| Sign In to gain access to subscriptions and/or personal tools. |
Palaeolimnological and sedimentary responses to Holocene forest retreat in the Scandes Mountains, west-central SwedenGeoBiosphere Science Centre, Quaternary Sciences, Lund University, Solvegatan 12, SE-223 62 Lund, Sweden dan.hammarlund{at}geol.lu.se
Zoological Institute, University of Bergen, Museplass 3, N-5007 Bergen, Norway
Department of Geography and Environmental Studies, Wilfrid Laurier University, Waterloo, ON N2L 3C5 Canada
Department of Earth Sciences and Quaternary Sciences Institute, University of Waterloo, Waterloo, ON N2L 3G1 Canada
GeoBiosphere Science Centre, Quaternary Sciences, Lund University, Sdlvegatan 12, SE-223 62 Lund, Sweden
Department of Earth Sciences, Goteborg University, Box 460, SE-405 30 Goteborg, Sweden
GeoBiosphere Science Centre, Quaternary Sciences, Lund University, Solvegatan 12, SE-223 62 Lund, Sweden
Department of Physical Geography and Quaternary Geology, Stockholm University, SE-106 91 Stockholm, Sweden
Tandem Laboratory, Uppsala University, Box 533, SE-751 21 Uppsala, Sweden A suite of analyses was performed on sediments accumulated during the last 10 700 years in Lake Spaime, a small, hydrologically open water body in the modem alpine tundra zone of the Scandes Mountains, west-central Sweden. The study aimed to evaluate (1) the nature of climate changes that forced the late-Holocene lowering of altitudinal tree limit in the region, the timing of which is known from prior studies based on radiocarbon dating of subfossil wood, and (2) the impact of these vegetational changes on an aquatic ecosystem. Arboreal pollen and plant macrofossil data confirm the persistence of trees in the lake catchment at least from c. 9700 cal. BP until c. 3700 cal. BP. Although growing-season temperature is commonly believed to be the dominant factor driving boreal forest tree-limit variations in the region, a chironomid-based reconstruction of mean July air temperature suggests that local deforestation during the late Holocene was not accompanied by a significant cooling. The tree-limit retreat was more likely caused by increasing effective moisture and declining length of the growing season. The ecohydrological response of Lake Spaime to this combination of climate and vegetational changes included a decline in primary productivity, as indicated by an abrupt decrease in sediment organic matter content, while associated increases in organic 613C, 615N and C/N point to diminished fluxes and altered balance of catchment derived nutrients following deforestation. The decline in aquatic productivity is also marked by a distinct change in the mineral magnetic properties, from a high magnetic concentration assemblage dominated by fine-grained magnetite of biogenic origin to one dominated by background levels of coarse-grained detrital magnetite.
Key Words: Holocene palaeoecology • alpine tree-limit dynamics • lake sediments • lacustrine nutrient cycling • stable isotope geochemistry • chironomidae • environmental magnetism • Sweden
The Holocene, Vol. 14, No. 6,
862-876 (2004) This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
|
|
 |
|
Sign In to gain access to subscriptions and/or personal tools.
