Original paper

Phytogeographic aspects of the occurrence of forest vascular plant species in Pomerania (northwest Poland)

Popiela, Agnieszka


Forest species occurring in Pomerania (NW Poland) are discussed from several points of view. The study considers the typology of their ranges in Pomerania, affiliations with geographical elements and the nature of their habitat. The material of the study includes 129 original maps of the species distribution in Pomerania. Taxa included in one type (subtype) of distribution have, in numerous cases, a similar general distribution. The typology of local ranges resulted in groupings of taxa associated with the same type of forest association. Hypotheses regarding the pathways and the age of forest species migration to the Pomerania territory in the Holocene were developed. The periods of most intense migration of forest species to Pomerania were the Boreal (9000–8000 14C BP) and Atlantic (8000–5000 BP) periods. It is postulated that in this period Pomerania was inhabited by most of the taxa associated with mesophilous deciduous forest. The earliest invaders in Pomerania were taxa associated with pine woods, part of which was already present in this area from the Preboreal or even the Late-Glacial. Somewhat later in the Preboreal the arrival and distribution of the carr association taxa took place. The taxa currently associated with beech woods and oak-hornbeam forests probably appeared already in Pomerania in the period of climatic optimum, i.e. before the appearance of beech and hornbeam in this territory. Prehistoric, historic and recent transformation of forest communities by human activity played a very important role in the distribution of forest species. Expansion of some widespread taxa could be bound to anthropogenic transformation of the vegetation. The relationship between selected abiotic factors and the contemporary distribution of forest species was statistically tested (log-linear analysis). The results of this analysis confirm that the distribution of forest taxa depends on the differentiation of Pomeranian climatic parameters, the type of geological substrate and the size of forest complexes.