Wild herbivores, shady forests, and traditional agriculture – which way out of the biodiversity crisis?

During his PhD studies Szymon Czyżewski researched the role of large herbivores in shaping the natural vegetation and biodiversity of humid temperate Europe. To explore this question Szymon Czyżewski studied the habitat preferences of forest plants, paleo-ecosystems going back 23 million years, the diet of wild-living large herbivores over summer and winter, and plant diversity in an ancient herbivory-sustained woodland. 

The new research findings provide evidence that open woodlands, likely maintained by large herbivores with a crucial role of winter herbivory, were the dominant vegetation type in pre-human humid-temperate Europe, sustaining higher biodiversity than present-day closed-canopy forests.

The PhD study was completed at the Center for Ecological Dynamics in a Novel Biosphere (ECONOVO), Department of Biology, Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Thursday, 24 September 2026 at 13.15
Place: Building 1532, room 122, Lecture Theatre G2, Department of Mathematics, Aarhus University, Ny Munkegade 118, 8000 Aarhus C
Title of PhD thesis: Temperate forest’s natural state: closed canopy or woodland mosaic? – How to uncover something that is no more?
Contact information: Szymon Czyżewski, e-mail: szymon.czyzewski@bio.au.dk, tel.: +45 52 23 96 43
Members of the assessment committee:
Professor Kari Anne Bråthen, Department of Arctic and Marine Biology, UiT - Arctic University of Norway, Norway
Associate Professor Jacob Heilmann-Clausen, Globe Institute, University of Copenhagen, Denmark
Associate Professor Alejandro Ordonez Gloria (chair), Department of Biology, Aarhus University, Denmark
Main supervisor: Professor Jens-Christian Svenning, Department of Biology, 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 Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C