Calvin Dytham | University of York (original) (raw)

Papers by Calvin Dytham

Access microbiology, Mar 1, 2019

Community profiling is one of the most utilised tools in microbial ecology today. The relationshi... more Community profiling is one of the most utilised tools in microbial ecology today. The relationships between microbial communities and their environment affect ecosystem function in fields spanning from medicine to agriculture; and understanding the community dynamics of a microbial community is key to understanding the complex effects of human intervention. In this study, we look at the effects of long-term tillage and fertilization regimes in soils from an agricultural block-designed field trial set up in 2001. By studying the microbial community composition, absolute microbial abundance and diversity of denitrification functional genes in the context of environmental data, we were able to address the question of how specific land management histories affect the diversity and distribution of bacteria and denitrification genes within agricultural soils. It was found that microbial communities appear to be largely unaffected by land management history, and cluster predominantly by spatial location within the field, despite lack of significant environmental variation. In this well-established agricultural field trial, Euclidean distance is the major identifiable determinant of microbial community dissimilarity (as well as dissimilarity in microbial abundance). That ecological drift, rather than physicochemical factors can be the major determinant of genetic potential may have consequences for attempts to understand nutrient availability in agricultural systems. Additionally, the overwhelming variation caused by spatial distance indicates that block designed experiments may not always have sufficient statistical power to identify any effects of human treatment.

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Oxford University Press eBooks, Mar 6, 2008

This chapter considers the signal of local dispersal which sits inside maps of the locations of i... more This chapter considers the signal of local dispersal which sits inside maps of the locations of individuals, and introduces spatial statistics as measures of spatial structure. It shows how dispersal plays a fundamental part in local population dynamics. Dispersal is also shown to have important implications for the outcome of local spatial competition between two species, the dynamics of metapopulations, and the structure of multispecies communities. Local dispersal causes clumping, slows down changes in density, and affects the asymptotic state ultimately achieved by a population. When different species compete, dispersal over greater distances gives a species an advantage which can eliminate competitive coexistence which might otherwise occur. However, in the presence of spatial environmental heterogeneity, where too much dispersal can move offspring away from favourable parts of the environment, dispersal over intermediate distances can allow faster population growth than dispersal over either short or long distances.

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Oxford University Press eBooks, Mar 6, 2008

This chapter discusses traits that determine dispersal of propagules by different vectors. It pay... more This chapter discusses traits that determine dispersal of propagules by different vectors. It pays special attention to dispersal by air, water, animals, and humans, since these vectors have received the greatest attention in scientific literature. It is clear from morphological and chemical traits that many species have evolved an enhanced ability to be dispersed by particular vectors. However, propagules may be moved by a number of vectors, both physical and biological. There is variation in these traits between species, between and within populations, and among propagules on the same plant. Mass, volume, and area determine the propensity of any propagule to be moved in air and water. Dispersal on the outside of animals is correlated with propagule shape, mass, and adhesive ability, while size relative to the mouth of the animal and chemical constituents determine which species will be ingested and how long they might be carried.

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Oxford University Press eBooks, Mar 6, 2008

This chapter discusses approaches that have been used to understand how particular shapes and sca... more This chapter discusses approaches that have been used to understand how particular shapes and scales of propagule distributions arise around a parent plant. It begins by contrasting two different methods of collecting dispersal data and two fundamentally different ways of presenting the results. It is shown that the frequency distribution of dispersal distance approaches zero at the source, increases to one (or more) maximum, and declines rapidly to a long tail. In contrast, the density of the seed rain declines rapidly with distance, being greatest close to the source plant. Examples are given of models that are being developed to predict dispersal by multiple vectors and over the entire dispersal season. The chapter concludes with a discussion of research methodologies, since these are critical to the success of future empirical research.

