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13
2010, : 13–20
ONLOBELIA DORTMANNA
Makavičiūtė
1
SiNkevičieNė
2
1Vilnius University, Department of Botany and Genetics, Čiurlionio Str. 21/27, LT-31011 Vilnius,
Lithuania; e-mail jurgita.makaviciute@gf.vu.lt
2 Institute of Botany of Nature Research Centre, Laboratory of Flora and Geobotany, Žaliųjų Ežerų
Str. 49, LT-08406 Vilnius, Lithuania; e-mail zoja.sinkeviciene@botanika.lt
Makavičiūtė J., Sinkevičienė Z., 2010: Initial data on populations of water lobelia (Lobelia
dortmanna) in Lithuania [Pirmieji duomenys apie ežerinės lobelijos (Lobelia dortmanna)
populiacijas Lietuvoje]. – Botanica Lithuanica, : 13–20.
The rst results about Lobelia dortmanna L. populations located in two no stratied semidistroc
lakes on sandy substrates typical for Lithuania are presented. The method that allows determination
of the density of virgin and generative individuals without removal of plants and disturbing the
natural structure of the population was applied. The average numbers of virgin and generative
L. dortmanna plants in Lake Ešerinis and Salaitis were 542±293 and 801±161 individuals/m2,
respectively, and the numbers of owering plants – 46±20 and 41±7 individuals/m2. The length of
inorescence stems varied from 27.0 to 72.5 (mean 43.3±11.7) cm in Lake Ešerinis and from 40 to
75 (mean 55.4±8.5) cm in Lake Salaitis. The numbers of seed capsules or owers ranged from 1–5
(mean 2.0±1.7) in Lake Ešerinis and from 2 to 6 (mean 3.4±0.9) – in Lake Salaitis. The maturity
age was determined for removed plants from 25 cm2 squares. Both populations comprise plants of
the main maturity stages (seedlings, juvenile + immature, virgin and generative). Seedlings (45 %)
and juvenile + immature (37 %) individuals were dominant in Lake Ešerinis, whereas virgin (49 %)
individuals – in Lake Salaitis. According to the density of virgin and generative individuals and
occurrence of plants of the main maturity age groups both populations are abundant and capable for
regeneration. The lakes are situated in protected area with low human activity, therefore natural and
global acidication in both lakes and concurrence with helophyte species in Lake Ešerinis are the
main threats.
Lobelia dortmanna, isoetid, population, density, maturity age.
INTRODUCTION
Water lobelia (Lobelia dortmanna L., Lobeliaceae R.
Br.) is one of isoetid species occurring in carbonate
poor (weakly buffered) and nutrient poor (oligotrophic)
water (
SmolderS
et al
., 2002; murphy
, 2002). This
interruptedly circumboreal species is distributed in
oceanic regions of temperate and cold climatic zones
in Northwest of Europe and North America (
meuSel
et
al., 1965). Lithuania is situated outside the continuous
distribution area of this species in Europe. The rarity of
softwater lakes with typical vegetation on the territory
of Lithuania is the main reason why L. dortmanna has
been rst recorded only in 1963 (
lekavičiuS
, 1965), and
till now it is reported only in ve lakes (
Strazdaitė
et al.,
1976;
Šarkinienė & trainauSkaitė, 1978; Šarkinienė,
1980; Balevičienė & Šarkinienė
, 1981;
ŠaBlevičiuS
,
1999). Currently this species occurs in lakes Kerotis,
14
Ešerinis, Salaitis and Salinis, and in about 1972 it
became extinct from Lake Girutiškis (S
inkevičienė,
2007). Known Lobelia-lakes are concentrated in eastern
part of the country and situated in protected areas of
Labanoras Regional and Aukštaitija National parks.
L. dortmanna, as an endangered species, has been
included in the Red Data Book of Lithuania since 1981
(
Balevičienė
&
BalevičiuS
, 1981;
BalevičiuS
, 1992;
S
inkevičienė, 2007
), and its communities are included
in the list of protected communities (
Balevičienė
,
2000). L. dortmanna is also protected in Eastern Baltic
countries (Estonia, Latvia, Poland and St. Petersburg
region of Russia) and in the northern part of Germany
and Denmark (
ingelög
et al., 1993). Furthermore, the
lakes with water lobelia communities are included in
the list (Anex I of Habitats Directive) of habitats of
European importance (
european commiSSion
, 2007;
raŠomavičiuS
et al., 2001).
