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© Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at Mire ecosystems in Latvia M. PAKALNE & L. KALNINA Abstract: In Latvia mires comprise 4.9 % of the total land area. Peat deposits, i.e. peatlands bigger than 1 ha and with more than 0.3 m peat, cover 10.4 % of the land and include, next to mires with thick peat layers, also some forest types, drained mires, and peat extraction sites. Both minerotrophic (fens and transitional mires) and ombrotrophic (raised bogs) mires occur in Latvia. Mires are distributed throughout the country but the area covered differs among the nature regions of Latvia. Distribution of mires and diversity of mire vegetation are determined by geology of area, origin of mires and climatic differences between coastal and continental parts of Latvia. Fens, started to develop in the early Holocene in the Preboreal 10.000 years BP in the lower areas of the lowlands and in the small glaciocarstic depressions of uplands. Later, during the Atlantic many fens transformed into transitional mires and gradually into raised bogs. About 35 % of mires have formed as a result of filling-in of basins, but others are formed in the result of land paludification. During the Bo- real, when climate became warmer, the formation of mires became more extensive. In the largest mires, like Kemeri Mire, Teici Mire raised bog vegetation developed. During the Atlantic Time mire formation conditions became favourable for mire development and witnessed the most extensive mire formation in Latvia. During that time the area was significantly influenced by the Baltic Sea stage Litto- rina Sea, when the water level was higher about 5-6 m than at present and large coastal areas of the present Coastal Lowland were covered by water. Fluctuations and decrease of the Littorina Sea level caused the formation of shallow lagoon lake basins where lake terrestrilization took place and large areas developed into mires (Sarnate Mire, areas around Kanieris, Engure and Babite Lakes). Mires are protected in the North Vidzeme Biosphere Reserve, National Parks (Slitere, Kemeri and Gau- ja), Strict Nature Reserves (Teici, Krustkalni and Grini), Nature parks and nature reserves, as well as in protected landscape areas. There are six Ramsar sites in Latvia — Kanieris Lake, Engure Lake, Teici and Pelecare Bogs, Northern Bogs, Lubana Wetland Complex and Pape Wetland Complex. In Latvia pristine and undamaged mire complexes are still found, most of which now are state protected. In total about 12 % from the Latvian mires are under state protection. On the other hand, about half of mires are influenced by various human activities, like drainage, peat cutting, eutrophication and fire and the degradation of the mires influenced by drainage continues. Key words: Minerogenous mires, ombotrophic mires. Introduction This has resulted in a high atmospheric hu- midity and a moderate temperature regime, The natural conditions and biological which determines the mild climate. The cli- diversity of Latvia are determined by its geo- mate becomes more continental towards the graphical location near the Baltic Sea (55° eastern part of Latvia. 40' and 58° 05' northern latitude and 20° 58' and 28° 14' eastern longitude), variable geo- Southwest, south, southeastern winds logical conditions, relief, hydrology and cli- prevail, but in summer western and north- mate (Fig. 1) Total area of Latvia comprises western winds are the most frequent. Annu- 64-635 km2. Geobotanically, Latvia belongs ally Latvia is crossed by an average of 120- to the hemiboreal (boreo-nemoral) vegeta- 140 cyclones. In January range of tempera- tion zone (AHTI et al. 1968) characterised by ture varies from -2.6 °C to -6.6 °C. In July, deciduous-coniferous (mixed) forests. correspondingly varies from +16.8 °C to The climate is influenced by the At- + 17.6°C. Annual precipitation is 500-800 Stapfia 85, zugleich Kataloge der OÖ. Landesmuseen lantic air masses and the near-by Baltic Sea. mm per year. The vegetation period (the Neue Serie 35 (2005), 147-174 147 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at also some forest types, drained mires, and peat extraction sites (Fig. 2). The degree of paludification in Latvia shows that the main factors promoting this process are geological processes, relief and characteristics of surface deposits. Most paludified areas are located in the inland lowlands with gently undulating relief of the till and glaciolimnic clay and silt. Many mires have formed as a