Diversity of Pinus pumila-dominated communities on the Kamchatka Peninsula

On the Kamchatka Peninsula, Far East Russia, Pinus pumila-dominated communities occur from sea level up to 1200 m and geographically from the southern extremity of the peninsula up to the Kamchatka Isthmus and the Koryak Upland. Variation in species composition and abundance in P. pumila stands are determined mainly by the habitat’s moisture, soil fertility (expressed as the litter-humus coefficient) and altitude. The fertility level of the habitats has a significant positive impact especially on the abundance of the herb layer species, and to a lesser extent on the cover of the shrub layer. The growth of dwarf-shrubs and lichens is inhibited in habitats with better fertility. In relation to the fertility gradient, the vertical structure of the communities is also changing explicitly; the thickness of snow cover and exposition has a modest effect on the vegetation of P. pumila stands on Kamchatka. The analysed set of 272 relevés were clustered into six community type groups: (i) pure dwarf-pine communities, (ii) shrub-rich communities, (iii) dwarf-shrub-rich communities, (iv) herb-grass-rich communities, (v) moss-rich communities and (vi) lichen-rich communities; further 18 community types were established. They have a fairly good correspondence with most of the syntaxa described by previous scholars, but this is not always the case.