The decline of water lobelia populations as well
as other isoetids is mainly attributed to acidication,
eutrophication and physical habitat change, especially
in small-sized softwater lakes (
murphy
, 2002). Despite
the decline of L. dortmanna, in major part of the
distribution area special populations studies are very
scarce. The series studies in two lakes of the northern
Poland by
Szmeja
(1987 a–e) provide a substantial data
on the populations of L. dortmanna in the territory
closest to Lithuania. The basic data on water lobelia
biology are summarized by
Farmer
(1989).
The above-mentioned Lithuanian publications
mainly include the data on distribution and communities
of L. dortmanna in Lithuania, but peculiarities of the
population of this species have never been studied.
The aim of this study was to determine the density
of L. dortmanna populations in two selected lakes,
applying sparing method without removal of plants,
and to estimate plants of which maturity age could
be precisely counted. Other important tasks were to
nd the evidences of reproduction by seeds (i.e. seed
capsules, germinated seeds or seedlings) and very
preliminary identify maturity stages of L. dortmanna.
This is important for initial determination of the status
and regeneration capacity of these populations and for
organization of future research.
MATERIALS AND METHODS
Study area
The lakes Ešerinis and Salaitis are situated in the
Eastern part of Lithuania, Švenčionėliai district on the
territory of Labanoras Regional Park, where human
activity is low with an exception of recreation. These
lakes are formed in sandy Labanoras plain mainly
occupied by Scots pine forests and mires (
kudaBa
,
1977). The communities of Dicrano-Pinion sylvestris
Libb. 1932 are dominant in surrounding forests on
sandy soils. The swampy shores are mainly occupied
by communities of Rhynchosporion albae W. Koch
1926, Caricion lasiocarpae Vanden Berghen in Lebrun
et al. 1949 and Sphagnion magellanici Kästner et
Flössner 1933. Whereas no morphometric data of these
lakes are available, and the main characteristics were
measured using maps or during eld investigations
and are presented in Table 1. The maximal depths in
both lakes do not exceed 3 m. The pH measured in the
sites of investigations was similar in both lakes and
ranged from 6.2 to 6.4. Preliminary the lakes can by
ascribed to the type of no stratied semidistrophic lakes
according to Estonian typology (
mäemetS & mäemetS,
1991). Organic peaty sediments predominate along the
swampy shores, but the bottom along mineral shores is
sandy, mainly in the eastern parts of both lakes where
studied populations of L. dortmanna are located. The
area occupied by lobelia stands reaches about 1 % of
the total area in both lakes. The water regime of Lake
Salaitis is slightly changed by a ditch connecting it with
Lake Pažemys. In general, human activity is very low
in this wooded territory, and the study sites have been
earlier used only for extensive recreation.
Material cOllectiON aNd aNalySiS
Two populations of Lobelia dortmanna occurring in
the eastern parts of lakes Ešerinis (55° 10' 43.6" N; 25°
Characteristics Lake Salaitis Lake Ešerinis
Area (ha) 28.6 19.4
Maximum length (km) 0.96 0.65
Maximum width (km) 0.48 0.39
Length of shoreline (km) 2.56 1.72
Number of islands 1 (area 2.2 ha) –
Table 1.
General characteristics of the Lakes Salaitis and Ešerinis
15
54' 10.5" E) and Salaitis (55° 14' 55.4" N; 25° 52' 47.7")
were studied.
Material was collected in July of 2008. The
density of L. dortmanna plants, expressed as number
of individuals per m2, was determined by counting of
rosettes distinguishable through a viewing box or with
the naked eye, in quadrates 1 m × 1 m. A square frame
divided into 10 cm × 10 cm squares was used. Four
squares in Lake Ešerinis in depth of 0.14 m; 0.15 m;
0.27 m; 0.58 m and three squares in Lake Salaitis in
depth of 0.25 m; 0.31 m; 0.32 m were studied. The co-
verage (%) of L. dortmanna and accompanying species
was also estimated using the frame.
