World-wide observations of current climate change, such as increased temperature and severe rain events and droughts are caused by release of CO2 by human activities using fossil fuels and by biogeochemical feed-back mechanisms (Solomon et al. 2007, Wesssel et al. 2004, Melillo et al. 2011). Such changes may disrupt the functioning of terrestrial ecosystems on our planet, which are vulnerable to disturbance (Millennium Ecosystem Assessment 2005, Elmendorf 2012).
Mycorrhizal symbiosis is crucial for most woody plants, especially in harsh environments such as the alpines. This project uses the perennial herb Bistorta vivipara as a model species to study ectomycorrhizal community ecology. The main aim is to reveal which factors (biotic or abiotic) that influence the fungal community structure. The variation in community structure is analyzed along various ecological gradients, including a primary successional gradient towards Blåisen. Pyrosequencing is used to analyze the fungal communities associated with the rootsystems of B. vivipara, a method that yield both quantitative and qualitative data about the communities.
A climate change experiment with open top chambers (OTCs) was established in the Dryas octopetala heath on Sanddalsnuten in 2000. Combined warming and nutrient addition has increased productivity and grass dominance at the cost of mosses, lichens, and small herbs, resulting in decreased diversity. In a seed sowing experiment we examined the relative role of dispersal and local interactions for alpine plant community diversity under climate warming. The long term effects of warming and local interactions on species recruitment and community dynamics will be examined in the coming years. This project is part of the International Tundra Experiment (ITEX).
Fine fescues are a large and ubiquitous group of morphologically similar fine leaved Festuca species. In this project we focus on F. rubra aggregate which is particularly interesting because taxonomy of the aggregate is largely unclear and it is well known for its high frequencies of systemic fungal endophytes – plant associated fungi that are suggested to expand distribution range of the host grass. In the symbiosis the host plants are associated with one fungal genotype which is maternally transmitted from mother plant to its offspring. Because these systemic endophytes often increase plant vigor, resistance to herbivores and pathogens, and tolerance to various environmental conditions, grass endophytes have usually been labeled as strong plant mutualists. Recently, however, an increasing number of exceptions to the purported endophytic mutualism have been reported, especially for native grasses.
Pyrosequencing is applied for the study of plankton and protist diversity in lake Finsevatn. This lake has been influenced by human activity, particularly since the tourism came to this high-mountain location with the opening of the Oslo-Bergen railway in 1909. Scientific investigations since 1986 have revealed the diversity of the lake's phytoplankton by microscopy, but new technology supplies a much more diverse picture involving microbial parasites and previously unknown protists - some with relatives in marine environments - see Bråte et al. (2010), Shalchian-Tabrizi et al. (2011).
Who are the pioneers on a fresh moraine? Predators like certain carabid beetles, spiders and Opiliones are present almost immediately, before any vegetation occurs. It is a paradox that predators are first. May be they eat springtails, which are also pioneers. Among plants, small moss colonies are typical pioneers.
Since 1970 the population fluctuations of small rodents and shrews have been followed by snap-trapping of two 1ha permanent grids at Finse, Hardangervidda, in June/July and August/September. Trapped animals are located to specific trap stations within the grids, and data on their weight and reproductive state are collected. Until the mid 1990s, trapping indicated rather regular fluctuations with quite variable population peaks every 3-4 years. Since the last great peak in 1994, no substantial peak in small rodent populations has been recorded here. A possible explanation for this change in pattern may be related to changes in the climate as mediated through the snow quality in late winter (cf Nature 456: 93-97).
In ecology, although there is a demand for it, there are very few long time series. So, after finishing the fieldwork for my master thesis in 1995, I decided to keep 90 of the Geranium sylvaticum L. individuals and continue to follow them up on a yearly basis, looking at between year variations as well as long-term trends. Every summer since 1995 I have measured; investments in reproduction (number of flowers, number of fruits, fruit:flower ratio, number of seeds) and vegetative growth (number of stalks and the height, number of leaves).
About 370 species of macromycetes have been identified in the area during sporadic visits since 1972. The main focus has been on Basidiomycota, especially the agarics. Many genera, for example most dark spored agarics, are still poorly known and many more species than those identified occur in the area. Part of the project has been to disclose connections between fungal species and vegetation types by means of studying the funga in a set of permanent plots
Hydrurus foetidus (Vill.) Trev. is one of the few macroscopic freshwater golden algae (Class Chrysophyceae) - and, contrary to most other sessile freshwater algae, it prefers winter conditions in rivers and brooks where temperature is near to 0° C. During the first months of spring, it may bloom and cover the bottom where turbulence is high and light conditions are best. At Finse, the Garpefoss out of lake Finsevatn is a locus classicus - studied by Strøm for his doctoral dissertation (see Strøm 1926), and where Hydrurus still occurs regularly from end of February through the spring months.
Populations of small rodents, especially lemmings in alpine and arctic environments, show extreme fluctuations in density from year to year and their cyclic dynamics have interested ecologists for nearly a century. Population dynamics of lemmings are, however, difficult to study because densities are often very low and the spatial distribution among different habitats depends highly on season and population density. This limits the usefulness of traditional studies of population dynamics in fixed trapping grids covering a limited area. In this project we look at seasonal and multi-annual patch occupancy dynamics of lemmings and other small rodents over several square kilometers and relate this to habitat characteristics and population density.
Here we look at life-history adaptation in the arctic charr in a high mountain environment with a particular emphazis on its life history strategies. As this is a marginal environment with regard to the number and variability of degree-days (i.e. the temperature sum), and the length and variability of the feeding season, the charr must trade-off energetic requirements to growth and gonad allocation, and potentially adopt a bet-hedging strategy. Thus, alternative life-history strategies may evolve in such harsh environments as compared to the founder population which exists in a very divergent lowland environment.
Growth and reproductive adaptations to low temperature, short season length, and/or fluctuating weather conditions are key traits for arctic and alpine plant species. Ranunculus glacialis in alpine area at Finse retains the perianth after the anthesis, but petals color change from white to purple, as opposed to most species that wither the perianths after petals have contributed to insect attraction during anthesis.
In recent decades, plant species in many mountain areas have expanded their distribution upwards, parallel with a trend of accelerated climate warming in many of these regions. To analyse the extent of floristic change in relation to local climate change over the long term, and to assess the sensitivity of mountain flora to changes in temperature, precipitation, and other potential drivers, a large span of sites and time periods, and a large variation in climate parameters is needed. Previous studies have shown that altitudinal shifts of vegetation are different for plant species found in snowbed communities and species found on ridges. In 1999 Einar Heegaard did a study of species distributions (vascular plants, bryophytes and lichens) from snowbeds to ridges using snowbed-ridge transects at different altitudes from approximately 1200 m above sea level and up to 1550 m. This summer we reanalyzed 21 of these transects. We will use these to study the differentiated altitudinal changes of vegetation of snowbed communities versus changes on the ridge communities.
Surviving the winter is a special challenge for herbivorous aquatic invertebrates in the alpine region due to long period of ice cover and cessation of primary production. Daphnids that reproduce parthenogenetically during the summer, with 2-3 generation through July and August, solve that problem with depositing sexually produced resting eggs in the autumn. However, the species at Finse, Daphnia umbra, also has an alternative strategy. Instead of producing parthenogenetic or sexual eggs in the autumn, they start storing lipid droplets in the body cavity.