Latvian Biodiversity Clearing-House Mehanism

Grasslands (meadows and pastures)

2006-09-01T00:00:00Z

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
- improvement

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.

Change of land-use types

Often grassland transformation into an arable land or forest soil takes place.

Pollution

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.

Grazing and mowing

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.

What causes fires?

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

Mapping

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.

Vegetation studies

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.

Ecology

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.

Monitoring

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

Nezāļu sugu skaita un sastāva dinamikas pētījumi labību sējumos

2006-09-04T00:00:00Z

Hogweed and its distribution in Latvia

2006-09-04T00:00:00Z

Primarily in Latvia the Hogweed was introduced as a cultivated plant. Great expectancy was put on it as a cultivated fodder and a nectar plant. Nowadays, the distribution of the Hogweed is out of human control and the species has spread almost all over Latvia, mainly in unmanaged land areas and near ditches.
In The National Programme of Biodiversity it was acknowledged that the Hogweed Heracleum sosnowskyi is a very expansive species that can invade and maintain not only in weedy places and on road margins but also in natural plant communities. It means that when starting to the growth of this plant for fodder, the most elementary precaution principles were not followed.
The Hogweed is very dangerous for humans and causes skin and mucous membrane burns and is particularly dangerous for children. To extinguish the Hogweed that has been growing for a longer time is almost impossible. Therefore, individual attempts have not given considerable results. The present results testify that to extinguish the Hogweed (not only to limit) all the possible complex of agricultural, technical and biological methods must be applied.
Recognising the seriousness of the established situation, Ministry of Agriculture of the Latvian Republic has provided financial support to elaborate Provisional Recommendations to localise the Hogweed in Latvia (only in Latvian).

Characteristics of the Hogweed species

Heracleum sibiricum L. is a native species Latvian flora, in English - Sibirian Hogweed. It is common all over the country on road margins, meadows, forests and as a weed in fields. Heracleum sibiricum is a morphologically variable species.

Later in Latvia have arrived the other species H. persicum Desf. ex Fischer, H. pubescens (Hoffm.) Marsch. - Bieb., H. villosum - and H. mantegazzianum Sommier et Levier - Giant Hogweed that is a decorative plant. There are also many hybrids between the Hogweeds.

According to the herbarium data of the Institute of Biology, University of Latvia, investigations and literature data, its possible to conclude that in the Baltic region in natural habitats two well distinguished taxa have spread - more common H. sosnowskyi, much more rare is H. mantegazzianum. Further research is needed to make the final conclusions. More rare in Latvia is the Giant Hogweed - H. mantegazzianum Sommier et Levier. This species of the Hogweed grows in Riga in the Bastejkalns park area. The origin of Giant Hogweed is in the Caucasus region. Already in the thirties of the last century it was introduced in Latvia as a decorative plant. Although there have not been more detailed observations, the botanists consider that in natural habitats this species occur rarely. The Sibirian Hogweed and the Giant Hogweed can be separated due to the different leaves.

Heracleum sosnowskyi Manden.appeared in Latvia in at the middle of the previous century as a cultivated plant and its origin is in the Caucasus region. Several botanists consider Heracleum sosnowskyi only as a subtaxa of H. mantegazzianum or H. pubescens. Therefore, Heracleum sosnowskyi does not appear in the lists of weedy flora of many West-European countries. For the first time Heracleum sosnowskyi as a species was described by I. Mandenova in 1944. More detailed studies were carried out by I. Saciperova. In Latvia Heracleum sosnowskyi was introduced in 1948 and has found a favourable environment for its distribution and nowadays actively spreads in the natural habitats becoming an unwanted and aggressive weed. At the same time it is also dangerous for the human health.

Photo: Normunds Rustanovics

There is a contradictory opinion about the life span of this species in Latvia. One view is that it is a biennial plant - in the first year it forms a large rosette and strong root system, on the second - great size and inflorescence with a considerable number of seeds. After fruiting the plant dies. Hogweed is a perennial plant. One of the supposed reasons of Heracleum sosnowskyi being a perennial plant is based on the different rate of seed germination in the period post- mature. It can last between 2 - 4 years. The second reason for being perennial can be that in the situation of mutual concurrence between the Hogweeds part of the plants are not able to produce inflorescence 2 - 5 years one after another. Therefore, the seed production and life span lasts between 3 - 6 years, sometimes even longer.

