Disputation: Tore Qvenild
Dr Philos candidate Tore Qvenild at the Department of Biosciences will be defending the thesis "Climatic impact on the crustacean species Lepidurus arcticus, Gammarus lacustris and Eurycercus lamellatus on brown trout Salmo trutta production in a high mountain area in Southern Norway" for the degree of Dr Philos.
Tore Qvenild. Photo: private.
Trial lecture 1
Apaption of some crustacean species to environmental change in the high Arctic - with special reference to the Arctic tadpole shrimp Lepidurus arcticus
Trial lecture 2
The match-mismatch hypothesis and fish recruitment in alpine lake ecosystems
Main research findings
Hardangervidda is the most extensive mountain plateau in Europe, where brown trout Salmo trutta is almost the only fish species present. A rich supply of crustacean food items such as Lepidurus arcticus, Gammarus lacustris and Eurycercus lamellatus is regarded as the main reason for the size and quality of brown trout. The lakes in the barren westerly area are colder and have dilute waters low in calcium, in contrast to the eastern part. The variety in environmental conditions and the distribution of the species have provided new information of their environmental demands.
The winter precipitation differs substantially in a west to east gradient with an almost four-fold decrease. Since the 1980s, annual winter precipitation has increased. During the same period, a significant increase in summer air temperatures has been documented. The trend with warmer lakes does not augur well for the fate of cold adapted species, especially Lepidurus arcticus. Brown trout populations on Hardangervidda have proved to be sensitive to change in climatic conditions, spanning populations that have neared collapsed and rebounded to years with very rich fisheries. Such climatic induced variations in recruitment and growth pattern may be stronger in a warmer, wetter and more unpredictable climate scenario.
Professor Johan Höjesjö, University of Gotheburg
Associate Professor Louise Chavarie, NMBU
Associate Professor Øystein Langangen, University of Oslo
Chair of defence
Professor Alexander Eiler, University of Oslo