Top-predators as structuring agents in dynamic marine environments
Global declines in top-predators are occurring due established and ongoing fisheries throughout the world’s oceans. In particular, dramatic declines have been observed for Atlantic cod (Gadus morhua) in the boreal sub-arctic and for reef sharks (mostly Carcharhinidae spp.) in coral reefs. The impact...
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ftunivtoronto:oai:localhost:1807/70140 2023-05-15T15:16:22+02:00 Top-predators as structuring agents in dynamic marine environments Ruppert, Jonathan Leo William Fortin, Marie-Josée Ecology and Evolutionary Biology WITHHELD_TWO_YEAR http://hdl.handle.net/1807/70140 en_ca eng http://hdl.handle.net/1807/70140 Marine Top-down Coral reef Sharks Atlantic cod Disturbance 0329 Thesis ftunivtoronto 2020-06-17T11:24:39Z Global declines in top-predators are occurring due established and ongoing fisheries throughout the world’s oceans. In particular, dramatic declines have been observed for Atlantic cod (Gadus morhua) in the boreal sub-arctic and for reef sharks (mostly Carcharhinidae spp.) in coral reefs. The impact of these declines on marine communities still remains largely unclear due to food web complexity, interacting factors, confounding variables, and fluctuating ecosystem states. Furthermore, as the impact of disturbances on communities can be press (e.g. fisheries), pulse (e.g. environmental variability) or combine, fisheries contribute to disturbance regimes that can generate heterogeneity in communities, meaning that their effects are likely not uniform across space and time. Determining the ecological role of top-predators, as top-down structuring agents, alongside ecosystem disturbances is fundamental to understanding baseline conditions and ultimately may help to inform conservation efforts. This thesis investigates the relative roles of top-predators and disturbances to build an understanding of how marine communities and food webs may be structured. This thesis aims to address: (i) how environmental variability may impact the role of top-predators, (ii) determine the ecological role of top-predators in coral reef environments, (iii) how top-down and bottom-up structuring agents impact variability in food webs, and (iv) how humans are modifying the role of top-down and bottom-up structuring agents. In this thesis I present three main findings: (i) top-predators have a strong top-down influence on marine communities and food webs alongside other disturbances, (ii) combined effects (between top-down and bottom-up structuring agents) can impact communities at broad and fine spatial scales, and (iii) spatial heterogeneity in structuring agents caused by human activities, impacts food web dynamics across multiple spatial scales. The findings in this thesis provide a foundation from which management decisions can be made to ultimately address restoration and conservation goals. PhD Thesis Arctic atlantic cod Gadus morhua University of Toronto: Research Repository T-Space Arctic |
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Open Polar |
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University of Toronto: Research Repository T-Space |
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ftunivtoronto |
language |
English |
topic |
Marine Top-down Coral reef Sharks Atlantic cod Disturbance 0329 |
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Marine Top-down Coral reef Sharks Atlantic cod Disturbance 0329 Ruppert, Jonathan Leo William Top-predators as structuring agents in dynamic marine environments |
topic_facet |
Marine Top-down Coral reef Sharks Atlantic cod Disturbance 0329 |
description |
Global declines in top-predators are occurring due established and ongoing fisheries throughout the world’s oceans. In particular, dramatic declines have been observed for Atlantic cod (Gadus morhua) in the boreal sub-arctic and for reef sharks (mostly Carcharhinidae spp.) in coral reefs. The impact of these declines on marine communities still remains largely unclear due to food web complexity, interacting factors, confounding variables, and fluctuating ecosystem states. Furthermore, as the impact of disturbances on communities can be press (e.g. fisheries), pulse (e.g. environmental variability) or combine, fisheries contribute to disturbance regimes that can generate heterogeneity in communities, meaning that their effects are likely not uniform across space and time. Determining the ecological role of top-predators, as top-down structuring agents, alongside ecosystem disturbances is fundamental to understanding baseline conditions and ultimately may help to inform conservation efforts. This thesis investigates the relative roles of top-predators and disturbances to build an understanding of how marine communities and food webs may be structured. This thesis aims to address: (i) how environmental variability may impact the role of top-predators, (ii) determine the ecological role of top-predators in coral reef environments, (iii) how top-down and bottom-up structuring agents impact variability in food webs, and (iv) how humans are modifying the role of top-down and bottom-up structuring agents. In this thesis I present three main findings: (i) top-predators have a strong top-down influence on marine communities and food webs alongside other disturbances, (ii) combined effects (between top-down and bottom-up structuring agents) can impact communities at broad and fine spatial scales, and (iii) spatial heterogeneity in structuring agents caused by human activities, impacts food web dynamics across multiple spatial scales. The findings in this thesis provide a foundation from which management decisions can be made to ultimately address restoration and conservation goals. PhD |
author2 |
Fortin, Marie-Josée Ecology and Evolutionary Biology |
format |
Thesis |
author |
Ruppert, Jonathan Leo William |
author_facet |
Ruppert, Jonathan Leo William |
author_sort |
Ruppert, Jonathan Leo William |
title |
Top-predators as structuring agents in dynamic marine environments |
title_short |
Top-predators as structuring agents in dynamic marine environments |
title_full |
Top-predators as structuring agents in dynamic marine environments |
title_fullStr |
Top-predators as structuring agents in dynamic marine environments |
title_full_unstemmed |
Top-predators as structuring agents in dynamic marine environments |
title_sort |
top-predators as structuring agents in dynamic marine environments |
publishDate |
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url |
http://hdl.handle.net/1807/70140 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic atlantic cod Gadus morhua |
genre_facet |
Arctic atlantic cod Gadus morhua |
op_relation |
http://hdl.handle.net/1807/70140 |
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1766346660007378944 |