Scots pine forests of the Vaccinio-Piceetea class in Europe: forest sites studied

The paper presents: a) the general differentiation of the pine forests of Europe, and b) the floristic differentiation of the ten study sites, located along the transect stretching between 50°28′ and 70°09′ N, as well as c) the relations between the geographical location and the climatic characteristics on the one hand, and the selected features of the richness and species diversity of the herb layer on the other. One can observe a dependence (p < 0.05) between the temperature and latitude on the one hand, and the number of species from some groups on the other. For the vascular plants, the indicators of linear correlation amount to, respectively, 0.64 and -0.63 (the number of the vascular species of the herb layer increases with the warming of climate and the movement towards the South), and for the numbers of lichen species: -0.81 and 0.78 (the dependencies have the opposite directions to the previous ones). The variability of the relative shares of the particular species groups is correlated with geographical location and climatic variables. Three basic patterns of spatial variability can in this context be identified. The first of these is represented by the share of the lignified chamaephytes (dwarfshrubs). In accordance with this pattern, the minimum shares are observed at the latitudes of Lithuania, Latvia, and Estonia. The second pattern of variability is represented by the shares of hemicryptophytes. In accordance with this pattern the maximum shares are observed between 53° and 56° N. The third pattern of variability is represented, in particular, by the share of the evergreen species which is proportional to the latitude.