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dated core from the near-by Lake Ostrezko-2 ( Т о п к о v, Ma r i n o v a , in
press).
In addition, two surface moss pollen samples collected around the present
tree-line from the northern approaches to the lake were analyzed thus providing
valuable information on the modern pollen dispersal in the study area.
RESULTS AND DISCUSSION
SURFACE MOSS POLLEN SAMPLES
The first surface sample was collected at 2000 m a. s. 1. from a coniferous
community composed of
Pinus рейсе
(80 %) and
Picea
(20 %). The ratio АР/
NAP
is 92.1 %:7.9 %. The results show dominance of
Pinus diploxylon-
type
pollen with 66.1 %, accompanied by
Pinus рейсе
9.7 %,
Picea
4.5 %,
Fagus
and
Quercus cerris-type
of 2.9 % each, Betula 2.4 %, Corylus 1.4 %. The rest
of arboreal pollen taxa are present with values below 1 %. An interesting find
was a pollen grain of
Ephedra fragilis-
type. This presumes the existence of a
high-mountain
Ephedra
species in the study area. In the botanical literature
there is no information for a recent presence of
Ephedra
in the Rila Mountains
although this genus was an important constituent of the Lateglacial and Early
Holocene ,,mountain-steppe“ vegetation at high altitudes according to the
palynological data ( B o z i l o v a et al., 1990; Bo z i l o v a , Т о п к о v, 2000).
The herb types established are diverse though in rather low quantities and
only pollen of Poaceae 1.9 % and spores of Polypodiaceae 3.7 % deserve
attention.
The second surface sample was collected at 2100 m a. s. 1. close to the tree
line from an almost monodominant community of
Pinus mugo
(90 %) with an
admixture of
Pinus рейсе
(10 %). The ratio
AP/NAP
is 91.5 %:8.5 %, quite
similar to the previous sample. Pollen of
Pinus diploxylon-
type dominates with
71.9%. Pollen of
Pinus рейсе
5.2 %,
Picea
6.1 %,
Fagus
1.1 %, and other
arboreal taxa with less than 1 % is present. A local maximum of
Vaccinium-
type pollen 3.7 % is also recorded. Pollen of Poaceae is established with 1.8%
while the rest of the herb taxa (
Artemisia
, Brassicaceae,
Achillea-Vype, Scrophularia-
type,
Dianthus-
type, etc.) are present with an average value of 0.5 %.
In total, 42 pollen types were established in both samples, 18 from the
group of
AP
and 24 from the group of
NAP.
The pollen percentages of the
main forest trees in the surface samples are in accordance with their specific
pollen production and dispersal capabilities for the study area as previously
established ( T o n k o v et al., 2000).
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Электронная Научная СельскоХозяйственная Библиотека