ALPINE VEGETATION

Alpine vegetation     The alpine vegetation of Sikhote Alin is composed of five types, viz. alpine tundras, alpine meadows, shrub thickets, creeping vegetation thickets, and sub-bald peak sparse elfin woodlands. These types are distinguished by prevalence therein of vital forms of plants that form the landscape physiognomic image. Alpine vegetation occupies just over 1 percent of the area of Sikhote Alin, but is distinguished by high diversity in connection with the difference in vital forms of dominants of alpine plant communities and the extreme patchiness of ecological conditions in the upper mountain belt.
   Alpine tundras occur over small sectors to alternate with thickets of shrubs and creeping vegetation from 1,300-1,400 m; again, higher than 1,500-1,600 m the alpine tundra landscape becomes predominant. Three groups of alpine tundra associations are most widespread.
   Detrital lichen tundra forms in most severe conditions on dome-like peaks aand gently sloping-bulging watersheds open to winds blowing from all directions. The surface is largely not covered with vegetation, the overall cover seldom exceeding 0.4. Deposited lichen species (from the genera Ledidea, Rhizocarpon, Girophora, etc.) and foliate lichen species (from the genera Cetrarta, Parmelia, etc.) prevail. Individual specimens and groves  of Potentilla elegans, Artemisia furcata, Saxifraga bronchialis, etc. are sattered in recesses with small fine earth accumulations and under the protection of large rocks.
   Heather-lichen alpine tundras occupy weakly bulging slopes of various expositions. Here we already have a soil cover, albeit not continuous and weakly developed. Detrital-rocky outcrops are relatively rare. Vegetation occupies a major portion of the surface. Shrubby lichen from the genera Cladonia, Cetraria, Alectoria, Cladina, etc. are absolutely prevalent here to form an almost continuous carpet, whose living and dying sections are up to 10-15 cm thick. Prevalent among low shrubs are Cassiope spp, Rhododendron spp,Salix spp, Empetrum nigrum, Vaccinium uliginosim, and V. vitis idaea; specimens of Pinus pumila, etc. also occur. Carex spp, Luzula spp, Saussurea kitamurna, Bistorta vivipara, etc. are common grass species.
   Shrub-moss tundra forms on sites with more developed, though thin, detritus soils with lengthily retained snow. Lichen-moss mosses are Aulocomnium, Polytrichum, Rhytidium, Rhacomitrium, Dicranum, etc. Prevalent among lichen is Cladonia, Vaccinium, Rhododendron, Ledum, Salix, Arctous, Diapensia, etc. Pinus pumila, short specimens of Betula lanata and Alnus fruticosa also occur. Herbaceous plants are few, Carex representatives prevailing.
   Alpine meadows. In Sikhote Alin, there are no real Alpine meadows typical of European highlands. Natural treeless areas of grass vegetation do occur in small patches at altitudes ranging from 1,200 to 1,600 m. They form preferentially in snow accumulation sites and do not form an independent altitudinal strip. The area of some sites seldom exceeds 0.5 ha, and is normally less.  Occurring most often are dense thickets tall grass highly diversified in composition with usually no clearly predominant species; however, the general background is created by representatives of the genera Aconutum, Cacalia, Saussurea, Angelica, etc. Besides such very dense one-tier tall-grass thickets, tall-grass meadows also occur with the second tier composed of ferns and forest shadow-resistant low grass areas composed of Maianthemum bifolium, Chamaepericlymenum canadensis, Linnea borealis, etc.). The fact that typically forest plants are part of the upper forest boundary and situated near it allows to assume that they are secondary formations in lieu of destroyed forests. In sites with seasonal icing, there are small perpetually existing reed grass-herbage meadows, which B. P. Kolesnikov (1969) called icing meadows.
   Creeping plant and shrub thickets. The ligneous formation of the elfin pine tree Pinus pumila is most widespread among creeping plants and shrub plant communities of the upper alpine belt of Sikhote Alin.  The phytocoenotic and botanical and geographic properties of P. pumila communities and their growth morphology allow taking them for a specific forest formation, viz. creeping forests. A biological property of creeping plants is their ability to lie on the ground after the first frosts to hide themselves under the snow from the bitterest winter cold.  For that reason, P. pumila avoids habitats where snow is blown off by winter winds. The motley natural conditions in the upland determine the diversity of associations formed by P. pumila.
   Dense and virtually impassable thickets form near the forest upper boundary; the diameter of tree trunks at the base is up to 20 and even 30 cm wide, the trunk length up to 5-7 m, and the thickets up to 3 m tall. The Ledum hupoleucum prevails in the lower tier, and the grass and moss-lichen tiers are weakly developed and poor in specific composition. P. pumila forms even thicker thickets on wind-protected sites of southern slopes near the upper forest boundary. Here, Hypnosa-Vacciniosa associations form. Among those groups of creeping plant thickets, scattered specimens of tree species (Betula lanata, Sorbus schneideriana, etc.) are present.
