Northern climates and woody plant distribution

Abstract

Climatic warming in northern latitudes will undoubtedly create new ecological opportunities for vegetation advance as ice sheets retreat and permanent snow cover is reduced. Depending on proximity to the oceans, and this includes the Arctic Ocean, the degree of winter versus summer warming is likely to differ. In northern regions the influence of oceanicity on plant distribution is very marked. The models described in this paper show that among some of the commonest woody species winter warming may in some cases cause a significant retreat in areas that where the climate is influenced by the ocean, while in other areas the species may make significant advances. Due to seasonal differentiation in responses to temperature the nature of the migration of species into these vacated areas or changing communities is unlikely to be a mere latitudinal shift northwards of existing species assemblages. It appears therefore highly probable that species migration will be strongly influenced by seasonality of temperature change, and for any one species similar patterns of climatic change in different parts of its range, could result in migration in opposite directions. Consequently, changing thermal conditions will be likely to alter species composition of existing northern plant communities. Attention will therefore have to be given to the roles of seasonality gradients as potential barriers to migration notwithstanding overall warming. © 2007 Springer-Verlag Berlin Heidelberg.