Poion violaceae • FloraVeg.EU

Alliance CT07A (TRI-07A)

Poion violaceae Horvat et al. 1937

Alpine and subalpine silicicolous grasslands on deep acidic soils in wind-sheltered habitats of the Balkan Peninsula

Vegetation
Juncetea trifidi
Seslerietalia comosae
Poion violaceae

Overview Nomenclature Distribution Habitats

Dominant life form: Perennial graminoids

Dominant life form

The dominant life forms of vegetation types reflect the environmental conditions. The life forms that dominate European vegetation types are defined here by combining various approaches to classifying plant life forms (Du Rietz 1931, Raunkiaer 1934, Klimešová et al. 2017) based on the morphological, physiological, and ecological adaptations of plants to changing environmental conditions. Each vegetation type is characterized by the life form that dominates its stands. If a vegetation type includes stands dominated by different life forms, more than one life form is indicated. For vegetation types with a complex vertical structure, the dominant life form is recorded for each vegetation layer. Bryophytes are recorded for those vegetation types where their presence is important to community structure and their cover exceeds 50% in at least some stands of the vegetation type. The following categories are distinguished:

Conifer trees – usually evergreen coniferous trees with either needle-like or scale-like leaves
Broad-leaved deciduous trees – trees that shed all their leaves at the beginning of the cold season
Sclerophyllous trees – trees with small, leathery evergreen leaves
Laurophyllous trees – trees with large, evergreen leaves
Palms – evergreen trees with a straight trunk and a bunch of large leaves on the top
Conifer shrubs – evergreen coniferous shrubby plants with either needle-like or scale-like leaves
Broad-leaved deciduous shrubs – shrubby plants that shed all their leaves at the beginning of the cold season
Sclerophyllous shrubs – shrubby plants with small, leathery evergreen leaves
Laurophyllous shrubs – shrubby plants with large, evergreen leaves
Broom-shrubs – shrubby plants that look like a broom and are assimilating primarily through slender green branches; they have sparse, small leaves that drop in summer to reduce water loss; in some species, the leaves are transformed into thorns; examples: Genista benehoavensis, G. corsica, Launaea arborescens, Retama spp., Spartocytisus supranubius, Stauracanthus boivinii, Ulex europaeus
Microphyllous shrubs – evergreen tall (up to 4 m) shrubby plants with tiny, needle-like leaves; examples: Adenocarpus foliosus, Erica arborea, E. platycodon
Dwarf shrubs – small woody plants with most of their overwintering buds located up to 25 cm above the soil surface; examples: Artemisia pauciflora, Astragalus siculus, Bruckenthalia spiculifolia, Calluna vulgaris, Daboecia cantabrica, Empetrum nigrum, Ephedra distachya, Erica carnea, Euphorbia spinosa, Genista cupanii, G. pilosa, creeping forms of Juniperus hemisphaerica and J. sabina, Prunus prostrata, Vaccinium myrtillus, V. vitis-idea
Suffruticose – plants with a woody base and herbaceous (sometimes succulent)

Anabasis aphylla, Artemisia thuscula, Euphorbia lamarckii, E. paralias, E. regis-jubae, Salvia canariensis, Sonchus acaulis

Perennial graminoids – long-lived grass-like herbaceous plants (Poaceae, Juncaceae, Cyperaceae)
Perennial non-graminoid herbs – perennial plants with herbaceous shoots and non-graminoid leaves
Succulents – perennial non-woody plants with succulent leaves or stems; examples: Astydamia spp., Crithmum maritimum, Frankenia laevis, Greenovia spp., Salicornia spp., Sedum spp., Sempervivum spp.
Annual graminoids – grass-like herbaceous plants that complete their life cycle during one growing season (Poaceae, Juncaceae, Cyperaceae)
Annual non-graminoid herbs – plants with herbaceous shoots and non-graminoid leaves that complete their life cycle during one growing season
Aquaphytes – perennial or annual plants that live exclusively in water
Bryophytes – mosses, liverworts and hornworts
Lichens – non-vascular plants composed of symbiotic algae and fungi

Data source and citation

Preislerová, Z. (2022). Dominant life form. – www.FloraVeg.EU.

