Plant cover of grassland ecosystems of the forest zone is formed by
perennial vascular plants. Precondition for their maintenance is human and
animal influence.
Natural or seminatural grasslands are most important for conservation of
biological diversity. These grasslands are biologically diverse and also
have a high cultural and historical value. Natural grasslands are an
important part of Latvian rural landscape and a testimony about human and
nature interaction.
From cultivated grasslands natural ones differ in species composition and
diversity as well as in plant cover structure, management traditions and
grassland age. More here: Features of natural and cultivated grasslands
Historical development of grasslands in Latvia
Latvian landscape has established in long-term interaction between nature
and people. Grasslands have developed under direct human influence. Before
people arrived in the territory of Latvia, similarly, like in the whole
forest zone, grasslands covered small areas where forest development was
disturbed by natural factors, like floods, large herbivores etc.
During long-term management grasslands have developed into complicated
ecosystems with a high biological diversity. According to grassland and
pasture location in relief, as well as soils, moisture and other factors,
different habitats develop where diverse plant communities occur that are
connected with many species of insects, birds and other animal species.
Especially high diversity of flora and fauna is in the contact zones to the
grasslands.
Beginning with the Neolithic time in the territory of Latvia agriculture
started to develop and the area covered by grasslands and pastures gradually
increased and reached its maximum at the beginning of the 20th century (30%
from the total area of Latvia). At this time wet meadows and pastures
dominated and covered 2/3 from the total grassland and pasture area.
Starting with the 20th century due to drainage plant communities changed
and the total area of grasslands and pastures rapidly decreased.
Flora
More than 520 vascular plant and filices (Pteridophyta) species
grow in Latvian grasslands and pastures comprising about 1/3 part of Latvian
flora. Species of other habitats occur there as well. More here
Vegetation
One of the most essential parts of biological diversity is habitat
diversity. Grasslands comprise a large part of Latvian habitats.
Here: Classification of Latvian natural grasslands
according to the Braun-Blanquet method.
Threats to ecosystem
Grasslands belong to those rare ecosystems that can not be maintained
without human assistance. Best way to protect forests, mires and
water-basins is not to have any human interference but it is just an
opposite in grasslands. Only long-term regular mowing and grazing maintain
these peculiar ecosystems.
- Abandonment of the grasslands
At present grassland diversity is greatly threatened. Natural grasslands
cover only 1% from the total land area of Latvia and occur mostly as small
areas of mosaic distribution (Kabucis 1997). Every year the area covered by
natural grasslands reduces and the main reason is the change of land use
types. Grassland communities are very dynamic. Ceasing of mowing and grazing
rapidly decrease species diversity because the old litter accumulates.
Microclimate, light intensity and moisture regimen changes. Regeneration of
many plant species is disturbed; therefore the species number growing in
grasslands reduces and seeds bank becomes poorer. When overgrow by tree
species starts, their landscape value reduces. With every year it becomes
more complicated and expensive to restore such an unmanaged grassland.
Due to the decrease of agricultural intensity there is more grassland than
its possible and is necessary to manage. Of course, the first grasslands
where management was stopped are those of lowest value from agricultural
point of view with small crops but with a high number of species of low
nutritive content in the plant communities. Sadly, these are the species
richest and botanical most valuable grasslands. Nowadays, a great part of
cultivated and productive grasslands are left without attention. Therefore,
in the nearest years we can not expect that the farmers will be interested
to take up the management of those grasslands and pastures that are
important for nature diversity.
-
Agriculture intensification
At present grassland improvement is not widespread although it can not be
excluded from the list of threatening factors. In this case improvement
should not be understood on as a radical interference in the ecosystem
processes with land ploughing or artificial grassland sowing but also as a
natural improvement of grasslands with sowing additional grasses and clover
and fertilisation with mineral fertilisers.
It must be mentioned that improvement is the main factor in the reduction
of the area covered by natural grasslands in the 20th century.
Drainage has drastically changed the distribution of grassland communities
in Latvia. Still, at the beginning of 20th century 65% from all natural
grasslands and pastures were moist (Sabardina 1957). Communities of moist
and wet habitats dominated (Orders Molinietalia, Caricetalia nigrae and
Magnocaricetalia).