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Oxford University Press eBooks, Mar 6, 2008

Ecologists, both practical and theoretical, now appreciate that to understand biological systems ... more Ecologists, both practical and theoretical, now appreciate that to understand biological systems they must consider the spatial dimension. Consequently, dispersal has become one of the hottest topics in plant ecology. However, in the midst of so much research output on dispersal, there is a need for a stock-take to determine the needs of future research: what has been achieved to date, where do current studies fit in, and what still needs to be determined? What are the implications of dispersal for those engaged in managing plant populations and communities? This is the first book for many years to present a synthesis of research on dispersal and its implications for plant population dynamics. The book consists of three sections: Section A reviews information on the biological and environmental processes that determine the path of an individual dispersing propagule, usually a seed, and the theory that has been developed to predict these trajectories; Section B discusses the distributions of seeds resulting from dispersal from an entire plant, theoretical research predicting the shapes of these distributions and design issues for future dispersal studies; Section C explores the implications of dispersal for expansion of populations, structure within existing populations and communities, and the evolution of dispersal traits.

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This research provides a large scale analysis of evidence previously only available as individual... more This research provides a large scale analysis of evidence previously only available as individual reports which is of significance to an understanding of social changes in the Palaeolithic. It also highlights why healthcare provisioning should be considered as a key evolutionary adaptation and so is of interest and importance to those studying cognitive, biological and anatomical changes. We are increasingly recognising many complex ways in which the ecological, social, cognitive and anatomical elements of our human evolutionary past interact and influence each other. One relatively new area of this type of interaction is the potential significance of healthcare provisioning on other realms of human evolution and behaviour. Evidence from skeletal remains for care has traditionally been considered to be subject to some debate. However, whilst precise interpretations remain open to discussion, widespread evidence for healthcare in Palaeolithic contexts is now widely accepted [1] [2] [3]. Healthcare practices are significant in several ways, such as by changing the profile of how injuries impact both group subsistence and individual survival, as well as having a profound impact of social relationships. Here we explore this issue through the interpretation of a large scale survey of evidence for care practices in early, archaic and modern humans. We consider the ecologica l basis for care for the ill and injured, how such care changes through time and in different contexts, the role of care practices in group survival, and the potential influence of increasingly sophisticated medical knowledge on care. Although healthcare provisioning has typically been seen in purely cultural terms, we argue that it is not only a significant and often overlooked element of social relationships throughout the Palaeolithic but is also of evolutionary significance. While other animals provision the ill and injured, none go to such lengths or with such competency as seen in archaic humans, as recent research has started to highlight [4] [5]. Healthcare practices in such groups are likely to have included not only provision of food and water and protection from predators, but also a knowledgeable approach to promoting wound healing and recovery from severe injury. We argue this adaptation was an important part of hominin sociality and may have become especially importan t to humans that were trying to survive in hostile environments. Bastir, M. Pulling faces. Nat Ecol Evol (2018). Comment on Godinho, R. M., Spikins, P., & O’Higgins, P. (2018). Supraorbital morphology and social dynamics in human evolution. Nature ecology & evolution, doi:10.1038/s41559-018-0528-0 Trinkaus, E. & Villotte, S. External auditory exostoses and hearing loss in the Shanidar 1 Neandertal. (2017) PLoS One 12, e0186684. Thorpe, N. 2016. The Palaeolithic Compassion Debate--Alternative Projections of Modern-Day Disability into the Distant Past. In Care in the Past: Archaeological and Interdisciplinary Perspectives, edited by L. Powell, W. Southwell-Wright, and R. Gowland, 93–109. Oxford: Oxbow Books. Spikins, P., Needham, A., Tilley, L. & Hitchens, G. Calculated or caring? Neanderthal healthcare in social context. (2018).World Archaeology. DOI: 10.1080/00438243.2018.1433060 Tilley, L. (2015) Care Among the Neandertals: La Chapelle-aux-Saints 1 and La Ferrassie 1 (Case Study 2). in Theory and Practice in the Bioarchaeology of Care 219–257 (Springer International Publishing, 2015).

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Current Biology, Nov 1, 2019

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Oxford University Press eBooks, Mar 6, 2008

This chapter considers aspects of the maternal parent, other than the tissues immediately around ... more This chapter considers aspects of the maternal parent, other than the tissues immediately around the seed, which contribute to the distances dispersed by plant propagules. It shows how plant phenotype, the abiotic environment, competition, and herbivory all help to determine where the trajectories of propagules begin. Plant phenology dictates when the force required separating the propagule from its parent is at a minimum, and therefore when the trajectory is likely to begin. This can be critical for the survival of animal vectors as well as for movement of seeds contained in fruits. In some cases, the parent provides an additional force to launch the propagule away from its parent.

