Roosting and Foraging Ecology of Forest Bats in the Southern Appalachian Mountains

145 Pages·2016·1.13 MB·English

Clemson University
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All Dissertations Dissertations
5-2009
Roosting and Foraging Ecology of Forest Bats in
the Southern Appalachian Mountains
Joy O'keefe
Clemson University, [email protected]
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TITLE PAGE

ROOSTING AND FORAGING ECOLOGY OF FOREST BATS
IN THE SOUTHERN APPALACHIAN MOUNTAINS
_____________________________________
A Dissertation
Presented to
The Graduate School of
Clemson University
_____________________________________
In Partial Fulfillment
of the Requirements for the Degree
Doctor of Philosophy
Wildlife and Fisheries Biology
_____________________________________
by
Joy Marie O’Keefe
May 2009
_____________________________________
Accepted by:
Dr. J. Drew Lanham, Committee Chair
Dr. Eric Britzke
Dr. Hoke Hill, Jr.
Dr. Susan Loeb
Dr. Chris Post
ABSTRACT

Although most bats in the southeastern United States depend on forests for roosting
and foraging, we know little about the ecological requirements of bats that live in this
region. The objective of this study was to use radio telemetry, acoustic sampling,
Akaike’s information theoretic procedures, occupancy modeling, and discriminant
function analyses to: 1) examine multi-scale roost-site selection for three forest bat
species [eastern pipistrelles (Perimyotis subflavus), eastern red bats (Lasiurus borealis),
and northern long-eared bats (Myotis septentrionalis)], 2) test the effects of timber
harvest on bat foraging ecology in riparian areas, and 3) compare and relate methods of
assessing vegetative clutter to the probability of detecting bats. We conducted our study
from 2004–2007 in a dense deciduous forest undergoing low-intensity timber
management in the southern Appalachian Mountains of western North Carolina, USA.
We radiotracked eight red bats to 19 roosts, seven pipistrelles to 15 roosts, and 16 male
and 18 female northern long-eared bats to 50 and 52 roosts, respectively. We recorded
48,456 bat passes in riparian areas during 8,309 hours on 832 detector-nights and
assessed bat detection probabilities and vegetative clutter at 71 points. Macrohabitat
factors were important to male red bats and pipistrelles whereas female northern long-
eared bats displayed mainly microhabitat roost-site preferences. Our results indicated that
maintaining a diversity of age classes should provide roosting habitat for pipistrelles, red
bats, and northern long-eared bats. Leaving large diameter trees and snags of preferred
genera (Quercus, Robinia, Carya) during harvests should ensure a continuous supply of
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suitable roost structures for reproductive female northern long-eared bats. Pipistrelles and
female northern long-eared bats may also benefit from retention of mature stands near
streams. Riparian areas near small streams in our study area served as foraging habitat for
≥4 bat species and forested buffers affect the foraging activity of bats in riparian areas
following timber harvest in adjacent forests. Quantitative measurements of individual
variables (specifically midstory live stem count and canopy crown volume) were the most
effective measures of clutter relative the other methods we tested because they were good
predictors of bat detection and were most effective in discriminating among survey points
of different ages and forest types. In future studies of bat foraging habitat, quantitative
measures should be used to assess clutter to facilitate comparisons among habitats or
studies.
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ACKNOWLEDGEMENTS

