THESIS HABITAT USE BY DALL SHEEP AND AN INTERIOR ALASKA MAMMAL COMMUNITY Submitted by Jeremy S. Dertien Graduate Degree Program in Ecology In partial fulfillment of the requirements For the Degree of Master of Science Colorado State University Fort Collins, Colorado Spring 2016 Master’s Committee: Advisor: Paul F. Doherty, Jr. Cameron Aldridge Calvin F. Bagley Copyright by Jeremy Stephen Dertien 2016 All Rights Reserved ABSTRACT HABITAT USE BY DALL SHEEP AND AN INTERIOR ALASKA MAMMAL COMMUNITY Anthropogenic disturbances are increasingly recognized for effects on the behavior and physiology of wildlife species. Military training, a potential source of disturbance, has shown mixed behavioral and physiological effects on wildlife, including mountain ungulates. Dall sheep (Ovis dalli dalli) are an important species for hunting and wildlife viewing in Alaska and have shown an aversion to some forms of human disturbance such as direct overflights. Military training is expanding into potential Dall sheep habitat on two training areas of Fort Wainwright, Alaska; Molybdenum Ridge and Black Rapids Training Area. I placed camera traps in expected optimal and sub-optimal Dall sheep habitat to estimate the spatiotemporal habitat use of sheep and to make training recommendations to the U.S. military. Then, I further explored the available data and estimated the habitat use of species in four different mammalian guilds and the co-occurrence of habitat use between apex predators and potential prey species. In Chapter 1, I introduce the impetus for the study, the use of 54 camera traps in respect to mountain sheep, and the overall study design. My cameras captured over 8,000 images of sheep during the continuous 15-month sampling period. I successfully captured images of sheep traveling, foraging, resting, and interacting with other individuals. Occupancy models of detection-non-detection data suggest that abiotic covariates including slope, snow depth, and distance to escape terrain were the most important factors determining habitat use. Seasonal differences in habitat use suggested higher use of the Molybdenum Ridge study site during pre- ii rut, rut, winter, and lambing seasons with limited use during the summer, while habitat use estimates of Black Rapids were too imprecise to make broader inferences. Detection probabilities were temporally constant, but were positively correlated with cameras on a wildlife trail. From these results, I recommend that the U.S. Army concentrates training on Molybdenum Ridge during the early-July to early-September period and minimize training on both study sites during the lambing periods of May and June. If training were to occur on Molybdenum Ridge outside of this period, training should be concentrated around the easternmost valley/bowl of the ridge and the eastern half of the major south-facing slope of the ridgeline. In Chapter 2, I expanded upon the analysis of Dall sheep habitat use and investigated the alpine habitat use of ten species within four mammalian guilds. I analyzed how spatial covariates and temporal patterns correlated with habitat use of these species within and between guilds. Further, I modeled two-species occupancy of grizzly bears and wolves with different prey species (e.g., caribou and sheep). My results suggest that small and large herbivore habitat use positively correlated with vegetation and rock ground coverages, while large herbivores also correlated with broader abiotic covariates. Meso- and apex predator detections were sparse possibly leading to imprecise estimates of habitat use and little support for most habitat covariates. Detection probabilities of Dall sheep and predators were improved by cameras on trails. Two-species models suggested co-occurrence of habitat use between grizzly bear/caribou and wolf/caribou and independence of habitat use between grizzly bear/squirrel and wolf/sheep. iii ACKNOWLEDGMENTS I would first like to thank my advisor Dr. Paul Doherty who gave me the opportunity to come back to Colorado State University to pursue this degree. Paul has encouraged and pushed me to conquer many challenges throughout this portion of my career, and I am better scientist and person for it. Calvin Bagley gave me the chance to be a part of this amazing project and taught me a lot about project and people management. I am forever indebted to both of these gentlemen for the knowledge and the opportunities they afforded me. I would also like to thank Dr. Cameron Aldridge for serving on my Master’s committee, for all his input on the project and encouragement throughout this process. This project would not have been possible without funding from the U.S. Army and the outstanding natural resources personnel at Fort Wainwright, Alaska. In particular, I would like to thank John Haddix and Aleya Brinkman for project backing and review of project proposals. Dan Rees and Elizabeth Neipert for their support in logistics and knowledge about the local environment, which aided mightily in project planning and execution. Amy Tippery, Adam Davis, and Monica Koop for their invaluable assistance in vegetation sampling and who ensured that the 2014 field season was a success. In addition, I would like to thank all the field technicians that ensured the success of this project, especially, Matt Cameron, Bob Schmidt, Patty McCall, and Megan Zarzycki for their assistance in camera set up and the 2014 wetland and forestry crew members who endured harsh conditions to collect all the vegetation data. It has been an honor to interact with so many amazing faculty and graduate students within the Department of Fish, Wildlife, and Conservation Biology and the Graduate Degree Program in Ecology. I would especially like to thank Dr. Larissa Bailey for her support in data iv analysis and answering all my random questions, Dr. Kate Huyvaert for all her advice and encouragement beginning as a TA for her at Pingree Park, and Dr. Kevin Crooks for his positive feedback and advice. I would like to thank all the members of the Doherty lab including Mark Peterson, Phillip Street, Eric Bergman, Jared Laufenberg, and Becky Ruzicka and the revolving members of the Wagar 113 Superpopulation, who have provided advice and helped me through many issues great and small. Also, all the visiting scholars to the Doherty lab that have enriched my life including Murilo Guimaraes, Luane Santos, Ana Maria Paschoal, Rodrigo Massara, Carmina Gutierrez, Miguel Gomez, Natalia Versiani, and Mauro Pichorim. Thank you to Franny Buderman and Brian Brost, for their R and ArcGIS support and for serving as a constant source of levity. In addition, a big thanks to the members of Dr. Bailey’s, Dr. Crooks’, and Dr. Liba Pejchar’s labs including Sara Bombaci, Cooper Farr, Courtney Larson, Anna Mangan, Danny Martin, and Brittany Mosher for all the intellectual and moral support. Finally, and most importantly, I would like to thank my wife Audrey for her unwavering support and the sacrifices she made to help me succeed in this project. Thank you to my parents who rooted hard work and tenacity into the core of whom I am, and for whom I credit all my accomplishments. Also special thanks to my brother and his family for their encouragement and support throughout my life. v TABLE OF CONTENTS Abstract ........................................................................................................................................... ii Acknowledgments.......................................................................................................................... iv List of tables ................................................................................................................................. viii List of figures ................................................................................................................................ xii Chapter 1: Habitat Use by Dall Sheep: An Occupancy Modeling Approach ................................. 1 Synopsis ...................................................................................................................................... 1 Introduction ................................................................................................................................. 2 Materials & Methods ................................................................................................................... 5 Study Site ................................................................................................................................ 5 Sampling Design: Camera Trap .............................................................................................. 6 Sampling Design: Vegetation ................................................................................................. 8 Data Processing & Analysis.................................................................................................... 8 Habitat Use Maps .................................................................................................................. 11 Predictions............................................................................................................................. 11 Results ....................................................................................................................................... 13 Camera Data.......................................................................................................................... 13 Model Results ......................................................................................................................