Craig Allen DeMars

231 Pages·2015·4.21 MB·English

Calving Behavior of Boreal Caribou in a Multi-predator, Multi-use Landscape

by

Craig Allen DeMars

A thesis submitted in partial fulfillment of the requirements for the degree of

Doctor of Philosophy

in

Ecology

Department of Biological Sciences
University of Alberta

© Craig Allen DeMars, 2015
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ABSTRACT
The boreal ecotype of woodland caribou (Rangifer tarandus caribou) is federally listed as
Threatened due to population declines throughout its distribution. High mortality rates of
neonate calves (≤ 4 weeks old) due to predation are a key demographic factor contributing to
population declines and increasing predation has been linked to landscape disturbance within
and adjacent to caribou range. To inform management strategies for improving rates of calf
survival, I investigated the space use and habitat requirements of female boreal caribou during
calving. Space is integral to the calving behaviour of boreal caribou with parturient females
dispersing widely on the landscape, a behaviour hypothesized to reduce predation risk. I
assessed potential evolutionary drivers of dispersion using simulation analyses that tracked
caribou-wolf encounters during the calving season. I specifically assessed whether dispersion
decreased predation risk by: (i) increasing predator search time, (ii) reducing predator
encounters because individuals are inconspicuous relative to groups, or (iii) eliminating the risk
of multiple kills per predator encounter of caribou groups. Simulation outputs show that
dispersion only becomes favourable when differential detectability based on group size is
combined with the risk of multiple kills per encounter. This latter effect, however, is likely the
primary mechanism driving parturient females to disperse because group detectability effects
are presumably constant year round. Simulation outputs further demonstrate that if females
become increasingly clumped – a pattern that may result if caribou avoid disturbance in highly
impacted landscapes – then calf survival is negatively affected. To specifically identify key
attributes of calving habitat, I used a three-step process. First, I identified GPS locations where
females were accompanied by neonate calves by developing two novel methods for predicting
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parturition events and neonate survival status based on female movement patterns. These
methods predicted parturition with near certainty and provided reasonable estimates of
neonate survival, which I further augmented with aerial survey data. Using the partitioned GPS
location data, I then developed resource selection functions using a generalized mixed effects
modelling approach that explicitly maintained the individual as the sampling and comparative
unit. I discriminated calving areas from other areas within caribou range by conducting
multiple comparisons based on season and maternal status. These comparisons show that
parturient females shifted from bog-dominated winter ranges to calving areas dominated by
fens. In general, reducing predation risk was a dominant factor driving calving habitat selection
although the shift to fen landscapes indicates that females may be trading off increased
predation risk to access higher quality forage because fens are riskier than bogs. As a third
step, I explicitly evaluated calving habitat quality by relating maternal selection and use of
resources to the probability of neonate survival. These analyses included spatially explicit
covariates of predator-specific risk. Surprisingly, variation in landscape disturbance had
minimal effect on calf survival; rather, survival was best explained by predation risk from black
bears (Ursus americanus). Collectively, my findings yield important insights into the habitat
requirements of boreal caribou during calving and highlight that management actions aimed at
improving calving habitat quality will need to be conducted at large spatial scales.
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PREFACE
Throughout this thesis, I use the first person singular to maintain consistency. Modern
ecological research, however, often requires collaboration. To that end, two of the chapters in
this thesis represent collaborative work with fellow researchers.
Chapter 2 has been published as DeMars, C.A., Auger-Méthé, M., Schlägel, U.E. & Boutin, S.,
“Inferring parturition and neonate survival from movement patterns of female ungulates: a
case study using woodland caribou”, Ecology and Evolution, vol. 3, 4149–4160. For this
analysis, I conceived the concept, designed the study, collected the data and composed the
manuscript. I assisted Marie Auger-Méthé and Ulrike Schlägel in method development and
data analysis.
Chapter 3 represents collaborative work with Drs. Greg Breed and Jonathan Potts. For this
work, I conceived the research question and was responsible for data collection, study design,
and manuscript composition. I assisted Drs. Breed and Potts in method development and data
analyses.
Chapters 1, 4, 5 and 6 are my own original work.
The research project, of which this thesis is a part, received research ethics approval from the
University of Alberta Animal Care and Use Committee, Project Name “Assessing Spatial Factors
Affecting Predation Risk to Boreal Caribou Calves: Implications for Management”, Nos.
748/02/12; 748/02/13 and AUP00000019.
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ACKNOWLEDGEMENTS
Completing a graduate degree is never a solo endeavour. Fortunately, I had an
extensive and knowledgeable support group to guide me through the journey. Of primary
assistance was my advisor, Dr. Stan Boutin, whose incredible ability to think critically always
impresses me. I am hopeful that over the past five years a tiny bit of that ability has been able
to rub off on me. Stan, thanks for taking a chance on a “mature” student undergoing a mid-life
career change. I am also grateful for the advice and support of my committee members Dr.
Andrew DeRocher, Dr. Scott Nielsen, and, initially, Dr. Mark Boyce. Andy always made sure that
the animal’s biology and natural history stayed in the picture and continually pushed – gently –
