Landscapes shaped by beavers provide favourable conditions for a number of species, including moose, voles and diving beetles. Beaver patches, or areas modified by beavers in nature – such as new and old inundated sites as well as beaver meadows formed after flooding – create diverse habitats that are at different stages of ecological succession, or the process of how species compositions change in ecological communities over time. As a result, a habitat suitability index calculated for different species and groups of species grew almost tenfold over a 54-year period. Thanks to beaver activity, the landscape develops to support a wider range of species and improves habitat connectivity.
“While the positive effects of the changes brought about by beavers in the boreal region are significant, their long-term effects on biodiversity dynamics remain partly unknown. This is why long time series are needed to understand the far-reaching ecological effects of these changes,” says Senior University Lecturer Petri Nummi from the Department of Forest Sciences, University of Helsinki.
Evo, an area in Finland that also has been planned as a national science park, is suitable for beaver research, among other lines of study, offering a unique time series on the effects of the return of beavers. This study highlights the role of beavers as natural restorers that improve the habitats of many species and boost biodiversity.
“Beavers are returning to many areas of Europe where they were once hunted to extinction. Whereas in our prior studies we observed patches shaped by beavers, this new study helps to understand the differences between landscapes in areas where beavers occur and where they are absent,” says University Lecturer Sonja Kivinen from the University of Eastern Finland.ä-Suomen yliopistosta.
Original article:
Kivinen, S. & Nummi, P. (2025). Immediate facilitation and engineering legacy of beavers: 54 years of patch dynamics in a boreal landscape. Science of The Total Environment 999, 180341. https://doi.org/10.1016/j.scitotenv.2025.180341
Further information:
University Lecturer Sonja Kivinen, University of Eastern Finland, tel. +358 46 920 5826
- Beaver patch: Beaver patches are parts of the landscape transformed by beavers. Beavers affect their habitats by constructing dams that alter the natural environment located close to aquatic areas and create new habitats. These areas can include a range of elements, including flooding shores and beaver meadows.
- Succession: Ecological succession is the process of ecosystem evolution and change over time. It usually begins with a disturbance, such as a flood or a forest fire, and progresses in stages. Each stage of succession provides different habitats and affects the composition of the species community in the area. Landscapes created by beavers go through their own stages of succession, as the areas change and develop as a result of beaver activity.
- Inundated site: Inundated sites refer to areas that are temporarily or permanently under water. This can be caused by natural or human-made changes, such as dams built by beavers, resulting in water rising and flooding into adjacent land areas. Inundated sites can establish unique habitats and affect the ecological dynamics of the area by providing resources or shelter for various species.
- Suitability index: All beaver patches were assigned a value describing their suitability for each individual species or species group. The suitability index is composed of the sum of the patch values, depending on the annual appearance of patches in the landscape.