the short-tailed shrew is one of
the deadliest predators in the world. The short-tailed shrew is a vigorous hunter that can
poison its prey with a venomous bite. Shrews have a high metabolism and must eat their
own weight in food several times a day. The diet of the short-tailed shrew includes
insects, snails, worms, and small mice (Burton, 2003). Mengak et al., (1989) stated
shrews favor moist environments. Smith et al., (1974) found positive correlations
between the abundance of southern short-tailed shrews with temperature precipitation.
Golden Mouse (Peromyscus nuttali)
The golden mouse measures approximately 86-97 millimeters from head to body
and its tail is approximately 76-91 millimeters. Its weight ranges from 19-25 grams. It is
described as being bright golden-cinnamon in color with a white belly. The golden
mouse can live in a variety of places such as forests, edges of canebrakes, moist thickets,
honey-suckle, green briar, and Spanish moss (Burt and Grossenheider, 1980). Being
arboreal it thrives in trees, vines, and brush. It constructs its nests with leaves and
3
shredded bark 1.5 – 3 meters above ground in vines, brush, and thickets (Harper and
Row, 1981). The golden mouse feeds on seeds and invertebrates and is described as
being highly social (Mirarchi et al., 2004a). Linzey and Packard (1977) suggest that
greenbriar is an important habitat component for the golden mouse as it used for nests
and food. Doing a discriminate function analysis Mengak and Guynn, (2003) found that
golden mice were associated with logs and dense pine overstory in naturally regenerated
stands. Dueser and Shugart, (1978) found that golden mice were associated with
evergreen forests and shrubby microhabitiat.
Cotton Mouse (Peromyscus gossypinus)
The cotton mouse measures 91-71 millimeters from head to body and its tail is
approximately 71-97 millimeters in length. It weighs 28-51grams and is slightly smaller
than the white footed mouse. The upper part of the cotton mouse is dark brown in color
with a tawny mixture below its tail (Burt and Grossenheider, 1980). The cotton mouse
likes wooded areas and can be found in dense under brush, swamps, upland forests, pine
forests, and even sand dunes (Wolfe and Linzey, 1977). It is an omnivore that feeds on
seeds, fungi, and insects (Mirarchi et al., 2004a). Mengak, (1987) found that cotton mice
were primarily associated with natural stands. In (Mengak and Guynn, 2003) cotton mice
were associated with CWD and a short overstory. Gentry et al. (1968) reported finding
cotton mice in cleared fields, flat pine forests, and upland pine forests.
Rice Rat (Oryzomys palustris)
The rice rat is grayish brown in color and has a gray belly. The tail is scaly and
the feet can be white in color. It can measure 121-132 millimeters from head to body and
the tail can measure 110-183 millimeters. It weighs approximately 40-80 grams and the
4
fur is short and soft (Burt and Grossenheider, 1980). The rice rat is semi-aquatic being
found in marsh and swamp habitats. It also lives in wet meadows, ditches and dense
vegetation. The diet includes green vegetation, seeds, snails, and other insects. Nests are
made of debris and are found above water levels (Mirarchi et al., 2004a).
Raccoon (Procyon lotor)
The raccoon has a stocky body shape with a broad head and pointed snout. The
raccoon measures 46-71 centimeters and the measures 20-30 centimeters. It can weigh
5.4-15.8 kilograms and is recognized by its black mask on a whitish face (Burt and
Grossenheider, 1980). Raccoons are found almost everywhere from residential areas,
farmlands, forests, fresh and saltwater marshes. They are even more common around
areas where there is water. The raccoon is an opportunistic omnivore that feeds on
anything from household garbage, fish, fruits and nuts to insects, corn, and eggs. They
live in underground dens or in the cavity of a hollow tree (Harper and Row, 1981).
Opossum (Didelphis virginiana)
The opossum is the only marsupial found north of Mexico. Its head to body length
measures 38-51centimeters and the tail is 22-33 centimeters in length. It can weigh
approximately 4-5.9 kilograms and has 50 teeth (Harper and Row, 1981). The opossum
is about the size of a house cat and has thin black ears often tipped with a whitish color.
It has a pointed nose and a long rat like tail. They vary in color from white to gray
depending on the geographic region (Burt and Grossenheider, 1980). It lives in all
habitats and can be also found in developed areas. It feeds on fruits, eggs, carrion, fish,
vegetation, and small invertebrates (Mirarchi et al., 2004a).
5
Spotted Skunk (Spilogale putorius)
Little is known about the spotted skunk in Alabama other than it is very rare. It
measure 34 centimeters from head to body and its tail is approximately 23 centimeters. It
is black in color, a white spot on its head, white stripes on its back and sides. The weight
ranges from 350-999 grams depending on the sex of the animal (Harper and Row, 1981).
Its habitat varies from wooded areas, stream banks, prairies, and rocky areas (Burt and
Grossenheider, 1980). The spotted skunk feeds on rodents, fruits, eggs, insects, fish,
carrion, and vegetative matter. It is a very good swimmer, climber, and described as
being very playful (Harper and Row, 1981).
Eastern Cottontail Rabbit (Sylvilagus floridanus)
The cottontail rabbit is 36-43 centimeters long and the ears are approximately 8
centimeters. It weighs 1-2 kilograms. It has a brownish to grayish color with a white
cotton ball tail. It thrives in habitats from swamps, thickets, farmlands, prairies, urban
areas, and forest edges (Burt and Grossenheider, 1980). It feeds on grasses mostly in
summer months but will eat twigs and bark in the winter months (Mirarchi et al., 2004b).
Forest Management Effects on Small Mammals
Forest practices can significantly alter the landscape, directly and indirectly
affecting small mammals. Forest practices such as thinning and burning indirectly alter
the landscape and biotic groups along with those targeted by management practices
(Elliot and Hewitt, 1997). Previous studies provide a mixed picture of the impact of forest
practices on small mammal communities. Partial harvesting may increase or not affect
6
small mammal abundance (Campbell and Clark, 1980; Martell, 1983; Swan et al., 1984;
Monthey and Soutiere, 1985). Another small mammal study concluded that increased
forest fragmentation created by clear cutting of small mammal stands increased numbers
of some rodents such as Peromyscus leucopus and Clethrionomys gapperi (Yahner,
1992). The response of small mammals to timber harvesting is strongly related to the
degree of which vegetation is altered (Van Horne, 1981; Medin and Booth, 1989). A
small mammal study in the Oauchita Mountains indicated that capture rates of small
mammals were influenced by grass like cover and pine basal area (Perry and Thill, 2005).
Although forest management practices are beneficial to some small mammal species,
other species may be more vulnerable to these disturbances.