Further references

Du Rietz G. E. (1931) Life-forms of terrestrial flowering plants I. Acta Phytogeographica Suecica, 3 (1), 1–95.
Klimešová J., Danihelka J., Chrtek J., de Bello F. & Herben T. (2017) CLO-PLA: a database of clonal and budbank traits of the Central European flora. Ecology, 98, 1179.
Raunkiaer C. (1934) The life forms of plants and statistical plant geography. Clarendon Press, Oxford.

Phenological optimum: Summer

Phenological optimum

The phenological optimum is defined here as a period when most vascular plants in the community are in flower. This period usually corresponds to the period of the peak biomass of vegetation. For vegetation types that have two or more dominant life forms with different phenological optima, the optimum is considered separately for each dominant life form. Some vegetation types (e.g. annual weed or ruderal vegetation) have two or three groups of species with different phenological optima, even within the same life form, resulting in different spring, summer and autumn aspects. Two or three phenological optima are recorded for these types. In the case of marine, some types of aquatic and monocarpic vegetation that may look similar throughout the year or at least throughout the growing season (e. g., Zosterion, Potamogetonion, Ranunculion aquatilis, Littorellion, Greenovion), the phenological optimum is considered to be the time of flowering of the dominant species or most of the species in the community. Phenological optimum categories have been defined primarily based on Central European phenological patterns and applied to vegetation in other regions of Europe. More than one phenological optimum was reported for vegetation types with an optimum that spans more than one category. Assignments to categories were based on field experience, descriptions in various literature sources, and were partially derived from vegetation-plot data.

Data source and citation

Preislerová, Z. (2022). Phenological optimum. – www.FloraVeg.EU.

Substrate humidity: Mesic

Substrate humidity

Substrate humidity reflects the soil moisture availability throughout the year.

Dry substrate is characterized by a low groundwater table, low water-holding capacity and long periods without precipitation
Mesic substrate holds a moderate amount of soil moisture throughout the year without pronounced drought, waterlogging or flooding
Wet substrate is characterized by a high water table, waterlogging or occasional flooding
Water substrate is specified for those vegetation types that occur in water

Data source and citation

Preislerová, Z. (2022). Substrate humidity. – www.FloraVeg.EU.

Substrate reaction: Acidic

Substrate reaction

Substrate reaction expresses soil pH and the content of calcium and other basic cations in the soil or water.

Acidic substrate has a low pH (usually between 3 and 6) and a low base content
Slightly acidic to near-neutral substrate has a pH usually between 6 and 7 and moderate base content
Alkaline substrate has a high pH (above 7) and a high content of calcium or other basic cations

Data source and citation

Preislerová, Z. (2022). Substrate reaction. – www.FloraVeg.EU.

Salinity: Non-saline

Salinity

Salinity refers to the concentrations of readily soluble salts (especially sodium, potassium, calcium, and magnesium sulphates, chlorides, and carbonates) in soil or water.

Non-saline substrate has no or very low concentrations of soluble salts
Slightly saline or brackish substrate has a low to moderate concentration of soluble salts
Saline substrate has a high concentration of soluble salts

Data source and citation

Preislerová, Z. (2022). Salinity. – www.FloraVeg.EU.

Nutrient status: Oligotrophic

Nutrient status

Nutrient status refers to the concentration of available nitrogen, phosphorus and potassium in soil or water.

Dystrophic substrate has a low amount of available nutrients, low oxygen concentration and a high amount of dissolved organic matter; it is often associated with mire complexes
Oligotrophic substrate has low nutrient availability but does not have the other characteristics that define dystrophic conditions
Mesotrophic substrate has a moderate amount of available nutrients
Eutrophic substrate has a high amount of available nutrients
Hypertrophic substrate has a very high amount of available nutrients, often due to anthropogenic eutrophication

Data source and citation

Preislerová, Z. (2022). Nutrient status. – www.FloraVeg.EU.

