influences of abiotic and biotic habitat characteristics on pika occupancy in select regions of the

71 Pages·2015·1.35 MB·English

INFLUENCES OF ABIOTIC AND BIOTIC HABITAT CHARACTERISTICS
ON PIKA OCCUPANCY IN SELECT REGIONS OF THE
GALLATIN NATIONAL FOREST, MONTANA

by
Lindsay Paterson Hall

A professional paper submitted in partial fulfillment
of the requirements for the degree

of

Master of Science
in
Science Education

MONTANA STATE UNIVERSITY
Bozeman, Montana

July 2015
© COPYRIGHT

by

Lindsay Paterson Hall

2015

All Rights Reserved
ii

ACKNOWLEDGEMENTS
First and foremost, I am extremely appreciative of the entire MSSE program and
its faculty. The opportunities for science teachers to pursue meaningful scientific research
whilst maintaining a full teaching schedule are limited; I am tremendously grateful for
the opportunity to deepen my understanding of science education and research through
the MSSE program.
Second, I would like to extend sincere gratitude to my project advisor, Dr. John
Winnie Jr. for his endless patience, knowledge, and passion for science. Without his
continual insight and mentorship, I would still be up in the talus fields figuring out my
initial methodology. I would also like to extend my thanks to Dr. Dave Willey who made
meaningful suggestions to improve my writing.
Finally, I would like to extend my endless appreciation to my friends and family
who endlessly listened, supported, and facilitated this process. My MSSE classmates
served as wonderful sounding boards, editors, and inspiring friends. In particular, Jenny
Edwards spent countless hours helping brainstorm, revise, and trouble shoot, & I am
endlessly appreciative of her support. Additionally, my husband Terrill Paterson provided
significant data analysis guidance, encouraged me in every step of the process, and kept
me well hydrated with Lime-Aide, for which I am eternally grateful.
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TABLE OF CONTENTS
1. INTRODUCTION AND BACKGROUND ................................................................... 1
Objectives ............................................................................................................... 1
Study Area .............................................................................................................. 2
2. CONCEPTUAL FRAMEWORK .................................................................................. 5
Diet .......................................................................................................................... 5
Feeding and Haying Behaviors ............................................................................... 6
Thermoregulation .................................................................................................... 7
Talus Habitat ........................................................................................................... 8
Territory Marking and Dispersal Patterns............................................................... 9
Extirpation of Pika Populations ............................................................................ 10
Hypotheses & Predictions ..................................................................................... 11
Abiotic Habitat Site Characteristics .............................................................. 12
Biotic Habitat Site Characteristics ................................................................ 15
3. METHODOLOGY ....................................................................................................... 16
Site Selection ........................................................................................................ 16
Abiotic Habitat Site Characteristics ...................................................................... 16
Biotic Habitat Characteristics ............................................................................... 18
Site Occupancy ..................................................................................................... 20
4. DATA AND ANALYSIS ............................................................................................ 22
5. RESULTS .................................................................................................................... 23
Abiotic Habitat Site Characteristics ...................................................................... 23
Slope, Aspect, and Solar Insolation .............................................................. 23
Elevation ....................................................................................................... 28
Talus Field Area and Mean Boulder Size ..................................................... 31
Distance to Nearest Neighbor ....................................................................... 34
Biotic Habitat Site Characteristics ........................................................................ 35
Vegetation Characteristics ............................................................................ 35
6. INTERPRETATION AND CONCLUSION ............................................................... 38
Implications for Pika Populations ......................................................................... 38
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TABLE OF CONTENTS (CONTINUED)
7. VALUE ........................................................................................................................ 43
Implications for Personal Practice & Teaching Science ....................................... 43
Implications for Science Education ...................................................................... 44
8. REFERENCES CITED ................................................................................................ 46
9. APPENDICES ............................................................................................................. 51
APPENDIX A: Abiotic Characteristics Transects Data Table ............................ 52
APPENDIX B: Vegetation Transects Data Table ............................................... 54
APPENDIX C: Survey Site Data & Characteristics ............................................ 56
APPENDIX D: Abiotic Site Characteristics & Pika
Occupancy Box and Whisker Plots ...................................................................... 58
APPENDIX E: Mean Elevation and Pika Equivalent Elevation ......................... 60
APPENDIX F: Average Percentage of Vegetation
Category and Pika Occupancy Box and Whisker Plots ........................................ 62
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LIST OF TABLES
1. Study Regions and Corresponding Mean Slope, Aspect, and Solar Insolation ............ 24
2. Mean Percentage of Vegetation By Category in Occupied and Unoccupied Sites ...... 35
