The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Hanna Kokko - One of the best experts on this subject based on the ideXlab platform.
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Territorial defense, territory size, and Population Regulation.
The American naturalist, 2005Co-Authors: Andrés López-sepulcre, Hanna KokkoAbstract:Abstract: The carrying capacity of an environment is determined partly by how individuals compete over the available resources. To territorial animals, space is an important resource, leading to conflict over its use. We build a model where the carrying capacity for an organism in a given environment results from the evolution of territorial defense effort and the consequent space use. The same evolutionary process can yield two completely different modes of Population Regulation. Density dependence arises through expanding and shrinking territories if fecundity is low, breeding success increases gradually with territory size, and/or defense is cheap. By contrast, when fecundity is high, breeding success sharply saturates with territory size, and/or defense is costly, we predict fixed territory sizes and Regulation by floaters. These “surplus” individuals form a buffer against Population fluctuations. Yet floaters can also harm breeder performance, and by comparing Population growth of a territorial popul...
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competition for breeding sites and site dependent Population Regulation in a highly colonial seabird the common guillemot uria aalge
Journal of Animal Ecology, 2004Co-Authors: Hanna Kokko, M P Harris, Sarah WanlessAbstract:Summary 1. The hypothesis of site-dependent Population Regulation predicts that birds utilize available nesting sites in a pre-emptive (ideal despotic) manner, leading to density dependence in heterogeneous habitats as poorer sites are used at higher Population densities. At small Population sizes adaptive site choice protects Populations against fluctuations (the buffer effect). 2. Common guillemots Uria aalge (Pontoppidan) breed at high density on sea-cliffs. The Population breeding on the Isle of May, Scotland increased by 60% between 1981 and 2000. A good nest-site is a prerequisite for successful breeding and there is much competition for the best sites. Throughout this period, site use correlated with two measures of site quality, and photographs taken in 1936 show that this pattern has been extremely stable. 3. The data indicate declining quality of sites that remain available as the Population has increased. Site-dependent Regulation was evident in that average breeding success declined over the years, but no declining trend was detected in the best (and most preferred) sites. 4. An individual guillemot generally uses the same nest-site from year to year, but a minority move, usually less than 2 m, between breeding seasons. These movements can be involuntary or voluntary. Involuntarily moving birds that had occupied very good sites before moving often spent several years as non-breeders (floaters) close to their previous site before breeding again, and then occupied poorer sites. Voluntarily moving birds significantly improved their site quality by moving. 5. Birds responded both to the physical site characteristics and to their own experience (breeding failure) when abandoning a site. Their behaviour thus combined aspects of the ‘win-stay, lose-switch’ strategy with direct assessment of site quality. Our data set is inconclusive with respect to the public information hypothesis, i.e. whether birds use conspecific cues of breeding success when settling in a new site.
Richard Mcelreath - One of the best experts on this subject based on the ideXlab platform.
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the importance of life history and Population Regulation for the evolution of social learning
Philosophical Transactions of the Royal Society B, 2020Co-Authors: Dominik Deffner, Richard McelreathAbstract:Social learning and life history interact in human adaptation, but nearly all models of the evolution of social learning omit age structure and Population Regulation. Further progress is hindered b...
Mark A. Beaumont - One of the best experts on this subject based on the ideXlab platform.
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Effects of the Ordering of Natural Selection and Population Regulation Mechanisms on Wright-Fisher Models.
G3 (Bethesda Md.), 2017Co-Authors: Mark A. BeaumontAbstract:We explore the effect of different mechanisms of natural selection on the evolution of Populations for one- and two-locus systems. We compare the effect of viability and fecundity selection in the context of the Wright-Fisher model with selection under the assumption of multiplicative fitness. We show that these two modes of natural selection correspond to different orderings of the processes of Population Regulation and natural selection in the Wright-Fisher model. We find that under the Wright-Fisher model these two different orderings can affect the distribution of trajectories of haplotype frequencies evolving with genetic recombination. However, the difference in the distribution of trajectories is only appreciable when the Population is in significant linkage disequilibrium. We find that as linkage disequilibrium decays the trajectories for the two different models rapidly become indistinguishable. We discuss the significance of these findings in terms of biological examples of viability and fecundity selection, and speculate that the effect may be significant when factors such as gene migration maintain a degree of linkage disequilibrium.
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Effects of the Ordering of Natural Selection and Population Regulation Mechanisms on Wright-Fisher Models
2016Co-Authors: Mark A. BeaumontAbstract:The Wright-Fisher model and its extensions are of central importance in Population genetics, and so far, they have formed the basis of most theoretical and applied Population genetic research. In the present work, we explore the effect that the ordering of natural selection and Population Regulation in the life cycle has on the resulting Population dynamics under the Wright-Fisher model, especially for the evolution of one- and two-locus systems. With weak natural selection, the details of how to order natural selection and Population Regulation in the life cycle do not matter in the Wright-Fisher model and its diffusion approximation. By contrast, we show that when there is strong natural selection and the Population is in linkage disequilibrium, there can be appreciable differences in the resulting Population dynamics under the Wright-Fisher model, depending on whether natural selection occurs before or after Population Regulation in the life cycle. We argue that this effect may be of significance in natural Populations subject to gene migration and local selection.
Dominik Deffner - One of the best experts on this subject based on the ideXlab platform.
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the importance of life history and Population Regulation for the evolution of social learning
Philosophical Transactions of the Royal Society B, 2020Co-Authors: Dominik Deffner, Richard McelreathAbstract:Social learning and life history interact in human adaptation, but nearly all models of the evolution of social learning omit age structure and Population Regulation. Further progress is hindered b...
Heikki Henttonen - One of the best experts on this subject based on the ideXlab platform.
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Multiannual Vole Cycles and Population Regulation during Long Winters: An Analysis of Seasonal Density Dependence.
The American naturalist, 1999Co-Authors: Thomas F. Hansen, Nils Chr. Stenseth, Heikki HenttonenAbstract:abstract: The small‐rodent community in northern Fennoscandia shows regular multiannual fluctuations in abundance. We analyze time series of spring and fall abundances covering 44 yr from the vole community at Kilpisjarvi, northern Finnish Lapland, which is dominated by the gray‐sided vole (Clethrionomys rufocanus). Treating spring and fall abundances as variables in a bivariate time‐series model, we study seasonal aspects of Population Regulation and thereby utilize more of the available data than in most previous analyses of rodent fluctuations. The analysis demonstrates substantial density dependence of Population growth during the winter. This includes a strong direct effect of previous fall density and a strong 2‐yr delayed effect of spring density. Population growth during the summer shows evidence of delayed density dependence but is generally weaker than that during the winter season. Winter Regulation appears to be a crucial element in the production of multiannual cycles in this community, and w...