Investigations in which the seeds were not allowed to mature due to mowing before the inflorescence was formed were carried out. The results showed on the second and the following years the species was able to pass the winter and produce seeds on the next year and then die after flowering. Many practical workers consider that even when the mother plant dies, the off-root buds are able to produce shoots giving rise to new plants and in such a way being perennial plants.
The new shoots Heracleum sosnowskyi are rather cold resistant and can bear 4 -7 degrees below zero. It is found out that starting from the second year in a snow less situation they can survive up to 25 degrees below zero and below the snow even up to 45 degrees below zero. Heracleum sosnowskyi is a light demanding plant and at the beginning of their growth do not bare shade. When the Hogweeds have taken roots then with their giant shape, fast growth and green mass they oppress the other plant species and form their own community.

Distribution in Latvia

Heracleum sosnowskyi was introduced in Latvia between 1950-1960. At the end of the 80-ties and beginning of 90-ties, its distribution in Latvia went out of human control. The Hogweed rapidly invaded not only in the open areas but also spaces along water-basins, roads and forests. Nowadays the distribution of the Hogweed is out of control and it has spread almost all over Latvia, mainly in unmanaged land areas and near ditches. Its distribution is favoured due to abandoned land, where earlier land management activities took place.
Already in 1986 plant protection specialist and botanist A. Rasiņs called it as a botanical "racoon" and considered it as especially dangerous quarantine weed.
Most of the specialists also now admit that the Hogweed is a dangerous plant whose growth is difficult to extinguish. The Hogweeds in Latvia is not a nature catastrophe, but a disturbing phenomenon that must be limited. A conclusion can be driven that the Hogweed becoming wild has become a weed difficult to limit.

Distribution of Heracleum sosnowsky in Latvia, 2005 (according to data from Institute of Biology, University of Latvia)

Activities

The analysis of the Hogweed distribution areas testify that the weed is most widespread in areas where 50 years ago there was an attempt to introduce as a perspective fodder plant. In open areas the struggle with the Hogweed is more an economic and agriculture managerial problem, rather than a technological one. More complicated is the elimination of its distribution at the watersides of water-basins, near ditches, on road edges, where the use of herbicides is restricted or not allowed. The variety of land ownership types in the Hogweed distribution areas witnesses that the elimination of the Hogweed in Latvia is not anymore only a problem of farmers and Ministry of Agriculture. To limit the distribution of the Hogweed co-ordinated activities of Ministry of Nature Conservation and Regional Planning and the Ministry of Traffic and Municipialities is needed.

Distribution of the Hogweed is favoured by production of many seeds that are distributed by wind, water, birds, etc. It is also thanks to the fact that the Hogweed germinates very fast, it exceeds in growths any other plant shading it and forcing out of the habitat. In the places where still 2 years ago wild plants were typical, nowadays only a 3 - 4 m long Hogweed growth occurs. This process is incredibly fast.
There is a conclusion of experts (scientists and practical workers) that the minimum increase of the weed in a year is ~ 10 % and the future prognosis for 2007 could cover 18271 ha land area.

Publications

Latvāņi. // Lauksaimniecības enciklopēdija. Liesma, R., 1966.

Rasiņs A., Fatare I. 1986. Sosnovska latvānis - Heracleum sosnowskyi Manden. - bīstama nezāle Latvijas florā. - Grām.: Retie augi un dzīvnieki. - Rīga, 8. - 10.lpp.

Enciklopēdija "Latvija un latviesi" Latvijas daba Nr. 3., 1995, Rīga, 89. - 90. lpp.

Flora of the Baltic countries 2., 1996, Eesti Loodusfoto AS Tartu, 230p.

Latvijas PSR flora. 1957., 3., LVI, Rīga, 416.-417. lpp.

Latvāņi, to izplatības ierobežosana // Pagaidu rekomendācijas. - Ozolnieki, LLKC, LLU, 2002.- 17 lpp.

Prepared by: M.agr. D.Obolevica
Latvia University of Agriculture

Putni Latvijas agroainavā

2006-09-04T00:00:00Z