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Journal of the Marine Biological Association of the United Kingdom, May 1, 1996

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Environmental Microbiology, 2021

Denitrification causes loss of available nitrogen from soil systems, thereby reducing crop produc... more Denitrification causes loss of available nitrogen from soil systems, thereby reducing crop productivity and increasing reliance on agrochemicals. The dynamics of denitrification and denitrifying communities are thought to be altered by land management practices, which affect the physicochemical properties of the soil. In this study, we look at the effects of long-term tillage and fertilization regimes on arable soils following 16 years of treatment in a factorial field trial. By studying the bacterial community composition based on 16S rRNA amplicons, absolute bacterial abundance and diversity of denitrification functional genes (nirK, nirS and nosZ), under conditions of minimum/conventional tillage and organic/synthetic mineral fertilizer, we tested how specific land management histories affect the diversity and distribution of both bacteria and denitrification genes. Bacterial and denitrifier communities were largely unaffected by land management history and clustered predominantly by spatial location, indicating that the variability in bacterial community composition in these arable soils is governed by innate environmental differences and Euclidean distance rather than agricultural management intervention. This article is protected by copyright. All rights reserved.

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In response to environmental stimuli, including variation in the presence of conspecifics, animal... more In response to environmental stimuli, including variation in the presence of conspecifics, animals show highly plastic responses in behavioural and physiological traits influencing reproduction. These responses have been extensively documented in males, but equivalent study of females is so far lacking. We expect females to be highly responsive to environmental variation, with significant impacts on fitness given females’ direct impact on offspring number, size, and developmental conditions. Using Drosophila melanogaster as a model, we manipulate (a) exposure to conspecific females, expected to influence their expectation of number of potential mates and larval density for their own offspring, and (b) test how prior consexual population density interacts with the spatial distribution of potential oviposition sites, with females expected to prefer clustered food resources that can support a larger number of eggs and larvae. After exposure to competition, females were slower to start ...

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Nature Communications, 2019

Advances in phenology (the annual timing of species’ life-cycles) in response to climate change a... more Advances in phenology (the annual timing of species’ life-cycles) in response to climate change are generally viewed as bioindicators of climate change, but have not been considered as predictors of range expansions. Here, we show that phenology advances combine with the number of reproductive cycles per year (voltinism) to shape abundance and distribution trends in 130 species of British Lepidoptera, in response to ~0.5 °C spring-temperature warming between 1995 and 2014. Early adult emergence in warm years resulted in increased within- and between-year population growth for species with multiple reproductive cycles per year (n = 39 multivoltine species). By contrast, early emergence had neutral or negative consequences for species with a single annual reproductive cycle (n = 91 univoltine species), depending on habitat specialisation. We conclude that phenology advances facilitate polewards range expansions in species exhibiting plasticity for both phenology and voltinism, but may...

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Biological Reviews, 2018

ABSTRACTIncreasingly imperative objectives in ecology are to understand and forecast population d... more ABSTRACTIncreasingly imperative objectives in ecology are to understand and forecast population dynamic and evolutionary responses to seasonal environmental variation and change. Such population and evolutionary dynamics result from immediate and lagged responses of all key life‐history traits, and resulting demographic rates that affect population growth rate, to seasonal environmental conditions and population density. However, existing population dynamic and eco‐evolutionary theory and models have not yet fully encompassed within‐individual and among‐individual variation, covariation, structure and heterogeneity, and ongoing evolution, in a critical life‐history trait that allows individuals to respond to seasonal environmental conditions: seasonal migration. Meanwhile, empirical studies aided by new animal‐tracking technologies are increasingly demonstrating substantial within‐population variation in the occurrence and form of migration versus year‐round residence, generating di...

