Why Do the Boreal Forest Ecosystems of Northwestern Europe Differ from Those of Western North America?

oscience. 2016 Sep 1;66(9):722-734. doi: 10.1093/biosci/biw080. Epub 2016 Jul 20.

Boonstra R¹, Andreassen HP¹, Boutin S¹, Hušek J¹, Ims RA¹, Krebs CJ¹, Skarpe C¹, Wabakken P¹.

Author information

1

Rudy Boonstra (boonstra@utsc.utoronto.ca) is a professor in the Department of Biological Sciences at the University of Toronto Scarborough. He studies the factors that regulate and limit animal populations in temperate and boreal ecosystems, and especially the role of stress in natural populations. Harry Andreassen (harry.andreassen@hihm.no) is the dean and a professor, Jan Hušek (jan.husek@nord.no) is a postdoctoral fellow, Christina Skarpe (christina.skarpe@hihm.no) is a professor, and Petter Wabakken (petter.wabakken@hihm.no) is an associate professor at Hedmark University College, in Evenstad, Norway. HA studies the causes of population fluctuations in the boreal forest, with special emphasis on the interaction between social factors and predation. JH studies avian ecology and behavior. CS's research deals with large herbivores and their ecological significance for soil and plants, predators, and each other. PW studies the behavioral ecology and population dynamics of large carnivores and avian predators. Stan Boutin (sboutin@ualberta.ca) is a professor of biological sciences at the University of Alberta. He studies the population dynamics and management of mammals in the boreal forest. Rolf Ims (rolf.ims@uit.no) is a professor of Arctic and marine biology at the University of Tromsø. He studies the dynamics of ecological interactions in Arctic ecosystems and how these are shaped by climate change and other anthropogenic impacts. Charles Krebs (krebs@zoology.ubc.ca) is an emeritus professor of zoology at the University of British Columbia. He studies boreal forest community dynamics in the southwestern Yukon.

Abstract

The boreal forest is one of the largest terrestrial biomes on Earth. Conifers normally dominate the tree layer across the biome, but other aspects of ecosystem structure and dynamics vary geographically. The cause of the conspicuous differences in the understory vegetation and the herbivore-predator cycles between northwestern Europe and western North America presents an enigma. Ericaceous dwarf shrubs and 3- to 4-year vole-mustelid cycles characterize the European boreal forests, whereas tall deciduous shrubs and 10-year snowshoe hare-lynx cycles characterize the North American ones. We discuss plausible explanations for this difference and conclude that it is bottom-up: Winter climate is the key determinant of the dominant understory vegetation that then determines the herbivore-predator food-web interactions. The crucial unknown for the twenty-first century is how climate change and increasing instability will affect these forests, both with respect to the dynamics of individual plant and animal species and to their community interactions.

KEYWORDS:

climate; dwarf and tall shrubs; food webs; population cycles; small mammals

PMID:

28533563

PMCID:

PMC5421309

DOI:

10.1093/biosci/biw080

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