3. Abiotic Characteristics Transects Data Table ............................................................... 53
4. Vegetation Transects Data Table .................................................................................. 55
5. Survey Site Data and Characteristics ............................................................................ 57
6. Mean Elevation and Pika Equivalent Elevation............................................................ 61
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LIST OF FIGURES
1. Study Area Overview & Regional Insets. ....................................................................... 4
2. Location of Idealized Boulder Transects Across a Talus Field. ................................... 18
3. Location of Idealized Vegetation Transects Extending Out Fom Talus Field. ............. 19
4. Ticker Counters to Facilitate Vegetation Categorization Along a 1 m tTansect . ........ 20
5. Example of Fresh Pellets .............................................................................................. 21
6. Haypile Categorized as “Inactive” and Haypile Categorized as “Active.” .................. 21
7. Example of Urine Stain and Pellets Left by Animal Other Than a Pika. ..................... 22
8. Mean Slope (Degrees) and Pika Occupancy. ................................................................ 25
9. Mean Slope (Degrees) and Pika Occupancy Within Hyalite Canyon. ......................... 26
10. Mean Aspect (Degrees) and Pika Occupancy. ............................................................ 27
11. Solar Insolation and Pika Occupancy Hyalite Canyon. .............................................. 28
12. Mean Elevation (Meters) and Pika Occupancy. ......................................................... 29
13. Mean Elevation (Meters) and Pika Occupancy Hyalite Canyon. ............................... 30
14. Mean Elevation (Meters) and Pika Occupancy Portal Creek. .................................... 31
15. Mean Area (Meters2) and Pika Occupancy. ................................................................ 32
16. Mean Boulder Size Across All Site Regions. ............................................................. 33
17. Mean Boulder Size (Boulders / Meter) and Pika Occupancy in Hyalite Canyon. ...... 34
18. Distance to Nearest Neighbor (Meters) and Pika Occupancy. ................................... 35
19. Average Coverage (Percentage) of Woody Plants and Pika Occupancy. ................... 37
20. Average Bare Ground Coverage (Percentage) and Pika Occupancy. ......................... 38
vii
ABSTRACT
This research project explores how several abiotic and biotic habitat
characteristics influence occupancy probabilities of the North American pika, Ochotona
princeps within select regions of the Gallatin National Forest. Pikas are possible indicator
species for climate change, as they are obligatory talus dwellers found in alpine and
subalpine ecosystems, and are extremely sensitive to high temperatures.
Slope, aspect, elevation, talus field dimensions, and mean boulder size likely
influence how pikas experience ambient temperatures within specific habitat sites and
consequently may influence occupancy probabilities. In addition, vegetation diversity and
abundance may also influence the likelihood of a talus field being occupied by pikas.
I investigated the relationship between abiotic and biotic habitat site
characteristics and pika occupancy. I visited three sites within the Gallatin National
Forest: Beehive Basin, Portal Creek, and Hyalite Canyon during the summer and fall of
2014. I surveyed 28 talus fields, quantifying a suite of habitat variables and determining
pika occupancy of each site.
The results of this study indicate that slope, aspect, and elevation were the
strongest predictors of pika occupancy, whereas solar insolation, talus field area, mean
boulder size, and distance to nearest neighbor were of less importance. Additionally,
vegetation type and abundance did not prove statistically significant as a predictor of pika
occupancy. Broadly speaking, pika occupancy within the Gallatin National Forest will
likely depend on specific combinations of local abiotic and biotic habitat attributes.
1
INTRODUCTION AND BACKGROUND
Objectives
The North American pika, Ochotona princeps, is a small (120 – 180 g), diurnal,
philopatric lagomorph typically found in rocky, mountainous regions throughout western
North America (Smith & Weston, 1990). They are obligatory talus dwellers and are very
sensitive to high temperatures, with relatively brief exposure (as few as six hours) in the
mid-70s Fahrenheit being fatal (Smith, 1974b). Due to their sensitivity to high
temperatures, pikas are viewed by many as early indicators of the effects of climate
change on alpine ecosystems. Some research suggests pikas are experiencing extirpations
at lower elevations, sites with less annual precipitation, and average temperatures higher
than those of extant population sites (Beever, Brussard, & Berger. 2003; Beever, Ray,
Mote, & Wilkening, 2010; Erb, Ray, & Guralnick, 2011; Grayson, 2005; Hafner, 1991;
McDonald & Brown, 1992). Consequently, in 2007, the pika was petitioned under
California State and federal laws to receive designation as an endangered species (Wolf,
Nowicki, & Siegel; 2007a, Wolf, Nowicki, & Siegel, 2007b). Research dedicated to
understanding the habitat requirements of the pika can reveal characteristics necessary for
site occupancy, persistence, and offer insights into possible management actions to
mitigate the effects of climate change.
The purpose of this study was to compare abiotic and biotic characteristics of
occupied and unoccupied talus slopes in an attempt to determine which factors determine
suitable pika habitat. The objectives of this project were to:
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1. Assess pika occupancy of talus slopes through absence/presence surveys (i.e.
currently occupied, past occupied, never occupied).
2. Compare the abiotic characteristics between occupied and unoccupied talus slopes
(e.g. slope, aspect, solar insolation, elevation, talus field area, distance to nearest
neighbor, mean boulder size).
3. Compare relative abundance and type of vegetation (e.g. graminoids, forbs,
woody plants, and cushion plants) between occupied and unoccupied talus slopes.
Study Area
I conducted this research project over 11 weeks in summer and fall 2014 and investigated
a series of lower and higher elevation pika habitat sites in southwestern Montana. As
pikas characteristically live in talus fields in montane ecosystems and use adjacent
meadows for foraging (Smith and Weston, 1990), I sought study sites that met this habitat
requirement. I divided the study area into three regions: Beehive Basin, Portal Creek, and