Soil organic matter: Mineral soil

Soil organic matter

The organic component of soil consists of plant and animal detritus in various stages of decomposition. Two categories are defined according to the predominant mineral or organic component. Aquatic vegetation types that do not root in soil are not classified.

Mineral soil – the mineral soil component predominates over the organic component
Organic soil – the organic soil component predominates over the mineral component

Data source and citation

Preislerová, Z. (2022). Soil organic matter. – www.FloraVeg.EU.

Vegetation zone: Nemoral, Submediterranean, Oro-Temperate

Vegetation zone

Vegetation zones are large areas of relatively uniform climate and vegetation. These zones often correspond to other land classification units such as biogeographical regions, ecoregions or biomes (Schultz 2005, Rivas-Martínez et al. 2004a, Mucina et al. 2016, Dinerstein et al. 2017, Bruelheide et al. 2018, EEA 2018). However, such classification systems are inconsistent across Europe and differ in the number of units defined and in the position of boundaries between them. Here, we propose a system largely based on a combination of the Biogeographic and Bioclimatic Maps of Europe by Rivas-Martínez (2004a, b) and European Biogeographical Regions (EEA 2018). We found this system optimal for describing the distribution of European phytosociological alliances (Mucina et al. 2016, Preislerová et al. 2022). It includes nine horizontally divided categories (Arctic, Boreal, Hemiboreal, Nemoral, Forest-steppe, Steppe, Submediterranean, Mediterranean and Macaronesian; Fig. 1) and three vertical categories (Oroboreal, Orotemperate and Oromediterranean) for alpine regions.

The assignment of vegetation types to zones is mainly based on the distribution maps of the European alliances (Preislerová et al. 2022). Since these maps do not provide sufficient details such as point distribution, we also used information from various literature and expert knowledge.

We defined the following zones:

Arctic – Arctic Biogeographical Region of Russia, Greenland, Svalbard
Boreal – northern part of the Boreal Biogeographical Region of Russia, Finland, Sweden and Norway (except for the southern parts of these three countries), Iceland, Faroe Islands
Hemiboreal – southern part of the Boreal Biogeographical Region of Russia, Estonia, Latvia, Lithuania, Belarus, the Kaliningrad Region of Russia, the southern part of Sweden except for the Skåne Peninsula and the southernmost parts of Finland and Norway
Nemoral – Atlantic and partly Continental Biogeographical Regions, including the British Isles, France with the exception of the Mediterranean part, the Atlantic part of the Iberian Peninsula, the Benelux countries, Denmark, Germany, Poland, Czechia, Slovakia, Switzerland, Austria, Alpine part of Italy, Slovenia, the Alpine Biogeograpical Region of Romania and Bulgaria, the Alpine and Continental Biogeographical Regions of Ukraine, the Continental Biogeographical Region of Russia, the higher elevations of the Southern Urals, the Caucasus countries and the Russian part of the Great Caucasus
Forest-steppe – Hungary, the extra-Carpathian parts of Romania, the Pannonian Biogeographical Region in northern Serbia, northern Moldova, the transition zone between the Continental and Steppic Biogeographical Regions in Ukraine and Russia and the mountain fringes of the Southern Urals
Steppe – Steppic part of Ukraine and Russia, southern Moldova, northern Crimea, low-lying areas in the Caucasus countries and in the Russian part of the Great Caucasus
Submediterranean – the northern interior part of Spain and the border areas between the Mediterranean and Continental Biogeographical Regions, including parts of France, Italy, Croatia, Bosnia and Herzegovina, Serbia, Kosovo, Macedonia, Montenegro, Albania, Bulgaria, Turkey and the southern part of Crimea; vegetation types occurring in the Supramediterranean elevation belt within the Mediterranean Biogeographical Region are also included in the Submediterranean zone
Mediterranean – Portugal, southern parts of Spain, France and Italy, the coastal areas of the Adriatic Sea, Greece and all Mediterranean islands; only vegetation types occurring in the Inframediterranean, Thermomediterranean and Mesomediterranean belts are included in this zone
Macaronesian – Canary Islands, Madeira and Azores
Oroboreal – high elevations in the Scandinavian Mountains, Northern and Central Urals; vegetation types from the elevations around or above the timberline are included
Orotemperate – Cantabrian Mountains, Pyrenees, Massif Central, Alps, Northern and Central Apennines, Vosges, Schwarzwald, Harz, Sudetes, Bohemian Forest, Carpathians, Dinarides, central Balkan mountain systems, Caucasus; vegetation types from the subalpine, alpine and nival elevational belts are included
Oromediterranean – mountain systems of the Iberian Peninsula south of the Cantabrian Range and the Pyrenees, Cevennes, mountain systems of the Mediterranean islands, Southern Apennines, Greek mountain systems; only vegetation types from the Oromediterranean to Cryomediterranean elevation belts are included

