Orchids of Subpolar Urals: features of biology and structure of populations

For the period 2010-2011, five species of the Orchidaceae ( Cypripedium calceolus L., Coeloglossum viride (L.) Hartm., Epipactis atrorubens (Hoffm. ex Bernh.) Bess., Gymnadenia conopsea (L.) R.Br., Leucorchis albida (L.) E. Mey) were studied in the basin of the middle and upper reaches of the Kozhim river. Distribution of these species is mainly connected with the outputs of calcium- bearing rocks. We found that orchids are well adapted to the conditions of the Subpolar Urals, as evidenced by the relatively high abundance of coenopopulations, successful self-maintenance and compliance of ontogenetic spectra with their biological characteristics. Only in populations of orchids belonging to root- tuber life form a slight increase in the share of young (immature) plants, because of their Northern location and longer ontogenesis of this species is observed. The main negative factor limiting reproduction of orchids in the North is a short vegetation period. Early summer frosts damage buds and freezing at the end of summer does not allow seeds to ripen, that affects the plants, especially early-blooming species. Besides, harsh conditions of the Subpolar Urals have impact on the habitus of plants as can be seen in the reduction of their size and the number of metameres (leaves, flowers) compared to the plants from more southern populations. At the same time the increase in the size of the flowers with a general decrease of habitus were marked for root-tuber species. This may be an additional device for maximizing seed renewal of these species.