Alex Córdoba-Aguilar (ed.)
- Published in print:
- 2008
- Published Online:
- September 2008
- ISBN:
- 9780199230693
- eISBN:
- 9780191710889
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199230693.001.0001
- Subject:
- Biology, Ecology, Animal Biology
This book is a collection of nineteen chapters where summaries of major ecological and evolutionary questions have been asked and responded using dragonflies and damselflies as study subjects. Each ...
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This book is a collection of nineteen chapters where summaries of major ecological and evolutionary questions have been asked and responded using dragonflies and damselflies as study subjects. Each chapter is written by a well-respected scientist. The topics covered are: demography, population and community ecology, life-history, distribution, abundance, migration, conservation, applied use, predator-prey interactions, mating isolation, lifetime reproductive success estimates, reproduction vs. survival, parasite-host relationships, cryptic female choice, sexual conflict, territoriality, sex-limited colour polymorphisms, sexual size dimorphism, flight performance, and wing evolution. Each chapter puts forward new data and hypothesis in relation to further ecological and evolutionary questions.Less
This book is a collection of nineteen chapters where summaries of major ecological and evolutionary questions have been asked and responded using dragonflies and damselflies as study subjects. Each chapter is written by a well-respected scientist. The topics covered are: demography, population and community ecology, life-history, distribution, abundance, migration, conservation, applied use, predator-prey interactions, mating isolation, lifetime reproductive success estimates, reproduction vs. survival, parasite-host relationships, cryptic female choice, sexual conflict, territoriality, sex-limited colour polymorphisms, sexual size dimorphism, flight performance, and wing evolution. Each chapter puts forward new data and hypothesis in relation to further ecological and evolutionary questions.
Graeme D. Ruxton, Thomas N. Sherratt, and Michael P. Speed
- Published in print:
- 2004
- Published Online:
- September 2007
- ISBN:
- 9780198528609
- eISBN:
- 9780191713392
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198528609.003.0007
- Subject:
- Biology, Animal Biology
Predators that rely on surprise may be persuaded to desist from attacking if prey use reliable signals that the predator has been detected. Prey may also be able to reliably signal to a predator that ...
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Predators that rely on surprise may be persuaded to desist from attacking if prey use reliable signals that the predator has been detected. Prey may also be able to reliably signal to a predator that they are difficult to catch or subdue, and that cause the predator to desist from attacking or switch their attack to another prey individual. The theory underlying such signals is considered and compared to the available empirical data to determine the evolution of such signals and their ecological prevalence.Less
Predators that rely on surprise may be persuaded to desist from attacking if prey use reliable signals that the predator has been detected. Prey may also be able to reliably signal to a predator that they are difficult to catch or subdue, and that cause the predator to desist from attacking or switch their attack to another prey individual. The theory underlying such signals is considered and compared to the available empirical data to determine the evolution of such signals and their ecological prevalence.
Graham Bell
- Published in print:
- 2007
- Published Online:
- May 2008
- ISBN:
- 9780198569725
- eISBN:
- 9780191717741
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198569725.003.0011
- Subject:
- Biology, Evolutionary Biology / Genetics
Members of a different species may be enemies, such as predators and parasites, or friends, such as mutualists. The linked evolutionary dynamics of strongly interacting species can be complex, and ...