result of terrestrial- i:ation of shallow lakes and ancient rivers or its' meanders, as well as filling-in of the for- mer lagoons. Approximately 28% of raised bogs initially formed as a result filling-in of some basins and comprise gyttja layer in the very bottom. The present surface topography of Latvia was mainly formed in the result of the last - Weischelian (Latvian) glacier and Fig. 1: Location of Latvia in daily average temperature above +5°C) be- its' melting water processes. Then main re- Europe. gins approximately in April 15 and last for lief macroforms - uplands and lowlands 180-200 days (KALNINA 1995). formed. Glacial deposits cover almost the In Latvia mires comprise 4.9% of the to- entire territory of Latvia. Exception are tal land area. Peat deposits, i.e. peatlands of coastal areas that were greatly changed dur- more than 1 ha large and with more than ing the Late Glacial period after the retreat 0.3 m peat, cover 10.4% of the land and in- of glacier and the Holocene when the area clude, next to mires with thick peat layers, was significantly influenced by the basins of PEATLANDS IN LATVIA Fig. 2: Distribution of peatlands in Latvia >*. V 148 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at Baltic Sea stages, mainly the Baltic Ice Lake During the Atlantic Timefens gradually and the Littorina Sea. The water level of transformed into transitional mires and lat- these basins was higher than at present and er into raised bogs. Development of raised large coastal areas were covered by waters bogs was associated with a rapid increase of and influenced by its' dynamics, e.g. erosion various Sphagnum species in mire vegeta- and sedimentation. The plains were formed tion. During the Subboreal Sphagnum fus- by Baltic Ice Lake and Littorina Sea and oc- cum, Scheuchzeria palustris and Eriophorum cupy the largest part of the Coastal Low- vaginatum often dominated in raised bog land, where marine sediments may be cov- vegetation, but during the Subatlantic ered by eolian sands. The present relief of Sphagnum mageUanicum, Andromeda polifolia Latvia over several thousand years in addi- and Calluna vulgaris became more wide- tion to the geological processes was influ- spread. Microclimate primarily determined enced by human activities, and has changed species composition in these raised bogs due to the increase of human population, (KALNINA 1998). more intensive use of natural resources and agriculture development. Mires in geobotanic Mires are distributed throughout the districts of Latvia country but the area covered differs among According to the differences in geologi- the nature regions of Latvia (PAKALNE & cal development, vegetation and soil fea- KALNINA 2000). The largest raised bogs oc- tures Latvia is divided into eight geobotani- cur in the East and Middle Latvia Lowland cal districts (KABUC1S 1995). Differences in and North Vidzeme Lowland, as well as in mire types, distribution, floristic peculiari- Tireli Plain, central part of Latvia. Raised ties and representation are observed among bogs are most widespread, although fens oc- the geobotanical districts. cur as well. The Coastal Lowland is situated along The oldest mires in Latvia were fens the coast of the Baltic Sea and Gulf of Riga. that formed in the lower areas about 10.000 Here mire vegetation covers quite large ar- years ago, during the Preboreal. During that eas and includes raised bogs as well as poor time fens originated also in many small and rich fens. Rich fens have developed glaciokarstic depressions in the uplands due near coastal Littorina Sea lagoon lakes, like to filling-in of small basins. Kanieris and Engure Lakes, situated in this area. In similar location is located also area During the Boreal, when climate be- of Sarnate Mire, where Littorina Sea la- came warmer, the formation of extensive goonal lakes were formed during the final mires commenced. Largest part of mires in stage of this sea. Latvia has been developing since the Boreal Time. During the Atlantic Time climatic Raised bogs of the Coastal Lowland be- conditions became favourable for for mire long to the western type, where Trichopho- development and witnessed the most exten- rum cespitosum occurs. Raised bogs can be sive mire formation in Latvia. The broad- dome-shaped and plateau-type bogs with a leaved forests surrounded mires. level centre, but occasionally with steep slopes (developed from shallow ancient la- In the early stages of mire development goon lakes). Mire types, characteristic for Phragmites and Carex