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Coastal habitats in Latvia
Vija Znotina
Saturs
The sea coast in Latvia extends over 490 km: 182 km along the Baltic Sea and 308 km along the Gulf of Riga. Coastal habitats are influenced by the sea or they are formed from these sea-influenced habitats.
The sea coast is changing all the time, at every moment. Some changes are temporary – small dune is formed around the cluster of grass, and blown away soon. There are also big changes - ice ages are replaced by warmer climatic periods, lands are mowing, the coastlines of seas and oceans are changing.
In some parts of the coast, abrasion or wash-out occurs. In other – accumulation of the sand. Depending of shore type, there are 3 shore types in Latvia:
- coasts of accumulation, where sand accumulates and foredunes develop;
- wash-out coasts which can be active or still;
- coasts of dynamic equilibrium where both development of foredunes and their wash-out occur.
The characteristic landform is a plain with dune relief with sandy soils. There are the outflows of 45 small and 3 large rivers and 3 lagoons. Typical habitats along the Latvian Baltic Sea coast are located in the following zones: sandy, less frequently boulder and pebble beaches, embryonic, white, grey and wooded dunes, and coniferous forests. Coastal meadows and brackish salt marsh communities are common in small areas.
Mostly, dunes are common along the sea shore. However, there are also some inland dunes in Latvia. They were formed at the end of ice-time. Inland dunes can be found in Trapene plain, around Daugavpils and in some other sites.
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Beach (pludmale, liedags in Latvian) is the first terrestrial habitat at the sea shore. Beach starts from the seawater minimum level and ends with the maximum (during storms) and is directly subjected to regular influence of coastal streams, waves and wind. Beach is formed by easily washed sediments (sand‚ gravel‚ pebbles) and cockleshells.
The width of the beach can be 5 - 10 - 25 m in the narrowest sites, 30 - 100 m in wider sites, sometimes also 150 - 100 m and more. Beaches can differ, depending on the material and slope of the sea coast. There are: sandy beaches, gravel and pebble beaches, boulder beaches.
Some beaches are without vegetation; in some beaches, various hidrofilous plant species are common. Plants can be distributed in belts along the sea shore.
As vegetation is influenced by brachish water, plants are scattered and the number of species is low. Typical plant species are Salsola kali‚ Cakile baltica‚ Atriplex littoralis‚ Honckenya peploides. These are halophytes – plants which can grow in salty habitats.
Sandy beaches are the most typical beaches in Latvia. Their length is appr. 240 km (of 496 in total sea coast in Latvia). There are various types of sandy beaches: dry, high and wet, low, with vegetation and without it. Wet, low beaches are common where the sea coast is flat. In more abrupt coasts, beach is dry, high.
Typical plant species in high beaches are: Salsola kali‚ Cakile baltica‚ Atriplex littoralis‚ Honckenya peploides. Rare plant species: Atriplex glabriuscula‚ A. longipes‚ Corispermum intermedium‚ Chenopodium acerifolium.
Typical plant species in low beaches are: Ranunculus sceleratus‚ Bidens tripartita‚ Polygonum mite‚ Rorippa palustris‚ Polygonum hydropiper‚ Juncus bufonius. Rare plant species: Juncus balticus‚ Aster tripolium‚ Atriplex calotheca.
Gravel and pebble beaches also can be with vegetation or without it. Plants are scattered. Typical plant species are Honckenya peploides‚ Cakile baltica‚ Atriplex species, Salsola kali.
Boulder beaches are beaches with many boulders. They can be covered with vegetation or without it. In low and moist boulder beaches, vegetation that consists of vascular plant species growing near the coast appears. In some places, beach vegetation leads to wetland vegetation characteristic for the shallow water zone. Typical plant species: Phragmites australis‚ Scirpus tabernaemontani‚ Bolboschoenus maritimus‚ Typha angustifolia.
For high boulder beaches, low vegetation is chacteristic. It is formed mostly by Honckenya peploides‚ in some places also Carex arenaria and other species.
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Dunes (kāpas in Latvian) are wind blown sandy bars. Dunes develop, if there is a barrier in the way of wind moved sand. Such barrier can be stump, bush, snag, plant etc. Sand accumulates before and after this barrier. Bit by bit, the hight of dune can reach several metres. If there is enough sand, proximal congeries connect, and elongated dunes develop. Dunes develop in those sites where is enough sand‚ low ground water level‚ constant governing winds and sparse plant cover.