The number of fertile plants in each 1 m2 square
and the number of seed capsules or/and owers were
counted and the length of inorescence stems (stalk
with inorescence) was measured in eld conditions.
In total 96 inorescence stems were measured in Lake
Ešerinis (25 stems from depth squares of 0.14 m,
0.15 m and 0.27 m and 21 – from 0.58 m) and 75 – in
Lake Salaitis (25 specimens from a depth of 0.25 m,
0.32 m and 0.31 m).
The number of seed capsules or owers was
counted for 75 specimens (25 specimens per depth of
0.14 m, 0.15 m and 0.27 m) in Lake Ešerinis and for 75
specimens (25 specimens per depth of 0.25 m, 0.31 m
and 0.32 m) in Lake Salaitis. The data were statistically
analysed with the aid of STATISTICA 6 and maximum,
minimum, mean, standard deviations and standard error
were recorded.
For initial determination of maturity age groups one
sample was taken from 25 cm2 square at a depth of 0.15
m in Lake Ešerinis and one sample – from a depth of 0.20
m in Lake Salaitis. The sampled plants were dispersed
one by one and herbarised. In the laboratory the maturity
of plants was determined according to seeds and
radicle remains, development of leaves and generative
organs. The maturity age groups usually distinguished
for herbaceous owering plants are the following:
seedlings (pl), juvenile (j), immature (im), virgin (v),
generative (g1, g2, g3), senile (ss, s, sc) (
raBotnov
,
1983;
FalinSka
, 1990).
Szmeja
(1987 b) divided the
onthogeny of L. dortmanna into such development
stages: germinating seeds and seedlings, juvenile,
mature, generative and subsenile. The description
of juvenile plants presented by
Szmeja
(1987 b)
corresponds to common group including juvenile and
immature plants, designated by other authors, whereas
group of mature plants correspond virginal age group.
The stage of seedlings is exhaustively studied and
described (
Woodhead
, 1951;
Farmer
, 1989;
Szmeja
,
1987 b), therefore it is easily distinguishable. Hardly
separable juvenile and immature plants were counted
together and further in the text are indicated as “juvenile
+ immature”.
RESULTS
vegetatiON
In eastern part of Lake Ešerinis L. dortmanna is dis-
tributed from the shore up to a depth of 0.8 m; it is a
dominant species in the lake. Solitary plants reach the
depth of 1 m. Other co-occurring plant species located
in this area reach a depth of 0.4 m, with the exception of
Sphagnum denticulatum, distributed through the whole
lake up to a depth of 2 m. Five species of helophytes
(Magnoliophyta) and 1 species of Bryophyta have
been recorded in the investigation plots with Lobelia
dortmanna in Lake Ešerinis (Table 2). Carex rostrata
was the most constant and abundant among accom-
panying species. Schoenoplectus lacustris L. Palla and
Menyanthes trifoliata L. have been noticed nearby.
In Lake Salaitis water lobelia formed monodominant
patches in a narrow zone of 0.2 to 0.4 m depth and only
Table 2.
Species diversity and coverage in the studied plots of Lake Ešerinis
Plant species Coverage (%)
Lobelia dortmanna L.70 80 85 50
Lysimachia thyrsiora L. 0.2 0.1 5
Carex rostrata Stokes 20 10 10
Carex lasiocarpa Ehrh.5.8
Calamagrostis canescens (F. H. Wigg.) Roth 1
Eleocharis palustris (L.) Roem. et Schult. 0.1
Sphagnum denticulatum Brid. 0.9
Total coverage (%) 100 90 100 50
Depth (m) 0.14 0.15 0.27 0.58
16
scarce Carex lasiocarpa and Eleocharis palustris have
been recorded outside the studied squares.