species dominated, the Coastal Lowland are calcareous fens and e.g. Phragmites austraUs, Carex dioica, C. ni- inter-dune mires. Sulphur springs with Cla- gra, C. panicea while trees and shrubs, such dium mariscus and Schoenus ferrugineus occur as Betula pubescens, Franguk. alnus, Pinus in the mires of the Kemeri National Park. sylvestris, Myricagale and Salix species dom- Also Slitere National Park and Engure Na- inated in fens. When the raised bog devel- ture Park including valuable mire vegeta- opment started, particularly during the At- tion are located in the Coastal Lowland. lantic, many of the currently rare plant species, like Myrica gale, Cladium mariscus, The North Vidzeme is characterised by Trapa natans, Salix myrtiUoides and Hammar- a high presence of mires and the dominance bya paludosa, were common. of vast raised bogs. In the western part of 149 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at this district there is the border of distribu- The West Latvia geobotanical district is tion of Chamaedaphne calyculata. This bor- not rich in mires. The minerotrophic mires der is considered to split raised bogs of west- that do occur in the in the depression be- ern and eastern type. Also fens occur in the tween morainic hills and hillocks and may region. Tall-sedge fens with Carex appropin- include lakes as well. Fens on calcareous quata, C. caespitosa, C. diandra, C. lasiocarpasoils comprise plant communities with Myri- are most widespread. Also small-sedge fens ca gale, Schoenus ferrugineus, Uparis loeselii with Carex nigra, C. panicea and C. flava oc- and Carex hostiana. Abava Nature Park and cur there. There are also fens with Salix lap- Stikli Mires Nature Reserve are located in ponum, S. rosmarinifoUa, S. myrsinifoUa andthis district. S. cinerea in the shrub layer and mires with Most common species in fens are Carex Betula humilis and Betula nana. Betula nana diandra, C. appropinquata, C. caespitosa and occurs mainly in the raised bogs located in C. vesicaria. There are also fens with a shrub the northern Latvia. layer consisting of Salix cinerea, S. rosmarini- The North Vidzeme Biosphere reserve is folia, S. lapponum and Betula humilis. In situated in this area and is especially rich in raised bogs Trichophorum cespitosum occurs. raised bogs. The East Latvia is one of the richest in The Central Vidzeme, Zemgale and mires areas in Latvia. Both ombrotrophic Central Latvia geobotanic districts are and minerotrophic mires occur there. much poorer in mires than other regions of Raised bogs belong to the eastern type with Latvia. In Central Vidzeme mires cover C/iamaeaap/me calyculata in the shrub layer. small areas. During the latest decades they The largest mire in Latvia - Teici Mire with have been drained and used for agricultural the total area of 16.000 ha is situated in the purposes. Raised bogs are rare. Fens and Jersika Plain and has developed both in the transition mires occur near lakes and in- result of lake terrestralizarion and soil palud- clude mire communities with Carex rostrata, ification (BAMBE 1993). Raised bogs are C. diandra, C. data, C. lasiocarpa and C. mostly covered with pine, more rarely they acutifarmis. In such mires SaUx myrtittoides are of open type. Lubana Wetland Complex and several rare orchids like Coraliorhiza tri- that is a Ramsar site is located in this area. fida, Hammarbya paludosa, JJparis loeselii, Epipactis palustris occur. Communities with In the South-East Latvia geobotanic Carex appropinquate are typical in river val- district mires are situated between hills near ley mires. the lakes. These mires have developed as a result of the filling-in of lakes. Ombrotroph- In Central Vidzeme, mires cover small ar- ic mires do occur in this district, although eas. Raised bogs are very rare. Fens dominate minerotrophic mire vegetation dominates. and occur mainly near lakes in the eastern part of the district. The common species of In the fen vegetation with Carex rostra- fens include Carex rostrata, C. diandra, C. elata and C. lasiocarpa dominates and may be ta, C. lasiocarpa. In the fens and transition accopmnied by Menyant/ies trifoliata and Co- mires rare species, like Salix myruüoides, marum palustre. Some of the mires of the Coratiorhiza trifida, Hammarbya paludosa, Li- area characterise by tall sedges - Carex op- paris loeselii, Epipactis palustris occur.. Wooded propinquata and C. elata. In some sites Salix mires and mires with very dense shrub layer rosmarinifolia, S. cinerea and Betula humilis occur in this region as