Impacts of Thinning
As for thinning different basal areas affect small mammal populations negatively
and positively. Numerous small mammal studies demonstrate a positive abundance
response by white-footed mice to silvicultural treatments that resulted in lower canopy
cover (Ford et al., 2000; Carey and Wilson, 2001; Fantz and Renken, 2005). The
response of the small mammal community reflects the increased complexity of understory vegetation found on the study site as a result of thinning (Muzika et al., 2004). In
western Washington Carey found that thinning had a positive effect on chipmunks but
negatively affected flying squirrels (Carey, 2000; 2001). In British Columbia researchers
discovered that small mammal communities were higher in thinned stands than in unthinned stands and old growth stands (Sullivan et al., 2001). Mean small mammal
abundance, diversity, and richness were unchanged until stands became more developed
7
(Sullivan et al., 2001). It seems in most studies of small mammal abundance, richness,
and diversity, thinning has an indirect effect. This indirect effect is related to the
reduction or loss of under-story vegetation. Small mammals utilize vegetation such as
vines, shrubs, and seedlings for food and cover.
Coarse Woody Debris
In relation to under-story vegetation the presence of coarse woody debris (CWD)
seem to positively increase small mammal abundance. Recent studies show that
researchers are now trying to relate the role of CWD to small mammal ecology (Mengak
and Guynn, 2003). CWD along with brush piles provide cover and nest sites (Greenberg,
2001). In addition, CWD also inhabits fungi and invertebrate food sources for some
rodents (Loeb, 1996).
Impacts of Prescribed Burning
Prescribed burning has a variety of effects on small mammal communities as
well. Brennan et al., (1998) found that small mammals can be affected by prescribed
burns directly due to mortality or indirectly due to habitat changes. Monroe and
Converse, (2006) stated that mortality depended on the intensity of the prescribed fire and
the physiological status of small mammals at the time of the fire. Habitat changes from
fire could have a greater impact on small mammals than direct mortality from fire
(Monroe and Converse, 2006). Kirkland et al. (1996) found a significant amount of small
mammals were collected in unburned stands rather than in burned stands. A fire impact
study on small mammals completed by (Tester, 1965) indicated that species such as
8
Peromyscus maniculatus moved into burned stands immediately following a fire. He also
stated that the reestablishment of small mammal populations in burned areas probably
originated from unburned adjacent forest (Tester, 1965). The white-footed mouse and
Maryland shrew (Sorex fontinalis) were the two most abundant species in both burned
and unburned habitats in the Central Appalachian deciduous forest (Kirkland et al.,
1996).
Impacts of Thinning and Burning
As for the effects of both burning and thinning conducted together, Kirkland et
al., 1996 noted, in the southeast forests have been greatly influenced starting with Native
Americans prescribed burning and thinning forest for agricultural use and grazing. Many
species of small mammals use resource rich early successional disturbed habitats because
they have evolved in environments labeled by periodic disturbances (Kirkland, 1990).
Southeastern forests have been greatly influenced by natural and anthropogenic
disturbances for thousands of years (Sharitz et al., 1992). White-footed mouse
populations significantly increased as a result of mechanical under-story thinning
followed by prescribed fire (Greenberg et al., 2006).
Relating Small Mammal Occurrence to Landscape Variables
Geographical Information Systems (GIS) are used commonly to evaluate the
effects of forest practices on animal populations that use landscape structure or other
habitat types (Wheatley et al., 2005). GIS can be used to make models that predict
relationships between animal populations and spatial habitat (Mackey and Lindenmayer,
9
2001). Rushton et al., (2000) states that once landscape variables are quantified animal
responses can be modeled by using GIS techniques such as Spatially Explicit Population
Dynamic Models which predict animal distributions based on interaction between
behavioral processes and landscape structure. GIS is now a common tool for sustainable
land management strategies (Rushton et al., 2004). GIS can give the researcher a broad
view of what is occurring on the landscape without having to physically take habitat
measurement or samples. Understanding how which animals respond to different
landscape features using GIS is necessary for sustainable forest planning by land
managers who rely heavily on digital forest inventories (Wheatley et al., 2005).
Constantine et al., (2005) examined corridor edge effects on small mammal
communities in a heterogeneous, intensively managed pine forest to identify relationships
between mammal captures and distance from corridor edge. The corridor edges are
mosaics of successional habitats within pine stands such as streamside management
zones (SMZ), corridors of uncut mature pine stands, and special habitat zones
(Constantine et al., 2005). Wike et al. (2000) examined hardwood stringers within
planted longleaf pine on the U.S. Department of Energy’s Savannah River Site in South
Carolina. Left over corridors in managed forest contribute to landscape heterogeneity and
creates ecotones between harvested and unharvested areas possibly affecting small
mammal populations (Constantine et al., 2004). There were no distinct species specific
patterns in distribution relative to corridor edge (Constantine et al., 2005). Wike (2000)
found that white-footed mice occurred in the interior of forest fragments at higher
numbers than at edges. Kingston and Morris (2000) stated that few studies have evaluated
small mammal distributions relative to forest edges which have only examined single
10
species responses. Therefore, more studies should evaluate the relationship of edge and
small mammal distributions.
Little is known about the relationship of stream density and small mammal
distributions on landscapes. Most, studies have only examined small mammal
distributions within SMZ’s. Therefore, this relationship needs to be further evaluated to
examine the relationship of small mammal distributions in relation to the amount of
available water in a landscape.
Maine et al. (1980) stated, SPB can impact members of Insectivora and Rodentia
orders by bringing vegetation closer to the ground causing increased food availability and
cover. After conducting a qualitative SPB analysis on wildlife Maine et al., (1980)
concluded that SPB had a positive impact on wildlife such as woodpeckers, quail, rabbits,
deer, and small mammals. These animals are indirectly affected by SPB due to increase
in edge and food availability. SPB increased the amount of linear edge in this study by
2,000 feet per acre of SPB spots (Maine et al., 1980). Still, there is little to no
information specifically on SPB effects of small mammal populations.