Fig. 1. European vegetation zones. The background map shows the country divisions based on European Biogeographical Regions according to Preislerová et al. (2022)

Data source and citation

Preislerová, Z. (2022). Vegetation zone. – www.FloraVeg.EU.

Further references

Bruelheide H., Dengler J., Purschke O., Lenoir J., Jiménez-Alfaro B., Hennekens S.M. ... Jandt U. (2018) Global trait–environment relationships of plant communities. Nature Ecology & Evolution, 2, 1906–1917. https://doi.org/10.1038/s41559-018-0699-8
Dinerstein E., Olson D., Joshi A., Vynne C., Burgess N.D., Wikramanayake E. … Saleem M. (2017) An ecoregion-based approach to protecting half the terrestrial realm. BioScience, 67/6, 534–545. https://doi.org/10.1093/biosci/bix014
EEA (2018) Mapping Europe’s Ecosystems. Copenhagen: European Environment Agency. https://doi.org/10.2800/850732
Mucina L., Bültmann H., Dierßen K., Theurillat J. P., Raus T., Čarni A., … & Tichý L. (2016) Vegetation of Europe: hierarchical floristic classification system of vascular plant, bryophyte, lichen, and algal communities. Applied Vegetation Science, 19 (Suppl. 1), 3-264. https://doi.org/10.1111/avsc.12257
Preislerová Z., Jiménez-Alfaro B., Mucina L., Berg C., Bonari G., Kuzemko A. … Chytrý M. (2022) Distribution maps of vegetation alliances in Europe. Applied Vegetation Science, 25, e12642. https://doi.org/10.1111/avsc.12642
Rivas-Martínez S., Penas A. & Díaz T. E. (2004a). Bioclimatic map of Europe - Bioclimates. Cartographic Service, University of León. https://doi.org/10.5616/gg110001
Rivas-Martínez S., Penas A. & Díaz T.E. (2004b) Biogeographic Map of Europe. Cartographic Service University of León.
Schultz J. (2005) The ecozones of the world. The ecological division of the geosphere, 2nd edition. Berlin, Springer.

Elevational vegetation belt: Subalpine, Alpine

Elevational vegetation belt

The elevational vegetation belts reflect the vertical zonation of vegetation in relation to changes in climatic conditions. In the Arctic and Boreal zones, we distinguish only the Boreo-Arctic lowland and the Boreo-Arctic mountain belts, as the distinction of more belts is often unclear because in maritime and northern areas, the timberline is at low elevations, and the vegetation of the lowland Arctic tundra is very similar and often spatially connected with alpine tundra. In the Hemiboreal, Nemoral, Forest-steppe, Steppe and Submediterranean zone, we use the division into lowland, colline, submontane, montane, subalpine, alpine, and nival belts. In the Mediterranean and Macaronesian zones, we use the division into Inframediterranean, Thermomediterranean, Mesomediterranean, Supramediterranean, Oromediterranean and Cryomediterranean belts. Each elevational belt may shift up or down in a given mountain range or region, depending on local environmental conditions and historical circumstances.

