GEOLINKS International Conference 2019, Book 3
ECOLOGY AND ENVIRONMENTAL STUDIES
ECOLOGY OF LOWER TREELINE OF KURAI INTERMOUNTAIN DEPRESSION (CENTRAL ALTAI)
Evgenii Timoshok, Iulia Raiskaya
The lower treeline of the Central Altai is strongly affected by land use and grazing. Traditional ways of the Altai people land use before early XX century were non-exhaustive, the population numbers were low and therefore grazing impact was minimal. The growth of the human population and the increase of Chuyskiy Trakt importance caused increasing of sheep grazing. It was increased even more during Soviet period because of extensive approach to land use. Overgrazing and extensive tree cutting caused a significant rising of the lower tree line. The decrease of overgrazing caused by the dissolution of USSR and following the financial and agricultural crisis created the possibility of lowering of the tree line. The possible ways of tree line dynamics under the impact of modern climate change may be different. If the influence of climate change (warming and aridization in the case of Altai) is great enough the tree line would remain the same or continue rising. If the one was not enough strong the tree line would descend. Our investigation allowed us to fetch out slow descending of the lower tree line and presence of “overgrazed low Artemisia steppe -> regenerated Stipa steppe -> Young Larix sibirica forest with Iris domination in the grass storey” secondary succession. The succession is slowed down by the presence of grazing but looks sustainable. The situation is a great illustration of the fact the change of land use in some cases may be important for ecosystem rehabilitation and be enough powerful to counterweight climate changes at least for some time. It also confirms the earlier hypothesis on the great ecological amplitude of Larix sibirica which still successfully colonizes previously forested areas despite the mentioned climate changes.
Lower treeline; Mountain treeline; Siberian Larch; Mountain forests; Overgrazing;