well. occur, as well as Betula pubescens and Alnus In Central Latvia fens and transition gluanosa. Also Betula nana is found in this mires dominate and appear mainly near the district. Several rare moss species - Moerck- lakes as have developed as a result of lake teria hibemica, Bryum neodamense and Meesia restrializarion. They include sedge vegetation triquetra are distinguished in the mires. In with C. acutiformis, C. acuta, C. rostrata, C. the South-East Latvia transition mires with riparia, C. vesicaria. Suda Mire including Oxycoccus palustris and Sphagnum teres and raised bog vegetation occurs in this district S. wamstorfH occur. Uparis loeseln is the pro- within the area of the Gauja National Park. tected orchid growing there. 150 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at State of the art and history A number of mire related studies are of investigations, mappings, carried out - study of metal concentration in moss species and peat, paleobotanical usage and conservation peat analysis, studies of mire insects, study of In Latvia the most important peatland bryophyte flora in the mires, evaluation of studies started in the 1926 by Mire and Peat plankton communities in mire lakes, study Research Laboratory of the University of of mammals. Plant species monitoring in- Latvia under the supervision of Professor P. cluding mire habitats is performed in the NOMALS. As a result, 6.763 peat deposits Slitere National Park. were recorded. Studies dealing mainly with mire distribution, structure, peat properties Research in Latvia has been carried out (botanical composition, ferrum, ash con- mostly in the protected mires of Latvia. Still tent, decomposition degree, etc.) and mire new localities of protected plant species are water chemical characteristics were carried being discovered, like the habitats with out in mires throughout Latvia. P. NOMALS Schoenus ferrugineus, Carex davaliiana and published results of the studies in a number Saxijraga hirculus. of books that contain summary reports on In 2004 Swertia perennis was found in a mire characteristics and evaluation for peat spring mire, close to the border of the Gau- extraction. Since that time mire research by ja National Park. This is a plant species that means of pollen compostion, mire stratigra- has not been found in Latvia for the last 50 phy and development was carried out by P. years. In the same area also another very GALENIEKS and M. LININA-GALENIEKS. Lab- rare species in Latvia Ligularia sibirica was oratory for Peat Studies was established at discovered. the University of Latvia. Group for mires worked also at the Ministry of Agriculture. Later, mire studies were devoted mainly to Mire terminology and mire geology, flora in a scope of overall in- classification systems vestigation of flora in Latvia. Mires have been often the study areas for ornithologists Mires in Latvia include minerotrophic as for professionals, as well as for amateurs. mires (fens and transition mires) and ombrotrophic mires (raised bogs). A number of organisations and researchers (geologists, geographers, botanists, Minerogenous (minerotrophic) mires: ecologists, ornithologists, hydrologists, etc.) fens are involved in mire research of Latvia. Fens presently are widely distributed in Most valuable peatlands of Latvia are iden- Latvia, wherever waterlogged conditions are tified, also those of international impor- maintained, in part at least, by ground wa- tance and meeting Ramsar Convention cri- ter. They range in a size from extensive fen teria. The value of the studied mires was de- complexes to small sites only of a few square tected and their conservation status evaluat- metres. ed (PAKALNE et al. 2004). Fens frequently occur as a zone of vari- Mire studies in protected areas are per- able extent around lakes, in waterlogged formed by its staff or by other scientists. Since hollows and raised bog margins, and in river the establishment of the Teici Strict Nature floodplains and are typically dominated by Reserve in 1992 mire studies are carried out sedges, like Carex lasiocarpa and C. rostrata. there that includes research of flora, vegeta- Other associated plant species include tion, birds, insects and mammals, geological Merkantiles trifoliata, Comarum palustre, development. Plankton communities have Eriophorum angustifolium, Lysimachia vulgaris, been investigated in bog lakes by a group of Peucedanum palustre, and Suctisa pratensis. hydrobiologists (DRUVIETIS et al. 1998) Fen vegetation is rich in bryophytes, e.g In the