Island Volcanic Ecosystems in the Pacific Mobile Belt as Sources of Continental Biosphere Formation

Abstract

Empirical-statistical modeling of the structure of island-arc forest ecosystems has been performed based on data from a large-scale landscape and ecological survey in the region of the Mendeleev Volcano (Kunashir Island, the Southern Kuril Ridge) and on regional bioclimatic data. These systems characterize one of the initial stages of the formation of the continental biosphere in the Pacific mobile belt. The causes of the general lowering of the boundaries of altitudinal bioclimatic belts and the shift of natural zones to the south in the extratropical Neopacific in comparison with the adjacent continent have been determined. It has been revealed that the dark-coniferous and mixed forests of Kunashir Island differ from their continental analogs by their higher productivity, which makes them similar to subtropical forests of Northwest Pacific. The predomination of the transpiration component in the heat balance provides a high level of autotrophic biogenesis, which results in the stability of island-arc forests under unfavorable cold oceanic conditions. The hypothesis that the geothermic energy of passive volcanoes favors the formation of climatically inadequate forests and enhanced evolution of island phytobiota has been, in general, empirically substantiated.