Projects/Activities

Study of the colonisation of mountain birch above timberline: -Determining age classes of trees (by dendrochronology)=> datation of colonisation event(s). -Inflence of climate change by comparison to climatic datas. -Determining fitness of individuals above timberline and comparison to individuals in the forest. -Origin of the individuals above timberline => kin relatedness study by molecular and morphometric methods.

Study of factors influencing flowering probability in Pinguicula vulgaris. Ongoing measurements in the field will continue.

Continuation of long standing UV-B x CO2 enrichment on the heath below the station as a possible pre-cursor to future EU funding.

Recent findings on the highly polyandrous and nuptial gift giving butterfly Pieris napi shows that females may use resources (nitrogen) from thorax, presumably from breakdown of wing muscles, to increase their reproductive potential and the results indicate that also males can use thorax material in their reproduction. This possibility that males in polyandrous species use thorax material in a similar way as females is up to now unknown. As the degree of polyandry increase, males invest more to reproductive parts and equals females with respect to size.This possibility that males in polyandrous species use thorax material in a similar way as females is up to now unknown and very interesting. As the degree of polyandry increase, males invest more to reproductive parts and equals females with respect to size. This shift between the sexes in how resources are used may also be valid to breakdown of resources in thorax. The first part of the study has focused on these aspects, i.e. what are the differences in how males of species with different mating systems use their resources (especially nitrogen). For this purpose we participate in a large comparative study of Swedish and US butterflies.In the Abisko area we are interested especially in collecting one satyrid species, Erebia pandrose, since this species (in contrast to other satyrid species)is highly polyandrous.

In this field project we will study vegetation characteristics along natural geographical gradients, and monitor vegetation dynamics in long-term field experiments. The measurements will be combined with remotely sensed images (i.e. satellite images) and computer models to quantify vegetation carbon exchange and to test whether these techniques are suitable to detect changes in the unique and vulnerable ecosystems of the arctic.﷡This summer a survey of leaf area indices along an east -west gradients of yearly rainfall and geography will be carried out, and one hillslope gradient and a small catchment will be studied in more detail. For each location leaf area estimates of the vegetation will be obtained using light measurements and the vegetation samples will be taken to be analysed in the lab.

Lichen flora of snowbeds in the Massif of Slattajakka and Njuollja will be studied in close relation to the objectives of Swedish-Czech project "Comparative ecology of cryogenic landforms in the Subarctic Scandes and the High Sudetes" (C.Jonasson, L.Papáčková-Soukupová). Sampling of lichen species and assessment of their abundance will be carried out repeatedly in short-, mid- and long-term snowbeds from the beginning to the end of melting season. Similar sites will be analysed both in Slattajakka-Njuollja Massif, N Scandes and Luční-Studniční Mt., the High Sudetes. In both massifs, specific lichen zonation is characteristic for various types of snowbeds occurring in different cryogenic landforms situated in the leeward of anemo-orographiic systems, which modify snow deposition in winter (Jeník 1961). Apart of in situ easily recognizable lichens, the determination of difficult groups will be performed in laboratory by standard LM procedures, spot reactions or - if necessary - by TLC. Poorly known and taxonomically difficult tundra microlichens will be selectively collected for eventual molecular analyses.

Fruit set in Linnaea borealis is known to be low. Plausible reasons for low fruit/seed set in self-incompatible plants are: pollinator shortage, xenogamous-pollen shortage and environmental conditions. Preliminary results from a study Abisko 2001 suggest that fruit set in L. borealis is partly pollinator limited. Wilcock and Jennings (1999) concluded, however, that fruit set in some Scottish populations of L. borealis was xenogamous-pollen limited. In a study on Ranuculus acris in the Norwegian mountains it was shown that the physical environment (temperature and wind) together with pollen shortage limited seed set.Does fruit set vary among populations of L. borealis along an altitude gradient in Swedish Lapland? Is fruit set higher in the valley than on the mountains? If so, what is the reason behind it? A way to compensate for low pollinator activity could be to extend flowering time. Is flowering time longer at higher elevations? If so, is it due to selection pressure or just a cause of lower metabolic rate in harsher climate? Is there a lower pollinator activity on higher elevation than on lower? Who are the pollinators of L. borealis in Abisko and is it the same along the altitudinal gradient? Is L. borealis self-incompatible in Abisko as in Scotland?Wilcock C.C. and Jennings S.B. 1999. Partner limitation and restoration of sexual reproduction in the clonal dwarf shrub Linnaea borealis L. (Caprifoliaceae).

The issue of biocomplexity, the pattern of processes governing biodiversity vill be studied in an alpine landscape in northern Swedish Lapland, Latnjajaure catchment. The ragged topograhy in combunation with strong winds give rise to extensive snow redistribution. As most of the annual preciptation here falls as snow, most of the atmospheric nitrogen deposition will relocated to snowbeds, wheras neighboring ridges receive a minor fraction of the input. This patchiness in nitrogen supply within the landscape is forecasted to increase as the atmospheric of mainly antropogeneous nitrogen increase exponentially. Snowbeds are by IPCC regarded as particularly vulnerable ecosystem,and our working hypothesis is that increased temperature and nitrogen supply in concert is the major threat. We combine monitoring of nitrogen deposition and measurement of nitrification potential in the soil with manipulation where a nitrogen input according to the forecast for 2050 is applied to selected snowbeds. Dynamic modelling at the landscape level will help us to provide prognoses for the future changes in the alpine tundra.

Population density estimates and temperature records in relation to topography will, together with other factors, be used to predict the likelihood of defoliating outbreaks of Epirrita autumnata in the mountain birch forest.Severe severe defoliation by E. autumnata larvae may lead to a die-back of old trees and initiate a regrowth of from basal sprouts and seedlings and thus changing the age-structure of the forest. The change to a younger successional stage may have implications for reindeer husbandary. The interactions between insect-herbivory and reindeer grazing is studied in other parts of the project.

Stordalen project

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.

The aim is to study the diversity and function of marine bacteria closely associated with marine sponges. The special character of life strategy of the community (symbiosis – commensalism), with special emphasis to the identity and the recruitment of bacteria during live cycle of the sponges will be described.

Since nearly all microalgae are associated with bacteria and some harbor intracellular bacteria, it is most likely that these bacteria are involved in the development or termination of natural occurring plankton assemblages. The diversity and development of associated bacteria in microalgae cultures and during phytoplankton succession will be described by molecular analysis of the bacterial community structure and by phylogenetic analysis of involved microorganisms.

Little is known about the consistency or phylogenetic affiliation of accociated intra- or extracellular bacterial populations in Echinodermata. Because certain taxa harbour bacteria and other not, these associations are presumably originated by coevolution and not by ecological circumstances. The intestine of echinodermata is populated by huge amounts of bacteria. Due to the different feeding strategy of echinoderms it is controversly discussed whether these bacteria are passively taken up or if they are permanently present. Hence it will be possible to elucidate if vertical transmission occurs or bacteria are recruted. With the knowledge of phylogenetic affiliations of microbial symbionts and their distribution (or localization) in different hosts, the physiological/biochemical status of the association will be investigated. The main emphasis will be the characterization of the in situ situation by adequate histological techniques (crysectioning) and “passive” (FT-IR) or “active” chemical imaging (confocal imaging, using fluorescent enzyme substrates or physiological dyes). The main experimental work in this WP bases on the creation of 16S-rDNA sequence libraries of echinoderrm associated bacteria (SCB & intestinal). Signature sequences will be analyzed and specific gene probes will be designed and applied.