S Engen

Summary

Affiliation: Norwegian University of Science and Technology
Country: Norway

Publications

  1. ncbi request reprint Heterogeneous communities with lognormal species abundance distribution: Species-area curves and sustainability
    Steinar Engen
    Department of Mathematical Sciences, Norwegian University for Science and Technology, N 7491 Trondheim, Norway
    J Theor Biol 249:791-803. 2007
  2. doi request reprint A quantitative genetic model of r- and K-selection in a fluctuating population
    Steinar Engen
    Center for Biodiversity Dynamics, Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Am Nat 181:725-36. 2013
  3. doi request reprint Evolution of a plastic quantitative trait in an age-structured population in a fluctuating environment
    Steinar Engen
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University of Science and Technology, NO 7491 Trondheim, Norway
    Evolution 65:2893-906. 2011
  4. ncbi request reprint A general model for analyzing Taylor's spatial scaling laws
    Steinar Engen
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University for Science and Technology, N 7491 Trondheim, Norway
    Ecology 89:2612-22. 2008
  5. ncbi request reprint Stochastic growth and extinction in a spatial geometric Brownian population model with migration and correlated noise
    Steinar Engen
    Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Math Biosci 209:240-55. 2007
  6. ncbi request reprint Heterogeneity in dynamic species abundance models: the selective effect of extinction processes
    Steinar Engen
    Department of Mathematical Sciences, Norwegian University for Science and Technology, N 7491, Trondheim, Norway
    Math Biosci 210:490-507. 2007
  7. ncbi request reprint Effective size of fluctuating populations with two sexes and overlapping generations
    Steinar Engen
    Population Biology Center, Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Evolution 61:1873-85. 2007
  8. doi request reprint Fixation probability of beneficial mutations in a fluctuating population
    Steinar Engen
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Genet Res (Camb) 91:73-82. 2009
  9. doi request reprint Reproductive value and the stochastic demography of age-structured populations
    Steinar Engen
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Am Nat 174:795-804. 2009
  10. doi request reprint Estimating the ratio of effective to actual size of an age-structured population from individual demographic data
    Steinar Engen
    Department of Mathematical Sciences, Centre for Conservation Biology, Norwegian University of Science and Technology, Trondheim, Norway
    J Evol Biol 23:1148-58. 2010