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Http Www Libreriasaulamedica Com, 2003

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Dispersal in Plants, 2008

This chapter considers the signal of local dispersal which sits inside maps of the locations of i... more This chapter considers the signal of local dispersal which sits inside maps of the locations of individuals, and introduces spatial statistics as measures of spatial structure. It shows how dispersal plays a fundamental part in local population dynamics. Dispersal is also shown to have important implications for the outcome of local spatial competition between two species, the dynamics of metapopulations, and the structure of multispecies communities. Local dispersal causes clumping, slows down changes in density, and affects the asymptotic state ultimately achieved by a population. When different species compete, dispersal over greater distances gives a species an advantage which can eliminate competitive coexistence which might otherwise occur. However, in the presence of spatial environmental heterogeneity, where too much dispersal can move offspring away from favourable parts of the environment, dispersal over intermediate distances can allow faster population growth than disper...

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Dispersal in Plants, 2008

This chapter provides both a flavour of, and some insight into, the evolutionary forces at work s... more This chapter provides both a flavour of, and some insight into, the evolutionary forces at work shaping the amazing diversity of dispersal strategies seen in plants. For all plants, there is a tension between the advantages of a sedentary or short-distance dispersal strategy and those of a more dispersive one. The selective forces that act to increase or decrease evolved dispersal rates or distances are reviewed. The dispersal strategy adopted by a plant species is clearly shaped by a long history of interacting and competing forces. The relative strengths of these forces will inevitably wax and wane, and the interactions between them shift to change the overall selective pressure to disperse.

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Quaternary Science Reviews, 2018

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Behavioral Ecology, 2021

In response to environmental stimuli, including variation in the presence of conspecifics, genoty... more In response to environmental stimuli, including variation in the presence of conspecifics, genotypes show highly plastic responses in behavioral and physiological traits influencing reproduction. Although extensively documented in males, such female responses are rather less studied. We expect females to be highly responsive to environmental variation and to differentially allocate resources to increase offspring fitness, given the major contribution of mothers to offspring number, size, and developmental conditions. Using Drosophila melanogaster, we (a) manipulate exposure to conspecific females, which mothers could use to anticipate the number of potential mates and larval density, and; (b) test how this interacts with the spatial distribution of potential oviposition sites, with females from higher densities expected to prefer clustered resources that can support a larger number of larvae. We found that high density females were slower to start copulating and reduced their copula...

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Oikos, 2019

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Access microbiology, Mar 1, 2019

Community profiling is one of the most utilised tools in microbial ecology today. The relationshi... more Community profiling is one of the most utilised tools in microbial ecology today. The relationships between microbial communities and their environment affect ecosystem function in fields spanning from medicine to agriculture; and understanding the community dynamics of a microbial community is key to understanding the complex effects of human intervention. In this study, we look at the effects of long-term tillage and fertilization regimes in soils from an agricultural block-designed field trial set up in 2001. By studying the microbial community composition, absolute microbial abundance and diversity of denitrification functional genes in the context of environmental data, we were able to address the question of how specific land management histories affect the diversity and distribution of bacteria and denitrification genes within agricultural soils. It was found that microbial communities appear to be largely unaffected by land management history, and cluster predominantly by spatial location within the field, despite lack of significant environmental variation. In this well-established agricultural field trial, Euclidean distance is the major identifiable determinant of microbial community dissimilarity (as well as dissimilarity in microbial abundance). That ecological drift, rather than physicochemical factors can be the major determinant of genetic potential may have consequences for attempts to understand nutrient availability in agricultural systems. Additionally, the overwhelming variation caused by spatial distance indicates that block designed experiments may not always have sufficient statistical power to identify any effects of human treatment.

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Oxford University Press eBooks, Mar 6, 2008

This chapter considers the signal of local dispersal which sits inside maps of the locations of i... more This chapter considers the signal of local dispersal which sits inside maps of the locations of individuals, and introduces spatial statistics as measures of spatial structure. It shows how dispersal plays a fundamental part in local population dynamics. Dispersal is also shown to have important implications for the outcome of local spatial competition between two species, the dynamics of metapopulations, and the structure of multispecies communities. Local dispersal causes clumping, slows down changes in density, and affects the asymptotic state ultimately achieved by a population. When different species compete, dispersal over greater distances gives a species an advantage which can eliminate competitive coexistence which might otherwise occur. However, in the presence of spatial environmental heterogeneity, where too much dispersal can move offspring away from favourable parts of the environment, dispersal over intermediate distances can allow faster population growth than dispersal over either short or long distances.