Maturity age grOupS
The studies of the water lobelia plants removed
from 25 cm2 squares revealed high density and
crowding of plants in this small area. The total number
of plants reached 95 and 61 individuals/25 cm2 in
lakes Ešerinis and Salaitis, respectively. The seedlings
were dominant in the sample from Lake Ešerinis and
nearly twice exceeded the number of seedlings in Lake
Salaitis (Fig. 1). Juvenile and immature individuals also
prevailed in Lake Ešerinis. In contrast, virgin individuals
predominated in Lake Salaitis. In general the adult
plants (virgin and generative) were more abundant in
Lake Salaitis, and juvenile stages (seedlings, juvenile
+ immature) – in Lake Ešerinis. No senile individuals
were found in the tested samples.
characteriSticS Of pOpulatiONS
Lake Ešerinis
The study of maturity age group revealed plants
with developed rosettes, i.e. only virgin and generative
individuals could be counted correctly without
disturbing the natural structure of the population
especially in places with turbid water at the bottom. The
average density (mean ± SD) of virgin and generative
L. dortmanna plants in Lake Ešerinis was 542±293
individuals/m2. The number of rosettes ranged from
130 in the deepest (0.58 m) to 760 in the shallowest
(0.14 m) samples (Fig. 2).
Fig. 1. Percentage of maturity age groups of
L. dortmanna determined for removed plants from
25 cm2 square
Fig 2. The number of virgin and generative individuals
of L. dortmanna estimated in 1 m2 plots at different
depths in Lake Ešerinis
The lowest number of owered plants was also
determined in the deepest sampling plot, and the
average mean was 46±20 generative individuals/m2.
The plants in the deepest location have developed
inorescence with pedicels remains, however no owers
or seed capsules have been found there. The plants with
developed but immature seed capsules dominated in the
squares of 0.14 m and 0.15 m depths; while mixed (with
owers and capsules) plants occurred in the 0.27 m
depth square. The maximal number of seed capsules
or owers was determined in the shallowest samples,
but plants lacking the initial seed capsules were noticed
in all sampled depths with the exception of 0.15 m
(Table 3, Fig. 3). Sterile owered plants comprise 28 %
of the total number of studied plants.
The inorescence stems of water lobelia were
43.3±11.7 cm long. The longest inorescence stems
occurred in the deepest square of 0.58 m, and they
insignicantly varied in other depths (Table 3, Fig. 4).
Lake Salaitis
In this lake L. dortmanna grew in a quite narrow
depth zone of 0.2–0.4 m, and three sampling plots were
distributed in a similar depth. The number of rosettes
ranged from 645 in a depth of 0.25 m to 966 in a depth
of 0.31 m (Fig. 5.). The average density of virgin and
generative lobelia plants in Lake Salaitis was 801±161
individuals/m2.
The number of generative plants was quite similar
in all studied depths (Fig. 5) reaching an average
of 41±7 generative individuals/m2. The plants with
immature seed capsules dominated in all three samples.
The number of seed capsules was similar in all depths
(Table 3) making an average of 3.4±0.9, but plants with
3 capsules were more frequent.
17
The inorescence stems were 55.4±8.5 cm long and
varied from 40 cm to 75 cm in Lake Salaitis (Table 3).
Maximum and averagely (59.5±9.8 cm) longest stems
were recorded in the sample at a depth of 0.31 m, and
the shortest (average 50.6±5.8) – at a depth of 0.25 m.
DISCUSSION
The Lithuanian populations of L. dortmanna could
be compared with those of lakes in Poland (
Szmeja
,
1987 a–e) but in our case the studies are not so detailed
and directed towards sparing investigation methods.
There are signicant differences in lake sizes, dominant
vegetation and growth depth of lobelia, which are related
to different water chemistry and physical conditions.
Fig. 3. The number of seed capsules or owers of
L. dortmanna at different depths in Lake Ešerinis
Table 3.
