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Buffering of life histories against environmental stochasticity: accounting for a spurious correlation between the variabilities of vital rates and their contributions to fitness.

Publication ,  Journal Article
Morris, WF; Doak, DF
Published in: The American naturalist
April 2004

Life-history theory predicts vital rates that on average make large contributions to the annual multiplication rate of a lineage should be highly buffered against environmental variability. This prediction has been tested by looking for a negative correlation between the sensitivities (or elasticities) of the elements in a projection matrix and their variances (or coefficients of variation). Here, we show by constructing random matrices that a spurious negative correlation exists between the sensitivities and variances, and between the elasticities and coefficients of variation, of matrix elements. This spurious correlation arises in part because size transition probabilities, which are bounded by 0 and 1, have a limit to their variability that often does not apply to matrix elements representing reproduction. We advocate an alternative analysis based on the underlying vital rates (not the matrix elements) that accounts for the inherent limit to the variability of zero-to-one vital rates, corrects for sampling variation, and tests for a declining upper limit to variability as a vital rate's fitness contribution increases. Applying this analysis to demographic data from five populations of the alpine cushion plant Silene acaulis, we provide evidence of stronger buffering in the vital rates that most influence fitness.

Duke Scholars

Published In

The American naturalist

DOI

EISSN

1537-5323

ISSN

0003-0147

Publication Date

April 2004

Volume

163

Issue

4

Start / End Page

579 / 590

Related Subject Headings

  • Time Factors
  • Silene
  • Selection, Genetic
  • Population Dynamics
  • Models, Biological
  • Ecosystem
  • Ecology
  • Biological Evolution
  • 31 Biological sciences
  • 06 Biological Sciences
 
Journal cover image

Published In

The American naturalist

DOI

EISSN

1537-5323

ISSN

0003-0147

Publication Date

April 2004

Volume

163

Issue

4

Start / End Page

579 / 590

Related Subject Headings

  • Time Factors
  • Silene
  • Selection, Genetic
  • Population Dynamics
  • Models, Biological
  • Ecosystem
  • Ecology
  • Biological Evolution
  • 31 Biological sciences
  • 06 Biological Sciences