Biodiversity in Norwegian regulated lakes

Norway has approximately 1200 lakes that are regulated for hydropower usage. Due to their ability to store large amounts of water, these reservoirs underpin the Norwegian hydropower system, which consists of more than 1600 hydropower plants and makes up around 96 % of the national power production. “Regulation” is the process where the water levels in the lake are manipulated in a flexible way allowing the power producers to increase or decrease production according to demand. This manipulation of water levels can affect the physical and chemical properties of the reservoir, and, as many of the Norwegian hydropower reservoirs are actually natural lakes which were turned into reservoirs when the hydropower dams were built, this can have consequences for living conditions of the species found in the lake.

Data collection and funding

For many years NINA researchers have been collecting biodiversity data from regulated lakes. These various projects have been funded by the Norwegian Environment Agency, Power Producing Companies and Local and Regional Government. Data are focused on fish species (sampled using standardised methods for test-fishing with multi-mesh gillnets) with some morphometric measurements, zooplankton (generally sampled using vertically and horizontally towed plankton nets), crayfish and benthic invertebrates.

These datasets are brought together in this collection, and we are undergoing a process of data standardisation in accordance with the Darwin Core Standards. The metadata (and in some cases data) for each project can be seen below; but as this is an ongoing project we expect the available data to increase and for more datasets to be made available in full in time.