Biodiversity conservation efforts often focus on preventing loss of species or ecological communities. But increasing attention is being focused on the importance of diversity below the species level, for example, between populations within a species. A new study published in the journal Conservation Letters uses economic portfolio theory to analyze data from salmon stocks in Idaho’s Snake River and Alaska’s Bristol Bay. The Idaho populations, which are heavily impacted by dams and habitat modification, were found to resemble a portfolio whose assets were highly synchronized, while the diversity among the less-impacted Alaska populations made them resemble the ideal well-balanced stock portfolio that provides constant returns over time. ‘Returns’ can be either a sustainable fishery without boom-and-bust cycles, or lower extinction risk in unharvested stocks. This lesson applies to terrestrial species as well, where inter-population diversity could aid retention of the potential to adapt to changing climates and other ecological dynamics. Although the paper’s theme is intuitive, the new methods the authors apply could help increase consideration of the value of biodiversity by policymakers.
Full article is here