Morphological characteristic of L. dortmanna at different depths in Lakes Ešerinis and Salaitis
Fig. 4. The length of inorescence stems of
L. dortmanna at different depths in Lake Ešerinis
Fig. 5. The number of virgin and generative individuals
of L. dortmanna estimated in 1 m2 plots at different
depths in Lake Salaitis
Depth
(m) nMin. Max. Mean SD Min. Max. Mean SD
Length of inorescence Number of seed capsules
lake eŠeriniS
0.14 25 27.0 44.0 35.4 4.99 0.0 5.0 2.7 1.70
0.15 25 32.0 44.0 37.1 2.66 2.0 5.0 3.5 0.82
0.27 25 32.0 45.0 40.4 4.18 0.0 3.0 1.5 0.96
0.58 21 53.0 72.5 63.6 4.83 0.0 0.0 0.0 0.00
lake SalaitiS
0.25 25 40.0 61.0 50.6 5.81 2.0 5.0 3.1 0.83
0.31 25 43.0 75.0 59.5 9.81 2.0 6.0 3.5 1.12
0.32 25 43.0 69.0 56.2 7.30 2.0 5.0 3.6 0.82
18
The maximum lobelia growing depth is very small in the
studied semidistrophic lakes and scarcely reaches 1 m,
whereas in Polish lakes – up to 2.7 m. But according
to
Farmer
(1989), L. dortmanna prefers sheltered con-
ditions and rarely grows below 2(3) m. In our lakes
the narrow grows interval is related also with humic
water. In both investigated lakes Ešerinis and Salaitis
the vegetation is very sparse, and isoetid species are
represented exclusively by water lobelia. In the closest
territories of Latvia (
SuŠko
, 1990), Poland (
Szmeja
,
1987 a–e) and Estonia (
mäemetS
, 1991) as well as the
whole Europe (
murphy
, 2002) L. dortmanna often
occurs in the same water bodies with Isoetes lacustris,
but usually in diverse depth and substrates as well as
different chemical conditions of water and substrates
(
SzańkoWSki & kłoSoWSki
, 1996, 2006). In Lithuania
these two isoetid species have never been reported
growing together and according to
SzańkoWSki &
kłoSoWSki (
2006) communities with dominant lobelia
in both lakes can be identied as separate association
Lobelietum dortmannae (Osvald 1923) Tx. ap. Dierssen
1972. In Lake Ešerinis this community is invaded by
helophyte species. According to dominant vegetation
the studied lakes are similar to LO-type (L. dortmanna)
described by
jenSen
(1979) in Sweden. Extremely poor
vegetation in Lake Salinis is probably related with
higher impact of humic matter and water acidication
(
SmolderS
et al., 2002), whereas the occurrence of
helophytes in Lake Ešerinis – with eutrophication
(
mäemetS
, 1991), however this presumption is not
supported by chemical data. Helophyte species
(C. lasiocarpa, Calamagrostis canescens, Eleocharis
palustris, Lysimachia thyrsiora, Schoenoplectus
lacustris) recorded in the sites of investigations and
especially constant Carex rostrata are quite common in
lobelia lakes around Baltic (
kanSanen & niemi
, 1974;
Farmer & Spencer
, 1987 b;
Szmeja
, 1987 a–e;
SuŠko
,
1990;
mäemetS
, 1991).
The average and maximum density of virgin
and generative individuals per 1 m2 in Lake Salaitis
exceed the numbers recorded in Lake Ešerinis. On the
other hand, this can be explained by larger interval of
growth depth in Lake Ešerinis, because the numbers
of individuals decrease with the increasing depth. The
lower density in Lake Ešerinis may be related with the
occurrence of helophytes, especially Carex rostrata,
because according to
Szmeja
(1987 d) the density of
lobelia in the communities of Caricetum rostrate is
over thirty times lower than in Isoeto-Lobelietum.
Thus future development of helophyte stands could
be unfavourable for the status of lobelia population in
Lake Ešerinis. The narrow depth interval of Lobelia
dortmanna growth in Lake Salaitis indicates the poor
light availability in probably more coloured water. So
in both lakes water lobelia occurs in quite extreme
conditions.
The initial determination and calculation of maturity
age groups in solitary samples of 25 cm2 could not
represent an exact situation in the whole population,
but several tendencies may be noted. For the lake
tending towards the dystrophic state
Szmeja (
1987 a)
