Two clear results stand out. First, newly built dune ponds can host remarkably rich wetland floras. Their species mix still differs from natural lakes, but they add many, and sometimes rare, species to landscapes where encroachment and accumulated organic matter have degraded older habitats. Second, in rewetted lowland fens former intensively farmed croplands, active management matters more than time: cattle and horse grazing consistently increased plant richness and diversity, while simply waiting more years after restoration made little difference. The takeaway for practice is direct: design new dune basins with dispersal pathways and landscape context in mind, and treat grazing as a core tool for biodiversity recovery after rewetting. The work shows that, with the right approach, species-rich wetlands can indeed be restored.

The PhD was completed at the Department of Agroecology, Faculty of Technical Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Wednesday, February 18^th, 2026 at 13.00
Place: building 8814, room 3075, Department of Agroecology, Aarhus University, Blichers Allé 20, 8830 Tjele
Title of PhD thesis: Rewetting for Biodiversity: Ecological Outcomes Across Two Restoration Pathways in Danish Wetlands
Contact: Michael Straarup, e-mail: Michael.straarup.91@gmail.com, tel.: +45 28 60 29 34
Assessment committee:
Associate Professor Sara Egemose, Department of Ecology, University of Southern Denmark, Denmark
Professor Aveliina Helm, Department of Ecology and Earth Sciences, University of Tartu, Estonia
Chair: Professor Mogens Nicolaisen, Department of Agroecology, Aarhus University, Denmark
Main supervisor: Professor Tommy Dalgaard, Department of Agroecology - Agricultural Systems and Sustainability, Department of Biology - Center for Sustainable Landscapes under Global Change, Aarhus University, Denmark
Co-supervisors:
Professor Signe Normand, Department of Biology - Ecoinformatics and Biodiversity, Center for Sustainable Landscapes under Global Change, Aarhus University, Denmark
Professor Jens-Christian Svenning, Department of Biology - Ecoinformatics and Biodiversity, Center for Ecological Dynamics in a Novel Biosphere (ECONOVO), Center for Sustainable Landscapes under Global Change, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English.
 

The defence is public.
The PhD thesis is available for reading at the Graduate School of Technical Sciences/GSTS, Ny Munkegade 120, building 1521, 8000 Aarhus C.