• Accounting for interspecific competition and age structure in demographic analyses of density dependence improves predictions of fluctuations in population size 

      Gamelon, Marlène; Vriend, Stefan; Engen, Steinar; Adriaensen, Frank; Dhondt, A.A.; Evans, Simon R.; Matthysen, Erik; Sheldon, Ben C.; Sæther, Bernt-Erik (Peer reviewed; Journal article, 2019)
      Understanding species coexistence has long been a major goal of ecology. Coexistence theory for two competing species posits that intraspecific density dependence should be stronger than interspecific density dependence. ...
    • An integrated population model for a long-lived ungulate: more efficient data use with Bayesian methods 

      Lee, Aline Magdalena; Bjørkvoll, Eirin Marie; Hansen, Brage Bremset; Albon, Steve D.; Stien, Audun; Sæther, Bernt-Erik; Engen, Steinar; Veiberg, Vebjørn; Loe, Leif Egil; Grøtan, Vidar (Journal article, 2015)
      We develop an integrated population model for Svalbard reindeer Rangifer tarandus platyrhynchus, and demonstrate how this type of model can be used to extract more information from the data and separate different sources ...
    • Characteristics of temporal changes in communities where dynamics differ between species 

      Solbu, Erik Blystad; Engen, Steinar; Diserud, Ola Håvard (Journal article; Peer reviewed, 2016)
      Communities with different phenotypic variation among species can have identical species abundance distributions, although their temporal dynamics may be very different. By using stochastic species abundance models, both ...
    • Consequences of barriers and changing seasonality on population dynamics and harvest of migratory ungulates 

      Van Moorter, Bram; Engen, Steinar; Fryxell, John M.; Panzacchi, Manuela; Nilsen, Erlend Birkeland; Mysterud, Atle (Peer reviewed; Journal article, 2020)
      Many animal populations providing ecosystem services, including harvest, live in seasonal environments and migrate between seasonally distinct ranges. Unfortunately, two major sources of human-induced global change threaten ...
    • Decomposing demographic contributions to the effective population size with moose as a case study 

      Lee, Aline Magdalena; Svalheim Markussen, Stine; Engen, Steinar; Solberg, Erling Johan; Haanes, Hallvard; Røed, Knut H.; Herfindal, Ivar; Heim, Morten; Sæther, Bernt-Erik (Journal article; Peer reviewed, 2020)
      Levels of random genetic drift are influenced by demographic factors, such as mating system, sex ratio and age structure. The effective population size (Ne) is a useful measure for quantifying genetic drift. Evaluating ...
    • Decomposing demographic contributions to the effective population size with moose as a case study 

      Lee, Aline Magdalena; Myhre, Ane Marlene; Markussen, Stine Svalheim; Engen, Steinar; Solberg, Erling Johan; Haanes, Hallvard; Røed, Knut; Herfindal, Ivar; Heim, Morten; Sæther, Bernt-Erik (Peer reviewed; Journal article, 2020)
      Levels of random genetic drift are influenced by demographic factors, such as mating system, sex ratio and age structure. The effective population size (N e) is a useful measure for quantifying genetic drift. Evaluating ...
    • Demographic buffering of life histories? Implications of the choice of measurement scale 

      Bjørkvoll, Eirin Marie; Lee, Aline Magdalena; Grøtan, Vidar; Sæther, Bernt-Erik; Stien, Audun; Engen, Steinar; Albon, Steve D.; Loe, Leif Egil; Hansen, Brage Bremset (Journal article; Peer reviewed, 2016)
      Life-history theory predicts that the vital rates that influence population growth the most should be buffered against environmental fluctuations due to selection for reduced variation. However, it remains unclear whether ...
    • Demographic routes to variability and regulation in bird populations 

      Sæther, Bernt-Erik; Grøtan, Vidar; Engen, Steinar; Coulson, Tim; Grant, Peter R.; Visser, Marcel E.; Brommer, Jon E.; Grant, B. Rosemary; Gustafsson, Lars; Hatchwell, Ben J.; Jerstad, Kurt; Karell, Patrik; Pietiäinen, Hannu; Roulin, Alexandre; Røstad, Ole Wiggo; Weimerskirch, Henri (Journal article; Peer reviewed, 2016)
      There is large interspecific variation in the magnitude of population fluctuations, even among closely related species. The factors generating this variation are not well understood, primarily because of the challenges ...
    • Ecological dynamics and large scale phenotypic differentiation in density-dependent populations 

