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