| Brief description of vegetation (% of total area.): |
The vegetation is dominated by pine forests, represented mainly by the forb-grass, shirokotravnymi, green forest, green forest, and steppe types of cranberry. Less common are grass-sphagnum bog and pine forests, and dolgomoshnye and belomoshnye forests are rare and only in minor parts. Occasionally (in areas protected from winter winds, mostly in the western part of the district) meet complex forests with an undergrowth of kustoobraznoy lime. In the pine forests on basic rocks generally have an admixture of larch, growing in the most adverse conditions, woody vegetation - on dry rocky slopes with thin soil cover on exposed to cold winds northern slopes, where some form of pine and larch woodland or small sparse larch forests. Under the canopy of bleached pine and larch-pine forests often come steppe shrubs and meadow-steppe species of herbaceous plants, giving these forests steppe character. For them, the very characteristic of some relict species of South Siberian origin - Saussurea controversa, Lathyrus gmelinii, Gentianopsis barbata, Geranium pseudosibiricum, Cerastium pauciflorum. Birch forests of Betula pendula in the district are distributed almost as widely as pine, but the vast majority of cases are derived from (and less frequently occurring aspen). By the nature of grass layer, they are analogues of the corresponding types of pine forests (the most common forb-grass and shirokotravnye types). Native birch (especially of Betula pubescens) are found in wetland habitats along the rivers and streams, on lakeshores and edges of swamps. Often, they have an admixture of black alder and gray, sometimes forming pure stands and. Very rare small areas of linden (some lakes on the islands) and the dark coniferous-deciduous forests (in the western part of the region). Forest area is very badly affected by logging and fires, thus represented almost exclusively by secondary vegetation, largely replaced by the derivatives birch. Large areas are occupied by meadows of various types, usually having poslelesnoe origin. On the slopes of mountain ridges in the ground water table out there mining the key tall grasslands, similar in composition to the bald area of tall alpine regions. On dry stony slopes of southern exposure extended community of mountain steppes - shrub (from Spiraea crenata, S. hypericifolia, Cerasus fruticosa, Cotoneaster melanocarpus), grass-forb (with Helictotrichon desertorum, Stipa pennata, S. dasyphylla, Festuca valesiaca, Koeleria cristata, Artemisia armeniaca, A. sericea, A. commutata, etc.) and petrofitnyh (with Echinops crispus, Centaurea sibirica, Dianthus acicularis, Aster alpinus, Artemisia frigida, Clausia aprica, Orostachys spinosa, Patrinia sibirica, etc.). On the shores of lakes and ponds on the site of the widespread bog communities - eutrophic sedge, mesotrophic sedge-sphagnum with Betula pubescens, oligotrophic Sphagnum with pine and herbal complex and shrubs typical of the taiga zone of swamps. In many lakes, greatly differing in chemical composition of water, soil characteristics, benthic and other conditions, and developed a very rich and diverse composition of aquatic and coastal-water community, which often act tsenozoobrazovatelyami species of the genus Potamogeton, Myriophyllum sibiricum, Stratiotes aloides, Ceratophyllum demersum , Nuphar lutea. In the lakes region are extremely rare find for the field types, as Isoëtes lacustris, Sparganium gramineum, Sagittaria natans, Potamogeton rutilus, P. filiformis, Caulinia flexilis, Batrachium eradicatum, Elatine hydropiper, E. orthosperma, E. triandra. |