Boreo-Arctic vegetation belts

Boreo-Arctic lowland – flat landscape with a mixture of deciduous (Betula-Alnus-Acer) and coniferous (Pinus-Larix-Picea) forests or coniferous forests only in the Boreal zone; mixture of shrub vegetation (Salix spp. or Betula pubescens), heathlands (Vaccinium spp., Salix spp., Empetrum spp.), grassy tundra and creeping Salix herbacea and S. polaris snow patches or polar desert tundra in the Arctic zone
Boreo-Arctic mountain – mountainous landscape with shrubby vegetation or open deciduous woodlands (Salix spp. or Betula pubescens), heathlands and grasslands

Temperate vegetation belts

Lowland – flat landscape with floodplain forests along rivers and deciduous thermophilous oak forests
Colline – hilly landscape with broad-leaved deciduous forests or Pinus forests in extreme habitats; agricultural landscape predominates
Submontane – submontane regions with the dominance of broad-leaved deciduous trees, Pinus forests on rock outcrops, coniferous plantations and agricultural landscapes
Montane – mountainous regions with mixed coniferous-deciduous forests, with increasing predominance of coniferous forests towards higher elevations
Subalpine – higher elevations with open coniferous forests, krummholz, heathlands and grasslands around the timberline
Alpine – grasslands and heathlands above the timberline
Nival – areas above the snow line and rocky summits with scattered vegetation dominated by bryophytes and lichens

Mediterranean vegetation belts

Inframediterranean – lowest elevations and latitudes of the Mediterranean with warm and arid climate; this belt is only developed in a small part of the Mediterranean, such as southernmost Spain and the Canary Islands.
Thermomediterranean – a belt usually located near the coast, with a long period of summer drought, with a potential natural vegetation dominated by evergreen sclerophyllous scrub
Mesomediterranean – a belt characterized by warm and dry summers and mild winters with almost no frost, suitable for the cultivation of the olive tree; the natural vegetation of this belt is the evergreen oak forest
Supramediterranean – a belt at middle elevations with less pronounced summer drought and occasional winter frost; the natural vegetation of this belt is broad-leaved deciduous forest; this belt corresponds to the colline belt in the nemoral zone
Oromediterranean – a belt below the timberline, characterized by heaths and pine and juniper forests; beech forests may occur on humid slopes; this belt corresponds to the montane and subalpine belt in the extra-Mediterranean vegetation zones
Cryomediterranean – the highest belt of the Mediterranean mountain ranges, located above the timberline; it is characterized by natural grasslands and heathlands; this belt corresponds to the alpine belt in the extra-Mediterranean vegetation zones

Data source and citation

Preislerová, Z. (2022). Elevational vegetation belt. – www.FloraVeg.EU.

Azonality: Scree, Alpine, snow-protected

Azonality

Azonality is defined by locally specific abiotic conditions that prevent the development of vegetation types that occupy large areas under similar climatic conditions (zonal vegetation) and promote the development of specific, locally confined vegetation types (azonal vegetation). Some vegetation types may be zonal in some areas but azonal in others, e.g. some types of arctic-alpine or mire vegetation are zonal in northern Europe but azonal in central or southern Europe. Fringe vegetation, which develops at the boundary between forests and herbaceous vegetation on widespread soil types, is zonal but included in the special category of Ecotone because of its patchy occurrence.

The following types of azonality are recognized:

