Changing Feeding Levels Reveal Plasticity in Elasmobranch Life History Strategies

Life history strategies are shaped by phylogeny, environmental conditions and individual energy budgets, and have implications for conservation biology. We summarised life history traits of 151 elasmobranch species into life history strategies for two contrasting feeding levels, representing two different environments, in a principal components analysis. Two axes, reproductive output and generation turnover, structure elasmobranch life history strategies. Species' positions in this life history space were not fixed but shifted to higher reproductive output when feeding level increased. We also found that both axes predicted population performance, but that population growth rate does not necessarily inform on a species' demographic resilience. Finally, neither axis predicted IUCN conservation status. Our analyses reveal plasticity in species life history strategies and warn against extrapolating the life history strategy framework from one environment to another when predicting a species' response to (climate) change, perturbations, and (over)exploitation.