    With increase in landscape altitude (absolute altitude), P. pumila thickets become rarer to decrease in height to 1-1.5 m and 0.5-0.6 in density to subsequently degrade to small groups and single specimens among alpine tundra.  P. pumila thickets with participation of Microbiota decussata from the family Cupressaceae, a Sikhote Alin endemic, is a completely unique grouping of Sikhote Alin alpine vegetation. So far, this group of thickets has occurred only in southern Sikhote Alin and at the Khor-Bikin watershed.
    In southern Sikhote Alin, M. decussata also forms independent thickets with its own absolute dominance. Their density is close to 1 m, and normally they are not over 1.0 m tall. The thicket specific composition is poor, and other species grow only in rare clearings in a canopy of continuous microbiota. Thin thickets consisting of small groups and individual Juniperus sibirica specimens, also belonging to the fam. Cupressaceae, occur on the upper parts of rocky slopes at altitudes of up to 1,500-1,550 m. They grow only on southern and southeastern slopes protected from winter winds, and with stable snow cover.
    Of foliate shrub thickets, the apparently most widespread species is Rhododendron aureum, which often forms single-dominant groupings and takes part in thickets of other dominants, and even in the underbrush of straight-trunk forests at the forest upper boundary. R. aureum thickets occupy weakly concave run-off ravines and other sufficiently humidified habitats with presence of at least thin and primitive soil. Closed thicket flowering results in an amazingly beautiful combination of very dark green leaves and whitish-golden large flowers to create a highly unique landscape.
    Weigela middendorfiana thickets are widespread near the forest upper boundary, and also among separated tongues of straight-trunk forests that form a sinuous and intermittent upper forest boundary. They occupy ravines in the upper parts of permanent and temporary run-offs. The density of these thickets is considerably less than that of creeping plants, microbiota thickets and rhododendrons; hence, the specific composition of the grass tier is more diversified. Calamagrostis landsdorfii, Chamaepericlymenum canadense, Ledum decumbens, Linnea borealis, Carex spp, etc. commonly occur here.
    Duschekia fruticosa thickets occur as odd sites on gently sloping and terrace-like sections of watersheds, and also as spots among thickets of other species, occupying preferentially leeward slopes. The grass tier of these thickets contains numerous plants typical of the forest belt that lies below.
    The elfin woodlands of Sikhote Alin represent transitional forms of arboreal vegetation from straight-trunk forests to creeping plant and shrub thickets. Nowhere do they form a continuous elevation belt, occupying diverse habitats with at least a small layer of sufficiently moist primitive soil. Elfin woodland sites occur most frequently on gently sloping areas and terrace-like benches of pre-watershed slopes, gently sloping ravines and valleys.
    The B. lanata with its highly crooked trunks and branches prevails in the tree stock. In the south, it is slightly mixed with Sorbus schneideriana and dwarf specimens of P. ajanensis and A. nephrolepis with crowns lowered to the ground. In these conditions, there were cases of rooting of lower P. ajanensis branches. In northern Primorye, the Larix spp. occurs in elfin woodlands to assume a creeping form itself on the upper forest boundary. In northern Primorye, A. nephrolepis normally does not rise higher than to 1,000 m. Elfin woodlands are from 2 to 4 m tall, and on windy sites just 1-1.5 m. P. pumila and heather shrubs and bushes often grow in the underbrush. The grass cover does not form a continuous tier. It commonly contains Calamagrostis spp, and Carex spp, and frequently the valuable medicinal plant, Bergenia pacifica, is subjected to uncontrolled purveyance.
    Elfin woodlands are highest forest outposts with remarkable slope-protection and water-regulation significance. When destroyed by fires, rocky talus and detritus replace them.
 

   V. ROSENBERG, Cand. Sci. (Biology), Leading Researcher,  Institute of Biology and Soil Science, F. E. Branch, Russian Academy of Sciences.

   E. SHATKOVSKAYA, Leading Engineer, Institute of Biology and Soil Science, F. E. Branch, Russian Academy of Sciences.

   I. LANDINA, Senior Lab. Researcher, Institute of Biology and Soil Science, F. E. Branch, Russian Academy of Sciences.

  S. KRASNOPEEV, S. M., Cand. Sci. (Physics and Maths), Senior Research Fellow, Pacific Institute of Geography, F. E. Branch, Russian Academy of Sciences

  T. KRASNOPEEVA, 1st Category Programmer,  Pacific Institute of Geography, F. E. Branch, Russian Academy of Sciences

  S. TOURCHANOV, 1st Category Programmer,  Pacific Institute of Geography, F. E. Branch, Russian Academy of Sciences

  E. SHESHIKOVA, 1st Category Programmer,  Pacific Institute of Geography, F. E. Branch, Russian Academy of Sciences

 T. SHASHURA, 1st Category Engineer, Pacific Institute of Geography, F. E. Branch, Russian Academy of Sciences
  
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