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This book summarizes research from the intensive study of a pristine subalpine lake ecosystem and its catchment over the last 50 years. A wide range of topics is presented, including several unique time series focusing on changes in ice cover, water temperature, zooplankton, benthos and fish. Significant changes in the lake fauna after the introduction of European minnow into an ecosystem where brown trout was the sole fish species have been documented. The area received substantial radioactive fallout from the Chernobyl accident in 1986, and two articles address long-term changes in radiocaesium activity concentrations in allochthonous plant material and in fish. Other topics include palaeoecology, mercury in fish and remote sensing of catchment snows. Such long-term research is crucial in a rapidly changing environment due to the impacts of climate change, long-range pollutants and alien species. This provides a solid basis for future monitoring and management of freshwater ecosystems.The book will not only be of interest to freshwater ecologists working in the field, but also for managers responsible for the protection and monitoring of natural areas. It illustrates the changes now taking place in pristine ecosystems as a result of human activities and will serve as a supplementary text for courses in environmental management.
List of contents
Preface.- The Norwegian reference lake ecosystem, Øvre Heimdalsvatn.- Holocene climate and environmental history of Brurskardstjørni, a lake in the catchment of Øvre Heimdalsvatn, south-central Norway.- The development of new algorithms for remote sensing of snow conditions based on data from the catchment of Øvre Heimdalsvatn and the vicinity.- Long-term trends in water temperature and ice cover in the subalpine lake, Øvre Heimdalsvatn, and nearby lakes and rivers.- Between-year variations in the development of crustacean zooplankton in the Norwegian subalpine lake, Øvre Heimdalsvatn.- Long-term changes in the littoral benthos of a Norwegian subalpine lake following the introduction of the European minnow (Phoxinus phoxinus).- The brown trout (Salmo trutta) in the lake, Øvre Heimdalsvatn: long-term changes in population dynamics due to exploitation and the invasive species, European minnow (Phoxinus phoxinus).- Diet overlap between introduced European minnow (Phoxinus phoxinus) and young brown trout (Salmo trutta) in the lake, Øvre Heimdalsvatn: a result of abundant resources or forced niche overlap?.- A long-term study of catchment inputs of 137Cs to a subalpine lake in the form of allochthonous terrestrial plant material.- Long-term trends and variation in 137Cs activity concentrations in brown trout (Salmo trutta) from Øvre Heimdalsvatn, a Norwegian subalpine lake.- The importance of size and growth rate in determining mercury concentrations in European minnow (Phoxinus phoxinus) and brown trout (Salmo trutta) in the subalpine lake, Øvre Heimdalsvatn.
