Permafrost

territories have natural and anthropogenic origin.
Eventually, all disturbed habitats with well drainage in the permafrost areas of strong
continental climate with small precipitations (tundra, forest-tundra, taiga) are grown over by
steppe plants (almost all Yakutia, Zabaikalie). The projective cover of these plants is small. Soil
similar to steppe ones are also formed: humus is accumulated but not peat, soil reaction is about
neutral, and the amount of exchangeable calcium and magnesium increases. The humus content
accounts for 1 – 1,5 % in upper horizons of minor soils and about 3 - 8 % in fine earth from
grass tussock. All investigated soils have neutral or close to neutral reaction. This process was
not market in Tynda (Amur region) because of the influence of Far East monsoon climate on
this region. This process was not market too in northern-western seaside part of Yakutia with
frequent drizzling rains (Tiksi, Chokhurdakh, Khroma bay) where disturbed habitats are grown
over by pioneer and apophyte vegetation. Such situation is near Vorkuta (tundra), Labytnangi
and Salechard (Yamal, forest-tundra), Khatanga (tundra) where the climate is more humid then
in north-east of Russia. We known from scientific publication that analogical situation exist in
north of European part of Russia too.
It is necessary to tell separately about pine forests. The pine forests are wide-spread in
Zabaikalye and in neighbouring territories. They grow on sandy sediment in intermountain
valleys. These forests penetrated into a steppe zone of Mongolia through high sandy ridge. They
were investigated in Verhnyeangarskaya depression during 2004 year (around Novy Uoyan
settlement, northwest of Buryatia).
The area is located in Moscow latitude. True altitude is more than 500 m. These pine
forests are "classical" types. Litter or lichen pine forests grow on high sandy ridge,
grass-cowberry-lichen forests distributed on flat surface. Soils here are sandy weakly podzolic
and podburs. The permafrost is deeply and does not affect the pedogenesis.
Forests around of settlement are under strong anthropogenic stress: unpaved roads, groove,
wood dumps and other. Light sands are formed here too. Disturbed sites slowly obliterate with
pioneer plants, and then steppe ones: wormwoods, thyme, steppe grasses and etc. Lawns in
settlement have steppe aspect also. Pioneer and steppe plants cover roadsides from railway
station to northwest.
The pine forests will be replaced by steppe as it takes place in south Buryatia without
application of special security measures.
Key words: Disturbed habitats, permafrost regions, pioneer plants, apophyte plants, steppe
plants and soils
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