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Members of a different species may be enemies, such as predators and parasites, or friends, such as mutualists. The linked evolutionary dynamics of strongly interacting species can be complex, and are important in understanding the evolution of disease. This chapter's first section is called Rivals and talks about the social environment; mutual modification; and social coevolution. The second section, Partners, describes the Transmission Hypothesis. It also gives a novel protist-bacterium partnership and talks about experimental evolution of cooperation in a bacterium-phage system; coevolution of bacteria; plasmids; quora and consortia; and finally offers a symbiosis. The third section called Enemies details serial passage; genetic specificity; anisomorphic social matrices; the cost of virulence and resistance; evolution of virulence; epidemics; and talks about arms cycles and arms races; phage wars; and finally perpetual evolution. The final section in this chapter is about ecosystems and talks about uqba; the evolution of trophic structure through sorting; evolutionarily Stable Webs; evolved webs; the innate immune system; the acquired immune system; selection at the ecosystem level; and finally evolution and whole-system properties.Less
Members of a different species may be enemies, such as predators and parasites, or friends, such as mutualists. The linked evolutionary dynamics of strongly interacting species can be complex, and are important in understanding the evolution of disease. This chapter's first section is called Rivals and talks about the social environment; mutual modification; and social coevolution. The second section, Partners, describes the Transmission Hypothesis. It also gives a novel protist-bacterium partnership and talks about experimental evolution of cooperation in a bacterium-phage system; coevolution of bacteria; plasmids; quora and consortia; and finally offers a symbiosis. The third section called Enemies details serial passage; genetic specificity; anisomorphic social matrices; the cost of virulence and resistance; evolution of virulence; epidemics; and talks about arms cycles and arms races; phage wars; and finally perpetual evolution. The final section in this chapter is about ecosystems and talks about uqba; the evolution of trophic structure through sorting; evolutionarily Stable Webs; evolved webs; the innate immune system; the acquired immune system; selection at the ecosystem level; and finally evolution and whole-system properties.
James A. Estes
- Published in print:
- 2008
- Published Online:
- May 2008
- ISBN:
- 9780195319958
- eISBN:
- 9780199869596
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195319958.003.0002
- Subject:
- Biology, Aquatic Biology
The chapter summarizes the current understanding of the kelp forest ecosystems of Alaska by focusing on the key role that otters, killer whales, and man have played in the ecological organization of ...
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The chapter summarizes the current understanding of the kelp forest ecosystems of Alaska by focusing on the key role that otters, killer whales, and man have played in the ecological organization of this ecosystem. The role of kelp, the effect of anti-predator chemistry, and sea urchin interactions are discussed. The history of the ecosystem as well as the science is covered and includes a discussion of the debate on the role of whaling in influencing otter–killer whale interactions, which may be further changing the ecology of this ecosystem.Less
The chapter summarizes the current understanding of the kelp forest ecosystems of Alaska by focusing on the key role that otters, killer whales, and man have played in the ecological organization of this ecosystem. The role of kelp, the effect of anti-predator chemistry, and sea urchin interactions are discussed. The history of the ecosystem as well as the science is covered and includes a discussion of the debate on the role of whaling in influencing otter–killer whale interactions, which may be further changing the ecology of this ecosystem.
Graeme D. Ruxton, Tom N. Sherratt, and Michael P. Speed
- Published in print:
- 2004
- Published Online:
- September 2007
- ISBN:
- 9780198528609
- eISBN:
- 9780191713392
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198528609.001.0001
- Subject:
- Biology, Animal Biology
The book discusses the diversity of mechanisms by which prey can avoid or survive attacks by predators, both from ecological and evolutionary perspectives. There is a particular focus on sensory ...
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The book discusses the diversity of mechanisms by which prey can avoid or survive attacks by predators, both from ecological and evolutionary perspectives. There is a particular focus on sensory mechanisms by which prey can avoid being detected, avoid being identified, signal (perhaps sometimes dishonestly) to predators that they are defended or unpalatable. The book is divided into three sections. The first considers detection avoidance through, for example, background matching, disruptive patterning, countershading and counterillumination, or transparency and reflective silvering. The second section considers avoiding or surviving an attack if detection and identification by the predator has already taken place (i.e., secondary defences). The key mechanism of this section is aposematism: signals that warn the predator that a particular prey type is defended. One particularly interesting aspect of this is the sharing of the same signal by more than one defended species (the phenomenon of Mullerian mimicry). The final section considers deception of predators. This may involve an undefended prey mimicking a defended species (Batesian mimicry), or signals that deflect predator’s attention or signals that startle predators. The book provides the first comprehensive survey of adaptive coloration in a predator-prey context in thirty years.Less
The book discusses the diversity of mechanisms by which prey can avoid or survive attacks by predators, both from ecological and evolutionary perspectives. There is a particular focus on sensory mechanisms by which prey can avoid being detected, avoid being identified, signal (perhaps sometimes dishonestly) to predators that they are defended or unpalatable. The book is divided into three sections. The first considers detection avoidance through, for example, background matching, disruptive patterning, countershading and counterillumination, or transparency and reflective silvering. The second section considers avoiding or surviving an attack if detection and identification by the predator has already taken place (i.e., secondary defences). The key mechanism of this section is aposematism: signals that warn the predator that a particular prey type is defended. One particularly interesting aspect of this is the sharing of the same signal by more than one defended species (the phenomenon of Mullerian mimicry). The final section considers deception of predators. This may involve an undefended prey mimicking a defended species (Batesian mimicry), or signals that deflect predator’s attention or signals that startle predators. The book provides the first comprehensive survey of adaptive coloration in a predator-prey context in thirty years.