Detail Information

Publications41

  1. ncbi request reprint Heterogeneous communities with lognormal species abundance distribution: Species-area curves and sustainability
    Steinar Engen
    Department of Mathematical Sciences, Norwegian University for Science and Technology, N 7491 Trondheim, Norway
    J Theor Biol 249:791-803. 2007
    ..The method is exemplified by analyzing three simulated data sets...
  2. doi request reprint A quantitative genetic model of r- and K-selection in a fluctuating population
    Steinar Engen
    Center for Biodiversity Dynamics, Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Am Nat 181:725-36. 2013
    ..For the theta-logistic model of density dependence, evolution tends to maximize the expected value of N(θ)...
  3. doi request reprint Evolution of a plastic quantitative trait in an age-structured population in a fluctuating environment
    Steinar Engen
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University of Science and Technology, NO 7491 Trondheim, Norway
    Evolution 65:2893-906. 2011
    ..The "age-specific selective weights" are related to the stable distribution of reproductive values among age classes. This allows partitioning of the change in the weighted mean character into age-specific components...
  4. ncbi request reprint A general model for analyzing Taylor's spatial scaling laws
    Steinar Engen
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University for Science and Technology, N 7491 Trondheim, Norway
    Ecology 89:2612-22. 2008
    ..We also show how properties of population dynamics in space and time determine this relationship...
  5. ncbi request reprint Stochastic growth and extinction in a spatial geometric Brownian population model with migration and correlated noise
    Steinar Engen
    Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Math Biosci 209:240-55. 2007
    ..However, as the area occupied by the species starts to decrease, the decrease is faster for populations with larger migration...
  6. ncbi request reprint Heterogeneity in dynamic species abundance models: the selective effect of extinction processes
    Steinar Engen
    Department of Mathematical Sciences, Norwegian University for Science and Technology, N 7491, Trondheim, Norway
    Math Biosci 210:490-507. 2007
    ....
  7. ncbi request reprint Effective size of fluctuating populations with two sexes and overlapping generations
    Steinar Engen
    Population Biology Center, Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Evolution 61:1873-85. 2007
    ..This ratio showed large interisland variation because of demographic differences among the populations. Finally, we calculate how N(e) in a growing house sparrow population will change over time...
  8. doi request reprint Fixation probability of beneficial mutations in a fluctuating population
    Steinar Engen
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Genet Res (Camb) 91:73-82. 2009
    ..Effective population size based on harmonic mean population size will therefore underestimate the expected fixation rate of beneficial mutations in fluctuating populations...
  9. doi request reprint Reproductive value and the stochastic demography of age-structured populations
    Steinar Engen
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Am Nat 174:795-804. 2009
    ..The estimates are based on yearly random samples of individual vital rates and require no information about the total population size...
  10. doi request reprint Estimating the ratio of effective to actual size of an age-structured population from individual demographic data
    Steinar Engen
    Department of Mathematical Sciences, Centre for Conservation Biology, Norwegian University of Science and Technology, Trondheim, Norway
    J Evol Biol 23:1148-58. 2010
    ..We also show how to incorporate uncertain paternity...
  11. ncbi request reprint Using reproductive value to estimate key parameters in density-independent age-structured populations
    Steinar Engen
    Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    J Theor Biol 244:308-17. 2007
    ..We illustrate the method by estimating the long-run growth rate and the environmental variance in an exponentially growing population of Bighorn Sheep...
  12. ncbi request reprint Generalizations of the Moran effect explaining spatial synchrony in population fluctuations
    Steinar Engen
    Department of Mathematical Sciences, Norwegian University for Science and Technology, N 7491, Trondheim, Norway
    Am Nat 166:603-12. 2005
    ..These analyses show exactly how spatial environmental covariation can synchronize fluctuations of spatially segregated populations with no interchange of individuals even if the dynamics are nonlinear...
  13. ncbi request reprint A dynamic and spatial model with migration generating the log-Gaussian field of population densities
    S Engen
    Institute for Mathematical Sciences, Norwegian University of Science and Technology, Gløshaugen, N 7491 Trondheim, Norway
    Math Biosci 173:85-102. 2001
    ..The model is generalized to describe communities of species leading to a dynamic and spatial lognormal species abundance model with migration...
  14. ncbi request reprint Extinction in relation to demographic and environmental stochasticity in age-structured models
    Steinar Engen
    Institute for Mathematical Sciences, Norwegian University for Science and Technology, N 7491 Trondheim, Norway
    Math Biosci 195:210-27. 2005
    ..We also compute estimates of the age-specific contributions to the total demographic variance from survival, fecundity and the covariance between survival and fecundity...
  15. pmc Reproductive value and fluctuating selection in an age-structured population
