The Norwegian reference lake ecosystem, Øvre Heimdalsvatn

Abstract

The subalpine lake, Øvre Heimdalsvatn and its catchment, situated in the mountains of southern Norway, has been the subject of extensive ecosystem studies over the last 50 years covering a wide range of disciplines. The lake is located at 1,088 m a.s.l., has an area of 0.78 km 2 , a maximum depth of 13 m, and a catchment area of 23.6 km 2 . It lies more or less on the limit of the birch forest, while the catchment extends up over 1,800 m a.s.l. and into the high alpine zone. The valley is little influenced by human activity and there is no permanent habitation, although the area is used for grazing of domestic livestock during summer. Otherwise the lake and its catchment have always been important for fish and game. The catchment also received major radionuclide fallout from the Chernobyl accident in 1986. The studies include Quaternary history, the development of algorithms for remote sensing of snow conditions, long-term changes in lake ice cover and temperature, the zooplankton and benthic communities, as well as the uptake of Chernobyl radionuclides and mercury by the biota. The consequences of the introduction of the European minnow (Phoxinus phoxinus) on the benthos, zooplankton and the brown trout (Salmo trutta) have also been investigated. The lake and its catchment are widely used in university teaching and thesis work. On account of the substantial knowledge base, Øvre Heimdalsvatn is well suited to long-term monitoring.

Long-term trends in water temperature and ice cover in the subalpine lake, Øvre Heimdalsvatn, and nearby lakes and rivers

“…1). The lake has been the subject of detailed interdisciplinary studies (Larsson et al, 1978;Vik, 1978;Brittain & Borgstrøm, 2010). The lake is shallow with a maximum depth of 13 m and a surface area of 0.78 km 2 (Grøterud & Kloster, 1978).…”

Plerocercoids of the cestode Diphyllobothrium ditremum in brown trout Salmo trutta: substantial increase in infection after establishment of European minnow Phoxinus phoxinus

“…The lake has a surface area of 0·78 km 2 and an average depth of 4·7 m. The period of ice‐cover usually lasts from the end of October to early June (Kvambekk & Melvold, ). There is no permanent habitation and except for grazing of domestic livestock during summer, the valley is little influenced by human activity (Brittain & Borgstrøm, ).…”

“…Ever since Jensen () started his study on S. trutta dynamics in 1957, the lake has been subject to extensive studies covering a wide range of disciplines and accordingly has become an important subalpine ecosystem reference site (Brittain & Borgstrøm, ). Salmo trutta was the only fish species in the lake until colonization by P. phoxinus , probably introduced by humans (Lien, ).…”

Between-year variations in the development of crustacean zooplankton in the Norwegian subalpine lake, Øvre Heimdalsvatn

“…Lake flow through rates are given in Grøterud & Kloster (1978). Further information about the lake is given in Brittain & Borgstrøm (2010) and in Larsson et al (1978).…”