Slitere, Kemeri, Gauja National CampyUum steüatum, Caüiergonella cuspidata, Parks, North Vidzeme Biosphere Reserve Fissidens adianthoides, Bryum pseudom- and Gauja National Park, Engure Nature quetrum, Drepanocladus revolvers and SCOT- Park mire researchers from University of pidiwn scarpioides. One can distinguish be- Latvia have studied mire vegetation. tween rich and poor fens. The Scheuchze- 151 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at When peat accumulates above the mineral groundwater, it becomes increasingly iso- lated from this nutrient source. In transition mires the influence of groundwater has strongly diminished and precipitation water starts to prevail. Transition mires are marked by the appearance of Sphagnum species that make up most of the moss layer. In transition mires common species include Carex ünosa, Carex rostrata, C. lasiocarpa and Rhynchospora alba that are accompanied by Eriophorum pdystachion, Scheuchzeria palustris, Andromeda polifolia. In the bryophyte layer Sphagnum teres, S. wamstorfü, and S. flexuosum are amongst the dominants. The Rhynchospore- tum albae and Caricetum limosae communities occur there. Protected species in fens Fig. 3: Fen vegetation in Bedne Mire. rio-Caricetea fuscae communities often oc- Mammals: Lutra luvra cupy these fens, like, Caricetum rostratae, Invertebrates: Acicula polita, Pupilla musco' C. lasiocapae and C. diandrae. rum, Hirundo officinalis, Papilio machaon, Where fens have developed over a lime- Dolomedes plantarius, Catocala adultera, stone substrate, rich fens have developed. Vertigo alpestris, Vertigo angustior, Vertigo One of the most distinct features of calcare- genesii, Carabanus menethriesi, Carcharo- ous fens is that they are very rich in plant dus flocciferus species, a number of which are rare and pro- Vascular plants: Carex davaliiana, Carex he- tected. Schoenus ferrugineus is a characteristic leonastes, Carex scandinavica, Cladium ma' species of calcareous fens and can be accom- riscus, Eriophorum gracile, ]uncus stygius,, panied by a range of plants, including Primu- la farinosa, Pamassia palustris, Pinguicula vul- Schoenus ferrugineus, Carex buxbaumii, garis, Carex hosaana and Sesleria caeruka. Or- Saussurea esthonica, Utricularia ochroleuca, chids, like Dactylorhiza incamata and Epipacus Hydrocotile vulgaris, Primula farinosa, DaC' palustris are well represented in calcareous tylorhyza cruenta, D. baltica, D. fuchsii, D. fens. Rich fens are characterised by high maculata, D. russouiii, D. incamata, Gym' species diversity. Another rich fen communi- nadenia conopsea, Liparis loselii, Ophrys in- ty includes Carex davaliiana that may occur sectifera, Pinguicula vulgaris, Hammarbya also in spring mires near the flushes. paludosa, Malaxis monophyllos, Pinguicula vulgaris, Saxifraga hirculus Vegetation of fens can be open or covered with shrubs, like Betula pubescens and Bryophytes: Moerckia hibemica, Riccardia Salix dnerea (P.AKALNE 1998). Sedge species multifida, Riccardia incurvata, Riccardia such as Carex lasiocarpa, C. rostrata, C. pan- chamaedryfolia, Cinclidium stygium, Byum icea are characteristic for minerotrophic neodamense, Trichocolea tomeruella, Hama- mires. Other associated species are Menyan- tocaulis vemicosus, Calhergon trifarium, Pa- thes trifoUata, Comarum palustre, Enophorum ludeüa squarrosa, Meesia triquetra, Drepan- polysutchion, E. laafoUum, Lysimachia vulgaris, ocladus lycopodioides, Meesia longiseta, Peucedanum palustre and Sucrisa pratensis. Meesia hexasncha, Meesia triquetra Reedswamps and tall-sedge communi- Protected species in transition mires ties, e.g. Phragmitetum australis and Carice- tum elatae often occur near lakes. The dom- Vascular plants:, Hammarbya paludosa, inant species here include Phragmites aus- Dactylorhiza maculata, Drosera intermedia, tralis associated with Scrrpus lacustris and Ty- Saxifraga hirculus, Carex paupercula, Rhyn- phalaafoiia. diaspora fusca, Salix myrailoides 152 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at Bryophytes: Calliergon trifarium, Lophozia rutheana, Splachnum rubrum, Sphagnum pukhrum, S. obtusum Ombrogenous (ombrotrophic) mires: raised bogs Raised bogs are present all over Latvia (Fig. 4)- Two regional raised bog types are recognised, namely the western type with Trichophorum cespitosum and the eastern type with Chamaedaphne calycuhua. These bogs can be dome-shaped or of the plateau- type and may be open or wooded. The central parts of the bogs are often open but the margins are wooded. The most common