Live Trapping Small Mammals
Depending on the objective of a study some techniques are more applicable than
others. Pitfall trapping, is commonly used to sample forest floor vertebrates and is
considered a better technique than using box traps (Corn and Bury, 1991). In the Oregon
Coast Range pitfall traps demonstrate a consistent capture of high diversities of small
mammals compared to Sherman live box traps (Suzuki and Hayes, 2003). Most small
mammals are too small to spring the trip pan inside the box trap. Animals weighing less
11
than 20 grams are not effectively caught. Medium sized mammals such as squirrels and
chipmunks are captured better in live traps. Since pitfall traps are in the ground and the
lip is flush with the surface they are more successful in catching smaller sized mammals
such as shrews and other animals that maneuver under forest floor litter (Francl et al.,
2002). Pitfall traps do have some disadvantages that can make them ineffective. Pitfall
traps need to checked on schedule and closed in the event of rain. Water can collect in
the pitfall causing a captured animal to drown. Pitfall traps result in the death of most
captured animals which is undesirable for long-term studies. Using pitfall traps will not
suffice for capturing animals such as squirrels and chipmunks. The animals are too large
and can easily escape from the trap and some deer mouse species, such as the kangaroo
rat can easily escape because of the jumping ability in their rear legs (Schemnitz, 1980).
12
CHAPTER 3
MATERIALS AND METHODS
Study Area
This study took place on the Bankhead National Forest (BNF), located in
northwestern Alabama (Figure 1). The BNF is a forest that has had problems from
Southern Pine Beetle (SPB) infestations to loblolly pine stands, resulting in many acres of
damaged timber (USDA Forest Service, 2003). According to the BNF Environmental
Impact Statement, the Forest Service proposes to implement a five-year timber rotation to
improve forest health and quality of vulnerable pine stands. This plan includes thinning
and prescribed burning of overstocked pine stands and reforestation of SPB damaged
stands (USDA Forest Service, 2003). The BNF was established in 1936 and has a long
history of logging and soil erosion caused by poor farming practices during the
depression era. The BNF is approximately 182,000 acres and lies within the Cumberland
Plateau region of the southern Appalachian Mountains. Over the past two centuries fire
has been excluded from forests throughout the Cumberland Plateau region. The absence
of fire has caused this disturbance regime to become uncommon throughout the natural
landscape of North Alabama. Approximately 176,000 acres are currently forested and
can be broadly classified as about 51% southern pines and 49% hardwoods (USDA
Forest Service, 2003).
13
Figure 1. Map of the Bankhead National Forest located mainly in Lawrence and Winston counties.
Thirty-six long-term study stands are distributed throughout the northern portion of the forest.
14
Experimental Design
Sixteen plots were established in 16 stands of 25-45 year old loblolly and Virginia
pine trees. These stands are 25-acre (9 ha) units distributed throughout the northern
portion of the BNF (Figure 2) and were ground-truthed for composition and structure
prior to selection. Four treatments from each of the four blocks in the overall study were
chosen to examine thinning and prescribed burning (Table 1). The experimental design
consisted of four plots each : 1) with no thinning and burning, 2) with both thinning and
no burning, 3) only thinning , and 4) only burning. Each of the sixteen plots were
sampled twice: 1) in the pre-treatment year, and 2) approximately the same time in the
post-treatment year (Table 2). Treatments were replicated in order to account for the
variability in burn and thinning intensities.
Thinning treatments were conducted during the growing season (March –
September) and prescribed burning was conducted in the dormant season (DecemberFebruary). Burn frequencies are burn or no burn. Thinning levels consisted of thinning
and no thinning. Thinning was designed to reduce basal area from 25-28 m2/ha to 11-17
m2/ha. (Table2). Prescribed burning resulted in a light surface fire that reduced the forest
floor litter layer and a portion of the under-story vegetation.
15
Figure 2. Map of Bankhead National Forest with Mammal Trapping Webs Locations (symbolized in
red) labeled by long-term block and treatment designations.
16
Table 1. Treatments applied to study stands in the Bankhead National Forest.
Treatments
Treatment 1(Control)
4 reps
Treatment 2
4 reps
Treatment 3
4 reps
Prescription
No Burn and No Stand Density Reduction(2528m2 /ha basal area)
Rx Burn and No Stand Density Reduction(Low
intensity surface fire)
No Burn and Residual Stand Density
Reduction2 stands (11m2ha-1) 2 stands
(17m2ha-1)
B= Blocks (1-4)
T= Treatments (1= No burn, No thin) (2&3= Burn and no thin) (4&5= No Burn, thin) (6-9= Burn and thin)
Table 2. Experimental design with four replicates of each treatment and four control stands.
Prescribed burns were conducted (December – February) and thinning (March – September).
Stands
Treatments
B1T1, B2T1, B3T1, B4T1
No Burn and No Thinning (Controls)
B1T2, B1T3, B2T3, B3T3
Burn and No Thinning
B1T4, B1T5, B2T4, B2T5
No Burn and Thinning
B1T6, B1T7, B1T8, B1T9
Burn and Thinning (Combination)
17
Trapping occurred during the summer months from May to August for pretreatment and then post-treatment. Each treatment was sampled once during the trapping
period. One trapping web of 160 traps was placed in a treatment for a period of four trap
nights. Traps were placed in a web approximately 11,406 m2, which covers an area of
approximately one hectare. The web (Figure 3) consists of eight lines starting from north
counting clockwise to northwest. Each line was 60 meters in length with 20 Sherman
traps place every three meters. This design was used under the assumption that the
population of animals in not a closed population (Anderson et al., 1983). A Tomahawk
wire-cage trap was placed at the end of each of the eight lines spaced 47m apart. Traps
were opened for five days and four nights and then closed after checking them on the
fourth trap night. Small mammals were captured using (7.6 x 8.9 x 23.3 cm) Sherman
live traps baited with peanut butter. Medium-sized mammals were captured using (60 x
18 x 18 cm) Tomahawk wire-cage traps baited with sardines, hamburger, sliced apples, or
a scent lure. The success of animal trapping is dependent upon the type of lure or bait
that will attract animals into the traps. Carnivores are attracted by using meat such as
hamburger and fish, which creates an odor (Schemnitz, 1980). All trapped animals were
identified by species, weighed, measured to length, and sexed. Rodents were toe clipped
and other species will receive a numbered stainless steal ear tag.
19
Figure 3. Modified trapping design (Anderson et al., 1983). The trapping web consisted of eight
lines of 20 Sherman live traps spaced 3 meters apart and a Tomahawk live trap on the end of each
line. Lines radiated out from a central point oriented toward North, NE, East, SE, South, SW, West,
and
NW
directions.
20
Landscape Variable Analyses
In addition to statistical analysis of the treatment effects, landscape variables were
analyzed using Geographical Information Systems (GIS). ArcGIS (version 9.0) was used
to overlay data such as the USDA Forest Service’s program of Continuous Inventory of
Stand Conditions (CISC) collected by the U.S. Forest Service updated in 2002. CISC, is
an automatic data processing system used for National Forests in the southern US that
continuously reflects up-to-date description of timber stands (USDA Forest Service,
1980). Shape-file data are derived from digitizing paper maps of individual compartment
and stands. These shape files were then compiled into GIS. CISC was used because the
database was readily available, although it is no longer used by the USDA Forest Service.