recorded the age pyramid at an optimum level where
mature (virgin) forms are prevalent (56.2 %), seedlings
constitute no more than 10 % of population, and the least
numerous are generative individuals (5.6 %). According
to the dominance of virgin individuals (49 %), the
population of Lake Salaitis is similar to the above-
mentioned description, but other proportions notably
vary – those of generative individuals and seedlings are
higher, and of juvenile forms – lower. Thus only about
a half of seedlings survive till juvenile stage. In Polish
populations the proportions of seedlings reaching 13 %
are characteristic of the shallowest locations (
Szmeja,
1987 a), but the dominance of seedlings determined in
Lake Ešerinis (45 %) is unusual and notably exceeds
maximum proportions (22 % and 26 %) recorded for
several Polish subpopulations (
Szmeja,
1987 c). Even
if the proportions for lobelia populations in our lakes
are determined insufciently correctly, the result that
main maturity age groups are present in both lakes is
very important. For more specic determination of
the structure of maturity age, the sample should be
taken from 0.1 m2 squares and at different depths of
L. dortmanna occurrence.
L. dortmanna is one of a few aquatic species that
produce many seeds and has low vegetative propagation
rate (
Farmer & Spence
, 1987 a). Water lobelia
populations in lakes Ešerinis and Salaitis made no
exception. At the end of July owering and potentially
fruiting plants (with immature seed capsules) were
noticed through the whole distribution area in both
lakes. Only plants with emergent inorescences were
observed in the sampled plots; although underwater
owering is known but may be characteristic for
populations occurring in deeper waters (
Szmeja
, 1987
b;
Farmer
, 1989). The naked (without owers or
initiated seed capsules) emerged inorescences were
found in Lake Ešerinis at a depth of 0.58 m where they
probably had been damaged by waving. The maximum
and average numbers of owers or fruits in Polish
lobelia populations (
Szmeja
, 1987 c) approximately
twice exceed the numbers determined in our lakes. It
was also true for the average and maximum length of
inorescence stems. This last parameter is positively
19
related with the growth depth (
Szmeja
, 1987 e) and
estimated for populations situated deeper than the
maximum depth of our samples.
CONCLUSIONS
In two studied semidistrophic lakes L. dortmanna
grows in condition unfavourable for other isoetids and
vascular plants and forms monodominant communities.
In both lakes the populations are comprised of plants
in the main maturity age groups: seedlings, juvenile +
immature, virgin and generative individuals.
According to the density of virgin and generative
individuals and occurrence of main maturity age
groups, both populations are abundant and capable of
regeneration.
Because the lakes are situated in protected area
with insignicant human activity, the natural and
global acidication in both lakes and concurrence of
helophyte species in Lake Ešerinis are the main threats
for L. dortmanna.
For detailed determination of the structure of
maturity age the samples should be taken from 0.1 m2
squares in the whole depth interval of L. dortmanna
occurrence.
REFERENCES
Balevičienė
J., 2000: Isoeto-Lobelietum R. Tx.
1937 – slepišerinis lobelijynas. –
Balevičienė j.,
gudžinSkaS z., Sinkevičienė
Z. (eds.), Lietuvos
raudonoji knyga. Augalų bendrijos: 39–40. –
Vilnius.
Balevičienė
J.,
BalevičiuS k.
, 1981: II dalis. Augalai. –
In: Lietuvos TSR raudonoji knyga: 52–83. – Vilnius.
Balevičienė j., Šarkinienė i.,
1981: Ežerų augalija. – In:
Lietuvos TSR nacionalinis parkas: 50–55. – Vilnius.
BalevičiuS k.
, 1992: Ežerinė lobelija (Lobelia
dortmanna L.) – In: Lietuvos raudonoji knyga:
223–224. – Vilnius.
european commiSSion
, 2007: The Interpretation Manual
of European Union Habitats , EUR 27.
FalinSka k., 1990:
Osobnik, populacja, tocenosa. –
Warszawa.
Farmer a. m
., 1989: Biological ora of the British
Isles. Lobelia dortmanna L. – Journal of Ecology,
: 1161–1173.
Farmer a. m
.,
Spence d. h. n
., 1987 a: Flowering,
germination and zonation of the submerged aquatic
plant Lobelia dortmanna L. – Journal of Ecology,
: 1065–1076.
Farmer a. m
.,
Spence d. h. n
., 1987 b: Environmental
control of the seasonal growth of the submersed
aquatic plant Lobelia dortmanna L. – New Phytolo-
gist, : 289–299.
ingelög
T.,
anderSon r., tjenBerg m
. (eds.), 1993:
Red Data Book of the Baltic Regions. Part 1. –
Upsala–Riga.
jenSen S
., 1979: Classication of lakes in southern
Sweden on the basis of their macrophyte composition
by means of multivariate methods. – Vegetation, :
129–146.
kanSanen a., niemi r., 1974:
On the production ecology
of isoetids, especially Isoetes lacustris and Lobelia
dortmanna, in Lake Pääjarvi, southern Finland. –
Annales Botanici Fennici, : 178–187.
kudaBa č.
