Ecological research concerning the forest vegetation at the pioneer stage in the Bucovina Ridges area, Suceava, Romania

The interactions occurred at the pioneer stage which subsequently directs the evolution of composition and vegetation structure still present many unknown facts, the studies being related to a reduced number of ecosystems. The study was conducted in two forest ecosystems from the Bucovina Ridges area, differentiated by ecological factors and component species but being at the same evolution stage (pioneer stage). The aim of this research was to determine the interactions and the interspecific association pattern according to certain ecological gradients, the species diversity and the interspecific competition’s level. For the studied ecosystems, there were identified a number of 17 species for each type of habitat and 28 species in total, some of the species being common to both ecosystems. The identification of the constant species, the general and specialized ones has highlighted the influence of ecological conditions from the two habitats but also the type of disturbance. The types of identified associations can be used for ecological reconstruction works of similar habitats from the Bucovina Ridges. The species diversity pointed out the presence of certain ecosystems with low stability, an aspect characteristic for the pioneer stage. The two ecosystems differentiate themselves by their species diversity, the ecosystem from Gura-Humorului region being a bit more developed. It can be therefore concluded that at this successional stage, the type of disturbance has the main role in the distribution and composition of the forest vegetation. The two ecosystems already contain, at the pioneer stage, main species (spruce, beech), which will direct the ecosystems through relations with the other species towards those described by the specialty literature for those areas.