How to preserve the tundra in a warming climate?

The anticipated warmer climate in the future is believed to change most of the current arctic-alpine tundra to forest or dense scrubland. This modification may trigger positive feedbacks, where vegetation changes speed up global warming by decreasing the global albedo. Our aim is to unravel the complex climate-animal-plant interaction of the tundra ecosystem and find out the capability of herbivorous mammals in controlling and inhibiting the expansion of woody vegetation. The role of domesticated animals in the deforestation of Eurasia has been discussed in several biogeographical texts. Our recent studies have demonstrated that at the arctic-alpine timberline, the expansion of erect woody plants can be prevented by the combination of a relatively sparse reindeer stocks (2-5 heads per km2) and natural populations of arvicoline rodents. Realizing this potential requires an interdisciplinary approach. In the ecological work packages, we study the dynamics of the natural food chains involving small herbivorous and the impacts of reindeer on the vegetation and the population dynamics of those arctic-alpine plants, which are most likely to become threatened in a warmer climate. In the climatic subprojects we study the impact of grazing-dependent vegetation differences on the fraction of solar energy which is converted to heat. In our socio-economic studies, we study the conditions for maintaining the economic and cultural viability of reindeer herding and directing land use so that it would maximize our chances of preserving open landscapes, suitable for arctic-alpine biota.