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Oxford University Press eBooks, Mar 6, 2008

This chapter discusses traits that determine dispersal of propagules by different vectors. It pay... more This chapter discusses traits that determine dispersal of propagules by different vectors. It pays special attention to dispersal by air, water, animals, and humans, since these vectors have received the greatest attention in scientific literature. It is clear from morphological and chemical traits that many species have evolved an enhanced ability to be dispersed by particular vectors. However, propagules may be moved by a number of vectors, both physical and biological. There is variation in these traits between species, between and within populations, and among propagules on the same plant. Mass, volume, and area determine the propensity of any propagule to be moved in air and water. Dispersal on the outside of animals is correlated with propagule shape, mass, and adhesive ability, while size relative to the mouth of the animal and chemical constituents determine which species will be ingested and how long they might be carried.

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Oxford University Press eBooks, Mar 6, 2008

This chapter discusses approaches that have been used to understand how particular shapes and sca... more This chapter discusses approaches that have been used to understand how particular shapes and scales of propagule distributions arise around a parent plant. It begins by contrasting two different methods of collecting dispersal data and two fundamentally different ways of presenting the results. It is shown that the frequency distribution of dispersal distance approaches zero at the source, increases to one (or more) maximum, and declines rapidly to a long tail. In contrast, the density of the seed rain declines rapidly with distance, being greatest close to the source plant. Examples are given of models that are being developed to predict dispersal by multiple vectors and over the entire dispersal season. The chapter concludes with a discussion of research methodologies, since these are critical to the success of future empirical research.

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Oxford University Press eBooks, Mar 6, 2008

Ecologists, both practical and theoretical, now appreciate that to understand biological systems ... more Ecologists, both practical and theoretical, now appreciate that to understand biological systems they must consider the spatial dimension. Consequently, dispersal has become one of the hottest topics in plant ecology. However, in the midst of so much research output on dispersal, there is a need for a stock-take to determine the needs of future research: what has been achieved to date, where do current studies fit in, and what still needs to be determined? What are the implications of dispersal for those engaged in managing plant populations and communities? This is the first book for many years to present a synthesis of research on dispersal and its implications for plant population dynamics. The book consists of three sections: Section A reviews information on the biological and environmental processes that determine the path of an individual dispersing propagule, usually a seed, and the theory that has been developed to predict these trajectories; Section B discusses the distributions of seeds resulting from dispersal from an entire plant, theoretical research predicting the shapes of these distributions and design issues for future dispersal studies; Section C explores the implications of dispersal for expansion of populations, structure within existing populations and communities, and the evolution of dispersal traits.

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This research provides a large scale analysis of evidence previously only available as individual... more This research provides a large scale analysis of evidence previously only available as individual reports which is of significance to an understanding of social changes in the Palaeolithic. It also highlights why healthcare provisioning should be considered as a key evolutionary adaptation and so is of interest and importance to those studying cognitive, biological and anatomical changes. We are increasingly recognising many complex ways in which the ecological, social, cognitive and anatomical elements of our human evolutionary past interact and influence each other. One relatively new area of this type of interaction is the potential significance of healthcare provisioning on other realms of human evolution and behaviour. Evidence from skeletal remains for care has traditionally been considered to be subject to some debate. However, whilst precise interpretations remain open to discussion, widespread evidence for healthcare in Palaeolithic contexts is now widely accepted [1] [2] [3]. Healthcare practices are significant in several ways, such as by changing the profile of how injuries impact both group subsistence and individual survival, as well as having a profound impact of social relationships. Here we explore this issue through the interpretation of a large scale survey of evidence for care practices in early, archaic and modern humans. We consider the ecologica l basis for care for the ill and injured, how such care changes through time and in different contexts, the role of care practices in group survival, and the potential influence of increasingly sophisticated medical knowledge on care. Although healthcare provisioning has typically been seen in purely cultural terms, we argue that it is not only a significant and often overlooked element of social relationships throughout the Palaeolithic but is also of evolutionary significance. While other animals provision the ill and injured, none go to such lengths or with such competency as seen in archaic humans, as recent research has started to highlight [4] [5]. Healthcare practices in such groups are likely to have included not only provision of food and water and protection from predators, but also a knowledgeable approach to promoting wound healing and recovery from severe injury. We argue this adaptation was an important part of hominin sociality and may have become especially importan t to humans that were trying to survive in hostile environments. Bastir, M. Pulling faces. Nat Ecol Evol (2018). Comment on Godinho, R. M., Spikins, P., & O’Higgins, P. (2018). Supraorbital morphology and social dynamics in human evolution. Nature ecology & evolution, doi:10.1038/s41559-018-0528-0 Trinkaus, E. & Villotte, S. External auditory exostoses and hearing loss in the Shanidar 1 Neandertal. (2017) PLoS One 12, e0186684. Thorpe, N. 2016. The Palaeolithic Compassion Debate--Alternative Projections of Modern-Day Disability into the Distant Past. In Care in the Past: Archaeological and Interdisciplinary Perspectives, edited by L. Powell, W. Southwell-Wright, and R. Gowland, 93–109. Oxford: Oxbow Books. Spikins, P., Needham, A., Tilley, L. & Hitchens, G. Calculated or caring? Neanderthal healthcare in social context. (2018).World Archaeology. DOI: 10.1080/00438243.2018.1433060 Tilley, L. (2015) Care Among the Neandertals: La Chapelle-aux-Saints 1 and La Ferrassie 1 (Case Study 2). in Theory and Practice in the Bioarchaeology of Care 219–257 (Springer International Publishing, 2015).

