Spruce Forests of Sette-Daban Range (Vostochnaya Khandyga River Basin, Northern-East Yakutia)

Abstract

The spruce forests of Yakutia occupy less than 1–2 % of the forested area. However, these forests create favorable plant habitat conditions that are not typical for the zone of light coniferous taiga. Vegetation plots were sampled during route studies based on generally accepted floristic and geobotanical methods. The Sette-Daban Range (the eastern part of the Verkhoyansk Range) is a north-eastern limit of the distribution area of Siberian spruce (Picea obovata). According to the published data, the eastern border of its distribution area is limited to the Aldan River Basin. However, in fact, the eastern border of the species lies about 120 km east and a little to the north of the Vostochnaya Khandyga River, elevated up to 500 meters above sea level. Spruce forests grow on high river banks, 1st and 2nd terraces above floodplain. This type of forest is rarely exposed to flooding and is represented by one type: Vaccinium-Hylocomium spruce forest. This type features a mixed forest stand with the obligatory presence of Larix cajanderi and herb-dwarf shrub cover dominated by Vaccinium vitis-idea. For eastern part of the Verkhoyansk Range, two rare plant species were recorded, Chrysanthemum zawadskii ssp. peleolepis and Cypripedium macranthon Sw. The latter is included in the Red Data Book of the Republic of Sakha (Yakutia).