Global warming and other human stressors are changing aquatic systems. These changes take place on a planet with seasonality, and many of the involved stressors and ecological interactions have some level of seasonality to them. Here I will focus on the interplay between the annual- and life-cycle scales. Much of our work is on behaviour and life history trade-offs in zooplankton species that are impacted by body-size dependent and seasonally varying predation risk caused by fish. Environmental changes are impacting these interactions and trade-offs in complex ways, including via changing duration and timing of the seasonal growth period. I present some of our findings and discuss the scope and constraints for adaptations (phenotypic plasticity as well as evolution) in traits such as body size, voltinism, energy storage, and seasonal timing. Responses are typically state-dependent and can depend on life history strategy, such as where on the gradient from income- to capital-breeding a species is placed. Reduced fecundity through capital breeding can then be one of the implications. New selection pressures have the power to restructure annual routines and life cycles. For instance, increasing size-specific predation risk selects for smaller body size and other characteristics of a faster life cycle, including shorter generation time. Our work illustrates how a range of life history trade-offs interact, are complicated by seasonality, and determine how organisms may adapt to environmental change.

Tutorial/Invited: Invited

Primary Presenter: Øystein Varpe, University of Bergen (oystein.varpe@uib.no)

Authors: