Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 818
Title: Improved viability of populations with diverse life history portfolios
Author: Correigh M. Greene, J. Hall, K. Guilbault, T. P. Quinn
Publication Year: 2009
Journal: Biology Letters
Volume: 6
Issue: 3
Pages: 382-386
Keywords: Biocomplexity, life history diversity

A principle shared by both economists and ecologists is that a diversified portfolio spreads risk, but this idea has little empirical support in the field of population biology. We found that population growth rates (recruits per spawner) and life history diversity as measured by variation in freshwater and ocean residency were negatively correlated across short time periods (one to two generations), but positively correlated at longer time periods, in nine Bristol Bay sockeye salmon populations. Further, the relationship between variation in growth rate and life history diversity was consistently negative. These findings strongly suggest that life history diversity can both increase production and buffer population fluctuations, particularly over long time periods. Our findings provide new insights into the importance of biocomplexity beyond spatio-temporal aspects of populations, and suggest that maintaining diverse life history portfolios of populations may be crucial for their resilience to unfavourable conditions like habitat loss and climate change.

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