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Functional diversity of sharks through time: past, present and future / JACK COOPER

Swansea University Author: JACK COOPER

DOI (Published version): 10.23889/SUThesis.68819

Abstract

Modern sharks have played multiple roles in marine ecosystems for over 250 million years. Yet, today, overfishing is driving over one-third of shark species towards extinction. Traditionally, scientists assess extinctions by evaluating changes in species diversity. However, the ecology of species de...

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Published: Swansea University, Wales, UK
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Pimiento, C., and Griffin, J. N.
URI: https://cronfa.swan.ac.uk/Record/cronfa68819
first_indexed 2025-02-06T16:02:10Z
last_indexed 2025-02-07T05:56:39Z
id cronfa68819
recordtype RisThesis
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spelling 2025-02-06T16:16:37.2750696 v2 68819 2025-02-06 Functional diversity of sharks through time: past, present and future 5bee81f19e912ca8068a4e96add6466f JACK COOPER JACK COOPER true false 2025-02-06 Modern sharks have played multiple roles in marine ecosystems for over 250 million years. Yet, today, overfishing is driving over one-third of shark species towards extinction. Traditionally, scientists assess extinctions by evaluating changes in species diversity. However, the ecology of species depends on their functional traits, the diversity of which (functional diversity) dictates how species contribute to ecosystem structure and stability. Thus, to understand the ecological consequences of extinctions, it is imperative to record changes in functional diversity. Determining how shark functional diversity has changed through time through their rich, continuous dental fossil record could draw an unprecedented parallel on how extinctions have shaped past, present and future marine communities.First, I assessed the extent to which dental characters can serve as proxies for functional traits in living sharks using a literature review and two validation analyses (chapter 2). This identified seven dental character proxies for body size, prey preference and feeding mechanism, providing a framework to infer these traits from fossil teeth. Second, I investigated changes in functional diversity over the last 66 million years using teeth (chapter 3). This found that shark functional diversity was relatively high for over 50 million years, before declining to its lowest level today over the last 10 million years due to the extinctions of functionally unique and specialised species that inordinately influence ecosystem functioning. Finally, I simulated future shark extinctions and quantified resulting changes in functional diversity (chapter 4). The results projected further declines, and poleward shifting of functional diversity by 2100 and near-worldwide increases in functional uniqueness, rendering virtually all marine habitats functionally susceptible to further extinctions, with the most functionally unique and specialised sharks at greatest risk.Overall, this thesis highlights the importance of prioritising protections for sharks disproportionately contributing to functional diversity to conserve the health of our oceans. E-Thesis Swansea University, Wales, UK Sharks, functional diversity, teeth, ecological role, extinction, traits 0 0 0 0001-01-01 10.23889/SUThesis.68819 A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information COLLEGE NANME COLLEGE CODE Swansea University Pimiento, C., and Griffin, J. N. Doctoral Ph.D Fisheries Society of the British Isles Fisheries Society of the British Isles 2025-02-06T16:16:37.2750696 2025-02-06T15:43:17.9398022 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Biosciences JACK COOPER 1 68819__33528__ef726920d77947a99c390978d21065dd.pdf 2024_Cooper_J.final.68819.pdf 2025-02-06T15:54:47.6805047 Output 13952257 application/pdf E-Thesis – open access true Copyright: The Author, Jack A. Cooper, 2024 true eng https://creativecommons.org/licenses/by-nc/4.0/
title Functional diversity of sharks through time: past, present and future
spellingShingle Functional diversity of sharks through time: past, present and future
JACK COOPER
title_short Functional diversity of sharks through time: past, present and future
title_full Functional diversity of sharks through time: past, present and future
title_fullStr Functional diversity of sharks through time: past, present and future
title_full_unstemmed Functional diversity of sharks through time: past, present and future
title_sort Functional diversity of sharks through time: past, present and future
author_id_str_mv 5bee81f19e912ca8068a4e96add6466f
author_id_fullname_str_mv 5bee81f19e912ca8068a4e96add6466f_***_JACK COOPER
author JACK COOPER
author2 JACK COOPER
format E-Thesis
institution Swansea University
doi_str_mv 10.23889/SUThesis.68819
college_str Faculty of Science and Engineering
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hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Biosciences{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Biosciences
document_store_str 1
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description Modern sharks have played multiple roles in marine ecosystems for over 250 million years. Yet, today, overfishing is driving over one-third of shark species towards extinction. Traditionally, scientists assess extinctions by evaluating changes in species diversity. However, the ecology of species depends on their functional traits, the diversity of which (functional diversity) dictates how species contribute to ecosystem structure and stability. Thus, to understand the ecological consequences of extinctions, it is imperative to record changes in functional diversity. Determining how shark functional diversity has changed through time through their rich, continuous dental fossil record could draw an unprecedented parallel on how extinctions have shaped past, present and future marine communities.First, I assessed the extent to which dental characters can serve as proxies for functional traits in living sharks using a literature review and two validation analyses (chapter 2). This identified seven dental character proxies for body size, prey preference and feeding mechanism, providing a framework to infer these traits from fossil teeth. Second, I investigated changes in functional diversity over the last 66 million years using teeth (chapter 3). This found that shark functional diversity was relatively high for over 50 million years, before declining to its lowest level today over the last 10 million years due to the extinctions of functionally unique and specialised species that inordinately influence ecosystem functioning. Finally, I simulated future shark extinctions and quantified resulting changes in functional diversity (chapter 4). The results projected further declines, and poleward shifting of functional diversity by 2100 and near-worldwide increases in functional uniqueness, rendering virtually all marine habitats functionally susceptible to further extinctions, with the most functionally unique and specialised sharks at greatest risk.Overall, this thesis highlights the importance of prioritising protections for sharks disproportionately contributing to functional diversity to conserve the health of our oceans.
published_date 0001-01-01T05:25:18Z
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score 11.089572

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