ИСТИНА

The existing extreme landscapes include very cold environments in Arctic, Antarctic and high mountainous areas, very dry deserts, caves, strongly changed by human activity and artificial ones. The study of the landscape processes in extreme environments can help us understanding the diversity of ecosystems in the world and the trends in their development throughout the history of the planet, and to predict possible change of landscapes. It is proposed to distinguish the landscapes of orthoextreme environmental conditions and landscapes of paraextreme conditions. Criteria of orthoextreme landscapes – weakly developed soil profiles and/or stressful state of biota and very low emission of C-containing gases from soil. By orthoextreme landscapes we understand a variety of crusts or protolandscapes (endolithic,hypolithic, certain types of rock varnish, etc.), landscapes with soils without or weakly developed humus and litter horizons which are regarded Arenosols, Nudilithic Leptosols, Regosols and some Solonchaks. Paraextreme landscapes are defined as a transition stage from orthoextreme landscapes to the common ones developing at a "structural-functional optimum". They are adequately described and studied by classical physical geography. According to the factors of extreme environment we propose to distinguish clima-extreme landscapes (especially at high latitudes and deserts, and high mountains), topo-extreme landscapes limited in development due to local relief conditions (caves, cliffs, etc.), litho-extreme landscapes limited by toxicity or low nutrients content in rocks, as well as their very poor physical properties, such as high rocky fragments content and the virtual absence of fine earth, and sedimentoextreme or briefly sedi-extreme landscapes with profiles constrained by sedimentation of aeolian, fluvial, volcanic and other material.