Stochastic variation in avian survival rates: Life-history predictions, population consequences, and the potential responses to human perturbations and climate change

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Edited by: David L. ThomsonEvan G. Cooch, and Michael J. Conroy

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Abstract

Stochastic variation in survival rates is expected to decrease long-term population growth rates. This expectation influences both life-history theory and the conservation of species. From this expectation, Pfister (1998) developed the important life-history prediction that natural selection will have minimized variability in those elements of the annual life cycle (such as adult survival rate) with high sensitivity. This prediction has not been rigorously evaluated for bird populations, in part due to statistical difficulties related to variance estimation. I here overcome these difficulties, and in an analysis of 62 populations, I confirm her prediction by showing a negative relationship between the proportional sensitivity (elasticity) of adult survival and the proportional variance (CV) of adult survival. However, several species deviated significantly from this expectation, with more process variance in survival than predicted. For instance, projecting the magnitude of process variance in annual survival for American redstarts (Setophaga ruticilla) for 25 years resulted in a 44% decline in abundance without assuming any change in mean survival rate. For most of these species with high process variance, recent changes in harvest, habitats, or changes in climate patterns are the likely sources of environmental variability causing this variability in survival. Because of climate change, environmental variability is increasing on regional and global scales, which is expected to increase stochasticity in vital rates of species. Increased stochasticity in survival will depress population growth rates, and this result will magnify the conservation challenges we face.

Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Stochastic variation in avian survival rates: Life-history predictions, population consequences, and the potential responses to human perturbations and climate change
ISBN 978-0-387-78150-1
DOI 10.1007/978-0-387-78151-8_19
Volume 3
Year Published 2009
Language English
Publisher Springer
Publisher location Boston, MA
Contributing office(s) Alaska Science Center
Description 21 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Modeling demographic processes in marked populations
First page 441
Last page 461