Kathryn L. Cottingham and Julia M. Butzler
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780198567080
- eISBN:
- 9780191717871
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198567080.003.0008
- Subject:
- Biology, Disease Ecology / Epidemiology
Vibrio cholerae, the causal agent of cholera, is a heterotrophic bacterium found in aquatic environments around the world. Although understanding the ecology of V. cholerae is ...
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Vibrio cholerae, the causal agent of cholera, is a heterotrophic bacterium found in aquatic environments around the world. Although understanding the ecology of V. cholerae is still in its infancy, community interactions likely play a key role in determining its abundance and disease outbreaks. For example, V. cholerae occurs both in a free-living state and when attached to phytoplankton, zooplankton, and benthic invertebrates. Parasitic or mutualistic interactions with host organisms influence bacterial survival in adverse conditions and have major effects on transmission to humans. Abundances can also be altered directly via interactions with predators and competitors, or indirectly if higher trophic levels alter the density or composition of predators or potential hosts for attachment. Thus, this system illustrates the importance of both direct and indirect biotic interactions for disease dynamics.Less
Vibrio cholerae, the causal agent of cholera, is a heterotrophic bacterium found in aquatic environments around the world. Although understanding the ecology of V. cholerae is still in its infancy, community interactions likely play a key role in determining its abundance and disease outbreaks. For example, V. cholerae occurs both in a free-living state and when attached to phytoplankton, zooplankton, and benthic invertebrates. Parasitic or mutualistic interactions with host organisms influence bacterial survival in adverse conditions and have major effects on transmission to humans. Abundances can also be altered directly via interactions with predators and competitors, or indirectly if higher trophic levels alter the density or composition of predators or potential hosts for attachment. Thus, this system illustrates the importance of both direct and indirect biotic interactions for disease dynamics.
Michio Kondoh
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198564836
- eISBN:
- 9780191713828
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198564836.003.0012
- Subject:
- Biology, Aquatic Biology
How do diverse species coexist in the complex networks of prey-predator interactions in nature? While most theoretical models predict that complex food webs do not persist, recent empirical studies ...
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How do diverse species coexist in the complex networks of prey-predator interactions in nature? While most theoretical models predict that complex food webs do not persist, recent empirical studies have revealed the very complex structure of natural food webs. This discrepancy between theory and observation implies that essential factors stabilizing natural food webs are lacking from previous models. This chapter reviews these studies on food web complexity and its community-level consequences. It contends that the architectural flexibility arising from foraging adaptation of consumer species is key to explaining linkage patterns and persistent mechanisms of complex food webs. A novel hypothesis is presented, which relates the complexity-stability relationship to evolutionarily history of the community.Less
How do diverse species coexist in the complex networks of prey-predator interactions in nature? While most theoretical models predict that complex food webs do not persist, recent empirical studies have revealed the very complex structure of natural food webs. This discrepancy between theory and observation implies that essential factors stabilizing natural food webs are lacking from previous models. This chapter reviews these studies on food web complexity and its community-level consequences. It contends that the architectural flexibility arising from foraging adaptation of consumer species is key to explaining linkage patterns and persistent mechanisms of complex food webs. A novel hypothesis is presented, which relates the complexity-stability relationship to evolutionarily history of the community.
Dietmar Straile
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198564836
- eISBN:
- 9780191713828
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198564836.003.0005
- Subject:
- Biology, Aquatic Biology
Studies on lakes provide some of the most complete investigations on the structure, dynamics, and energetics of food webs encompassing organisms from bacteria to vertebrates. The life cycle of ...
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Studies on lakes provide some of the most complete investigations on the structure, dynamics, and energetics of food webs encompassing organisms from bacteria to vertebrates. The life cycle of organisms in temperate lakes is adapted to a highly seasonal environment. Food web interactions in these lakes depend on the seasonal overlap of the occurrence of potential prey, competitor, or predator species. This seasonal overlap (i.e., the match-mismatch of food web interactions) depends strongly on the seasonal dynamics of the physical environment of lakes, such as temperature, light availability, and mixing intensity. Consequently, climate variability influences food web interactions and hence the structure, dynamics, and energetics of lake food webs. This chapter provides examples and discusses the importance of seasonality for the understanding of various aspects of lake food webs and the impact of climate variability thereon.Less
Studies on lakes provide some of the most complete investigations on the structure, dynamics, and energetics of food webs encompassing organisms from bacteria to vertebrates. The life cycle of organisms in temperate lakes is adapted to a highly seasonal environment. Food web interactions in these lakes depend on the seasonal overlap of the occurrence of potential prey, competitor, or predator species. This seasonal overlap (i.e., the match-mismatch of food web interactions) depends strongly on the seasonal dynamics of the physical environment of lakes, such as temperature, light availability, and mixing intensity. Consequently, climate variability influences food web interactions and hence the structure, dynamics, and energetics of lake food webs. This chapter provides examples and discusses the importance of seasonality for the understanding of various aspects of lake food webs and the impact of climate variability thereon.
Simon Jennings
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198564836
- eISBN:
- 9780191713828
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198564836.003.0009
- Subject:
- Biology, Aquatic Biology
This chapter presents size-based analyses of aquatic food webs, where body size rather than species identity is the principle descriptor of an individual's role in the food web, provides insights ...
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This chapter presents size-based analyses of aquatic food webs, where body size rather than species identity is the principle descriptor of an individual's role in the food web, provides insights into food web structure and function that complement, and extends those from species-based analyses. Focus is given to body size because it underpins predator-prey interactions and dictates how the biological properties of individuals change with size. Thus, size-based food web analyses offer an approach for integrating community and ecosystem ecology with energetic and metabolic theory.Less
This chapter presents size-based analyses of aquatic food webs, where body size rather than species identity is the principle descriptor of an individual's role in the food web, provides insights into food web structure and function that complement, and extends those from species-based analyses. Focus is given to body size because it underpins predator-prey interactions and dictates how the biological properties of individuals change with size. Thus, size-based food web analyses offer an approach for integrating community and ecosystem ecology with energetic and metabolic theory.
David M. Wilkinson
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780198568469
- eISBN:
- 9780191717611
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198568469.003.0003
- Subject:
- Biology, Ecology
The problems faced by a hypothetical planet with only one species strongly suggest that any functioning ecological system must have organisms from at least two major ecological guilds: autotrophs and ...
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The problems faced by a hypothetical planet with only one species strongly suggest that any functioning ecological system must have organisms from at least two major ecological guilds: autotrophs and decomposers. While conventional predators do not seem to be crucial to planetary ecologies it is likely that parasites will quickly evolve, and through density dependent processes help to regulate population sizes. Density dependence may be crucial in preventing the runaway population growth of a species, leading to it monopolizing a planet's ecology. While density independent processes (be they a cold winter on a local scale, or the impact of a large meteorite at the planetary scale) can greatly affect abundance, they cannot provide regulation; this requires the ‘thermostat’ like behaviour of density dependence. As such, both multiple guilds and the presence of parasites are likely to have positive Gaian effects in most biospheres.Less
The problems faced by a hypothetical planet with only one species strongly suggest that any functioning ecological system must have organisms from at least two major ecological guilds: autotrophs and decomposers. While conventional predators do not seem to be crucial to planetary ecologies it is likely that parasites will quickly evolve, and through density dependent processes help to regulate population sizes. Density dependence may be crucial in preventing the runaway population growth of a species, leading to it monopolizing a planet's ecology. While density independent processes (be they a cold winter on a local scale, or the impact of a large meteorite at the planetary scale) can greatly affect abundance, they cannot provide regulation; this requires the ‘thermostat’ like behaviour of density dependence. As such, both multiple guilds and the presence of parasites are likely to have positive Gaian effects in most biospheres.
