Evaluating genetic resources of forest trees by means of life history traits – a Norwegian example

Abstract

Additive variation in adaptive traits is a prerequisite for selectionand adaptation to future environmental changes, but distribution of adaptivegenetic variability between and within populations is poorly known in mostforest trees. Owing to this deficiency, life history traits such as geographicrange, pollination vector and seed dispersal capability, which significantlyaffect gene flow and thus the distribution of genetic variability, were used toevaluate the genetic resources in 23 Norwegian native forest tree species. Basedon the combination of life history traits the species' genetic resourceswere classified either as viable, potentially vulnerable or vulnerable, assuminga decrease in within-population variability in this sequence. Twelve widelydistributed species with generally effective dispersal of pollen and seeds wereconsidered viable (Pinus sylvestris, Picea abies,Juniperus communis, Betula pubescens, B. pendula,Alnus incana, A. glutinosa, Salix caprea, Populustremula, Corylus avellana, Sorbus aucuparia, Prunus padus)and have as such no particular conservation needs. Effective seed dispersal of these species, asinferred from post-glacial migration rates, may be partly responsible for theirgenerally early post-glacial appearance, and may, in combination with the wideranges and relatively large evolutionary potential, indicate that viable speciesare best able to cope with climatic change. Among species with restricted rangesand more limited gene flow eight were considered potentially vulnerable (Quercuspetraea, Q. robur, Fraxinus excelsior, Acer platanoides,Taxus baccata, Ilexaquifolium, Fagus sylvatica, Ulmus glabra) and threewere considered vulnerable (Tiliacordata, Malus sylvestris, P. avium). Application of differentintensities of a multiple population breeding system (MPBS) is considered the most appropriate mode of conservinggenetic resources in these species.