With an intensive start of drainage already in 1967 about 2/3 from all
moist grasslands and pastures were drained. As a result there was a rapid
decrease of wet meadow and pasture occurrence.
Not always drainage has a negative impact. Regulation of hydrological
regimen in grasslands and pastures started already in the 19th century
(mainly hand-made shallow ditches. Continuing the traditional management in
such areas the change of dominating species was observed in plant
communities but on the whole they maintained a diverse species composition.
In such areas it is recommended to maintain the drainage system.
Often grassland transformation into an arable land or forest soil takes
place.
Both dry and moist grasslands are endangered not only by overgrow but
also by nearby agricultural lands. Especially, it is characteristic for
river valleys where on the terrace slopes grasslands are located but outside
the valley fertilised fields are occur. Together with water, fertilisers
reach grasslands and the same effect is gained as if fertilising the
grassland. In wet grasslands soil enrichment with the nitrogen favours a
rapid reed distribution. It becomes a dominating species but at the same
speed from the plant cover orchids, primroses, rare sedge species disappear
until the coloured plant cover is replaced by reed growth.
Eutrophication is favoured also by nitrogen deposits from the air.
- Low level of information of grassland owners and managers about the
management necessity and type.
There is a lack of information what is biologically right and what is
adequate management in various grassland types.
Management and protection activities
- Fertilisation - advisable or not
Optimum management regimen differs for various grassland types. Still, in
grasslands a diverse species composition can develop only if the grassland
is not regularly intensively fertilised and additional grass is not sown.
Due to fertilisation, many species disappear as they are competed by species
more demanding for nutrients (mainly grasses - Dactylis glomerata,
Festuca pratensis, Phleum pratense, in more wet places Alopecurus
pratensis that can better receive nutrients from soil.
Nevertheless, grassland does not impoverish if it is not fertilised.
Grassland species store nutrients also in lower parts, like roots, tissues
at root basis, underground browses. If grass is not mown too late in autumn,
the plants manage to store nutrients for the next year. Also in the same
vegetation period the grass after mowing grows again as even the mown plants
maintain a lot of nutrients that they can use for the development of
aftermath. The roots of vascular plants produce large biomass. With the
die-off of some roots, new nutrients are formed in the soil.
Medium fertilisation every several years does not harm species diversity.
Previously, the low productive farms the farmers fertilised with manure from
time to time. The only type where medium fertilisation is admitted is
medium moist and moist grassland. Fertilisation can be given
only so much to regain back in the ecosystem the organic substances that
have been taken out with hay and grazing. In such a way soil impoverishing
can be prevented and the rich floristic composition maintained.
For the maintenance of plant and animal species diversity more favourable
is grazing without binding domestic animals with chains but leaving in
stockyards. In more distant coastal fishing villages many diverse meadows
have maintained because they were mown by hands and cows grazed
freely.
For medium moist and moist habitats in rich soils regular hay
cutting is important. In medium moist poor habitat grasslands and
pastures where Agrostis tenuis, Anthoxanthum odoratum, Plantago
lanceolata, Leontodon autumnalis, Trifolium repens etc. grows the best
is grazing. Then low plant cover characteristic for grazed land develops
with species that are adapted to grazing. These species can not develop in
those grasslands where mowing takes place because they are competed by
plants of larger shape.
Less intensive management is needed for dry grasslands both on poor
sandy soils (Class Koelerio-Corynephoretea; Festuca ovina, Pilosella
officinarum, Lychnis viscaria, Hylotelephium triphyllum, Nardus stricta,
Galium verum grows) and on calcareous soils (Class Festuco-Brometea;
Filipendula vulgaris, Helictotrichon pratense, Phleum phleoides, Cirsium
acaule, Trifolium montanum grows). Best management type is grazing, may
be it is possible to graze every several years. Traditionally, in such
grasslands sheep and goat are grazed. Still, it is necessary to be careful
not to have too high grazing intensity.
