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Ecological and evolutionary effects of predation in environmental gradients
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Understanding species interactions and how they affect densities and distributions of organisms is a central theme in ecological research. Studying such interactions in an ecosystem context is challenging as they often depend on species-specific characteristics and rates that not only change during the ontogeny of an organism, but also are affected by the surrounding environment. This thesis focuses on two separate questions and study systems that highlight different aspects of how effects of predation can depend on environmental conditions. In the first part of the thesis, we studied how temperature affects attack rate and handling time, two ecological rates with profound importance for predator-prey dynamics. Using a metaanalysis, we first show that the currently dominating model for temperature dependence in predator-prey interactions, i.e. the Arrhenius equation, has weak support in available empirical literature. This suggests that we need new rules for how and when we can generalize on the temperature-dependence of intake rates. We then use a simple model and a series of experiments to demonstrate that differences in the relative physiological capacity between predator and prey can impose strong non-linear effects on temperature-response curves of attack rate. In the second part of the thesis, we study the role of predation along a benthic-pelagic habitat gradient in promoting divergence and resource polymorphism among prey. We show that presence of a large piscivorous predator, the northern pike (Esox lucius), induces dwarfs, giants or divergence into both ecotypes in populations of European whitefish (Coregonus lavaretus) depending on lake characteristics. Using dated introductions of whitefish as controlled natural experiments, we show that pike presence induces rapid life history divergence between pelagic and littoral habitat use strategies, and that this divergence can translate into partial reproductive isolation in a matter of decades. Our results demonstrate the potential for thresholds in a crucial ecological rate, setting the stage for tipping points with potentially far reaching implications for effects of warming on predator prey dynamics and ecosystem stability. Moreover, they illustrate the potentially drastic consequences of such tipping points by demonstrating the importance of a single predator species as a driving force behind the creation and maintenance of biodiversity in a natural system.  

Place, publisher, year, edition, pages
Umeå: Umeå universitet , 2012. , 23 p.
National Category
Ecology
Identifiers
URN: urn:nbn:se:umu:diva-59465ISBN: 978-91-7459-464-5 (print)OAI: oai:DiVA.org:umu-59465DiVA: diva2:552381
Public defence
2012-10-05, KBC-huset, Stora Hörsalen, 10:05
Opponent
Supervisors
Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2012-09-14Bibliographically approved
List of papers
1. Temperature dependence of the functional response
Open this publication in new window or tab >>Temperature dependence of the functional response
2011 (English)In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 14, no 9, 914-21 p.Article in journal (Refereed) Published
Abstract [en]

The Arrhenius equation has emerged as the favoured model for describing the temperature dependence of consumption in predator-prey models. To examine the relevance of this equation, we undertook a meta-analysis of published relationships between functional response parameters and temperature. We show that, when plotted in lin-log space, temperature dependence of both attack rate and maximal ingestion rate exhibits a hump-shaped relationship and not a linear one as predicted by the Arrhenius equation. The relationship remains significantly downward concave even when data from temperatures above the peak of the hump are discarded. Temperature dependence is stronger for attack rate than for maximal ingestion rate, but the thermal optima are not different. We conclude that the use of the Arrhenius equation to describe consumption in predator-prey models requires the assumption that temperatures above thermal optima are unimportant for population and community dynamics, an assumption that is untenable given the available data.

Place, publisher, year, edition, pages
Wiley, 2011
Keyword
Arrhenius, attack rate, functional response, handling time, optimum, parasitoid, predator, prey, response curve, temperature
National Category
Earth and Related Environmental Sciences Ecology
Research subject
biology, Environmental Science
Identifiers
urn:nbn:se:umu:diva-46321 (URN)10.1111/j.1461-0248.2011.01661.x (DOI)21752171 (PubMedID)
Available from: 2011-08-30 Created: 2011-08-30 Last updated: 2017-12-08Bibliographically approved
2. Temperature-dependence of predation depends on relative performance of predators and prey
Open this publication in new window or tab >>Temperature-dependence of predation depends on relative performance of predators and prey
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(English)Manuscript (preprint) (Other academic)
Publisher
11 p.
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-59460 (URN)
Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2013-02-25Bibliographically approved
3. Predation drives rapid and repeated sympatric divergence in European whitefish (Coregonus lavaretus)
Open this publication in new window or tab >>Predation drives rapid and repeated sympatric divergence in European whitefish (Coregonus lavaretus)
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(English)Manuscript (preprint) (Other academic)
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:umu:diva-59462 (URN)
Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2013-02-25Bibliographically approved
4. The chronology of incipient speciation in whitefish
Open this publication in new window or tab >>The chronology of incipient speciation in whitefish
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(English)Manuscript (preprint) (Other academic)
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:umu:diva-59464 (URN)
Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2013-02-25Bibliographically approved

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Citation style
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Output format
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