, 1977: Geomorfologinės Baranavos
draustinio ypatybės. – In: Baranavos draustinis:
5–7. – Vilnius.
lekavičiuS a.
, 1965: Novyje v Litve vidy vysšykh
rastenij, najdenyje v 1963 g. – Trudy Akademii
Nauk Litovskoj SSR, Ser. B, : 23–28.
meuSel h., jäger e., rauSchert S., Weinert e
., 1965:
Vergleichende Chorologie der Zentraleuropäischen
Flora, 2. – Jena.
mäemetS a.,
1991: Makroty. – In:
timm
T. (ed.), Sos-
tojanie miagkovodnykh ozior Estonii: 80–122. –
Tartu.
mäemetS a., mäemetS a.
, 1991: Obščaja kharakteristika
ozior. – In:
timm
T. (ed.), Sostojanie miagkovodnykh
ozior Estonii: 9–39. – Tartu.
murphy k. j
., 2002: Plant communities and plant
diversity in soft water lakes of northern Europe. –
Aquatic Botany, : 287–324.
raBotnov
T. A., 1983: Fitocenologija. – Moskva.
raŠomavičiuS v., Sinkevičienė
z., BalSevičiuS a., čiup-
lyS r., patalauSkaitė d., olenin S., daunyS d.,
2001: Europinės svarbos buveinės Lietuvoje. – Vilnius.
Sinkevičienė
Z., 2007: Lobelia dortmanna – In:
raŠomavičiuS
V. (ed.), Lietuvos Raudonoji knyga:
517. – Vilnius.
SmolderS a. j. p., lucaSSen e. c. h. e. t., ruelF j. g. m
.,
2002: The isoetids environment: biogeochemistry
and threats. – Aquatic Botany, : 325–350.
Strazdaitė j., jankevičienė r. l., lazdauSkaitė ž.
,
1976: Rastitel’nost’ ozer botaniko-zoologičeskikh
zakaznikov Baranava i Kanio Raistas. – Trudy Aka-
demii Nauk Litovskoj SSR. Ser. B., :21–27.
SuŠko u., 1990:
Rietumu Garezera ora. – Daugavpils.
SzankoWSki m., kloSoWSki S.,
1996: Habitat variability
of the phytocoenoses of Isoeto-Lobelietum in
Poland. – Fragmenta Floristica et Geobotanica,
: 255–267.
20
LOBELIA DORTMANNA
Makavičiūtė
SiNkevičieNė
Santrauka
Ežerinė lobelija (Lobelia dortmanna L.) yra vie-
na iš rečiausių minkšto vandens augalų rūšių, Lie-
tuvoje aptikta tik 5 ežeruose, už ištisinio arealo
Europoje ribos. Straipsnyje pateikiami duomenys apie
Ešerinio ir Salaičio ežerų (Labanoro regioninis par-
kas, Švenčionių r.) ežerinės lobelijos populiacijas.
Tirtieji ežerai maži (<50 ha), rūgštūs (pH 6,2–6,4),
pelkių apsupti pusiau distroniai. – lobelija auga tik
mineraliniame grunte, mažiau kaip 1 m gylyje dau-
giausia rytinėse jų dalyse. Abiejuose ežeruose ežerinė
lobelija vyrauja (Lobelietum dortmannae (Osvald
1923) Tx. ap. Dierssen 1972), tačiau Ešerinio ežere su
ženklia helotų priemaiša.
Populiacijų tankio tyrimai atlikti, neišraunant
augalų, 1 m2 laukeliuose, išdėstytuose 0,14; 0,15;
0,27; 0,58 m gyliuose Ešerinio ir 0,25; 0,32; 0,31 m
gyliuose Salaičio ežere. Žiedynkočių ilgis išmatuotas
96 augalams Ešerinio ir 81 Salinio ežere. 75 augalams
kiekviename ežere suskaičiuotas užsimezgusių vai-
sių skaičius. Ešerinio ežere virgininių ir generatyvinių
individų tankis (individų skaičius/m2) kito nuo 130
(0,58 m gylyje) iki 760 (0,14 m gylyje), vidurkis ±
standartinis nuokrypis – 542±293; vidutinis žydėjusių
individų skaičius 46±20; mažiausias žiedynkočių ilgis
(27,0 cm) nustatytas 0,14 m, didžiausias (72,5 cm)
0,58 m gylyje (vidurkis 43,3±11,7 cm); žiedų arba
užmegztų vaisių skaičius kito nuo 1 iki 5 (vidurkis
2,0±1,7).
