Oecologia

, Volume 161, Issue 4, pp 685–695

Geographical variation in the influence of density dependence and climate on the recruitment of Norwegian moose

  • Vidar Grøtan
  • Bernt-Erik Sæther
  • Magnar Lillegård
  • Erling J. Solberg
  • Steinar Engen
Terrestrial Vertebrate Ecology - Original Paper

DOI: 10.1007/s00442-009-1419-5

Cite this article as:
Grøtan, V., Sæther, BE., Lillegård, M. et al. Oecologia (2009) 161: 685. doi:10.1007/s00442-009-1419-5

Abstract

The effects of variation in climate on population dynamics are likely to differ within the distributional range of a species, yet the consequences of such regional variation on demography and population dynamics are rarely considered. Here we examine how density dependence and different climate variables affect spatio-temporal variation in recruitment rates of Norwegian moose using data collected over a large geographical area during the hunting season. After accounting for observation error by a Bayesian Markov chain Monte Carlo technique, temporal variation in recruitment rates was relatively independent of fluctuations in local population size. In fact, a positive relationship was as common as a density-dependent decrease in fecundity rates. In general, high recruitment rates were found during autumn 1 year after years with a warm February, and after a warm May or cold June in year t − 1 or in year t. Large regional variation was also found in the effects of some of the weather variables, especially during spring. 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.

Keywords

Alces alcesDensity dependenceEnvironmental stochasticityGeographical demographic variationStochastic population dynamics

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Vidar Grøtan
    • 1
  • Bernt-Erik Sæther
    • 1
  • Magnar Lillegård
    • 2
  • Erling J. Solberg
    • 3
  • Steinar Engen
    • 2
  1. 1.Department of Biology, Centre for Conservation BiologyNorwegian University of Science and TechnologyTrondheimNorway
  2. 2.Department of Mathematical Sciences, Centre for Conservation BiologyNorwegian University of Science and TechnologyTrondheimNorway
  3. 3.Norwegian Institute for Nature ResearchTrondheimNorway