Both the ongoing global warming and the removal of top-predators modify trophic interactions in marine food webs.

As evolutionary adaptations in three-spined stickleback (hereafter stickleback) morphology can affect the behavior of the individuals, the ecosystem effects of the recent drastic increase in stickleback abundance in the Baltic Sea may depend on the morphotype-prevalence.

Questions we want to adress:

1. how evolutionary adaptations in a meso-predator affect traits in benthic food web
2. whether warming modifies these responses

At Askö Laboratory in Sweden, we conducted a mesocosm experiment with three trophic levels in ambient and warmed (+4°C) water:

• meso-pradators (fully and partially plated sticklebacks),
• meso-grazers (gastropod, amphipod and isopod grazers) and
• macroalgal foundation species (Fucus vesiculosus and F. radicans)

We assessed how warming, stickleback presence and morphotype altered traits at each trophic level.