Salinio ežere virgininių ir generatyvinių individų
tankis (individų skaičius/m2) kito nuo 645 (0,25 m
gylyje) iki 966 (0,31 m gylyje), vidurkis 801±161;
vidutinis žydėjusių individų skaičius 41±7; mažiausias
žiedynkočių ilgis (40 cm) nustatytas 0,25 m, didžiausias
(75 cm) 0,31 m gylyje (vidurkis 55,4±8,5 cm); užmegztų
vaisių skaičius kito nuo 2 iki 6 (vidurkis 4±0,9).
Pagal bandomuosius mėginius iš 25 cm2 plotelių,
Ešerinio ir Salaičio ežerų populiacijas sudaro įvairių
svarbiausių brandos amžiaus tarpsnių individai, ati-
tinkamai – daigai (45,26 %), juveniliniai+imaturiniai
(37,13 %), virgininiai (13,49 %) ir generatyviniai
(5,12 %). Detalesniam brandos amžiaus tarpsnių ištyri-
mui, nepaisant didesnio augalų paėmimo iš gamtos,
reikėtų mėginius imti iš 0,1 m2 visame ežerinės lobelijos
augimo gylio intervale. Pagal virgininių ir generatyvinių
individų tankį ir brandos amžiaus tarpsnių struktūrą
abi ežerinės lobelijos populiacijos yra gausios, vyksta
dauginimasis ir atsinaujinimas sėklomis.
Kadangi abi populiacijos aptinkamos ežeruose,
esančiose saugomoje teritorijoje su nežymia žmogaus
veikla, svarbiausias grėsmės faktorius abiems popu-
liacijoms yra natūralus ir globalus vandens rūgštėjimas,
Ešerinio ežere prisideda konkurencija su helotais.
SzankoWSki m., kloSoWSki S.,
2006: Habitat variability
of the Littorelletea uniorae plant communities in
Polish Lobelia lakes. – In:
caFFrey
J. M.,
dutartre
A.,
haury
J.,
murphy
K. J.,
Wade
P. M. (eds.),
Macrophytes in aquatic ecosystems: From biology
to managements, 117–126. – Dordrecht.
Szmeja j., 1987
a: The structure of a population of Lo-
belia dortmanna along a gradient of increasing depth
in an oligotrophic lake. – Aquatic Botany, : 1–13.
Szmeja j., 1987
b: The seasonal development of Lobelia
dortmanna L. and annual balance of its population
size in an oligotrophic lake. – Aquatic Botany, :
15–24.
Szmeja j., 1987
c: The ecology of Lobelia dortmanna L.
I. The plasticity of individuals within a constant
depth interval in oligotrophic lakes. – Ekologia
Polska, : 497–522.
Szmeja j., 1987
d: The ecology of Lobelia dortmanna L.
II. Population structure and dynamics within a
constant depth interval in oligotrophic lakes. –
Ekologia Polska, : 523–544.
Szmeja j., 1987
e: The ecology of Lobelia dortmanna L.
III. The plasticity of individuals along gradient of
increasing depth in oligotrophic lakes. – Ekologia
Polska, : 545–558.
ŠaBlevičiuS B.
, 1999: Retosios augalų rūšys Aukštaitijos
nacionaliniame parke 1978–1998 m. – Ignalina.
Šarkinienė i., 1980
: Lobeliniai – Lobeliaceae Juss. –
In:
natkevičaitė-ivanauSkienė
M.,
jankevičienė
r., lekavičiuS a.
(eds.), Lietuvos TSR ora, :
23–25. – Vilnius.
Šarkinienė i., trainauSkaitė i.
, 1978: Retieji ir globotini
Lietuvos TSR vandens augalai. – In:
ButkuS v
.
(ed.), Augalai ir žmogus: 52–57. – Vilnius.
Woodhead n., 1951:
Biological ora of the British
Isles. Lobelia dortmanna L. – Journal of Ecology,
: 458–464.