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Current Biology, Nov 1, 2019

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Oxford University Press eBooks, Mar 6, 2008

This chapter considers aspects of the maternal parent, other than the tissues immediately around ... more This chapter considers aspects of the maternal parent, other than the tissues immediately around the seed, which contribute to the distances dispersed by plant propagules. It shows how plant phenotype, the abiotic environment, competition, and herbivory all help to determine where the trajectories of propagules begin. Plant phenology dictates when the force required separating the propagule from its parent is at a minimum, and therefore when the trajectory is likely to begin. This can be critical for the survival of animal vectors as well as for movement of seeds contained in fruits. In some cases, the parent provides an additional force to launch the propagule away from its parent.

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Bookmarks Related papers MentionsView impact

Journal of the Marine Biological Association of the United Kingdom, May 1, 1996

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Environmental Microbiology, 2021

Denitrification causes loss of available nitrogen from soil systems, thereby reducing crop produc... more Denitrification causes loss of available nitrogen from soil systems, thereby reducing crop productivity and increasing reliance on agrochemicals. The dynamics of denitrification and denitrifying communities are thought to be altered by land management practices, which affect the physicochemical properties of the soil. In this study, we look at the effects of long-term tillage and fertilization regimes on arable soils following 16 years of treatment in a factorial field trial. By studying the bacterial community composition based on 16S rRNA amplicons, absolute bacterial abundance and diversity of denitrification functional genes (nirK, nirS and nosZ), under conditions of minimum/conventional tillage and organic/synthetic mineral fertilizer, we tested how specific land management histories affect the diversity and distribution of both bacteria and denitrification genes. Bacterial and denitrifier communities were largely unaffected by land management history and clustered predominantly by spatial location, indicating that the variability in bacterial community composition in these arable soils is governed by innate environmental differences and Euclidean distance rather than agricultural management intervention. This article is protected by copyright. All rights reserved.

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In response to environmental stimuli, including variation in the presence of conspecifics, animal... more In response to environmental stimuli, including variation in the presence of conspecifics, animals show highly plastic responses in behavioural and physiological traits influencing reproduction. These responses have been extensively documented in males, but equivalent study of females is so far lacking. We expect females to be highly responsive to environmental variation, with significant impacts on fitness given females’ direct impact on offspring number, size, and developmental conditions. Using Drosophila melanogaster as a model, we manipulate (a) exposure to conspecific females, expected to influence their expectation of number of potential mates and larval density for their own offspring, and (b) test how prior consexual population density interacts with the spatial distribution of potential oviposition sites, with females expected to prefer clustered food resources that can support a larger number of eggs and larvae. After exposure to competition, females were slower to start ...