If you go in the terrestrial direction from the sea, you can cross dunes of various types, and observe the stages of dune development. Initially, there will be low embryonic dunes with scattered vegetation. The next are foredunes which are higher. After foredunes, grey dunes are typical. Here, the development of soil has started. Typically, black dunes are following after grey dunes. Black dunes are covered by forest.
You will not find these stages of dune development in sites, where the amount of sand is insufficient for dune development as well in sites which are low and moist and in sites, where abrasion occurs – the sea is eroding the shore, “taking away” the sand and carrying it alongshore.
Dunes are subdivided in primary dunes and secondary dunes. Primary dunes are the first dunes near the beach. The development of primary dunes depends on the quantity of sand in the beach.
Primary dunes are dunes located most closely to the sea and at the seaside border with the beach. Primary dune development directly depends from the amount of sand on the beach. In Latvia, the total length of primary dunes reaches about 240 km. Primary dunes are subdivided in embryonic dunes and foredunes (or white dunes).
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Secondary dunes develop after primary dunes. In secondary dunes, the vegetation of grey dunes, forest and grassland can be found.
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Embryonic dunes are the first stage of dune development. They are small, about 10 - 50 cm high sandy bars with sparse vegetation of halophylous plant species such as Leymus arenarius‚ Honckenya peploides‚ Calammophila baltica‚ Elytrigia littorea. More rare plant species in embryonic dunes are Elytrigia junceiformis‚ Linaria loeselii‚ Crambe maritima.
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Foredunes (or white dunes) develop after embryonic dunes. Similarly as in embryonic dunes, active sand blowing occurs in foredunes. The vegetation is sparse or scattered and it is formed by species of sandy habitats. Foredunes may be also without vegetation. Typical plant species of foredunes are: Ammophila arenaria‚ Calamagrostis epigeios‚ Leymus arenarius‚ Festuca arenaria‚ Hieracium umbellatum‚ Artemisia campestris.
Rare plant species are: Eryngium maritimum‚ Lathyrus maritimus‚ Linaria loeselii‚ Tragopogon heterospermus.
Often, many shrub species are growing in foredunes. They can be both planted and self-established. Typical shrub species in foredunes are: Salix daphnoides‚ S. viminalis‚ S. rosmarinifolia. Rare plant species: Salix repens‚ Lonicera caerulea var. pallasii.
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Grey dunes are the next stage of development after foredunes. Grey dunes are relatively stable dunes - the moving of sand does not occur here or it is very little.
The plant cover in grey dunes consists mainly of bryophytes‚ lichens and low perennial plant species as well as sparse trees and shrubs. These species can grow in very dry soils. The vegetation is sparse – the ground is not covered by plants, bare sand is visible between the plants. There are two types of grey dunes in Latvia – grey dunes with low vascular plant vegetation and grey dunes with shrubs and trees.
In grey dunes with low vascular plant vegetation, vegetation consists mainly of bryophytes, lichens and low perennial plants. Typical plant species are: Koeleria glauca‚ Carex arenaria‚ Thymus serpyllum‚ Pulsatilla pratensis, as well as bryophytes, like Racomitrium canescens and Tortula ruralis. Rare plant species are: Alyssum gmelinii‚ Dianthus arenarius‚ Silene borysthenica.
In grey dunes with shrubs and trees, separate trees‚ shrubs or their groups are common. In some places, groups of dwarf shrubs develop. Typical sgrub species are: Juniperus communis‚ Pinus sylvestris‚ Salix daphnoides. Rare species are: Lonicera caerulea var. pallasii‚ Salix repens.
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Between dunes, dune slacks (starpkāpu ieplakas in Latvian) can be located. Dune slacks develop in ample relief depressions between dunes, in places with a high ground water level. Dune slacks are characteristic in places with several rows of foredunes. Usually, dune slacks are narrow. They are temporal and change fast due to overgrowing by trees or land paludification.
There are several types of dune slacks. Dune slacks with pioneer vegetation are located in periodically moist depressions with scarce or continuous plant cover that is formed by pioneer species. Typical plant species are: Sagina nodosa‚ Equisetum variegatum‚ Carex flacca. Rare plant species: Centaurium littorale‚ Juncus balticus.