William J. Sutherland and Rhys E. Green
- Published in print:
- 2004
- Published Online:
- September 2007
- ISBN:
- 9780198520863
- eISBN:
- 9780191706189
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198520863.003.0011
- Subject:
- Biology, Biodiversity / Conservation Biology
Most field studies incorporate measures of habitat extent and quality. How to devise a protocol for recording habitat is described. The section on physical environment describes how to measure ...
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Most field studies incorporate measures of habitat extent and quality. How to devise a protocol for recording habitat is described. The section on physical environment describes how to measure temperature, rainfall and wetness, slope, and water chemistry. The means for documenting vegetation structure, species composition, and habitat types are presented. Methods for assessing analysing habitat relationships are explored.Less
Most field studies incorporate measures of habitat extent and quality. How to devise a protocol for recording habitat is described. The section on physical environment describes how to measure temperature, rainfall and wetness, slope, and water chemistry. The means for documenting vegetation structure, species composition, and habitat types are presented. Methods for assessing analysing habitat relationships are explored.
Michael Doebeli
- Published in print:
- 2011
- Published Online:
- October 2017
- ISBN:
- 9780691128931
- eISBN:
- 9781400838936
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691128931.003.0005
- Subject:
- Biology, Biodiversity / Conservation Biology
This chapter discusses adaptive diversification due to predator–prey interactions. It has long been recognized that consumption, that is, predation, can not only exert strong selection pressure on ...
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This chapter discusses adaptive diversification due to predator–prey interactions. It has long been recognized that consumption, that is, predation, can not only exert strong selection pressure on the consumer, but also on the consumed species. However, predation has traditionally received much less attention than competition as a cause for the origin and maintenance of diversity. By using adaptive dynamics theory as well as individual-based models, the chapter then illustrates that adaptive diversification in prey species due to frequency-dependent predator–prey interactions is a theoretically plausible scenario. It also describes conditions for diversification due to predator–prey interactions in classical Lotka–Volterra models, which requires analysis of coevolutionary dynamics between two interacting species, and hence of adaptive dynamics in two-dimensional phenotype spaces.Less
This chapter discusses adaptive diversification due to predator–prey interactions. It has long been recognized that consumption, that is, predation, can not only exert strong selection pressure on the consumer, but also on the consumed species. However, predation has traditionally received much less attention than competition as a cause for the origin and maintenance of diversity. By using adaptive dynamics theory as well as individual-based models, the chapter then illustrates that adaptive diversification in prey species due to frequency-dependent predator–prey interactions is a theoretically plausible scenario. It also describes conditions for diversification due to predator–prey interactions in classical Lotka–Volterra models, which requires analysis of coevolutionary dynamics between two interacting species, and hence of adaptive dynamics in two-dimensional phenotype spaces.
Thomas W. Cronin, Sönke Johnsen, N. Justin Marshall, and Eric J. Warrant
- Published in print:
- 2014
- Published Online:
- October 2017
- ISBN:
- 9780691151847
- eISBN:
- 9781400853021
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691151847.003.0011
- Subject:
- Biology, Evolutionary Biology / Genetics
This chapter discusses how darkness provides excellent advantages for a wide variety of animals, for the simple reason that vision—a primary sense for predators and foragers alike—becomes severely ...