mi- crorelief feature of raised bogs is the alterna- tion of relatively dry hummocks and ridges with wet hollows and open-water bog pools. Bog pools are mainly large and elongated. Vegetation of ombrotrophic mires has a Aquila chrysaetos, Ciconia nigra, Caprimul- Fig. 4: Raised bog vegetation in significant cover of dwarf shrubs with the gus europaeus, Pandion haUatus Janisu-Dainu Mire in the North Vidzeme Biosphere Reserve. dominance of Sphagnum species in the Nesting and feeding: Lagopus lagopus, La- bryophyte layer. Sphagnum magellanicum, S. nius coüurio, L. excubitor, Circaetu gallicus, Tubellum and S. fuscum often occur on hum- Pluvialis apricaria, Grus grus, Aquila chry- mocks. Caüuna vulgaris, Empetrum nigrum, saetos, Gavia arctica, Numenius phaeopus, Oxycoccus palustris, Andromeda polifolia and Circus aeruginosus, C. pygargus, Numenius Drosera rotundifolia are prominent on hum- arquata, Falco columbarius, Asio flammeus, mock ridges. Between the hummocks are rare - Cygnus cygnus, Limosa limosa, Trin- hollows where bryophytes, like Sphagnum ga totanus, Larus ridibundus, very rare - cuspidatum and S. teneüum are common Gugatnis Phibmachus pugnax while Scheuchzeria palustris, Rhynchospara al-Reptiles: Coronella austriaca, Lacerta agilis ba and Drosera angUca are typical vascular Invertebrates: Vertigo ronnebyensis, Clossia- plants in these microhabitats. Also lakes oc- na frigga, Clossiana freija, Erebia embla, cur in the raised bogs. Carabanus menethriesi Vascular plants: Trichophorum caespitosum, Communities of Oxycocco-Sphagnetea Drosera intermedia, Lycopodiella inundata, are well presented in the raised bogs. The Betula nana, Salix myrtilbides Sphagnetum magellanici often occurs on Bryophytes: Calypogeia sphagnicola, Odonto- hummocks as well as Empetro nigri-Sphag- schisma sphagni, Sphagnum lindbergii, netum fusci. In the eastern Latvia Sphagnum moüe, Odontoschisma denuda- Chamaedaphne-Sphagnetum magellanici tum, Splachnum pensylvanicym, Splachnum community is common, but in the western sphaericum and northern part Eriophoro-Trichophorum cespitosi occurs. Mire protection in Latvia Protected species in raised bogs According to the Latvian legislation Mammals: Nyctalus noctula, Vespertiüo muri- mires are protected in a wide range of pro- nus, Pipistrellus nathusii, Maoris daubento- tected nature areas, like TeiCi and Krust- ni, Lutra lutra, Eptesicus nilssonii, Ursos kalni Nature Reserves, Slitere, Kemeri, and arctos Gauja National Parks, North Vidzeme Bios- Bird species phere Reserve, nature reserves, nature parks On the margins of raised bogs: Aegolius fu- (Engure Nature Park, Abava Nature Park), nereus, Columba oenas, Circaetu galikus, and protected landscape areas. These sites Dryocopus maraus, Hahaetus albiciüa, include raised bogs, fens and lakes. 153 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at At presently 6 Ramsar sites are designat- matic conditions. Paleobotanical studies reed in Latvia: Teici un Pelecare Mires, En- veal that upwards in peat botanical sequence gure Lake, Kanieris Lake, the Lubana Wet- increases the number of Sphagnoks. Gradual- land Complex, Northern Bogs, and Pape ly fen and transitional peat layers are covered Wetland Complex. by raised bog peat. During the first half of the Atlantic Time the largest part of Suda Mire There are 336 prospective Natura 2000 has developed into raised bog. sites that include a wide diversity of forest, freswater, coastal, grassland habitats, in ad- Nowadays Suda Mire is a typical raised dition to all the mire types of Latvia. bog with a number of bog lakes and pools. There are open bog areas as well as wooded There are protected habitats of Europe ones. There are a lot of smaller and larger (according to Habitats Directive) that occur lakes in the mire. In the southern part sul- in the mires of Latvia: phur springs occur, as well as several miner- • Active raised bogs al islands. • Degraded raised bogs still capable of natu- Transition mire vegetation with Carex ral regeneration rostrata and C. lasiocarpa occurs on the mire • Transitional mires and quaking bogs margins and near some of the bog lakes. • Fennoscandian mineral-rich springs and Rare species include Sphagnum balacum and spring fens Salix myrtilloides. Typical species of hum- • Calcareous fens with Cladium mariscus mocks are Empetrum nigrum, Calluna vul- and species of the Caricion davallianae garis, Eriophorum vaginatum, Rubus chamae- • Petrifying springs with tufa formation morus, Polytrichum juniperinum but in hol- (Cratoneurion) lows and