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Testing life history predictions in a long-lived seabird: a population matrix approach with improved parameter estimation

Oikos

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, , , , , , and

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Abstract

Life history theory and associated empirical generalizations predict that population growth rate (lambda) in long-lived animals should be most sensitive to adult survival; the rates to which lambda is most sensitive should be those with the smallest temporal variances; and stochastic environmental events should most affect the rates to which lambda is least sensitive. To date, most analyses attempting to examine these predictions have been inadequate, their validity being called into question by problems in estimating parameters, problems in estimating the variability of parameters, and problems in measuring population sensitivities to parameters. We use improved methodologies in these three areas and test these life-history predictions in a population of red-tailed tropicbirds (Phaethon rubricauda). We support our first prediction that lambda is most sensitive to survival rates. However the support for the second prediction that these rates have the smallest temporal variance was equivocal. Previous support for the second prediction may be an artifact of a high survival estimate near the upper boundary of 1 and not a result of natural selection canalizing variances alone. We did not support our third prediction that effects of environmental stochasticity (El Ni?o) would most likely be detected in vital rates to which lambda was least sensitive and which are thought to have high temporal variances. Comparative data-sets on other seabirds, within and among orders, and in other locations, are needed to understand these environmental effects.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Testing life history predictions in a long-lived seabird: a population matrix approach with improved parameter estimation
Series title:
Oikos
Volume
105
Issue:
3
Year Published:
2004
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
606-618
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Oikos
First page:
606
Last page:
618
Number of Pages:
13