Dune slacks with grassland vegetation occur in depressions in a transition zone between foredunes and grey dunes and shrub zone or forest. In the plant cover, grassland species dominate. Typical plant species are: Rhinanthus vernalis‚ Poa pratensis‚ Anthoxanthum odoratum‚ Ranunculus acris. Rare plant species are: Dactylorhiza incarnata‚ D. baltica‚ Epipactis palustris.
In very wet sites, dune slacks with calcareous fen vegetation occur. These are depressions where calcareous fen species are characteristic. Peat layer is lacking or may be very shallow. Typical plant species are: Carex flacca‚ Potentilla erecta‚ Molinia caerulea‚ Galium boreale. Rare plant species are: Schoenus ferrugineus‚ Cladium mariscus‚ Primula farinosa.
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Bluffs (stāvkrasti in Latvian) are the coasts which are developed under the influence of wash-off or abrasion. Total length of coasts with bluffs in Latvia is. 123 km; their height is appr. 6 - 15 meters. Bluffs can change periodically, both under the influence of natural and anthropogenic factors.
In some bluffs, the process of wash-off dominates over the sand accumulations. In other, wash-off has stopped and bluff is partly or totally covered by vegetation. Bluff can be formed by various substrates - moraine, sand, grawel, sandstone and other.
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Coastal pool (pludmales peļķe in Latvian) is a habitat with very unusual flora and fauna. Coastal pools can be constant or drying-out.
Constant coastal pools are water basins with permanent brackish water, in the zone of fore dunes or grey dunes. Typical plant species are: Bolboschoenus maritimus‚ Typha angustifolia‚ Sparganium species. Rare plant species is: Juncus balticus.
Drying-out pools are periodically drying-out slightly salty water pools in the beach or dune slacks. They can be found in low, wet beaches. Annual amphibic plants can be found here.
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Coastal wetlands with the growths of tall vascular plants (piekrastes mitrāju augsto lakstaugu audzes in Latvian) occur in the seacoast shallow water zone. In Latvia it is rare habitat and can be found in some sites in Gulf of Riga, for example, in Mersrags and in Ainazi. Usually, these stands consist of Phragmites australis‚ Sium latifolium‚ Scirpus tabernaemontani, Bolboschoenus maritimus.
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According to the “List of protected habitat types” (2000), following habitats are protected in Latvia:
- Wet beaches with springs;
- Grey dunes with trees and shrubs;
- Grey dunes with low vascular plant vegetation;
- Foredunes with Eryngium maritimum;
- Dune slacks with calcareous fen vegetation.
Following habitats of Habitats Directive (1992) can be found in Latvia:
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Mudflats and sandflats not covered by seawater at low tide
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Annual vegetation on drift lines
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Perennial vegetation of stony banks
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Vegetated sea cliffs of the Atlantic and Baltic coasts
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Salicornia and other annuals colonising mud and sand
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Embryonic shifting dunes
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Shifting dunes along the shoreline with Ammophila arenaria (white dunes)
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Fixed coastal dunes with herbaceous vegetation (grey dunes)
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Decalcified fixed dunes with Empetrum nigrum
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Dunes with Salix repens ssp. argentea
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Wooded dunes of the Atlantic, Continental and Boreal region
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Humid dune slacks
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Dry sand heaths with Calluna and Empetrum nigrum
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Inland dunes with open Corynephorus and Agrostis grasslands
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Boreal Baltic coastal meadows
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- Āboltiņš, O. 1995. Kāpas. Latvijas daba: 2. Latvijas Enciklopēdija, Rīga, 223.- 224. lpp.
- Biotopu rokasgrāmata, 2000. Preses nams, Rīga, 140 lpp.
- Kabucis, I. 1995, Kāpu veģetācija. Latvijas daba: 2. Latvijas Enciklopēdija, Rīga, 228. lpp.
- Laime, B., 2000. Pludmales un primāro kāpu aizsardzības plāns. Rīga, 45 lpp.
- Noteikumi par īpaši aizsargājamo biotopu veidu sarakstu (2000).
- Latvijas biotopi, 2001. Latvijas Dabas fonds, Rīga, 96 lpp.
- Pastors, A., 1997. Baltijas jūras piekraste un Rīgas jūras līcis. Latvijas ģeogrāfija, „Zinātne” , Rīga, 54 - 73. lpp.
- Latvijas daba
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