I am grateful to my research advisor, Dr. Susan Loeb, for guidance, support, and
friendship. I thank Dr. Drew Lanham for advice and for the opportunity to teach
Nongame Management, which I thoroughly enjoyed. I am grateful to Dr. Hoke Hill, Jr.
for the many hours spent on statistics, to Dr. Eric Britzke for research advice, and to Dr.
Chris Post for facilitating my use of GIS. Thanks to Dr. Pat Gerard for help with statistics
for Chapter Three.
Funding for my research study was provided by the USDA Forest Service Southern
Research Station, Bat Conservation International, Touchstone Energy, and Sigma Xi. I
was also supported by graduate and teaching assistantships from the Clemson University
Department of Forestry and Natural Resources and Department of Biological Sciences,
respectively; a Clemson University Graduate Fellowship; and a Wade Stackhouse
Fellowship. Thanks to Dr. Tafadzwa Kaisa for allowing me to teach for three years and
for his friendship during that time.
I am indebted to Dylan Horvath for stellar field assistance from 2005–2007 and for
his friendship. Special thanks to Timothy Sichmeller for his enthusiasm and dedication to
my project. E. Blizzard, B. Carey, C. Cooke, N. Gikas, A. Janicki, E. MacDonald, O.
Pearman, P. Swenson, M. Vindigni, and M. Vukovich also provided invaluable field
assistance.
I appreciate logistical help from the staff of the Wayah Ranger District of the
Nantahala National Forest; Dr. R. Davis, M. Gaines, Dr. D. Guynn, D. Jones,

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Dr. P. Layton, S. McElreath, L. McFalls, S. Pedric, L. Rice, C. Wakefield (Clemson
University), and B. Clinton (Coweeta Hydrologic Laboratory, USDA Forest Service,
Southern Research Station). Thanks to Dr. R. Baldwin (Clemson University), Dr. D.
Miller (Weyerhaeuser NR Company), Dr. T.B. Wigley (National Council for Air and
Stream Improvement, Inc.), and Dr. M.D. Yates (Furman University) for comments or
advice that improved a portion of my dissertation.
I am grateful to my family for support and patience through all of my schooling.
Mom, thanks for the webpage and for reminding me that there are other animals besides
bats. Dad, your consistent interest and prodding has been much appreciated. Thanks also
to my “new” family, the Vukovich clan, for their support.
Lastly, I want to thank my best friend and husband, Mark Vukovich, for love,
laughter, advice, thoughtful conversation, encouragement, and support during my tenure
at Clemson.
This project was completed under Clemson University Animal Use Protocol 40065.
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TABLE OF CONTENTS

Page

TITLE PAGE .................................................................................................................... i

ABSTRACT ..................................................................................................................... ii

ACKNOWLEDGMENTS .............................................................................................. iv

LIST OF TABLES ........................................................................................................ viii

LIST OF FIGURES ........................................................................................................ xi

CHAPTER

1. MACROHABITAT FACTORS AFFECT DAY ROOST
SELECTION BY EASTERN RED BATS AND
EASTERN PIPISTRELLES IN THE SOUTHERN
APPALACHIAN MOUNTAINS, USA ........................................................... 1

Abstract .................................................................................................. 1
Introduction ........................................................................................... 2
Materials and Methods .......................................................................... 5
Results ................................................................................................. 11
Discussion ............................................................................................ 21
Management Implications ................................................................... 25

2. ROOST ECOLOGY OF MALE AND FEMALE
NORTHERN LONG-EARED BATS IN THE SOUTHERN
APPALACHIAN MOUNTAINS, USA ......................................................... 27

Abstract ................................................................................................ 27
Introduction ......................................................................................... 28
Materials and Methods ........................................................................ 31
Results ................................................................................................. 40
Discussion ............................................................................................ 56
Management Implications ................................................................... 64

vi
Table of Contents (Continued)

Page

3. RIPARIAN BUFFER WIDTH AFFECTS ACTIVITY
AND DETECTION OF COMMON BAT SPECIES ..................................... 66

Abstract ................................................................................................ 66
Introduction ......................................................................................... 67
Materials and Methods ........................................................................ 70
Results ................................................................................................. 75
Discussion ............................................................................................ 85
Management Implications ................................................................... 91

4. QUANTIFYING CLUTTER: A COMPARISON OF
FOUR METHODS AND THEIR RELATIONSHIP
TO BAT DETECTION .................................................................................. 92

