Ecological assessment of larch sparse trees in the forest tundra ecotone of Western Siberia (on the example of Mongayurbey river valley)
A. V. FAKHRETDINOV, S. P. AREF’EV, D. V. MOSKOVCHENKO
Tyumen Scientific Centre SB RAS, IPOS, Tyumen, Russia
Keywords: tundra, climate change, dendrochronology, Taz peninsula
Abstract
Ecological condition of extrazonal larch sparse trees in the val.y of Mongayurbey river (the Taz peninsula) has been studied on the base of remote sense data and tree-ring chronologies. The site is one of the northernmost enclaves of taiga vegetation in Western Siberia. The analysis of Terra-MODIS satellite images from 2000 to 2020 showed that vegetation index value (NDVImean) revealing average quantity of photosynthetical active phytomass over the summer period depends most on the average annual air temperature (correlation coefficient R=0.69). However, there is no statistical. significant trend of the vegetation index despite the stable trend in the rising of summer temperatures that is connected to the inertness of the shrub-moss-lichen ground cover. Correlation of maximum vegetation index values (NDVImax) and total width rings (TRW) of Larix sibirica Ledeb. revealed close link ( R = 0,72) on the border with the watershed, where is the young tree stand with the most crown density and abundant undergrowth. On the contrary, there is a digression of the tree stand in the val.ys areas, associated with deterioration of nature conditions (changes in drainage, soil characteristics, permafrost and geochemical conditions). At continuation warming, we can expect the spread of larch trees from the river floodplain towards watershed that confirms the current movement to the north of the border of forest vegetation.
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