Previously also wet meadows were mown (Class
Phragmito-Magnocaricetea, Class Scheuchzerio-Caricetea nigrae) where mainly
sedges grow. Under the influence of mowing high species diversity develops.
Grazing and grass cutting limits the too wide distribution of sedges which
then do not form large hummocks that are characteristic for abandoned
grasslands. Just thanks to mowing many orchid species, like Dactylorhyza
sp., Orchis sp., Epipactis palustris, Liparis loeselii, Platanthera
sp.etc. can grow. At present, such meadows appear in Latvia but a large
part of them have started to overgrow.
Many people have understood that natural grasslands should be maintained
for nature diversity and also own joy. At the same time mistakes are made in
their management. In many places grasslands are not mown or grazed but
because of the lack of money or other reasons they are burned in spring. It
causes even a larger disaster than grassland not management at all. Of
course, grassland does not overgrow; the purpose in some kind is reached.
Already on the first year after burning there is not a splendid plant cover.
Many species have become extinct. Especially suffer grasses with dense
tussocks, like Helictotrichon pratense, Phleum phleoides also many
species of dicotyledons disappear. In a burned grassland only few species
survive, mainly these are rootstock grasses - Brachypodium pinnatum,
Calamagrostis epigeios that spread rapidly reducing species diversity
and the botanical and landscape value of the grassland.
During the litter fires disappear not only plant species but also many
insect and other invertebrate species. In the ecosystem the balance between
different organism groups is destroyed where every living being has its own
role.
Grassland protection activities and programmes
Protection of natural grasslands can be evaluated as insufficient. Most
of grassland habitats that are important for biological diversity are not
adequately represented in protected nature territories. Even in protected
nature areas, like calcareous grasslands in the Abava River Valley Nature
Park, Randu Meadows Nature Reserve in the coastal area, wet meadows in the
Diļļu Meadows Nature Reserve and other natural grasslands overgrow as almost
no management is carried out and protection regimen is not ensured.
At present most important activities for protection of natural grasslands
are connected with EU special before entry programme for agriculture and
countryside development
SAPARD subprogram "Conservation of Biological Diversity and Rural
Landscapes".
Research and monitoring
Natural grasslands were mapped in the frame of project "Mapping and geobotanical regionality of
Latvian vegetation" carried out by the Institute of Biology, Academy of
Sciences (1953-1970, leader of theme was Laima Tabaka) The elaborated map is
not published.
At present mapping of natural grasslands takes place in the frame of the
project carried out by the Latvian Fund for
Nature "Mapping of Natural Grasslands". Project is leaded by Ivars
Kabucis.
Extensive studies of natural grassland vegetation started with the work
of G. Sabardina in the Institute of Biology, Academy of Sciences, Laboratory
of Botany in the frame of the project "Phytosociology of natural grasslands"
(1951-1957, leader of the theme was Gali Sabardina). Research results are
published in one monograph and several publications. Research was carried
out according to the floristic-dominant method that was widely applied in
the territory of the previous Soviet Union.
From 1960-ties to 1980-ties studies of natural grasslands were fragmentary.
Separate publications had K. Birkmane and J. Jukna. In the second half of
1980-ties more intense research started and was carried out according to the
floristical-ecological Braun-Blanquet method.
Ecological studies in the ecosystems of natural grasslands up to now are
not well- developed. During 1950-1970 they were carried out at the
Laboratory of Botany, Institute of Biology and were mainly connected with
grassland species occurrence in relation to different trace elements of
soil. At present most important research is carried out in Randu Meadows
where continouos monitoring is carried out.
Randu Meadows. Research was started in 1996 and is carried out by
the Laboratory of Bioindication, University of Latvia under the leadership
of V. Melecis. Main research objects are grass layer anthropoids and
vegetation structure.
(Lit.: Melecis V., Karpa A., Kabucis I., Savičs F., Liepiņa
L. 1997. Distribution of grassland arthropods along a coenocline of seashore
meadow vegetation. Proceedings of the Latvian Academy of Sciences. 51 (5/6):
222-233.)