Abstract ................................................................................................ 92
Introduction ......................................................................................... 93
Materials and Methods ........................................................................ 96
Results ............................................................................................... 104
Discussion .......................................................................................... 115
Management Implications ................................................................. 118

APPENDIX

A: Decay Classes (From Ormsbee 1996)...................................................... 121

B: Candidate Microhabitat Model Set for Male and
Female Northern Long-Eared Bats....................................................... 122

C: Candidate Macrohabitat Model Set for Male and
Female Northern Long-Eared Bats....................................................... 123

LITERATURE CITED ................................................................................................ 124

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LIST OF TABLES

Table Page

1.1 Mean, standard error, minimum, and max values for tree and
microhabitat variables for roosts used by eastern red bats and
eastern pipistrelles ......................................................................................... 16

1.2 Stand and landscape variables used in candidate models of roost
selection by eastern red bats and eastern pipistrelles .................................... 17

1.3 Akaike's information criterion for small sample sizes, difference in
AICc value when compared to the model with the lowest AICc
value, and Akaike weight for models with ∆AICc ≤ 2 from the a
priori set of 175 candidate models used to predict stand and
landscape level roost-site selection by eastern red bats and
eastern pipistrelles ......................................................................................... 17

1.4 Model averaged parameter estimates, unconditional standard errors,
odds ratios, and sum of Akaike weights of predictor variables
found in plausible models for eastern red bat and eastern
pipistrelle roost selection............................................................................... 18

1.5 Mean, standard error, minimum, and maximum values of stand and
landscape variables measured for eastern red bat roosts and
associated random sites. ................................................................................ 19

1.6 Mean, standard error, minimum, and maximum values of stand and
landscape variables measured for eastern pipistrelle roosts and
associated random sites ................................................................................. 20

2.1 Tree and plot variables used in microhabitat and macrohabitat roost-
site selection models for northern long-eared bats ........................................ 46

2.2 Akaike's Information Criterion for small sample sizes, difference in
AICc value when compared to the model with the lowest AICc
value, and Akaike weight for models with substantial empirical
support from a priori set of candidate models used to assess
microhabitat roost-site selection by northern long-eared bats ...................... 47

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List of Tables (Continued)

Table Page

2.3 Model averaged parameter estimates, unconditional standard errors,
odds ratios, and sum of Akaike weights of predictor variables
found in models with ∆AICc ≤ 2 from a priori set of candidate
models used to assess microhabitat roost-site selection by
northern long-eared bats ................................................................................ 48

2.4 Mean, standard error, minimum, and maximum values for
microhabitat variables for northern long-eared bat roosts ............................ 49

2.5 Akaike's Information Criterion for small sample sizes, difference in
AICc value when compared to the model with the lowest AICc
value, and Akaike weight for models with substantial empirical
support from a priori set of candidate models used to assess
macrohabitat roost-site selection by northern long-eared ............................. 50

2.6 Model averaged parameter estimates, unconditional standard errors,
odds ratios, and sum of Akaike weights of predictor variables
found in models with ∆AICc ≤ 2 from a priori set of candidate
models used to assess macrohabitat roost-site selection by
northern long-eared bats ................................................................................ 51

2.7 Mean, standard error, minimum, and maximum values for
macrohabitat variables for roosts used by northern long-eared
bats ................................................................................................................ 52

3.1 Pre-harvest activity by position for four riparian sites in southwestern
North Carolina, USA ..................................................................................... 78

3.2 Significance tests for fixed effects in mixed linear models for the
change in activity from 2005 to 2006 and 2005 to 2007............................... 79

3.3 Pre- and post-harvest detection probabilities and standard errors for
four phonic groups of bats detected in acoustic surveys of
riparian buffers .............................................................................................. 80

3.4 Naïve occupancy rates for four phonic groups in three treatment sites
in riparian areas ............................................................................................. 80

4.1 Fourteen plot structure variables measured in 0.04 ha plots at bat
survey points in temperate deciduous forests............................................. 107
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