Three landscape variables stream density, ecotone (“edge”) density, and presence of
southern pine beetle infestation points were analyzed from this database using a 10-ha
(180-m radius) sampling circular window over-layed onto the center of the trapping web
(Figure 4). Mengak and Guynn (2003) used a circular plot with a 10m radius centered on
each trap station to conduct small mammal microhabitat. These variables were chosen
based upon observations in the study stands. It was observed that more animals were
being caught towards the ends of trap lines. The ends of these lines were usually located
in a drain. Therefore, it was assumed that animals were being caught because they were
browsing for a water source. In addition, it was observed that high numbers seemed to be
associated with the presence of down wood due to SPB infestation. It was determined
that edge was important under the theory of animals moving in and out of adjacent
stands. Total stream length and ecotone were both calculated using the ruler tool in
21
ArcGIS within the 10ha circular plot. SPB points were measured inside the circle and
summed for the 10-ha sampling area (Figure 5, 6, 7).
Statistical Analysis
All data were analyzed using Statistical Package for the Social Sciences 10.0
(SPSS Inc., Chicago, IL). Analyses was based on the capture/recapture method which is
used in ecological studies to estimate population sizes. A significance level of (P≤ 0.05)
was used for statistical significance for all tests. Tests were conducted to determine forest
disturbance effects on species richness, diversity, and abundance. Species richness is
simply the number of species captured, and species diversity was calculated using the
Shannon-Weiner diversity index (Shannon and Weaver, 1949). Shannon-Weiner is one
of several diversity indices commonly used to measure diversity in wildlife communities.
A two-way ANOVA was used to test the treatment by year effects of the four
thinning and burning treatments during the two years of the study (Dowdy and Wearden,
1983). Each of the four treatments were replicated four times for a total 16 samples. The
two years are designated as pre-treatment and post-treatment.
Simple regression analyses, conducted separately, for each of these landscape
variables against total small mammal abundance were performed using Statistical
Package for the Social Sciences 10.0 (SPSS Inc., Chicago, IL).
22
Figure 4. Example of the trapping web across the landscape with the 10-ha circle. B1T2 was one of
a few stands that contained a stream within the 10-ha circle.
23
a.)
200
180
160
140
120
100
80
60
40
20
0
Stream Density
B1T1 B2T1 B3T1 B4T1 B1T2 B1T3 B2T3 B3T3 B1T4 B1T5 B2T4 B2T5 B1T6 B1T7 B1T8 B1T9
b.)
Stream distance
Stream
Figure 5 a.) Total stream distance for each stand measured within the 10-ha circle. Only three stands
contained streams within the 10-ha circular plot. b.) Illustration of stream distance being measured
using the ruler tool in ArcMap.
24
a.)
1200
1000
Edge density
(m)
800
600
400
200
0
B1T1B2T1B3T1B4T1B1T2B1T3B2T3B3T3B1T4B1T5B2T4B2T5B1T6B1T7B1T8B1T9
b.)
Edge distance
Figure 6. a) Total edge distance for each stand measured within the 10-ha circle. b.) Illustration of
edge distance being measured using the ruler tool in ArcMap. Adjacent forest cover types usually
consisted of Oak (Quercus) species.
25
a.)
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
SPB Points
B1T1 B2T1 B3T1 B4T1 B1T2 B1T3 B2T3 B3T3 B1T4 B1T5 B2T4 B2T5 B1T6 B1T7 B1T8 B1T9
b.)
SPB Point
Figure 7. a.) Total number of Southern Pine Beetle (SPB) points located within a 10-ha circle
centered on the small mammal trapping web for each study stand. b.) Illustration of a SPB point
located within the 10-ha circle for a control stand over-layed on GIS land cover data.
26
CHAPTER 4
RESULTS AND DISCUSSION
A total of 83 individuals (Table 3) were captured during the trappings seasons of
2005 and 2006. A total of 28 individuals were captured during pretreatment and 57
during post treatment. The most common species captured was the white-footed mouse.
This single species composed most (81%) of the small mammal community. Similarly,
the white-footed mouse comprised 60.9% and 62.1% of small mammals captured in
Kirkland et al. (1996) study in the Central Appalachian forest. The number of captured
white-footed mice tripled from the first year to the second year. Additionally, eight other
species of small and medium-sized mammals were captured during the two year study
period (Table 3).
The abundance of small mammal species by treatment and year are depicted in
(Figure 8). A two-way ANOVA on small mammal abundance indicated that there was no
significant (P≥0.05) treatment by year interaction (Table 4). Similarly, white-footed mice
abundance did not differ significantly (P≥0.05) among treatments by year (Table 4).
However, there was a significant difference (P=0.028) in white-footed mice abundance
by year (Table 4) with more mice captured in post-treatment stands. A two-way ANOVA
(Table 5) indicated no significant differences in treatment response by year for richness
or species diversity.
27
Table 3. Small mammal species list and number of captures for each year. A total of 83 mammals
were captured for both years (2005-2006). White-footed mice had the highest number of individuals
captured.
Genus species
Peromyscus
leucopus
Peromyscus nuttali
Peromyscus
gossypinus
Blarina bervicauda
Oryzomys palustris
Procyon lotor
Didelphis
virginiana
Spilogale putorious
Sylvilagus
floridanus
Bankhead Small Mammal Species List
Number Caught
Common Name
Yr.1
Number
Caught Yr.2
17
3
50
0
Cotton mouse
Northern Short tailed shrew
Rice rat
Raccoon
1
3
1
1
0
1
0
1
Oppossum
Spotted skunk
1
1
2
0
Eastern cotton tail rabbit
0
1
28
55
White-footed Mouse
Golden mouse
Total number of individuals
29
83
Figure 8. Small mammal abundance for 2005-2006. Pre-treatment data indicated that some stands
already contained high numbers of small mammals prior to treatment applications. Mammal
numbers increased post treatment in most stands, especially in treatments that were thinned.
30
Table 4 a.) Two-way ANOVA results for small mammal abundance 2005-2006 which indicated no
significance for the (treatment X year) interaction (P≥0.05). b.) Two-way ANOVA results for whitefooted mice abundance which indicated no significance for the (treatment X year) interaction
(P≥0.05). There is a significant difference between years (P≤0.05).
a.)
Source
Sum of Squares
df
Mean Square
F
Sig.
TRT
64.125
3
21.375
2.644
.072
YEAR
24.500
1
24.500
3.031
.094
TRT * YEAR
3.250
3
1.083
.134
.939
Error
194.000
24
8.083
b.)
