The importance of seedbanks in river restoration
Many streams in Northern Sweden have been channelized or otherwise impacted by human activities which led to decreased complexity of those streams. This decreased complexity can result in changes in stream processes such as flooding, plant survival and seed dispersal. Channelization thereby resulted in changes in species composition. Restoration of stream complexity does often not lead to the return of the desired species composition, and it is often concluded that the absence of species is hampered by the limited availability of seeds. After restoration seeds may be available from two sources: Seeds that are recently dispersed or from the seedbank (e.g. seeds that are previously dispersed and got incorporated in the soil). Stream complexity is hypothesized to affect dispersal and subsequent recruitment by affecting stranding patterns and soil moisture. Previous studies focused on soil moisture. Stream complexity may therefore however also affect seed bank formation and it is hypothesized that there is a correlation between the ability to trap seeds and seed bank size. Seeds in the seed bank may be the first to be present and germinate after restoration, thereby gaining priority and dominance over seeds that arrive later via dispersal. In order to develop successful restoration methods, it is of utmost importance to understand recolonization processes after restoration. This research therefore aims to understand the importance of seed banks after restoration by testing the relation between stream complexity, vegetation and seedbank composition.
This project was funded by the Ruth and Gunnar Björkman fund.
Eliza Hasselquist (SLU)
Lovisa Lind (SLU)
Christer Nilsson (UMU)
Laura McManus (Utrecht University)
Anouk Bosch (Utrecht University)