Arctic lemmings show dramatic fluctuations in their population dynamics. Some years densities can be very high followed by a sharp decline and crash in numbers. These changes in numbers are also known to follow a cyclic pattern with three to four...
In the Arctic, willows are often dominant in the terrestrial vegetation. They play important ecological roles by being food plants for many herbivores, adding organic material to the soil and stabilizing it through their extensive root systems....
Caribou and reindeer (Rangifer ssp.) are widely distributed in the circumpolar Arctic and sub-arctic regions and have adapted to survive a wide range of conditions. General characteristics of the regions they inhabit are the short period of the...
Most small mammals are for obvious antipredator reasons cryptically coloured. The Norwegian lemming (Lemmus lemmus) is an exception to this rule in that it is contrastingly patterned in orange-yellow, white, and black. At times, especially when...
Different species of grasses and sedges are common plants in the tundra and dominant in many of the most widespread vegetation types. These species (collectively called graminoids) are also important food plants for same of the most abundant...
This is a study of the relationship between predators and their prey. We shall focus on the Arctic fox Alopex lagopus, the Arctic skua Stercorarius parasiticus and the long-tailed skua S. Longicaudus, all of which are dependent on lemmings as a...
An important goal in ecology is to understand the mechanisms that permit fluctuations in population size yet prevent extinction at low densities. Nevertheless, understanding of how animal populations are regulated is poor, although numerous...
Understanding the processes that maintain the distribution and abundance of different species has been an issue of fundamental importance for biologists for centuries. It is one of the most important questions that were given a theoretical...
Compared to biomes in more southerly latitudes, there is little fauna and flora diversity on the tundra. Furthermore, the structure of ecological communities is relatively simple in the Arctic. This provides an ideal opportunity for studies on the...
The research plan for this project covered a comprehensive description of site variability at different locations in the Arctic with special emphasis on soils and soil microbes. These should be used as a link between the above-ground and...
Molecular techniques make it possible to quantify infraspecific genetic diversity within plants and animals. This knowledge can help us to answer important questions about the life history and evolution of organisms. Until recently almost all...
All terrestrial ecosystems have a high, and largely unknown, species richness of fungi. It is estimated that 1.5 million species of fungi exist on earth. Fungi are the most species rich group of organisms after insects. The overwhelming majority...
The Arctic has often been regarded for vascular plants and probably also for other groups – as a ”sink”, recruited almost entirely by immigration. Some researchers (see Böcher et al.) even ask for evidence of in situ evolution for all...
Most plant species in the Arctic pose no immediate problem for the taxonomist. They are easy to determine and well-delimited from their nearest relatives. The opposite situation is, however, also met with. In a number of Arctic genera the...
Arctic biota underwent dramatic changes during Quaternary glacial-interglacial periods, and these historical processes are reflected in the genes and gene pools of Arctic species. Geographic isolation in different glacial refugia generated genetic...
The present project addresses the question: What regulates the number of species in an ecological context? This issue has two aspects: The question of the number of species that can co-exist in a given area. How these particular species have been...
The ultimate aim is to compare the geographical pattern of mtDNA variation and the distribution of chromosome races in the collared lemming to draw inferences concerning the origin of chromosome races. Scientific background The present...
One of the most unknown yet numerous insect groups in the Arctic, as well as in the world, is a small soil dwelling insect called the springtail (Collembola in latin). It is one of the oldest insects with a fossil record dating back 400 million...
This project forms an extension of a research programme called “Ecological genetics of the Daphnia pulex complex – An Arctic, circumpolar survey” (Hobæk 1995; Hobæk and Weider 1999). Our programme is based on collaborative efforts by...
The biodiversity of any ecosystem includes all the species present in the standing crop (i.e. the juvenile and adult population) and the pool of species stored in dormant stages (e.g. seed banks, cysts or long-lived larval stages in insects). Our...