Source
Sum of Squares
df
Mean Square
F
Sig.
TRT
55.344
3
18.448
2.966
.052
YEAR
34.031
1
34.031
5.472
.028
TRT * YEAR
6.094
3
2.031
.327
.806
Error
149.250
24
6.219
31
Table 5. a.) Two-way ANOVA results for species richness which indicated no significance (P≥0.05).
b.) Two-way ANOVA results on (Shannon-Weiner) diversity also indicated no significance (P≥0.05).
a.)
Source
Sum of Squares
df
Mean Square
F
Sig.
TRT
3.125
3
1.042
1.786
.177
YEAR
.000
1
.000
.000
1.000
TRT * YEAR
4.750
3
1.583
2.714
.067
Error
14.000
24
.583
Source
Sum of Squares
df
Mean Square
F
Sig.
TRT
.218
3
7.266E-02
1.033
.396
YEAR
3.568E-02
1
3.568E-02
.507
.483
TRT * YEAR
.350
3
.117
1.656
.203
Error
1.688
24
7.034E-02
b.)
32
Regression analyses indicated a weak relationship of small mammal abundance
and forest edge for pre-treatment (R2=0.1222, P=0.184) (Figure 9). There was also no
relationship post treatment for abundance and edge (R2=0.000, P=0.991) (Figure 9).
Surprisingly, there was no relationship (R2=0.0023, P=0.859) between small mammal
abundance and stream density during pre-treatment and no relationship post treatment (R2
= 0.0520, P=0.396) (Figure 10). Finally, the relationship between the number of captures
and the number of southern pine beetle spots within each stand (Figure 11) was analyzed.
There was a negative relationship pre-treatment (R2=0.0351, P=0.487) and negative
relationship post treatment (R2=0.0734, P=0.396). However, only one trapped stand had
a SPB point located within the 10-ha area making the relationship difficult to decipher.
Discussion
Total numbers of small mammals were surprisingly low after trapping for two
years. Only, nine species of small mammals were captured. Only 28 individuals were
captured in the first year and 55 in the second. White-footed mice were the most
commonly captured species. This species could be caught in most treatment stands. It
was observed the higher numbers could be caught in areas with SPB deadfall,
accumulated slash, and in the controls. This species was not associated with any specific
cover and habitat. It would be difficult to narrow habitat specifics with the white-footed
mouse because it is adaptive to not only to forest fragmentation, but it does not choose
habitats based on forest composition (Henein et al., 1998).
33
The golden mouse was the second most captured mammal and third was the
Northern short tailed shrew. Golden mice captures for both years were low with total of
three captured individuals. The three captures occurred during the first year prior to
treatment. It was observed that this species was caught in areas that had some understory growth. Most stands were dense pine stands with little to no under-story vegetation.
Some stands contained canopy gaps due SPB deadfall which allowed sunlight penetration
and allowed under-story growth such as green-briar, shrubs, and other early successional
vegetation. The golden mouse is described as being arboreal living above ground in such
habitat conditions (Harper and Row, 1981). There were no golden mice captured after
treatments in the second year probably due to decrease in the preferred habitat.
Northern short tail shrew numbers decreased from 2005-2006 with three
individuals captured in the first year and only one individual the second year. It was
observed that this species was correlated with dense pine stands and no under-story living
primarily under the pine needle leaf litter. Most shrews favor moist conditions and cool
temperatures which the pine needle leaf layer provided (Mengak et al., 1989). Captures
were probably low due to decrease in insect populations below the leaf litter and decrease
in moisture.
For most captured species numbers were to low to make any habitat or treatment
observations. Small mammal numbers were either high or low in some stands possibly
due to their cyclic nature from the first year to the second (Oli and Dobson, 1999).
Recapture numbers were very low and it is likely that previously captured mammals
moved out of the treatment areas and new mammals replaced the old. The data taken was
recorded only after one year of treatment. Therefore, the treated stands and mammals in
34
them may not have enough time to fully recover. Changes in habitat due to treatment
were not significant therefore we could not draw possible conclusions as to which
treatments had an effect. In hindsight, treatment applications were sometimes
unsuccessful or mediocre for research purposes. During the treatment prescriptions,
burning intensity was not consistent throughout the treatments due to wet conditions.
Some fires did not carry evenly across the stands, but met the prescribed fire objectives of
the BNF. Some thinning treatments were over harvested resulting missed basal area
targets due to operator error. Thinned stands were not uniformly thinned and burning
conditions in burned stands varied considerably. Therefore, the results of this study could
be possibly skewed, because of variations from year to year, treatment applications, and
stand conditions. All stands within the study area should have been similar in stand
structure, age, and species composition. However, some stands contained tree mortality
due to southern pine beetle infestations. Standing dead timber and down woody debris
were found in stands, which possibly altered the homogeneity of the stands prior to
treatment. In essence, stands were all the same because there was no treatment applied in
year one. The stands became uniquely different in year two after treatments were applied.
Regardless of treatment, small mammal abundance, richness, and diversity were not
affected.
35
a.) Pre-treatment
12
Small mammal captures
10
8
6
4
2
0
-2
Rsq = 0.1222
-200
0
200
400
600
800
1000
1200
y = 0.003001x + .300
Edge Density m/10ha
b.) Post-treatment
12
Small mammal captures
10
8
6
4
2
0
-2
-200
Rsq = 0.0000
0
200
400
600
800
1000
1200
y = 0.00003485x + 3.483
Edge Density m/10ha
Figure 9. a.) Illustration of regression analyses results with trend line. There was a slight increase
of edge and small mammal abundance pre-treatment but not significant. b.) There was no
relationship between edge and small mammal captures post-treatment.
36
a.) Pre-treatment
12
Small mammal captures
10
8
6
4
2
0
-2
-100
Rsq = 0.0023
0
100
200
y = -0.00195x + 1.800
Stream Density m/10ha
b.) Post-treatment
12
Small mammal numbers
10
8
6
4
2
0
-2
-100
Rsq = 0.0520
0
100
200
y = -0.0128x + 3.826
Stream Density m/10ha
Figure 10. a.) Illustration of regression analyses results with trend line. Stream density seemed to
have a negative effect on small mammal captures. There was also a negative relationship for posttreatment as well. Few stands contained a stream within the 10-ha circle making the correlation
difficult to decipher.