that the thesis be completed in a timely manner. Scott was instrumental in guiding me through
the arcane world of resource selection functions and arriving at appropriate statistical
inference. Unfortunately for Scott, I directed many other students his way because of his ability
to explain complex concepts in easy to understand language. I always remarked that I could
learn more from Scott in 30 seconds than I could in an hour from most anyone else on the
subject. Mark unfortunately had to leave the committee just prior to my candidacy exam but
he provided sound critical advice on study design during the initial stages of my research.
A graduate degree is also never completed without considerable leaning on your fellow
grad students. For that, I thank the members of the Boutin and Bayne labs, in particular Kim
Dawe, Jessica Haines, Kristin Van Katwyck, Dario Moreira, Meghan Anderson, Eric Neilson,
Jamie Gorrell, Melanie Dickie, Samuel Hache, Erin Cameron, Corey Scobie, Janet Ng, Diana
Stralberg and Jeff Ball. Two others from the Boutin lab deserve special recognition. The first is
Ainsley Sykes, who showed incredible patience from my excessive door knocking during the
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past five years as I sought her invaluable assistance in navigating almost all matters of the grad
student experience, whether they actually related to my research or not. I am sure that Ainsley
has been “enjoying the silence” now that I have relocated away from Edmonton (though there
is always email....). The other person is Rob Serrouya. Rob has become a good friend and
conversations with him over the past few years about all things caribou have made me a better
scientist. Thanks Rob for continually reminding me that i) numbers matters as much, if not
more, than space, and ii) female survival matters as much, if not more, than calf survival. Rob
also provided timely and effective criticism on all chapters contained in this thesis. I look
forward to collaborating with Rob in the years to come.
I am further indebted to the lab members of Dr. Mark Lewis, who didn’t realize he was
inadvertently gaining another “lab member” as I sought the assistance of his graduate students
on all matters statistical and mathematical. Marie Auger-Méthé and Ulrike Schläegel provided
mathematical wizardry and invaluable support during the development of the methods
outlined in Chapter 2, which has now been published. I further want to thank both, Marie in
particular, for insisting that I learn R before I finish my degree [Marie, I am now a convert...].
For Chapter 3, I managed to tap the massive brainpower of Drs. Greg Breed and Jonathan Potts.
With their support, I was able to answer a question that I initially never thought was possible. I
further enjoyed the many philosophical discussions I had with Greg and Jon as we worked out
the methods to answer said question.
I extend a big thank you to Charlene Nielsen for providing invaluable assistance in all
GIS analyses. Charlene is one of those good people who never says no when her assistance is
asked, even when the queried task could probably be accomplished by the grad student on
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his/her own with a little more diligence. I also thank Al Richard and Kevin Smith (Ducks
Unlimited Canada) for facilitating my use of Ducks Unlimited GIS data and providing technical
support in its use.
The backbone of any ecology thesis is its research project. For initiating the project on
which this thesis is based, I am indebted to Conrad Thiessen, a BC government biologist who
approached Stan about putting a grad student on some caribou data he had. Over the course
of the project, Conrad has become a good friend and assisting him with animal capture and
collaring activities during the project’s first two years are memories I will simply never forget.
Conrad has since relocated to Smithers, BC and his positive outlook and dedication to boreal
caribou conservation in NE BC are missed. For facilitating continued assistance on the part of
the BC government, I extend thanks to Megan Watters (BC MFLNRO, Fort St. John) and Morgan
Anderson (BC MFLNRO, Fort St. John).
My research project could not have been initiated without the generous support of a
diverse group of funding partners. To that end, I extend thanks to:
BC Ministry of Forest, Lands and Natural EOG Resources
Resource Operations
Imperial Oil
Science, Community, and Environmental
Natural Sciences and Engineering Research
Knowledge (SCEK) Fund
Council (NSERC) of Canada
Canadian Natural Resources Ltd.
Nexen
Canadian Wildlife Federation
Penn West
ConocoPhillips
Petroleum Technology Alliance Canada
Devon
Progress Energy
Ducks Unlimited Canada
Quicksilver Resources
Encana
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I am especially grateful to Scott Wagner (Nexen), Lorraine Brown (Penn West), James
Wild (Penn West) and Sarah Fulton (Penn West) for organizing and facilitating the collaborative
effort on the part of the oil and gas industry. I am particularly thankful to Brian Thomson for
facilitating support from SCEK and providing excellent advice on project management. Brian
was able to transition me from a wide-eyed grad student to a semi-competent project
manager, imparting a skill set that will be invaluable moving forward in my career.
For general oversight of the project, I thank the members of the project’s steering
committee: Chris Ritchie (BC Ministry of Forests, Lands, and Natural Resource Operations), Gary
Sargent (Canadian Association of Petroleum Producers), Scott Wagner (Nexen), and Steve
Wilson, Ph.D. (EcoLogic Research). Their collective contributions greatly improved the overall
structure of the project and their insight helped me navigate through occasional logistical
challenges.
Collecting field data always requires field assistance and for that I relied on an extensive
network stretching from Fort Nelson, BC to Ottawa, ON. I extend thanks to Kathy Needlay (Fort
Nelson First Nation), Lenny Tsakoza (Prophet River First Nations) and Deirdre Leowinata (U. of
Ottawa) for assisting in field work. All managed to maintain cheerful demeanors while working
in often hot, wet, and buggy conditions. For assistance in navigating the landscape surrounding