near bog pools Rhynchospora alba • Natural dystrophic lakes and ponds and Scheuchzeria palustris are accompanied • Bog woodland by the bryophytes, like Sphagnum cuspida- According to the legislation of Latvia turn, S. tenellum, Cladopodiella fluitans and protected mire habitats of Latvia are distin- Calypogeia sphagnicola. guished: The presence of mineral islands with • Mineral rich springs and spring fens different types of forest adds to the species • Petrifying springs with tufa formation richness of the mire. The mire supports a pe- • Sulphur springs culiar species composition, having together • Calcareous fens with Carex davallUma species of western and eastern distribution • Calcareous fens with Schoenus ferrugineus in Latvia, such as Trichophorum cespitosum • Fens with Juncus subnodulosus and Chamaedaphne calyculata. • Calcareous fens with Cladium mariscus Sphagnetum magellanici and Empetro • Transition mires with Rhynchospora fusca nigri - Sphagnetum fusci characterise the Mires in specially bog hummocks, but Rhynchosporetum al- protected nature areas bae, Caricetum limosae and Scheuchzerio- Sphagnetum cuspidati are found in the hol- Mires in the Gauja National Park lows. Sphagnum magettanicum lawns with Tri- Mires in the Gauja National Park in- chophorum cespitosum occur also. Suda Mire clude raised bogs, fens, transition mires. includes a rare mire community in Latvia Suda Mire is the largest mire in the Gauja the Eriophoro-Trichophoretum cespitosi. National Park with the total area of 2.575 ha from which 2.339 ha includes raised bog In the Gauja National Park communi- vegetation, 188 ha transition mire vegeta- ties of the Class Montio-Cardaminetea are tion and 48 ha fen vegetation. widespread and occur near springs and along flushes. Springs that have developed at the Suda Mire has developed as a result of foots of river ravines, like on the left bank of ground paludification during the second part Amata River or near Perlupe River. of the Preboreal (aproximately before 9200- 9400 years), when reed-wooden-cotton grass Springs in the Gauja National Park oc- peat has formed in the area under die wet cli- cur on the river ravine slopes. When the slo- 154 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at pes are steep the sites are characterised by there are rheocrenes (gushing springs) the the dominance of Cratonoeron filicinum, Pa- water spurts out of a horizontal or down lustrieUa commutata, Plagiomnium eüipticum, sloping strata and immediately races down Fissidens adianthoides, Bryum pseudotrique- into the valley. There are also Hmnocrenes trum, Peüia endivifolia and Conocephalum co- (spring basins) the water wells up from be- nicum. At the foot of river ravines slopes low. In the ravine itself helocrenes (seepages and in forest springs with Cratonoeron filici- or spring fen) has developed where the wa- num, Palustrielia commutata, Plagiomnium el- ter seeps up through the ground. The mar- Upticum and other plants species like Cirsium gins lead to the mire vegetation. oleraceum, Caltha palustris, Chrysosplenium In Kazu Ravine rich fen vegetation is altemifolium, Myosotis palustris, Golium pa- characterised by Caricetum rostratate and lustre, Crepis paludosa Cardamine amara, Ver- includes Carex rostrata, C. panicea, Epipactis onica beccabunga, Myosoton aquaticum, Chry- palustris, Dactylorhyza incamata, Cirsium ol- sospleruum altemifolium, Geum rivale, Crepis eraceum, Galium palustre, Equisetum palustre, paludosa, Plagiomnium undulatum, P. elatum, Primula farinosa and mosses Bryum pseudotri- Plagiochila asplenoides occur. Some sites in- quetrum, Calliergoneda cuspidata, Calliergon clude also protected bryophyte species Tri- giganteum, Fissidens adianthoides, CampyUum chocolea tomentelia. stellatum and Plagiomnium ellipticum. Springs in Kazu Ravine are rich in calcium. Davida Springs are located on the left bank of Vaive River. It is a place where from In addition to the common spring the Plavinu Formation deposits 34 springs species, also other bryophytes like Thuidium run out (SKRUPSKELE 1994). Small waterfalls pfiliberti, Rhytididelphus subpinatus, Cir- are located on the steep slopes. From the riphillum piliferum and Eur/iync/iium pulchel- spring water iron hydroxides are deposited. lum occur. There is also an ecotone zone It is a complex including Montio-Car- that leads to the spring fen vegetation. This daminetea communities on the steep slopes, marginal zone between the spring vegeta- PhragmitO'Magnocaricetea and fragments tion and mire vegetation includes