37
a.) Pre-treatment
12
Small mammal numbers
10
8
6
4
2
0
-2
-.2
Rsq = 0.0351
0.0
.2
.4
.6
.8
1.0
1.2
1.0
1.2
y = -1.867x + 1.867
Number of SPB points/10ha
b.) Post-treatment
12
Small mammal numbers
10
8
6
4
2
0
-2
-.2
Rsq = 0.0734
0.0
.2
.4
.6
.8
y = -3.733x + 3.733
Number of SPB points/10ha
Figure 11. a.) There was a negative relationship of mammal numbers and Southern Pine Beetle
points pre-treatment. b.) There was a negative relationship post treatment as well. Only one stand
contained a SPB point within the 10-ha circular plot making this correlation difficult to analyze.
38
It is possible that other influences such as weather, past disturbance history, and
landscape variables affected small mammal populations from year to year. Results from
GIS and regression analysis did not reveal any patterns to support this observation. There
were SPB damage locations within some stands that did not show up or was not recorded
with the SPB GIS data. It was also observed that high small mammal captures were
occurring at the ends of the trap lines which were usually located in some type of
drainage or on a slope. The theory behind the captures was that these areas had more
moisture. The trapping web is designed where higher numbers of captures occur towards
the center of the plot because there is a higher density of traps towards the center
(Anderson et al., 1983). With drought conditions occurring during the study, this theory
seemed to make sense. The GIS analysis revealed that there were no consistent patterns
of this theory in other stands. Climatic variables were not recorded and analyzed but
should be considered in the future.
Some literature indicated that the use of pitfall traps would yield higher numbers
in diversity. Pitfall traps were not used in this study; however, a similar herpetofauna
study saw diverse captures of small mammals such as Peromyscus gossypinus,
Peromyscus leucopus, and Blarina brevicauda. Consideration for using pitfall traps
should be taken in the future to capture better diversity. Williams and Braun (1983)
indicated that pitfalls are more efficient than snap traps such as Sherman box traps.
Francl et al. (2002) stated that pitfall traps were more successful at capturing animals 20
grams or less, but Sherman traps attained the highest species richness. It was
recommended that a combination of traps need to be used to fully examine small
mammal populations and that no single trapping method is effective at capturing all
39
species (Francl et al., 2002). It would have been very difficult to implement additional
trapping methods to this study due to time and man power restraints.
40
CHAPTER 5
CONCLUSION AND RECOMMENDATIONS
This study revealed that there were no significant treatment effects among the
stands. However, this does not mean the treatments were not effective. For further
investigation with this study stands that were thinned should be investigated more in
depth. Stands that received a thinning seemed to have some effect on small mammals
although statistically that was not supported. In hindsight, the timing of thesis study was
too early to see any treatment responses. As for the trapping an alternative method needs
to be implemented to figure what will yield the most captures. In the neighboring
herpetofauna study drift fencing in combination with pitfall traps yielded more small
mammal captures along with reptiles and amphibians. The pitfall traps had a high
number of mortality of some small mammals and it is unknown if the neighboring study
traps are currently affecting small mammal abundance, diversity, and richness. In
comparison the Sherman box traps yielded a low number of diversity of animals. In
conjunction with the herptofauna study, small mammals captured in the pitfall traps
should be calculated in the overall small mammal population size. It is very possible
that recapture numbers are low due to animals being caught in the pitfall traps and dying.
Due to low number of captures and no significance among treatments
management suggestions can not be made. As this study progresses there should be some
41
pattern or signs of treatment effects on small mammals. As these treated stands enter into
their early successional stages, they will become more adequate to maintain a diverse
numbers of small mammals. Stands will eventually mature having large diameter poles,
large crowns, and a diverse under-story (Sullivan et al., 2001).
Several areas of variation need to be evaluated closely and be more standardized.
Areas such as time of day, season, and web location all should be more standardized to
minimize variations. We trapped in the summer months mainly due to conflicting class
schedules during the fall, winter, and spring. Although, web locations covered an area
close to one hectare some portions of the stands were not intensively trapped. Again, it
was very difficult to accomplish trapping and covering the landscape with only two
people. More man power will be needed to effectively trap these stands more intensively.
In the future more emphasis needs to put on the white-footed mouse as a target
species due to its high abundance in most of the BNF cover types. It has been proven
that there is no problem catching them with the use of peanut butter baits and Sherman
box traps.
42
BIBLIOGRAPHY
Anderson, David R., Burnham, Kenneth P., White, Gary C., and Otis, David L. 1983.
Density Estimation of Small Mammal Populations Using A Trapping Web and
Distance Sampling Methods. Ecology 64 (4) pp. 674-680.
Baker, James C. and William Hunter. 2002. Effects of forest management on terrestrial
ecosystems. Pp 91-112 in: Wear, David and John Greis, Eds. 2002. Southern
forest resource assessment. Gen Tech Rep SRS-53. Ashville, NC: USDA Forest
Service, Southern Research Station. pp. 635.
Brennan, L.A., Engstrom, R.T., Palmer, W.E., Hermann, S.M., Hurst, G.A., Burger,
L.W., and Hardy, C.L. 1998. Whither wildlife without fire? Transaction of the
63rd North American Wildlife Natural Resources Conference 63, 402-414.
Buckner, C.A., and Shure, D.J. 1985. The response of Peromyscus to forest opening size
in the southern Appalachian mountains. Journal of Mammalogy 66, 299-307.
Burt, William Henry and Grossenheider, Richard Philip. 1980. The Peterson Field Guide
Series: Field Guide to the Mammals. 3rd Edition.
Burton, L. Devere. 2003. Fish and Wildlife Principles of Zoology and Ecology. 2nd
Edition. Delmar. Albany, NY. pp. 197.
Campbell III, T.M., and Clark, T.W. 1980. Short term effects of logging on red-backed
voles and deer mice. Great Basin Naturalist. 40, 183-189.
Carey, A.B., and Wilson, S.M. 2001. Induced spatial heterogeneity in forest canopies:
Responses of small mammals. Journal of Wildlife Management 65, 1014-1027.
Chandler, C. P., Cheney, P., Thomas, L. Traubaud, and D. Williams. 1983. Fire in
forestry. 2 vols. John Wiley and Sons Inc., New York. pp. 789.
Constantine, Nicole L., Campbell, Tyler A., Baughman, William M., Harrington,
Timothy B., Chapman, Brian R., and Miller, Karl V. 2004. Effects of clearcutting
with corridor retention on abundance, richness, and diversity of small mammals in
the coastal plain of South Carolina, USA. Forest Ecological Management 202,
293-300.
43
Constantine, Nicole L., Campbell, Tyler A., Baughman, William M., Harrington,
Timothy B., Chapman, Brian R., and Miller, Karl V. 2005. Small mammal
distributions relative to corridor edges within intensively managed southern pine
plantations. Southern Journal of Applied Forestry 29 (3): 148-151.