    Steinar Engen
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University of Science and Technology, Trondheim, Norway
    Genetics 183:629-37. 2009
    ..We develop statistical methods for measuring the expected selection on the reproductive value weighted allele frequency in a fluctuating age-structured population...
  16. pmc Effective size of a fluctuating age-structured population
    Steinar Engen
    Department of Mathematical Sciences, Norwegian University of Science and Technology, Trondheim
    Genetics 170:941-54. 2005
    ..A formula for the effective population size over longer time intervals incorporates deterministic growth and environmental stochasticity to account for changes in N...
  17. doi request reprint Geographical variation in the influence of density dependence and climate on the recruitment of Norwegian moose
    Vidar Grøtan
    Department of Biology, Centre for Conservation Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
    Oecologia 161:685-95. 2009
    ..These patterns demonstrate both direct and delayed effects of weather on the recruitment of moose that possibly operate through an effect of body mass on the proportion of the females that sexually mature as 1.5 or 2.5 years old...
  18. doi request reprint Estimating fluctuating selection in age-structured populations
    S Engen
    Department of Mathematical Sciences, Centre for Conservation Biology, Norwegian University of Science and Technology, Trondheim, Norway
    J Evol Biol 25:1487-99. 2012
    ..The method is illustrated by an analysis of age-specific selection in house sparrows on a fitness-related two-dimensional morphological trait, tarsus length and body mass of fledglings...
  19. ncbi request reprint Population dynamical consequences of climate change for a small temperate songbird
    B Saether
    Department of Zoology, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Science 287:854-6. 2000
    ....
  20. pmc Inferring patterns of migration from gene frequencies under equilibrium conditions
    J Tufto
    Norwegian Institute for Nature Research, Trondheim, Norway
    Genetics 144:1911-21. 1996
    ..Possible ecological extensions of the model are discussed...
  21. pmc Analysis of genetic structure and dispersal patterns in a population of sea beet
    J Tufto
    Norwegian Institute for Nature Research, 7005 Trondheim, Norway
    Genetics 149:1975-85. 1998
    ..Finally, we note that the data also appear to contain some information about this ratio...
  22. ncbi request reprint Demographic characteristics and population dynamical patterns of solitary birds
    Bernt Erik Saether
    Department of Zoology, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Science 295:2070-3. 2002
    ..These results suggest that patterns in avian population fluctuations can be predicted from a knowledge of life-history characteristics and/or temporal variation in certain demographic traits...
  23. doi request reprint Fixation of slightly beneficial mutations: effects of life history
    Yngvild Vindenes
    Center for Conservation Biology, Department of Biology, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Evolution 64:1063-75. 2010
    ..The demographic variance also determines what influence population size has on the fixation probability. This model represents a substantial generalization of earlier models, covering a large range of life histories...
  24. doi request reprint Critical parameters for predicting population fluctuations of some British passerines
    Bernt Erik Saether
    Centre for Conservation Biology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
    J Anim Ecol 78:1063-75. 2009
    ..7. These results show that constructing PPI by stochastic simulations may be a useful tool for obtaining reliable population projections...
  25. doi request reprint Influence of soil acidification in southern Norway on the 137Cs exposure of moose?
    Eiliv Steinnes
    Department of Chemistry, Norwegian University of Science and Technology, NO 7491 Trondheim, Norway
    Sci Total Environ 407:3905-8. 2009
    ....
  26. doi request reprint Spatial and temporal variation in the relative contribution of density dependence, climate variation and migration to fluctuations in the size of great tit populations
    Vidar Grøtan
    Department of Biology, Centre for Conservation Biology, Norwegian University of Science and Technology, Trondheim, Norway
    J Anim Ecol 78:447-59. 2009
    ..This effect of environment on the interchange of individuals among populations is important for predicting effects of global climate change on the pattern of population fluctuations...
  27. ncbi request reprint Climate and spatio-temporal variation in the population dynamics of a long distance migrant, the white stork
    Bernt Erik Saether
    Department of Biology, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    J Anim Ecol 75:80-90. 2006
    ..6. Our results illustrate that evaluating the effects of common environmental variables on the spatio-temporal variation in population dynamics require estimates and modelling of their influence on the local dynamics...
  28. ncbi request reprint The extended Moran effect and large-scale synchronous fluctuations in the size of great tit and blue tit populations
    Bernt Erik Saether
    Department of Biology, Norwegian University of Science and Technology, NO 7491 Trondheim, Norway
    J Anim Ecol 76:315-25. 2007
    ....
  29. ncbi request reprint Generation time and temporal scaling of bird population dynamics
    Bernt Erik Saether
    Department of Biology, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Nature 436:99-102. 2005
