Work Package 4
Moth-reindeer-birch dynamics in northernmost Fennoscandia

One consequence of a milder climate is a change in the occurrence, geographical distribution and severity of episodic geometrid moth outbreaks in mountain birch forests. During the last decade, a massive outbreak has swept across northern Fennoscandia, affecting as much as 1/3 of the birch forest belt by severe defoliation in one or more years. In recent decades, the outbreak ranges of both autumnal moth (Epirrita autumnata) and the more oceanic winter moth (Operophtera brumata) have expanded into more continental and colder inland areas, where cold winters previously protected birches. Complicating the picture is the invasion of a third more southern species, scarce umber (Agriopis aurantiaria). All three species also exploits dwarf birches, and defoliation has been observed far above the alpine tree line.

In areas grazed by reindeer in summer, the impact of moth outbreak can be permanent deforestation, as reindeer eat the basal recovery sprouts of birches. This is exemplified by the large areas in northernmost Finnish Lapland, which are marked as tundra on newest topographic maps but which were covered by continuous birch forests before the 1965 outbreak. In a climate change perspective this is good news, as it suggests that forest expansion can be reversed. We will study the impacts of moth outbreaks and reindeer grazing on the mountain birch forest ecosystem in order to understand the role of both these herbivores as drivers of vegetation change in mountain birch forest. Specifically, we will investigate damage levels, vegetation recovery and succession and the use of the damaged areas by medium sized and large herbivores, in replicated pairs of fenced and unfenced study plots established in contrasting forest types (rich versus poor), reindeer densities (low versus high) and recent outbreak history (single- versus multiple years of defoliation).

The birch moth ecology group at University of Tromsø and NINA

The University of Tromsø

The Norwegian Institute for Nature Research (NINA)

FRAM – High North Research Centre for Climate and the Environment

Plant Ecology and Population Biology group at University of Oulu

Docent Annamari Markkola, Univ. of Oulu (Annamari.Markkola[at]

Senior Res. Jane Uhd Jepsen, Norwegian Institute for Nature Research (NINA) (Jane.Jepsen[at]

Prof. Pekka Niemelä, Univ. of Turku (pnieme[at]

Prof. Rolf Anker Ims, Univ. of Tromsø (rolf.ims[at]

Prof. Juha Tuomi, Univ. of Oulu (juha.tuomi[at]

Newest Publications

     Content Editor


    Keskitalo, E.C.H, Horstkotte, T., Kivinen, S., Forbes, B., and Käyhkö, J. (2015). "Generality of mis-fit"? The real-life difficulty of matching scales in an interconnected world. Accepted for publication in Ambio.

    Saccone P. and Virtanen R. (2015). Extrapolating multi-decadal plant community changes based on medium-term experiments can be risky: evidence from high-latitude tundra. Oikos. DOI: 10.1111/oik.02399.

    Stark, S. and Ylänne H. (2015). Grazing in Arctic peatlands – an unknown agent in the global carbon budget. Environmental Research Letters, 10: 051002. DOI: 10.1088/1748-9326/10/5/051002.

    Ylänne, H., Stark, S., and Tolvanen, A. (2015). Vegetation shift from deciduous to evergreen dwarf shrubs in response to selective herbivory offsets carbon losses: evidence from 19 years of warming and simulated herbivory in the sub-arctic tundra. Global Change Biology,  21: 3696–3711.

    Ruffino, L., Oksanen, T., Hoset, K.S., Tuomi, M., Oksanen, L., Korpimäki, E., Bugli, A., Hobson, K.A., Johansen, B., and Mäkynen A. (2015). Predator-rodent-plant interactions along a coast-inland gradient in Fennoscandian tundra. Ecography. DOI: 10.1111/ecog.01758.

    Björkman, C. and Niemelä, P., eds. (2015). Climate Change and Insect Pests. CABI Climate Change Series 7. 279 pp.

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