both typ- of Scheuchzerio-Caricetea fuscae mire vege- ical spring species, like Cirsium oleraceum, tation. Here springs, streams, fen communi- and Pellia endivifolia and fen species, like C. ties occur near the flushes. lepidocarpa, Cirsium palustre and Equisetum palustre. Characteristic species include Cirsium oleraceum, Deschampsia cespitosa, Veronica From the all the above mentioned sites beccabunga, Myosoton aquaticum Equisetum differs the spring mire located near Suda palustre, Chrososplenium altemifolium, Caltha River not far from Suda Mire (PAKALNE &. palustris, Cratonoeron filicinum, Cono- CAKARE 2001). It is a complex of springs cephalum conicum, Plagiomnium elUpticum that includes mire vegetation. The spring and Bryum pseudotriquetrum. area is characterized by Cirsium oleraceum, Poa palustris, Menyant/ies trifoliata, Chrysos- In the area of Davida springs on the plenium alternifoUum, Caltha palustris, Poa slopes with springs and streams, spring mire palustris, Crepis paludosa, Gaüum palustre, vegetation has developed. The characteris- MenyantJies trifoliata, Cirsium palustre and tic species in the fen vegetation are Carex Myosotis palustris associated with Callier- hostiana, C. panicea and Epipactis palustris. In gonella cuspidata and Bryum pseudotri- separate places in the fen springs reach the quetrum. It borders with vegetation that surface and include other species like Cirsi- passes into transition mire vegetation with um oleraceum and Cratonoeron filicinum. Betula humiUs, B. pubescens, Salix rosmarini- The steep slopes of the Kazu Ravine in- folia and Frangula olnus in the schrub layer, clude springs, streams and flushes. In the but Eriophorum vaginatum, Comarum palus- Kazu Ravine mire vegetation has developed tre, Equisetum palustre and Potentilla erecta and includes also springs. Spring vegetation occur in the herb layer. Sphagnum teres and is a part of mire that is characterised by S. squarrosum grow in the moss layer and ap- Scheuchzerio-Caricetea fuscae vegetation pear together with Aulacomnium palustre (Caricetum rostratae). On the ravine slopes and CaJIiergon stramineum. In this case the 155 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at i i ainiuwt za E3 dmxcp.d. ]<MJ% Fig. 5: Pollen diagram from Lielais Kemeri mire vegetation development is clearly ob- Lielais Kemeru tirelis Mire Tirelis Mire, served in this spring area and there is not a Lielais Kemeru tirelis Mire is one of the sharp boundary between the springs and ad- largest raised bogs in Latvia. Since 1977 the jacent mire vegetation. largest part of the mire (5.762 ha) is a protected nature area, but since 1997 is includ- Springs and spring mires in Latvia are ed in the Kemeri National Park. Lielais Ke- associated with rare and protected plant spe- meru tirelis Mire is the one that orinated be- cies, such as Ligularia sibirica, Swertia peren- fore the other mires of the Kemeri National nis, Saxifraga hirculus, Uparis loeselii, Maiaxis Park and has been developing since the Bo- monophyllos, Primula farinosa, Epipacas palus- real Time. It has formed mainly as the result tris, Schoenus ferrugienus, Carex davalliana, of ground paludification. Before 8500-7500 Chdium mariscus, Dactylorhiza incamata, D. B.P fen vegetation started to develop and ochrokuca, Maiaxis onophyllos and Epipacas fen peat accumulated except some areas palustris as well as bryophytes, like Hamato- where small lakes were located, which be- caulis vemicosus, Paludella squarrosa, Tricho- came terretrialized. colea tomentelia, Hebdium blandowii and Bry- um weigeUi. Lielais Kemeri Ttrelis Mire has developed in the area that was covered by the Mires in the Kemeri National Park Baltic Ice Lake (NlKODEMUS et al. 1997). The Kemeri National Park is rich in After the retreat of the Baltic Ice Lake, fine mires and includes three raised bogs. The sand deposits formed the surface of the area. largest is Lielais Kemeri Tirelis Mire with Gradually, climate became milder and more the total area of 6.192 ha (GALENIEKS & humid and paludication processes of miner- KRAUKLIS 1995). Zalais Mire (1.586 ha) al sediments started in large areas of gently (NUSBAUMS 1998) and Raganu Mire (1.129 sloping and undulated plain, because of non ha) (KRAUKLIS 1997) are smaller. Mire veg- permiable dolostone formations close to the etation occurs also near Kudraine, Dunu surface, as well as ancient dunes have and Kanieris Lakes. stopped water flow to the Gulf of Riga. Peat sedimentation started during the Boreal about 8500 years ago. Sedges, reeds and 156