The Subalpine Lake Ecosystem, ØVre Heimdalsvatn, and Its Catchment: Local and Global Changes Over the Last 50 Years

ISBN-13: 9789048193875 / Angielski / Twarda / 2010 / 126 str.

John E. Brittain; Reidar Borgstrom

Opis

environmental variables are estimated and then applied to fossil assemblages under the assumption Plant and animal remains are often found well that the biota is in equilibrium with concurring preserved and in large quantities as fossils in lake environmental conditions. We have used fossil pollen sedimentary deposits. The composition of the fossil assemblages to reconstruct changes in past mean July assemblages, the biological proxies, can be used to air temperatures and changes in mean annual prec- infer environmental conditions at the time of de- itation (Birks & Birks, 2003). Plant macrofossils were sition. This is based on the uniformitarian assumption used to con?rm and to give more robust interpre- that particular species assemblages of the past have tions about past vegetation and climate than the been shaped by speci?c sets of environmental pollen evidence alone (Birks & Birks, 2000) and has conditions, and that these conditions are re?ected been widely used to con?rm the local presence of tree by the same species assemblages today (Rymer, species in studies of past tree-lines (Barnekow, 2000; 1978; Birks & Birks, 1980). Different proxies used to Bjune, 2005; Eide et al., 2006). Chironomids (n- reconstruct past environmental conditions have in- biting midges) were used to infer past mean July air vidual strengths and weaknesses.

Spis treści

Preface John E. Brittain and Reidar Borgstrøm The Norwegian reference lake ecosystem, Øvre Heimdalsvatn John E. Brittain and Reidar Borgstrøm Holocene climate and environmental history of Brurskardstjørni, a lake in the catchment of Øvre Heimdalsvatn, south-central Norway Gaute Velle, Anne E. Bjune, Jorunn Larsen and H. John B. Birks The development of new algorithms for remote sensing of snow conditions based on data from the catchment of Øvre Heimdalsvatn and the vicinity Rune Solberg, Hans Koren, Jostein Amlien, Eirik Malnes, Dagrun Vikhamar Schuler and Nils Kristian Orthe Long-term trends in water temperature and ice cover in the subalpine lake, Øvre Heimdalsvatn, and nearby lakes and rivers Ånund Sigurd Kvambekk and Kjetil Melvold Between-year variations in the development of crustacean zooplankton in the Norwegian subalpine lake, Øvre Heimdalsvatn Petter Larsson, Heidi Hansen and Linda Kristin Bjørnstad Helland Long-term changes in the littoral benthos of a Norwegian subalpine lake following the introduction of the European minnow (Phoxinus phoxinus) Frode Næstad and John E. Brittain 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) Reidar Borgstrøm, Jon Museth and John E. Brittain 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? Jon Museth, Reidar Borgstrøm and John E. Brittain A long-term study of catchment inputs of 137Cs to a subalpine lake in the form of allochthonous terrestrial plant material John E. Brittain and Helge E. Bjørnstad Long-term trends and variation in 137Cs activity concentrations in brown trout (Salmo trutta) from Øvre Heimdalsvatn, a Norwegian subalpine lake John E. Brittain and Jan Egil Gjerseth The importance ofsize and growth rate in determining mercury concentrations in European minnow (Phoxinus phoxinus) and brown trout (Salmo trutta) in the subalpine lake, Øvre Heimdalsvatn Marthe T. Solhaug Jenssen, Reidar Borgstrøm, Brit Salbu and Bjørn Olav Rosseland

Blurb

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.