Corn, P.S., and Bury, R.B. 1991. Small mammal communities in the Oregon Coast
Range. Pp. 241-254 In: L.F. Ruggiero, K.B., Aubry, A.B., Carey, and M.H. Huff,
technical coordinators. Wildlife and vegetation of unmanaged Douglas fir forests.
U.S. Forest Service, Pacific Northwest Research Station, General Technical
Report PNW-GTR-285.
Dickson, James G. 1981. Impact of Forestry Practices on Wildlife in Southern Pine
Forests. In: Effects of Forest Practices on Fish and Wildlife Production. A Joint
Technical Session of Working Groups on Wildlife and Fish Ecology and Forest
Ecology. September 29, 1981 pp 21-26.
Dowdy, Shirley and Wearden, Stanley. 1983. Statistics For Research. John Wiley and
Sons Inc., New York. pp. 330.
Dueser, R.D. and Shugart Jr., H.H. 1978. Microhabitat in a forest-floor small-mammal
fauna. Ecology 60, 108-118.
Dueser, R.D., and Porter, J.H. 1986. Habitat use by insular small mammals: relative
effects of competition and habitat structure. Ecology 67, 195-201.
Elliot, K.J. and Hewitt, D. 1997. Forest species diversity in upper elevation hardwood
forests in the southern Appalachian Mountains. Castanea 62, 32-42.
Entwistle, A.C. and P.J. Stephenson. 2000. Small mammals and the conservation agenda.
Pp 119-140 in: Priorities for conservation of mammalian diversity (A. Entwistle
and N. Dunstone, eds.) Cambridge University Press. Cambridge, United
Kingdom.
Fahnestock, G. 1973. Use of fire in managing forest vegetation. Trans. Amer. Soc. Agr.
Eng. 16:410-419.
Fantz, D.K. and Renken, R.B. 2005. Short term landscape scale effects of forest
management on Peromyscus spp. Mice within Missouri Ozark forests. Wildlife
Society Bulletin 33, 285-292.
Ford, W.M., Menzel, M.A., McCay, T.S., Gassett, J.W., and Laerm, J. 2000. Woodland
salamander and small mammal responses to alternative silvicultural practices in
the southern Appalachians of North Carolina. Proc. Annu. SEAFWA 54, 241-250.
44
Ford, W.M., Menzel, M.A., McGill, D.W., Laerm, J., and McCay, T.S., 1999. Effects of
a community restoration fire on small mammal and herpetofauna in the southern
Appalachians. Forest Ecology and Management 114, 233-243
Francl, Karen E., Ford, W. Mark, and Castleberry, Steven B. 2002. Relative efficiency of
three small mammals traps in central Appalachian wetlands. Georgia Journal of
Science. http://findarticles.com/p/articles/mi_qa4015/is_200201/ai_n9061884. 16
Nov 2007.
Gentry, J.B., Golley, F.B., and Smith, M.H. 1968. An evaluation of the proposed
International Biological Program census method for estimation small mammal
populations. Acta Theriologica 13, 313-327.
Greenburg, Cathryn H. 2002. Response of white-footed mice (Peromyscus leucopus) to
coarse woody debris and microsite use in southern Appalachian treefall gaps.
Forest Ecology and Management 164, 57-66.
Greenburg, Cathryn H., Otis, David L., and Waldrop Thomas A. 2006. Responses of
white-footed mice (Peromyscus leucopus) to fire and fire surrogate fuel reduction
treatments in a southern Appalachian hardwood forest. Forest Ecology and
Management 234, 355-362.
Gullion, G.W. 2003 Forest and Wildlife Management. Chapter 14 in: Introduction to
forest Ecosystems Science and Management, 3rd edition (Young, R.A. and R.L
Giese, eds). John Wiley and Sons Inc., Hoboken, NJ. pp. 560.
Hanski, I. 1987. Pine sawfly population dynamics: Patterns, Processes, Problems. Oikos.
50: 327-335.
Harper and Row. 1981. Complete Field Guide to North American Wildlife-Eastern
Edition. New York, New York.
Heinin, K., Wegner, J., and Merriam, G. 1998. Population effects of landscape model
manipulation on two behaviorally different woodland small mammals. Oikos 81,
168-186.
Hoffmeister, D. F. 1989. Mammals of Ilinois. University of Illinois Press, Urbana, IL pp.
348.
Kingston, S.R., and Morris, D.W. 2000. Voles looking for an edge: Habitat selection
across forest ecotones. Canadian Journal of Zoology 78 (12): 2174-2183.
Kirkland Jr., Gordon L., Snoddy, Heather W, and Tereas L. Amsler. 1996. Impact of Fire
on Small Mammals and Amphibians in a Central Appalachian Deciduous Forest.
American Midland Naturalist, Vol. 135, No. 2. Apr., 1996 pp. 253-260.
45
Kirkland, G. L., 1990. Patterns of initial small mammal community change after
clearcutting of temperate North American forests. Oikos 59, 131-320.
Linzey, D.W. and Packard, R.L. 1977. Ochrotomys nuttalli. Mammology. Species No. 75
pp.6.
Loeb, S.C. 1996. The role of coarse woody debris in the ecology of southeastern
mammals. In: McMinn, J.W. Crossley Jr, D.A. (Eds), Biodiversity and Coarse
Woody Debris in Southern Forests. USDA Forest Service General Technical
Report SE-94, Pp. 1108-118.
Lomolino, M.V. and Perault, D.R. 2000. Assembly and disassembly of mammal
communities in a fragmented temperate rain forest. Ecology. 81:1517-1532.
Mackey, B.G. and Lindenmayer, D.B. 2001. Towards a hierarchical framework for
modeling the spatial distribution of animals. Journal of Biogeography 28, 11471166.
Maine, John D. 1979. A qualitative analysis of the southern pine beetle’s impact on
wildlife, wildfire, and grazing. M.S. Thesis, Virginia Polytechnic Institute and
State University. pp. 62-63.
Martell, A.M. 1983. Changes in small mammal communities after logging in northcentral
Ontario. Can. Journal of Zoology. 61, 970-980.
Medin, D.E., and Booth, G.D. 1989. Responses of birds and small mammals to singletree selection logging in Idaho. USDA Forest Service Intermountain Forest and
Range Research Station, Research Paper. Int-408.
Mengak, Michael T., and Guynn Jr, David C. 2003. Small mammal microhabitat use on
young loblolly pine regeneration areas. Forest Ecology and Management 173,
309-317.
Mengak, Michael T., and Guynn Jr., David C. 1987. Pitfall and snap Traps for Sampling
Small mammals and Herpetofauna. American Midland Naturalist, Vol 118, No. 2
Oct 1987 pp. 284-288.