      Engen, Steinar; Sæther, Bernt-Erik (Journal article; Peer reviewed, 2019)
      Spatial differentiation of phenotypes is assumed to be determined by a combination of fluctuating selection producing adaptations to the local environment and a homogenizing effect of migration. We present a model with ...
    • Effective size of density dependent populations in fluctuating environments 

      Myhre, Ane Marlene (Doctoral theses at NTNU;2017:156, Doctoral thesis, 2017)
      Knowledge of the effective size of populations, Ne, and the ratio of effective population size to the size of the mature population Ne/N, provide important information of the genetic diversity and fitness of populations. ...
    • Harvest-induced phenotypic selection in an island population of moose, Alces alces 

      Kvalnes, Thomas; Sæther, Bernt-Erik; Haanes, Hallvard; Røed, Knut; Engen, Steinar; Solberg, Erling Johan (Journal article; Peer reviewed, 2016)
      Empirical evidence strongly indicates that human exploitation has frequently led to rapid evolutionary changes in wild populations, yet the mechanisms involved are often poorly understood. Here, we applied a recently ...
    • Heterogeneity among species and community dynamics – Norwegian bird communities as a case study 

      Solbu, Erik Blystad; Diserud, Ola Håvard; Kålås, John Atle; Engen, Steinar (Journal article; Peer reviewed, 2018)
      We have in this study analysed bird communities across Norway with a heterogeneous species abundance model, where dynamical parameters can vary among species. Similarity in community composition over time, used as a measure ...
    • Interactions between demography and environmental effects are important determinants of population dynamics 

      Gamelon, Marlène; Grøtan, Vidar; Nilsson, Anna L. K.; Engen, Steinar; Hurrell, James W.; Jerstad, Kurt; Phillips, Adam S.; Røstad, Ole Wiggo; Slagsvold, Tore; Walseng, Bjørn; Stenseth, Nils Christian; Sæther, Bernt-Erik (Journal article; Peer reviewed, 2017)
      Climate change will affect the population dynamics of many species, yet the consequences for the long-term persistence of populations are poorly understood. A major reason for this is that density-dependent feedback effects ...
    • Interactions between demography and environmental effects are important determinants of population dynamics 

      Gamelon, Marlène; Grøtan, Vidar; Nilsson, Anna; Engen, Steinar; Hurrell, James W.; Jerstad, Kurt; Phillips, Adam S.; Røstad, Ole Wiggo; Slagsvold, Tore; Walseng, Bjørn; Stenseth, Nils Christian; Sæther, Bernt-Erik (Journal article; Peer reviewed, 2017)
      Climate change will affect the population dynamics of many species, yet the consequences for the long-term persistence of populations are poorly understood. A major reason for this is that density-dependent feedback effects ...
    • Reversal of response to artificial selection on body size in a wild passerine bird 

      Kvalnes, Thomas; Ringsby, Thor Harald; Jensen, Henrik; Hagen, Ingerid Julie; Rønning, Bernt; Pärn, Henrik; Holand, Håkon; Engen, Steinar; Sæther, Bernt-Erik (Journal article, 2017)
      A general assumption in quantitative genetics is the existence of an intermediate phenotype with higher mean individual fitness in the average environment than more extreme phenotypes. Here we investigate the evolvability ...
    • Spatial covariation of competing species in a fluctuating environment 

      Lee, Aline Magdalena; Sæther, Bernt-Erik; Engen, Steinar (Journal article; Peer reviewed, 2020)
      Understanding how stochastic fluctuations in the environment influence population dynamics is crucial for sustainable management of biological diversity. However, because species do not live in isolation, this requires ...
    • Spatial scales of population synchrony in predator-prey systems 

      Jarillo, Javier Diaz; Sæther, Bernt-Erik; Engen, Steinar; Cao-Garcia, Francisco (Peer reviewed; Journal article, 2020)
      Many species show synchronous fluctuations in population size over large geographical areas, which are likely to increase their regional extinction risk. Here we examine how the degree of spatial synchrony in population ...
    • Temporal changes in parameters describing stochastic population dynamics 

      Solbu, Erik Blystad (Master thesis, 2011)
      The solution of a stochastic differential equation with temporally dependent parameters is the basis for the following analysis of stochastic population dynamics with temporal changes in the parameters. A discrete density ...
    • Towards a predictive conservation biology: the devil is in the behaviour 

      Sæther, Bernt-Erik; Engen, Steinar (Peer reviewed; Journal article, 2019)
      One of the most important challenges in conservation biology is to predict the viability of populations of vulnerable and threatened species. This requires that the demographic stochasticity strongly affecting the ecological ...