NCEAS Project 8141

Stochastic demography for an increasingly variable world

  • William F. Morris
  • Catherine A. Pfister
  • Shripad Tuljapurkar

ActivityDatesFurther Information
Working Group18th—22nd April 2004Participant List  
Working Group6th—10th October 2004Participant List  
Working Group4th—8th March 2005Participant List  
Working Group6th—9th November 2005Participant List  

Members Only Area

Both the means and the variances of such important environmental variables as growing-season temperature and rainfall are projected to increase in many regions over the 21st century. While effects on organisms of changes in mean conditions have often been anticipated, the potential effects of increasing variability have been relatively neglected. We propose a Stochastic Demography Working Group to assess how increasing environmental variability is likely to impact populations of plants and animals. Using unpublished demographic data for a diverse set of taxa and new theoretical tools developed by group members, we will compare the effects of changes in the means vs. the variances of environmental variables, as well as the pattern of sensitivity to environmental variability across species, life histories, and habitats. In addition, we will ask whether the demographic processes that most influence population growth are the least sensitive to environmental variation, a pattern that has been observed in the relatively small number of species previously tested and that would serve to buffer populations against increasing environmental variability. Our ultimate goal is to improve the ability of ecologists to forecast the consequences for the long-term viability of populations of not only overall trends in environmental conditions but also expected changes in year-to-year variability.

TypeProducts of NCEAS Research
Journal Article Boyce, Mark; Haridas, Chirakkal V.; Lee, Charlotte; Boggs, Carol; Bruna, Emilio M.; Coulson, Tim; Doak, Daniel F.; Drake, John M.; Gaillard, Jean-Michel; Horvitz, Carol C.; Kalisz, Susan; Kendall, Bruce E.; Knight, Tiffany M.; Mastrandrea, Michael Dechen; Menges, Eric S.; Morris, William F.; Pfister, Catherine A.; Tuljapurkar, Shripad. 2006. Demography in an increasingly variable world. Trends in Ecology & Evolution. Vol: 21(3). Pages 141-148.
Data Set Horvitz, Carol C. 2006. Calathea ovandensis demography data. (Abstract) (Online version)
Data Set Koop, A. L. 2006. Ardisia elliptica (invasive exotic) demography in Florida: Light and moisture dependence. (Online version)
Journal Article McLoughlin, Philip D.; Boyce, Mark; Coulson, Tim; Clutton-Brock, Tim. 2006. Lifetime reproductive success and density-dependent multi-variable resource selection. Proceedings of the Royal Society B-Biological Sciences. Vol: 273. Pages 1449-1454.
Journal Article McLoughlin, Philip D.; Gaillard, Jean-Michel; Bonenfant, C.; Messier, F.; Duncan, P.; Delorme, D.; Van Moorter, B.; Said, S.; Klein, F. 2007. Lifetime reproductive success and composition of the home range in a large herbivore. Ecology. Vol: 88(12). Pages 3192-3201.
Journal Article McLoughlin, Philip D.; Coulson, Tim; Clutton-Brock, Tim. 2008. Cross-generational effects of habitat and density on life history in red deer. Ecology. Vol: 89(12). Pages 3317-3326. (Online version)
Presentations Morris, William F. 2005. Population consequences of increasing climatic variability, 11 March 2005. Biology Department, University of Montana.
Journal Article Morris, William F.; Pfister, Catherine A.; Tuljapurkar, Shripad; Haridas, Chirakkal V.; Boggs, Carol; Boyce, Mark; Bruna, Emilio M.; Church, Don R.; Coulson, Tim; Doak, Daniel F.; Forsyth, Stacey; Gaillard, Jean-Michel; Horvitz, Carol C.; Kalisz, Susan; Kendall, Bruce E.; Knight, Tiffany M.; Lee, Charlotte; Menges, Eric S. 2008. Longevity can buffer plant and animal populations against changing climatic variability. Ecology. Vol: 89(1). Ecological Society of America. Pages 19-25.
Data Set Pascarella, John. 2006. Hurricane related demography of Ardisia escallonioides (FL) . (Abstract) (Online version)