Effects of reproductive trade-offs, conspecific density, and invasive species on oak savanna wildflower populations under climate change
department or school: Arts, Faculty of
department or school: Geography, Department of
data provider: DSpace
degree campus: UBCV
creator: Loesberg, Jenna
issued: 2025-10-15T20:12:03Z
issued: 2025
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: The widespread loss of biodiversity expected under climate change is ultimately driven by how individual populations respond to climate. Predicting whether populations will persist under climate change first requires understanding how climate directly and indirectly influences the demographic rates (survival, growth, and reproduction) underlying population growth. In my dissertation, I paired a rainfall manipulation experiment in a natural plant community with mesocosm experiments and population modeling (integral projection models, count-based population viability analysis, and competition models) to understand the climatic and demographic drivers of population change under climate change in Garry oak savannas. Each chapter addresses a potential indirect effect of climate variation on population dynamics: in my first two data chapters, I examined how seasonal climate and reproductive trade-offs jointly influence population growth in a long-lived perennial, Primula hendersonii. Specifically, Chapter 2 examines how costs of sexual reproduction vary across climate and changes in flowering effort. Chapter 3 incorporates trade-offs between clonal and sexual reproduction with interactions with conspecific neighbors. In Chapter 4, I examine direct climate impacts and indirect effects of competitive interactions on demographic rates and population growth for two native annual forbs, Plectritis congesta and Claytonia perfoliata, and an annual invasive grass, Bromus sterilis. While I found demographic rate-specific responses to seasonal climate, rainfall manipulation, and reproductive trade-offs, I primarily found negative effects of increased spring temperature for two of the native species, positive effects of increased summer temperature for the perennial species, and positive effects of increased winter temperature on an increasingly common invasive grass. Overall, only density-dependence had a large indirect effect, where predictions of population growth rates and effec…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/92626
note: Effects of reproductive trade-offs, conspecific density, and invasive species on oak savanna wildflower populations under climate change by Jenna Loesberg B.A., Pitzer College, 2018 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Geography) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) October 2025 © Jenna Loesberg, 2025 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Effects of reproductive trade-offs, conspecific density, and invasive species on oak savanna wildflower populations under climate change submitted by Jenna Loesberg in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Geography Examining Committee: Jennifer Williams, Associate Professor, Geography, UBC Supervisor Amy Angert, Professor, Botany, UBC Supervisory Committee Member Tara Martin, Professor, Forest and Conservation Sciences, UBC University Examiner Michelle Tseng, Associate Professor, Botany and Zoology, UBC University Examiner Additional Supervisory Committee Members: Rachel Germain, Assistant Professor, Zoology, UBC Supervisory Committee Member Jeannette Whitton, Associate Professor, Botany, UBC Supervisory Committee Member iii Abstract The widespread loss of biodiversity expected under climate change is ultimately driven by how individual populations respond to climate. Predicting whether populations will persist under climate change first requires understanding how climate directly and indirectly influences the demographic rates (survival, growth, and reproduction) underlying population growth. In my dissertation, I paired a rainfall manipulation experiment in a natural plant community with mesocosm experiments and population modeling (integral projection models, count-based population viability analysis, and competition models) to unders…
has type: Thesis/Dissertation
date issued: 2025-11
is shown at: 10.14288/1.0450435
language: eng
degree discipline: Geography
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Williams, Jennifer L.
type: Text
identifier URI: http://hdl.handle.net/2429/92626