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Nature Communications, 2019

Advances in phenology (the annual timing of species’ life-cycles) in response to climate change a... more Advances in phenology (the annual timing of species’ life-cycles) in response to climate change are generally viewed as bioindicators of climate change, but have not been considered as predictors of range expansions. Here, we show that phenology advances combine with the number of reproductive cycles per year (voltinism) to shape abundance and distribution trends in 130 species of British Lepidoptera, in response to ~0.5 °C spring-temperature warming between 1995 and 2014. Early adult emergence in warm years resulted in increased within- and between-year population growth for species with multiple reproductive cycles per year (n = 39 multivoltine species). By contrast, early emergence had neutral or negative consequences for species with a single annual reproductive cycle (n = 91 univoltine species), depending on habitat specialisation. We conclude that phenology advances facilitate polewards range expansions in species exhibiting plasticity for both phenology and voltinism, but may...

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Biological Reviews, 2018

ABSTRACTIncreasingly imperative objectives in ecology are to understand and forecast population d... more ABSTRACTIncreasingly imperative objectives in ecology are to understand and forecast population dynamic and evolutionary responses to seasonal environmental variation and change. Such population and evolutionary dynamics result from immediate and lagged responses of all key life‐history traits, and resulting demographic rates that affect population growth rate, to seasonal environmental conditions and population density. However, existing population dynamic and eco‐evolutionary theory and models have not yet fully encompassed within‐individual and among‐individual variation, covariation, structure and heterogeneity, and ongoing evolution, in a critical life‐history trait that allows individuals to respond to seasonal environmental conditions: seasonal migration. Meanwhile, empirical studies aided by new animal‐tracking technologies are increasingly demonstrating substantial within‐population variation in the occurrence and form of migration versus year‐round residence, generating di...

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Http Www Libreriasaulamedica Com, 2003

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Dispersal in Plants, 2008

This chapter considers the signal of local dispersal which sits inside maps of the locations of i... more This chapter considers the signal of local dispersal which sits inside maps of the locations of individuals, and introduces spatial statistics as measures of spatial structure. It shows how dispersal plays a fundamental part in local population dynamics. Dispersal is also shown to have important implications for the outcome of local spatial competition between two species, the dynamics of metapopulations, and the structure of multispecies communities. Local dispersal causes clumping, slows down changes in density, and affects the asymptotic state ultimately achieved by a population. When different species compete, dispersal over greater distances gives a species an advantage which can eliminate competitive coexistence which might otherwise occur. However, in the presence of spatial environmental heterogeneity, where too much dispersal can move offspring away from favourable parts of the environment, dispersal over intermediate distances can allow faster population growth than disper...

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Dispersal in Plants, 2008

This chapter provides both a flavour of, and some insight into, the evolutionary forces at work s... more This chapter provides both a flavour of, and some insight into, the evolutionary forces at work shaping the amazing diversity of dispersal strategies seen in plants. For all plants, there is a tension between the advantages of a sedentary or short-distance dispersal strategy and those of a more dispersive one. The selective forces that act to increase or decrease evolved dispersal rates or distances are reviewed. The dispersal strategy adopted by a plant species is clearly shaped by a long history of interacting and competing forces. The relative strengths of these forces will inevitably wax and wane, and the interactions between them shift to change the overall selective pressure to disperse.

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Quaternary Science Reviews, 2018

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Behavioral Ecology, 2021

In response to environmental stimuli, including variation in the presence of conspecifics, genoty... more In response to environmental stimuli, including variation in the presence of conspecifics, genotypes show highly plastic responses in behavioral and physiological traits influencing reproduction. Although extensively documented in males, such female responses are rather less studied. We expect females to be highly responsive to environmental variation and to differentially allocate resources to increase offspring fitness, given the major contribution of mothers to offspring number, size, and developmental conditions. Using Drosophila melanogaster, we (a) manipulate exposure to conspecific females, which mothers could use to anticipate the number of potential mates and larval density, and; (b) test how this interacts with the spatial distribution of potential oviposition sites, with females from higher densities expected to prefer clustered resources that can support a larger number of larvae. We found that high density females were slower to start copulating and reduced their copula...

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Oikos, 2019

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