Abstract
The aim of the present study is to further our understanding of the processes underlying the transition between alternative stable states in lakes and wetlands and how these transitions affect biodiversity and ecosystem functioning. Changes in alternative states, especially from a macrophyte dominated clear-water state to a turbid, phytoplankton dominated state, result in a dramatic reduction in biodiversity and a degradation of ecosystem functioning. Here, we intend to study the importance of seasonal mass-migration of cyprinids between lakes and their tributaries, the mechanisms behind this migration and its importance as a driving force for the transition between states. Further, we intend to study how changes in seasonal migration affects biodiversity and ecosystem function in these systems. Our main hypothesis is that relative predation risk differs between habitats seasonally and during winter it is highest in the lake, which forces cyprinids to utilise refuges in tributaries. Changes in migration patterns should affect organisms at lower trophic levels, resulting in effects on biodiversity and ecosystem functioning. The hypotheses will be tested using a combination of surveys and large-scale field experiments. The project is a continuation grant, including two PhD student positions, and is to all major parts following the original plans.
Sweden