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This chapter discusses how darkness provides excellent advantages for a wide variety of animals, for the simple reason that vision—a primary sense for predators and foragers alike—becomes severely disabled when faced with a paucity of light. Thus, in a fiercely competitive rainforest, the cover of night provides respite from visually dependent predators and competitors, a fact that has encouraged the evolution of nocturnal activity in many different taxa. In the endlessly dim world of the deep ocean, the cover of darkness is instead permanent, and vision is relentlessly pressed at the limits of the physically possible. In some species the eyes have evolved extreme adaptations for extracting the most fleeting of visual cues. Others have given up the fight altogether, their eyes having regressed to mere vestiges.Less
This chapter discusses how darkness provides excellent advantages for a wide variety of animals, for the simple reason that vision—a primary sense for predators and foragers alike—becomes severely disabled when faced with a paucity of light. Thus, in a fiercely competitive rainforest, the cover of night provides respite from visually dependent predators and competitors, a fact that has encouraged the evolution of nocturnal activity in many different taxa. In the endlessly dim world of the deep ocean, the cover of darkness is instead permanent, and vision is relentlessly pressed at the limits of the physically possible. In some species the eyes have evolved extreme adaptations for extracting the most fleeting of visual cues. Others have given up the fight altogether, their eyes having regressed to mere vestiges.
André M. de Roos and Lennart Persson
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691137575
- eISBN:
- 9781400845613
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691137575.003.0001
- Subject:
- Biology, Ecology
This chapter provides a summary of the topics covered by the present volume. The summary serves the purpose of clearly showing how different chapters fit together in a general framework with respect ...
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This chapter provides a summary of the topics covered by the present volume. The summary serves the purpose of clearly showing how different chapters fit together in a general framework with respect to model approaches as well as results obtained. Reading this summary chapter will show readers the different types of community modules that will be analyzed as well as provide a clear impression of the results and insights that presented in this book. Topics discussed include biomass overcompensation, ontogenetic (a)symmetry in energetics, emergent community effects of biomass overcompensation, ontogenetic niche shifts in consumer life history, ontogenetic niche shifts in predator life history, competition between consumers with and without ontogenetic niche shifts, and ontogenetic (a)symmetry in energetics and population dynamics.Less
This chapter provides a summary of the topics covered by the present volume. The summary serves the purpose of clearly showing how different chapters fit together in a general framework with respect to model approaches as well as results obtained. Reading this summary chapter will show readers the different types of community modules that will be analyzed as well as provide a clear impression of the results and insights that presented in this book. Topics discussed include biomass overcompensation, ontogenetic (a)symmetry in energetics, emergent community effects of biomass overcompensation, ontogenetic niche shifts in consumer life history, ontogenetic niche shifts in predator life history, competition between consumers with and without ontogenetic niche shifts, and ontogenetic (a)symmetry in energetics and population dynamics.
André M. de Roos and Lennart Persson
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691137575
- eISBN:
- 9781400845613
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691137575.003.0002
- Subject:
- Biology, Ecology
This chapter first considers the question of how ecologists have conceptualized populations. In other words, how has their research looked at “group[s] of individuals of one species”? It reflects on ...
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This chapter first considers the question of how ecologists have conceptualized populations. In other words, how has their research looked at “group[s] of individuals of one species”? It reflects on the classical models that form the theoretical basis of population ecology: the Lotka–Volterra competition model, Lotka–Volterra predator–prey model, and Fretwell–Oksanen food chain model. It then argues that much of ecologists' understanding about populations and communities and their dynamics is couched in terms of mathematical models. The remainder of the chapter discusses individual- versus population-level assumptions, the population dynamical triad, growth patterns and ecology of ontogenetic development, body-size scaling and magnitude of body-size changes, and changes in ecological roles over ontogeny.Less
This chapter first considers the question of how ecologists have conceptualized populations. In other words, how has their research looked at “group[s] of individuals of one species”? It reflects on the classical models that form the theoretical basis of population ecology: the Lotka–Volterra competition model, Lotka–Volterra predator–prey model, and Fretwell–Oksanen food chain model. It then argues that much of ecologists' understanding about populations and communities and their dynamics is couched in terms of mathematical models. The remainder of the chapter discusses individual- versus population-level assumptions, the population dynamical triad, growth patterns and ecology of ontogenetic development, body-size scaling and magnitude of body-size changes, and changes in ecological roles over ontogeny.
