Abisko Scientific Research Station: projects/activities

Damming leads to depletion of major elements in boreal river water, with potential effects on biological production in coastal marine areas (Humborg et al. 2002, Global Biogeochem. Cycles 16 in press), such as the Baltic Sea. Today, the causal mechanism to this element depeltion is unknown. The present project aims to estimate biological nutrient retention in a dammed river system (Luleälven) and an unregulated system (Torneälven). As to lenthic production, lake Torne träsk offers excellent opportunities to study the pelagic productivity regime of a pristine boreal aquatic system. Our field programme includes measurements of mictic conditions, nutrients (P, N, Si), dissolved and particulate constituents (major and minor elements), stabile isotopes (C, N, Sr, O), primary productivity, zooplankton abundance, and fish.

Bud dynamic in mountain birch, Betula pubescens ssp. czerepanovii, is affected by biotic and abiotic factors such as temperature, light and herbivory. Climate probably has a large impact on module life history strategies i.e. survival, sexual and vegetative reproduction. (Modules are here defined as partially autonomous, repetitive and multicellular subunits within a tree.) Trade-off between present reproduction and future growth and/or reproduction occurs if resources are limiting. There is no direct trade-off between male catkin production and axillary bud production in mountain birch since male catkins are produced at the terminal bud of long-shoot. This bud is aborted when no catkin is present. However, same resources are used for both male catkin production and axillary bud production indicating that trade-offs occur in mountain birch. In my study I have simulated herbivory in order to study what effect trade-offs have on growth of long-shoot and bud performance.

Continuation and completion of radiation experiment that was started in 2001. It is established under the UV lamps right beside the station (near road). We are studying the effects of enhanced UV radiation on the synthesis of cortical UV screening compounds in the lichen Flavocetraria nivalis.

1. Behavioural study of Bombus and Psithyrus spp., notably nesting, foraging and diurnal patterns. To compare with same or related UK species, in relation to UK BAP and UK Bumblebee Working Group. Prior work of Bo Svensson et al is noted and will form basis for further study.2. Behavioural study of butterflies of Abisko area. Since 1982 study by Henriksen and Keutzer, there is little published work other than collectors' reports. The project is to observe mate location, nectar sources used, ovipositing, mating, diurnal patterns etc. as well as compile information about habitat, vertical and horizontal distribution etc.Both studies will involve both stills and video photography. Publication in the form of journal articles is anticipated. Both studies are contributary to monographs in preparation, one on European butterflies, the other on Bumblebees currently under consideration bt HarperCollins.

Arctic tundra landscapes exist as a mosaic of vegetation (graminoid-, dwarf-shrub and lichen-dominated) related to topography, soil type and hydrology (wet, mesic, dry tundra). The key driver of this fine-scale mosaic is the pattern, depth and duration of snow-lie. Changes in snow-lie within the landscape, resulting from climate change, may alter the vegetation and soils of the tundra regions that modulate fluxes of trace gases (CO2 and CH4, H2O) between tundra and atmosphere. Current models do not take account of this. Our key objective is therefore to improve quantification of seasonal trace gas flux and energy balance between surface and atmosphere at the landscape scale in high latitude tundra, and the potential feedbacks to radiative forcing of climate, taking into account this fine-scale landscape mosaic mediated by the dynamics of winter snow cover and its duration.

The goal of this research is to explore how a subarctic terrestrial ecosystem in the North of Sweden will respond to climate change. The research will be organized around the effects of climate change on plant and soil processes and their linkages, the effects of climate change on the chemical quality of plant tissues in the context of forage quality, and the effects of climate change on community structure. The manipulation involves plant and soil warming and atmospheric CO2 doubling, alone and together, in the understory of an open birch forest close to the treeline.

In attempt to adress the importance of the sediments in the degradation of organic matter in lakes, we want to measure respiration in some alpine lakes in the Lake Torne Area. Earlier work have been made trying to measure the saturation of CO2 in surface water of lakes all over Sweden. The measurements of respiration will also be conducted in several lakes in southern Sweden. In the end we want to make whole system carbon budgets, so that we can estimate if lakes are sources or sinks of carbon.

To evaluate some factors controlling the relative performance of the four dominating species in this community (i.e. the dediduous Vaccinium uliginosum and V. myrtillus and the evergreen V. vitis-idaea and Empetrum hermaphroditum). The study includes removal of species and nutrient additions. Responses are studied in permenent plots.

Relating budburst and leaf absicssion in the mountain birch to climatic conditions.

The study aims to optimise the used of landscape data as satellite images, aerial photos, maps, weather data when assessing conditions contributing to accidental risks. So far the study has focused on slope processes along the railway between Kiruna and Riksgränsen (Norwegian border).