Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, WA 98112, USA.
Biol Lett. 2010 Jun 23;6(3):382-6. doi: 10.1098/rsbl.2009.0780. Epub 2009 Dec 9.
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.
经济学家和生态学家都认同一个原则，即多元化的投资组合可以分散风险，但这一理念在种群生物学领域几乎没有经验支持。我们发现，在 9 个布里斯托尔湾红大麻哈鱼种群中，在短时间内（一到两代），种群增长率（每个产卵者的繁殖体数量）和通过淡水和海洋居住变化来衡量的生活史多样性呈负相关，而在较长时间内呈正相关。此外，增长率变化和生活史多样性之间的关系始终是负相关的。这些发现强烈表明，生活史多样性既可以增加产量，又可以缓冲种群波动，特别是在长时间内。我们的研究结果为种群的生物复杂性的重要性提供了新的认识，超越了种群的时空方面，并表明维持种群多样化的生活史组合对于它们适应不利条件（如栖息地丧失和气候变化）的恢复力至关重要。
