Spatial heterogeneity contributes more to portfolio effects than species variability in bottom-associated marine fishes.

ABSTRACT: Variance of community abundance will be reduced relative to its theoretical maximum whenever population densities fluctuate asynchronously. Fishing communities and mobile predators can switch among fish species and/or fishing locations with asynchronous dynamics, thereby buffering against variable resource densities (termed 'portfolio effects', PEs). However, whether variation among species or locations represent the dominant contributor to PE remains relatively unexplored. Here, we apply a spatio-temporal model to multidecadal time series (1982-2015) for 20 bottom-associated fishes in seven marine ecosystems. For each ecosystem, we compute the reduction in variance over time in total biomass relative to its theoretical maximum if species and locations were perfectly correlated (total PE).

SUBMITTER: Thorson JT 

PROVIDER: S-EPMC6191698 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature