In aquatic food webs, predation (top-down regulation) regulates the abundance and behavior of communities, and also affects the physical-chemical water quality. Therefore, disturbances that affect predator-prey interactions can have substantial impacts on the ecosystems. For instance climate change affects numerous characteristics of lake ecosystems, with consequences for the functioning of aquatic food webs.
We have carried out numerous field sampling campaigns and experimental studies on this subject area. We have shown for instance, that in clay-turbid conditions, top-down regulation may not work in a manner predicted by the trophic cascade hypothesis. This is because turbidity has differential effects on top-down regulation exerted by fish and invertebrate predators. Another large project explored the effects of climate change on inter- and intraspecific interactions in fish and invertebrate communities via increasing water color and turbulence. The effects of refuges (clay turbidity, low oxygen, high color, macrophyte stands) on predator-prey interactions have also had an important role in many studies.
The studies have been funded by the Academy of Finland, University of Helsinki and Lake Vesijärvi Foundation.