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dc.contributor.authorRogers, Matthew C.
dc.descriptionDissertation (Ph.D.) University of Alaska Fairbanks, 2021en_US
dc.description.abstractDietary ecology is one of the most important drivers of brown bear fitness at the individual and population levels. However, researchers do not have an in-depth understanding of the trophic niche breadth, diet composition, and seasonal diet variation for most Alaskan populations. I set out to better understand multiple facets of brown bear dietary ecology using stable isotope analysis (¹³C & ¹⁵N) as the primary tool to infer brown bear diet and gain insights into their trophic niche, dietary seasonality, dietary generalism and specialism, and isotopic trophic discrimination factors. I determined that using sectioned hair samples is the best practice for determining the isotopic trophic niche of brown bears. Additionally, I determined amino acid trophic discrimination factors for brown bears and explored the ability to separate salmon species in bear diets. I also used stable isotope mixing models with sectioned hair samples to infer seasonal dietary patterns of individual bears in five distinct Alaskan ecosystems. Approximately one-quarter of bears relied solely on vegetation over multiple years despite access to other sources of nutrition; these bears could be considered specialists. Other bears, approximately half, switched diets seasonally but had the same pattern of resource use year over year, a foraging class that I termed persistent seasonal generalism. Approximately one-quarter of bears did not have a persistent dietary pattern across years and could be considered true generalists. Most bears appear to have preferred dietary patterns that are persistent through time, which may be indicative of foraging inertia; maintaining foraging patterns even when faced with changing resource availability due to natural fluctuations, disturbance, or climate change. The sum of this work advances our understanding of brown bear dietary ecology from the individual seasonal level to population level degrees of generalism and specialism, and the methods developed can be applied to many species for which dietary ecology information is difficult to obtain.en_US
dc.description.tableofcontentsChapter 1: Geneneral introduction -- 1.1 Dietary ecology of Alaskan brown bears using stable isotope analysis -- 1.2 Aim, terms and scope of the dissertation -- 1.3 Citations. Chapter 2: Splitting hairs: dietary niche breadth modeling using stable isotope analysis of a sequentially grown tissue --2.1 Abstract -- 2.2 Introduction -- 2.3 Methods -- 2.3.1 Study area and population descriptions -- 2.3.2 Bear capture & sampling -- 2.3.3 Stable isotope analysis -- 2.3.4 Isotopic niche breadth modeling -- 2.4 Results -- 2.4.1 Bear capture and stable isotope analysis -- 2.4.2 Isotopic dietary niche breadth estimates -- 2.5 Discussion -- 2.6 Conclusions -- 2.7 Acknowledgements and authors' declarations -- 2.8 Citations. Chapter 3: Creatures of habit? Alaskan brown bear dietary ecology and testing a framework for evaluating degrees of individual dietary specialism and generalism -- 3.1 Abstract -- 3.2 Introduction -- 3.3 Methods -- 3.3.1 Study areas and population descriptions -- 3.3.2 Bear capture and sampling -- 3.3.4 Stable isotope analysis -- 3.3.5 Stable isotope dietary mixing models -- 3.3.6 Seasonal dietary patterns and generalist vs. specialist classifications -- 3.4 Results -- 3.4.1 Bear capture and stable isotope analysis -- 3.4.2 Stable isotope dietary mixing models -- 3.4.3 Site level and individual diet proportions -- 3.4.4 Dietary patterns, Latent Class Analysis, and degree of specialism and generalism -- 3.5 Discussion -- 3.5.1 Foraging patterns and degree of specialism versus generalism -- 3.5.2 Site and individual level diet -- 3.6 Citations. Chapter 4: Amino acid carbon isotopes in brown bear diets: trophic discrimination and separating dietary sources of salmon by species -- 4.1 Abstract -- 4.2 Introduction -- 4.3 Methods -- 4.3.1 Animal husbandry and controlled diet study design -- 4.3.2 Salmon species bulk isotope and amino acid delta¹³C differentiation -- 4.3.3 Amino acid delta¹³C analysis -- 4.4 Results -- 4.4.1 Amino acid stable Isotope trophic discrimination factors -- 4.4.2 Salmon species amino acid delta¹³C differentiation -- 4.5 Discussion -- 4.5.1 Amino acid stable isotope trophic discrimination factors -- 4.5.2 Salmon species amino acid delt¹³C differentiation -- 4.6 Conclusions -- 4.7 Trade names disclaimer -- 4.8 Citations. Chapter 5: General conclusions -- 5.1 Citations -- Appendix.en_US
dc.subjectBrown bearen_US
dc.subjectStable isotopes in ecological researchen_US
dc.subject.otherDoctor of Philosophy in Biological Sciencesen_US
dc.titleApplications of stable isotope analysis to advancing the understanding of brown bear dietary ecologyen_US
dc.identifier.departmentDepartment of Biology and Wildlifeen_US
dc.contributor.chairBarnes, Brian
dc.contributor.chairWelker, Jeffrey
dc.contributor.committeeBrinkman, Todd
dc.contributor.committeeGustine, David
dc.contributor.committeeHilderbrand, Grant

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    Includes WIldlife Biology and other Biological Sciences. For Marine Biology see the Marine Sciences collection.

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