    ..These results indicate that the relationships between demographic and life-history traits in birds translate into distinct population dynamical patterns that are apparent only on a scale of generations...
  30. ncbi request reprint Demographic characteristics of extinction in a small, insular population of house sparrows in northern Norway
    Thor Harald Ringsby
    Department of Biology, Norwegian University of Science and Technology, N 7491, Trondheim, Norway
    Conserv Biol 20:1761-7. 2006
    ..Our results strongly emphasize the importance of access to data on temporal variation that can be used to parameterize simple population models that allow estimation of critical parameters for credible prediction of time to extinction...
  31. ncbi request reprint Predicting fluctuations of reintroduced ibex populations: the importance of density dependence, environmental stochasticity and uncertain population estimates
    Bernt Erik Saether
    Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
    J Anim Ecol 76:326-36. 2007
    ..Credible population predictions require that this uncertainty is properly quantified...
  32. pmc Climate variation and regional gradients in population dynamics of two hole-nesting passerines
    Bernt Erik Saether
    Department of Biology, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Proc Biol Sci 270:2397-404. 2003
    ..In both species, the effects will be larger in those parts of Europe where large changes in climate are expected...
  33. pmc Pattern of variation in avian population growth rates
    Bernt Erik Saether
    Department of Zoology, Norwegian University of Science and Technology, Realfagsbygget, N 7491 Trondheim, Norway
    Philos Trans R Soc Lond B Biol Sci 357:1185-95. 2002
    ..We illustrate that the concept of population prediction interval can be useful in evaluating the consequences of these uncertainties in the population projections for the choice of management actions...
  34. ncbi request reprint Understanding mating systems: a mathematical model of the pair formation process
    Aline Magdalena Lee
    Centre for Conservation Biology, Department of Biology, Norwegian University of Science and Technology, Realfagsbygget, N 7491 Trondheim, Norway
    Theor Popul Biol 73:112-24. 2008
    ..This emphasizes the importance of using a model of this type to study mating systems, rather than relying solely on the variance in reproductive success as a descriptor of different systems...
  35. ncbi request reprint Estimation of population parameters from aerial counts of North American mallards: a cautionary tale
    Magnar Lillegård
    Centre for Conservation Biology, Department of Mathematical Sciences, Norwegian University of Science and Technology, N 7491 Trondheim, Norway
    Ecol Appl 18:197-207. 2008
    ..Our results underline the importance of reducing the magnitude of sampling error in the design of large-scale monitoring programs of population fluctuations...
  36. doi request reprint Geographical gradients in the population dynamics of North American prairie ducks
    Bernt Erik Saether
    Department of Biology, Centre for Conservation Biology, Norwegian University of Science and Technology, Trondheim, Norway
    J Anim Ecol 77:869-82. 2008
    ..5. These results suggest that future management of these species could be improved by implementing harvest models that account explicitly for spatial variation in density effects and environmental stochasticity on population abundance...
  37. doi request reprint Individual heterogeneity in vital parameters and demographic stochasticity
    Yngvild Vindenes
    Centre for Conservation Biology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
    Am Nat 171:455-67. 2008
    ..Thus, we provide a general theoretical framework for analyzing how individual heterogeneity caused by different biological mechanisms affects fluctuations of especially small populations...
  38. doi request reprint Rarity, life history and scaling of the dynamics in time and space of British birds
    Bernt Erik Saether
    Centre for Conservation Biology, Department of Biology, Norwegian University of Science and Technology, NO 7491 Trondheim, Norway
    J Anim Ecol 80:215-24. 2011
    ..g. due to human activities, key population dynamical characteristics will change because of density-dependent stochastic effects, which in turn are dependent on species-specific life-history characteristics...
  39. pmc Estimating the time to extinction in an island population of song sparrows
    B E Saether
    Department of Zoology, Norwegian University of Science and Technology, Trondheim
    Proc Biol Sci 267:621-6. 2000
    ..This study shows that ignoring uncertainties in population dynamics produces a substantial underestimation of the extinction risk...
  40. ncbi request reprint Effects of climate change and variability on population dynamics in a long-lived shorebird
    Martijn Van de Pol
    Centre for Conservation Biology, Department of Biology, Norwegian University of Science and Technology NTNU, NO 7491 Trondheim, Norway
    Ecology 91:1192-204. 2010
    ..Disturbingly, such data are unavailable for most species of conservation concern...
  41. doi request reprint An efficient multivariate approach for estimating preference when individual observations are dependent
    Steinar Engen
    Department of Mathematical Sciences, Centre for Conservation Biology, Norwegian University for Science and Technology, Trondheim, Norway
    J Anim Ecol 77:958-65. 2008
    ..4. The method is demonstrated using a data set of radio-tagged dispersing juvenile goshawks and their site characteristics, and can be used as a general tool in resource or habitat selection analysis...