ISSN 1067-4136, Russian Journal of Ecology, 2009, Vol. 40, No. 1, pp. 44–47. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © N.V. Peshkova, N.I. Andreyashkina, 2009, published in Ekologiya, 2009, No. 1, pp. 49–52.
Under the effect of climate warming, Siberian larch
Ledeb.) forest communities in highlands
of the Polar Urals are undergoing transformations
involving shifts in their boundaries. Thus, in the
Engayou–Kerdomanshor interﬂuve, where our data
have been collected, the upslope expansion of closed
and open forests over the past 90 years has reached 80
and 77 m, respectively (Shiyatov et al., 2005).
In this study, we made an attempt to ﬁnd out what
changes take place in the lower layers of typologically
identical tree communities upon transformation of open
forest into closed forest. Successions were studied in a
spatial series rather than in time, with conclusions
being based on the comparison of different segments of
the same altitudinal transect.
MATERIAL AND METHODS
The study area was 3 km east of Mount Tchernaya
in the Polar Urals (66
E). The structure of
the lower vegetation layers was compared in an open
larch forest (219–223 m a.s.l.) and in a closed larch for-
est of the same dwarf birch–herb–dwarf shrub–moss
type growing at a lower elevation (182–185 m a.s.l.) on
the same slope of eastern exposure. In each community,
vegetation was described in three 20
20-m test plots.
Both segments of the transect were characterized by
pit-and-mount microtopography and abundant mois-
ture supply. The open forest was on mountain-tundra
peaty gley loamy soil; the closed forest, on mountain
peaty humus-gley loamy soil.
The shrub and herb–dwarf shrub layers consisted of
61 vascular plant species in the open forest and of
52 species in the closed forest, with 38 species being
common to both communities. In the moss layer,
comnium palustre, Dicranum majus
prevailed in both communities;
schreberi, Polytrichum strictum
, and the liverwort
were less abundant; and
was abundant only in the closed forest.
The physiognomic similarity of the lower vegetation
layers in both communities (for description, see Andre-
yashkina, 2005) made it necessary to analyze their
structure by statistical methods with regard to simple
parameters such as coverage and species richness,
which may be highly informative in the case of a large
The term “coverage” is applicable to individual spe-
cies, layers, and whole communities. This index is usu-
ally expressed as a percentage of the test plot area, but
there also are scales for scoring coverage in grades. The
most popular scale is based on visual estimation to an
accuracy of 10% (Voronov, 1973). At the ﬁrst stage of
this study, we converted percent estimates into grades:
(1) 1–10%, (2) 11–20%, (3) 21–30%, etc. Such group-
ing allowed us to level off minor (less than 10%) differ-
ences and reveal more general trends.
Structural–Functional Organization of Lower Vegetation Layers
in Tree Communities of the Upper Timberline Ecotone
in the Polar Urals
N. V. Peshkova and N. I. Andreyashkina
Institute of Plant and Animal Ecology, Ural Division, Russian Academy of Sciences,
ul. Vos’mogo Marta 202, Yekaterinburg, 620144 Russia;
Received June 9, 2006
—Typologically identical (dwarf birch–herb–dwarf shrub–moss) open and closed larch forests grow-
ing on the same altitudinal transect have proved to differ in the structural–functional organization of lower veg-
etation layers. Coverage, general species composition, and species richness of the herb–dwarf shrub layer are
higher in the open forest than in the closed forest. Correlations between individual species of vascular plants
weaken upon transition from the open to the closed forest. Conversely, the coverage of the lichen–moss layer
increases in the closed forest, which contributes to its role as a factor of selection of vascular plant species
against the background of the prevailing inﬂuence of the tree layer.
: tree communities, lower vegetation layers, coverage of layers and dominants, species richness of
the herb–dwarf shrub layer, correlation between species richness and coverage.