André M. de Roos and Lennart Persson
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691137575
- eISBN:
- 9781400845613
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691137575.003.0004
- Subject:
- Biology, Ecology
This chapter discusses the emergence of a positive feedback between the density of predators and the availability of its food, mediated through biomass overcompensation in the prey life history stage ...
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This chapter discusses the emergence of a positive feedback between the density of predators and the availability of its food, mediated through biomass overcompensation in the prey life history stage that it forages on. This positive feedback between predation, prey availability, and thus predator population growth rate manifests itself at the population-level as an Allee effect for the predator: a predator population at low density will decline to extinction, whereas at high densities predators will manage to establish themselves in a community with prey. However, this positive relation between predator density and its population growth rate does not result from any positively density-dependent interactions among the predators themselves, which generally form the basis of an Allee effect. Instead, predators only interact with each other through exploitative competition for prey. The Allee effect emerges solely as a consequence of the demographic changes in the prey population, which are induced by the mortality that the predator imposes. For this reason this phenomenon is referred to as an “emergent Allee effect.”Less
This chapter discusses the emergence of a positive feedback between the density of predators and the availability of its food, mediated through biomass overcompensation in the prey life history stage that it forages on. This positive feedback between predation, prey availability, and thus predator population growth rate manifests itself at the population-level as an Allee effect for the predator: a predator population at low density will decline to extinction, whereas at high densities predators will manage to establish themselves in a community with prey. However, this positive relation between predator density and its population growth rate does not result from any positively density-dependent interactions among the predators themselves, which generally form the basis of an Allee effect. Instead, predators only interact with each other through exploitative competition for prey. The Allee effect emerges solely as a consequence of the demographic changes in the prey population, which are induced by the mortality that the predator imposes. For this reason this phenomenon is referred to as an “emergent Allee effect.”
André M. de Roos and Lennart Persson
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691137575
- eISBN:
- 9781400845613
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691137575.003.0005
- Subject:
- Biology, Ecology
This chapter discusses a variety of positive interactions between predators foraging on different stages of the same prey species, which all emerge owing to the biomass overcompensation that may ...
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This chapter discusses a variety of positive interactions between predators foraging on different stages of the same prey species, which all emerge owing to the biomass overcompensation that may occur in prey life history stages in response to increased mortality. These interactions include emergent facilitation of specialist predators by generalists that forage on the same prey individuals as the specialists, but in addition forage on smaller or larger prey individuals as well. Furthermore, the chapter shows that two predators that specialize on different life-history stages of prey can facilitate each other to the extent that one predator relies on the presence of the other for its persistence. A stage-specific predator may act as a catalyst species, which promotes and in fact is necessary for the invasion of another predator species, but is subsequently outcompeted by the latter.Less
This chapter discusses a variety of positive interactions between predators foraging on different stages of the same prey species, which all emerge owing to the biomass overcompensation that may occur in prey life history stages in response to increased mortality. These interactions include emergent facilitation of specialist predators by generalists that forage on the same prey individuals as the specialists, but in addition forage on smaller or larger prey individuals as well. Furthermore, the chapter shows that two predators that specialize on different life-history stages of prey can facilitate each other to the extent that one predator relies on the presence of the other for its persistence. A stage-specific predator may act as a catalyst species, which promotes and in fact is necessary for the invasion of another predator species, but is subsequently outcompeted by the latter.
André M. de Roos and Lennart Persson
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691137575
- eISBN:
- 9781400845613
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691137575.003.0007
- Subject:
- Biology, Ecology
This chapter discusses mixed interactions from a different perspective, taking as its point of departure the models for a structured prey, structured predator community with exclusive resources for ...
