Abstract
The aim of this project is to assess the impact of fish introduction on diversity and process rates in aquatic ecosystems. Most experimental evidence for biodiversity effects on ecosystem functioning has come from terrestrial ecosystems and has focused on single trophic level primary producers. However, since predation is one of the major factors influencing prey population dynamics evaluating impacts of biodiversity loss on ecosystem function requires expanding the scope of current research to multi level food webs. In this project I will specifically study if locally adapted species, i.e. species with limited dispersal ability and thereby low geneflow, are more vulnerable and at a higher risk of extinction due to inappropriate antipredator defenses when a new predator is added to a foodweb. I will study consequences of this on ecosystem process rates (decomposition, grazing). I will also test non-lethal effects of fish on decomposition processes. I will determine how many generations it will take for a prey species to evolve an adapted response to the new predator, which may lead to a possible co-existence. I will also determine species richness and process rates in multiple ponds that differ in predator regimes. By providing a testable conceptual framework involving “predator naive” prey species, this project could potentially increase our knowledge of the consequences of fish stocking and also species invasions on diversity and ecosystem processes in aquatic systems.
Sweden