Engure Lake Nature Park. Research was started in 1995. Under the
leadership of V. Melecis. Vegetation studies are carried out by Laboratory
of Botany, Institute of Biology leaded by V. sulcs. Monitoring is carried
out in different habitats among which are also several moist and wet natural
grassland habitats.
(Lit.:Gavrilova G., Jermacāne S. 2002. Nemeža biotopu
lakstaugu stāva dinamika Engures ezera dabas parkā. LU 60. zinātniskā
konference. Ģeogrāfija, ģeoloģija, zemes zinātne. Referātu tēzes. Rīga.
45-47.lpp.;
Melecis V., Karpa A. 2002. Zāles stāva kukaiņu sugu daudzveidības izmaiņas
Engures ezera dabas parkā. LU 60. zinātniskā konference. Ģeogrāfija,
ģeoloģija, zemes zinātne. Referātu tēzes. Rīga. 94. lpp.)
Abava River Valley. Research was started in 2000 in the frame of
Eurograssland project. Project is realised by Latvian Fund for Nature (S. Jermacāne, I.
Kabucis). Aim of monitoring is to determine the change of different
calcareous grassland types and pasture plant cover under permanent but not
regular management influence and grassland vegetation recovery in previous
arable lands under the influence of grazing and mowing.
International collaboration
Project "Eurograssland". In co-operation with Overaisel province
in the Netherlands, in the frame of Eurograssland project in 1998 the Latvian Fund for Nature realised a project
Abava River Valley Grasslands. The aim of the project was to elaborate of an
action plan for the protection of natural grasslands with active involvement
of farmers and state institutions. In the frame of this project also
monitoring of calcareous meadows and pastures was started.
Project "Mapping of Natural Grasslands". Latvian Fund for Nature in co-operation
with the Netherlands. The project was started in 2000. Aim of the project is
to map the plant cover of natural grasslands.
WWF project in Pape in co-operation with
Denmark.
Publications
Informative booklets on nature diversity conservation in
grasslands
Strazdiņa E., Auniņs A., Kabucis I.,
Priednieks J. 2000. Dabas daudzveidības saglabāsana lauku ainavā.
Latvijas Dabas fonds, 20 lpp.
Kabucis I., Strazdiņa E., sternbergs M. Bagātības lauku ainavā.
Latvijas Dabas fonds, 22 lpp.
Vegetation
Birkmane K. 1960. Ainažu-Salacgrīvas
jūrmalas pļavu veģetācija. Latvijas PSR veģetācija 3: 59-69.lpp
Jermacāne S. 1998. Gaujas augsteces rajona purvaino pļavu augu
sabiedrības. Latvijas purvu veģetācijas klasifikācija un dinamika. Latvijas
Universitātes Zinātniskie Raksti. Rīga, 613: 67-75
Jermacāne S. 1999. Smaržzāles-parastās smilgas sabiedrību
Anthoxantho-Agrostietum tenuis Sill. 1933 em. Jurko 1969 klasifikācija un
ekoloģija Latvijā (Piejūras zemiene, Austrumzemgale, Vidzemes augstiene).
Latvijas Veģetācija 2: 29-80
Jermacāne S., Laiviņs M. 2001. Dry calcareous dolomite outcrop and
grassland communities on the Daugava River bank near "Dzelmes". Latvijas
Veģetācija 4: 51-70
Sabardina G. 1949. Rīgas-Jelgavas līdzenuma dabīgās pļavas. Latvijas
PSR ZA Vēstis 3: 69-84
Information on traditional management
Dumpe L. 1964. Ražas novāksanas veidu
attīstība Latvijā. LPSR Vēstures Muzeja Raksti. Etnogrāfija. Rīga.
Dumpe L. 1985. Lopkopība Latvijā 19. gs. un 20. gs. sākumā.
Etnogrāfisks apcerējums. Rīga. Zinātne.
Dumpe L. 1999. Mežu izmantosanas attīstība Latvijā. Gr. Latvijas
mežu vēsture līdz 1940. gadam. H.Strods (red.). WWF - Pasaules Dabas Fonds.
Rīga. 305-358 lpp.
Author: M. geogr. Solvita Rusina
Grasslands (meadows and pastures)