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This chapter discusses mixed interactions from a different perspective, taking as its point of departure the models for a structured prey, structured predator community with exclusive resources for both prey and predator that were analyzed in Chapter 6. For both the stage-structured biomass model and the size-structured model based on Kooijman–Metz energetics discussed in Chapter 6, it investigates how an increasing resource overlap between predators and consumers will change community structure and dynamics. The end point of such increasing resource overlap is a model in which consumers and predators compete for the same shared resource and adult predators feed partially or exclusively on juvenile, small-size consumers. This end point is close to the models analyzed by van de Wolfshaar, de Roos, and Persson (2006) and Hin, Schellekens, et al. (2011); the results will be discussed in the light of those publications.Less
This chapter discusses mixed interactions from a different perspective, taking as its point of departure the models for a structured prey, structured predator community with exclusive resources for both prey and predator that were analyzed in Chapter 6. For both the stage-structured biomass model and the size-structured model based on Kooijman–Metz energetics discussed in Chapter 6, it investigates how an increasing resource overlap between predators and consumers will change community structure and dynamics. The end point of such increasing resource overlap is a model in which consumers and predators compete for the same shared resource and adult predators feed partially or exclusively on juvenile, small-size consumers. This end point is close to the models analyzed by van de Wolfshaar, de Roos, and Persson (2006) and Hin, Schellekens, et al. (2011); the results will be discussed in the light of those publications.
André M. de Roos and Lennart Persson
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691137575
- eISBN:
- 9781400845613
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691137575.003.0008
- Subject:
- Biology, Ecology
This chapter considers how stage structure and ontogenetic niche shifts may affect the coexistence between two consumer species competing for two resources in the absence and presence of predators, ...
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This chapter considers how stage structure and ontogenetic niche shifts may affect the coexistence between two consumer species competing for two resources in the absence and presence of predators, and how ontogenetic niche shifts may give rise to alternative stable states. More specifically, the analysis will use techniques developed within the consumer-resource framework of Tilman (1982), including consumption and renewal vectors (Schellekens, de Roos, and Persson 2010). Tilman showed that stable coexistence between consumers feeding on the same two resources is possible if each consumer species feeds proportionally more on the resource that limits its own growth most. Stable coexistence is, however, also affected by the form of resource-dependent growth isoclines, which represent combinations of resource densities that lead to equal population growth of consumers. It is shown that ontogenetic niche shifts per se affect the form of resource-dependent growth isoclines, which in turn may lead to coexistence through niche partitioning. The chapter also discusses how predation may promote the performance of a species undergoing ontogenetic niche shifts even in the case where it is both the inferior competitor and the preferred prey of the predator.Less
This chapter considers how stage structure and ontogenetic niche shifts may affect the coexistence between two consumer species competing for two resources in the absence and presence of predators, and how ontogenetic niche shifts may give rise to alternative stable states. More specifically, the analysis will use techniques developed within the consumer-resource framework of Tilman (1982), including consumption and renewal vectors (Schellekens, de Roos, and Persson 2010). Tilman showed that stable coexistence between consumers feeding on the same two resources is possible if each consumer species feeds proportionally more on the resource that limits its own growth most. Stable coexistence is, however, also affected by the form of resource-dependent growth isoclines, which represent combinations of resource densities that lead to equal population growth of consumers. It is shown that ontogenetic niche shifts per se affect the form of resource-dependent growth isoclines, which in turn may lead to coexistence through niche partitioning. The chapter also discusses how predation may promote the performance of a species undergoing ontogenetic niche shifts even in the case where it is both the inferior competitor and the preferred prey of the predator.
Lev Ginzburg and Mark Colyvan
- Published in print:
- 2003
- Published Online:
- September 2007
- ISBN:
- 9780195168167
- eISBN:
- 9780199790159
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195168167.003.0005
- Subject:
- Biology, Ecology
In order to appreciate fully the advantages of the inertial view of population growth, it is necessary to discuss some of the details of and debates about the predator-prey account of population ...
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In order to appreciate fully the advantages of the inertial view of population growth, it is necessary to discuss some of the details of and debates about the predator-prey account of population cycles. This chapter argues that the ratio-dependant idealization of the predator-prey interaction is quite different from the more traditional prey-dependent idealization. Moreover, the former view is not conducive to cyclic behavior.Less
In order to appreciate fully the advantages of the inertial view of population growth, it is necessary to discuss some of the details of and debates about the predator-prey account of population cycles. This chapter argues that the ratio-dependant idealization of the predator-prey interaction is quite different from the more traditional prey-dependent idealization. Moreover, the former view is not conducive to cyclic behavior.
