Juncus bulbosus in the Otra River (Norway)
Mass development of the native macrophyte J. bulbosus is among the most serious environmental problems in rivers in southern Norway. Annually, on average 250 000 € are spent on abatement measures, but regrowth is generally observed after few years.
The Otra River is subject to acid precipitation, hydromorphological alterations, climate change and anthropogenic pollution, and the river is used for recreation and hydropower generation. The stakeholder involved in this case study is “Krypsivprosjektet på Sørlandet”, a consortium of hydroelectric power companies, Energy Norway, the Norwegian Water Resources and Energy Directorate (NVE), and representatives from Norwegian environmental authorities.
Top left: Otra River at Rysstad with Juncus bulbosus (June 2019); top right: Juncus bulbosus; bottom left: Juncus bulbosus growth forms; bottom right: removal of Juncus bulbosus in June 2019. All pictures © NIVA