'Pacific Institute of Geography, Far East Branch Russian Academy of Science, Vladivostok, Russia 2Reserve "Kurilskiy", Yuzhno-Kurilsk, Russia
The stages of grassland development on Kunashir and Iturup Islands (Southern Kuril Islands) and Lesser Kuril Ridge are reconstructed based on pollen analysis and radiocarbon dating of soil profiles. There are anthropogenic grasslands and meadows in wind shadows formed during cooling events in Late Holocene; these formations have been relatively stable during last 1500-2000 years. Grasslands on small islands in the south of the Lesser Kuril Ridge have existed last 4000-6000. Floristic components began to change in the Late Pleistocene. Grassland soils have multiple profiles. Grasslands have various floristic compositions. Herbaceously rich meadows are located on terraces and divides, with Sasa on some terrace surfaces and slopes. Shrub-grass associations developed on supersaturated substratum; herb-graminoid - on well drained areas. Grass associations typical for swamp accumulative lowlands are developed on low coastal plains.
The lithogenic component of landscapes is most dynamic on the islands and it quickly responds to climatic changes and changes in sea level. For example, substratum renewal has largely been a response to aeolian processes during small amplitude regressions in the Middle and Late Holocene. Sand buildup and the addition of volcanic ash with varied chemical compositions have changed water and mechanical soil characteristics that greatly influenced grass associations. Supersaturated sedge and sedge-herb meadows even on low isthmuses shifted to herb-graminoid and the role of xerophilous species increased.
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