Menkak, M. T., Guynn Jr, D.C., Van Lear, D.H. 1989. Ecological implications of loblolly
pine regeneration for small mammal communities. Forest Science 35, 503-514.
Mirarchi, Ralph E., Bailey, Mark A., Haggerty, Thomas M and Troy L. Best. 2004 (b).
Alabama Wildlife: A Checklist of Vertebrates and Selected Invertebrates:
Aquatic Mollusks, Fish, Amphibians, Reptiles, Birds, and Mammals. Vol. 3. The
University of Alabama Press, Tuscaloosa, Alabama.
46
Mirarchi, Ralph E., Bailey, Mark A., Haggerty, Thomas M and Troy L. Best. 2004 (a).
Alabama Wildlife: A Checklist of Vertebrates and Selected Invertebrates:
Aquatic Mollusks, Fish, Amphibians, Reptiles, Birds, and Mammals. Vol. 1. The
University of Alabama Press, Tuscaloosa, Alabama.
Monroe, Michelle E and Converse, Sarah J. 2006. The effects of early season and late
season prescribed fires on small mammals in a Sierra Nevada mixed conifer
forest. Forest Ecology and Management 236, 229-240.
Monthey, R. W. and Soutiere, E.C. 1985. Responses of small mammals to forest
harvesting in northern Maine. Can. Field-Naturalist. 99, 13-18.
Muzika, R.M, Grushecky, S.T., Liebhold, A.M., and Smith, R.L. 2004. Using thinning as
a management tool for gypsy moth: the influence on small mammal abundance.
Forest Ecology and Management 192, 349-359.
Oli, Madan K., and Dobson, Stephen F.1999. Population cycles in small mammals: the
role of age at sexual maturity. Oikos, Vol. 86, No. 3 September 1999 pp.557-565.
Pank, L.F. 1974. A bibliography of seed-eating mammals and birds that affect forest
regeneration. USDI Fish Wildlife Service Special Science Report. pp 174.
Perry, Roger W., and Thill, Ronald E. 2005. Small-mammal responses to pine
regeneration treatments in the Ouachita Mountains of Arkansas and Oklahoma,
USA. Forest Ecology and Management 219 (2005) 81-94.
Rushton, S.P., Lurz, P.W.W., Gurnell, J. and Fuller, R. 2000. Modeling the spatial
dynamics of parapoxvirus disease in red and gray squirrels: a possible cause of
the decline in the red squirrel in the UK? Journal of Applied Ecology 37, 9971012.
Rushton, S.P., Ormerod, S.J. and Kerby, G. 2004. New paradigms for modeling species
distributions? Journal of Applied Ecology 41, 193-200.
Schemnitz, Sanford D. 1980. Wildlife Management Techniques Manual. 4th Edition. The
Wildlife Society, Inc. pp 61.
Shannon, C.E., and W.Weaver. 1949. The mathematical theory of communication.
University of Illinois press, Urbana. pp. 177.
Sharitz, R. R., Boring, L.R., Van Lear, D. H., Pinder III, J.E., 1992. Intergrating
ecological concepts with natural resource management of southern forests.
Ecological Applications. 2, 226-237.
47
Sharp, Nicholas W. 2004. Effects of Fire and Fire Surrogates on the Small Mammal
Population of the Long Leaf Pine Ecosystem. M.S. research proposal, Auburn
University pp. 5.
Sharpe, Grant, Clare Hendee, and Shirley Allen. 1976. Introduction to Forestry. 4th
edition. McGraw-Hill, Inc. New York. pp. 246.
Smith, C.F and S.E. Aldous. 1947. The influence of mammals and birds in retarding
artificial and natural regeneration of coniferous forest of the United States.
Journal of Forestry. 45: pp. 361-369.
Smith, David M., Bruce Larson, Matthew Kathy, and Mark Ashton. 1997. The Practice of
Silviculture. Applied Forest Ecology. 9th edition. John Wiley and sons, Inc.
Hoboken, NJ. pp. 210.
Smith, M. H, Gentry, J.B., and Pinder, J. 1974. Annual fluctuations in small mammal
populations in an eastern hardwood forest. Journal of Mammalogy 66, 22-35.
Sullivan, Thomas P., Sullivan, Druscilla S., and Pontus M.F. Lindaren. 2001. Stand
Structure and Small Mammals in young lodgepole pine forests: 10-year results
after thinning. Ecological Society of America, 11 (4) 2001. pp. 1151-1173.
Swan, D., Freedman, B., and Dilworth, T. 1984. Effects of various hardwood forest
management practices on small mammals in central Nova Scotia. Can. Field-Nat.
98, 362-364.
Tester, John R. 1965. Effects of a Controlled Burn on Small Mammals in a Minnesota
Oak-Savanna. American Midland Naturalist, Vol. 74, No.1 July., 1965 pp. 240243.
USDA Forest Service. 1980. The southern pine beetle. Expanded southern pine beetle
research and applications program. Forest Service, Science and education
administration, Technical Bulletin 1631 Pp. Chapter 8.
USDA Forest Service. 1981. The effects of fire and other disturbances on small mammals
and their predators in an annotated bibliography. USDA Forest Service general
technical Report INT-106. Intermountain Forest and Range Experiment Station.
Pp.1-2.
USDA Forest Service. 2003. Final Environmental Impact Statement Forest Health and
Restoration Project, National Forest Alabama, Bankhead National Forest. pp. 136.
Van Horne, B. 1981. Demography of Peromyscus maniculatus populations in serial
stages of coastal coniferous forest in southeast Alaska. Canadian Journal of
Zoology 59, 1045-1061.
48
Vaughan, Terry A. 1972. Mammalogy. W.B. Sanders Company, West Washington
Square. Philadelphia, PA. pp. 141-178.
Wheatley, Matthew, Fisher, Jason T., Larsen, Karl, Litkes, Joseph and Boutin, Stan.
2005. Using GIS to relate small mammal abundance and landscape structure at
multiple spatial extents: the northern flying squirrel in Alberta, Canada. Journal
of Applied Ecology 42, 577-586.
Wike, L.D. 2000. Role of edge effect on small mammal populations in a forest fragment.
U.S. Department of Energy technical report WSRC-TR-2000-00103. Savannah
Rive Site pp.1-10.
Williams, D. F. and Braun, S.E. 1983. Comparison of pitfall and conventional traps for
sampling small mammal populations. Journal of Wildlife Management, 47: 841845.
Yahner, Richard H. 1992. Dynamics of a Small Mammal Community in a Fragmented
Forest. American Midland Naturalist, Vol. 127, No. 2. Apr., 1992 pp. 381-391.
49