Fort Nelson and facilitating field work activities, I extends thanks to Sonja Leverkus, Lawrence
McLeod, Peter Smith (BC Oil & Gas Commission – Fort Nelson office), Katherine Wolfenden
(Fort Nelson First Nations), Michelle Edwards (Fort Nelson First Nations), Charlie Dickie (Fort
Nelson First Nations), and Brian Wolfe (Prophet River First Nations). I am also grateful to the
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Alberta Cooperative Conservation Research Unit (ACCRU) for coordinating the use of a truck for
all field work.
For his outstanding skill and expertise in the safe capture of wild animals, I extend
thanks to Brad Culling. I am also grateful to Diane Culling for sharing caribou GPS location data
to assist in the analyses of female movement patterns and calving habitat selection. I further
acknowledge the incredible skill and expertise of Cam Allen, Zonk Dancevic, Mike Koloff and the
other pilots of Qwest Helicopters in Fort Nelson. This crew allowed me to safely observe wild
and scenic images that few people ever get to see.
And last, but certainly not least, I extend a massive thank you and equally massive hug
to my wife Nicole and daughter Sadie. Without their support and love, I could not have
pursued this dream. How many people would endure three years in graduate student housing
in their 40s, especially when they are not the ones returning to school? I suspect not many and
for that, Nicole, you are saint. Sadie, I promise to no longer be chained to my office. Let’s go
out and have a great family summer. I love you both.
One should never stop learning; but after 15 years in post-secondary school and four
degrees, I hope I am now “educated”.....
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TABLE OF CONTENTS
Abstract ............................................................................................................................................. ii
Preface ............................................................................................................................................. iv
Acknowledgements............................................................................................................................ v
Chapter 1 ...........................................................................................................................................1
General Introduction ..........................................................................................................................1
Overview of Thesis ................................................................................................................................ 6
Study System ......................................................................................................................................... 8
Literature Cited ....................................................................................................................................... 10
Chapter 2 ......................................................................................................................................... 15
Inferring Parturition and Neonate Survival from Movement Patterns of Female Ungulates: a Case
Study Using Woodland Caribou ....................................................................................................... 15
Methods .................................................................................................................................................. 18
Caribou Movement Data ..................................................................................................................... 18
Population-based Method .................................................................................................................. 20
Individual-based Method .................................................................................................................... 24
Evaluating Method Performance ........................................................................................................ 26
Results ..................................................................................................................................................... 27
Parturition Status ................................................................................................................................ 27
Neonate Survival Status ...................................................................................................................... 28
Effects of Data Quality ........................................................................................................................ 30
Discussion................................................................................................................................................ 33
Parturition Status ................................................................................................................................ 33
Neonate Survival Status ...................................................................................................................... 35
Conclusion ........................................................................................................................................... 39
Literature Cited ....................................................................................................................................... 40
Appendix 2.1: R Code for the Population-based Method ....................................................................... 45
Threshold Establishment .................................................................................................................... 45
Data Analysis ....................................................................................................................................... 48
Literature Cited ................................................................................................................................... 50
Appendix 2.2: Likelihood Functions Used in the Individual-based Method ........................................... 51
Literature Cited ................................................................................................................................... 55