Marine – sea littoral with sea-grass vegetation
Coastal wetlands – permanently wet dune slacks affected by saltwater
Inland aquatic – aquatic vegetation of freshwater lakes and ponds
Inland wetland – places with a high level of fresh groundwater or near springs; the soil is saturated with water throughout the year or for part of the year
Riverine – vegetation that develops along streams and in stream beds
Shallow soil – often dry or rapidly drying, usually with low nutrient availability
Steep slope – slopes with an inclination greater than 35°, usually affected by erosion, fast water runoff, and in some places in alpine areas, by avalanches
Rock – outcrops and cliffs without soil, stressed by lack of water and extreme temperatures; develops patchily in crevices, on ledges and terraces
Scree – unstable mixture of rock fragments that are moved downward by gravity
Dunes and beaches – coastal or inland sandy habitats with extreme temperature fluctuations, low water storage, low nutrient content, and limited nutrient availability
Ultramafic and heavy-metal soil – outcrops or shallow soils on peridotite, ophiolite, serpentinite and other rocks that contain high concentrations of heavy metals such as Fe, Mn, Cu, Cr, Ni, Pb, Co, and Cd, which are toxic to many plant species; some heavy-metal soils are also anthropogenic and occur on mining tailing piles
Gypsum – layers of hydrated calcium sulfate that forms a hard surface crust that is difficult for plants to penetrate; gypsum soils are often deficient in macronutrients and dry out due to heavy water runoff
Badland – landscape on clay substrate subject to severe erosion during heavy rain storms, resulting in steep slopes; upper soil layers dry out during dry periods and accumulate salt
Saline – habitats with high concentrations of soluble salt ions (sodium, potassium, calcium and magnesium sulfates, chlorides and carbonates) that are toxic to many plant species
Mediterranean eroded slope – eroded slopes both at low (usually on lava flows) and high elevations of the Mediterranean mountain ranges, characterized by disturbances combined with summer drought and winter frost
Snow patch – arctic and alpine habitats where snow melts much later than in the surrounding area, resulting in a short growing season and locally increased moisture
Alpine, snow-protected – leeward slopes or depressions in high mountains where snow accumulates, protecting vegetation from frost and providing soil with moisture from snowmelt; unlike in snow patches, snow melts early in the season
Alpine, wind-exposed – high-mountain sites exposed to wind; in winter, wind blows away snow and exposes vegetation to frost; in summer, wind causes desiccation
Salt-sprayed site – coastal cliffs and slopes affected by horizontal precipitation from the sea, which affects vegetation by salt spray
Foggy site – wind-facing slopes affected by clouds that bring moisture to otherwise dry sites and reduce direct solar radiation
Ecotone – linear vegetation types that develop at the transition between two vegetation types of different structure, e.g. forest and grassland
Zonal – vegetation and habitat types other than those defined above that occur over large areas under the abiotic conditions that prevail in the region

Data source and citation

Preislerová, Z. (2022). Azonality. – www.FloraVeg.EU.

Successional status: Mid-successional, Late-successional

Successional status

Successional status reflects the stage of vegetation development either on a new substrate (e.g. volcanic features; primary succession) or following disturbance (e.g. fire; secondary succession). Three successional stages are distinguished. Some vegetation types may be assigned to more than one stage.

Early-successional – vegetation occurs at recently or frequently disturbed sites (e.g. river bars, exposed pond bottoms, screes, lava fields, dunes, trampled sites, arable fields, heaps, mining sites) or in extreme habitats (rocks, scree, walls); frequently disturbed sites are dominated by short-lived species and undergo a directional vegetation change toward types with a higher proportion of long-lived species; extreme habitats are often dominated by long-lived species
Mid-successional – vegetation undergoes a directional change (with less intense or frequent disturbance), with early-successional species decreasing and late-successional species increasing
Late-successional – vegetation undergoes no directional changes unless it is severely disturbed; it is usually dominated by long-lived plant species and is in dynamic equilibrium with the abiotic conditions at the site

Data source and citation

Preislerová, Z. (2022). Successional status. – www.FloraVeg.EU.

Origin: Natural

Origin

The origin defines the degree to which vegetation development depends on humans.

Natural vegetation has developed naturally without human intervention and has not been severely disturbed by humans for a long time
Semi-natural vegetation is managed by humans, but consists largely of species native to the area, most of which regenerate without direct human intervention. Subcategories include semi-natural forests (tree plantations) , in which the dominant trees have been planted while the herb layer has regenerated spontaneously from the local species pool; and semi-natural grasslands, which have developed at the sites of former forests and are managed as either hay meadows or pastures
Semi-natural (disturbed, unmanaged) vegetation develops at sites that have been disturbed and altered by human activities (e.g. quarries, sod removal sites, spoil heaps and forest clearings) and then left unmanaged, resulting in secondary succession
Anthropogenic vegetation is intensively managed or disturbed by humans and is characterized by weeds on arable land or ruderal species at uncultivated ruderal sites; this category also includes stands dominated by alien species and grasslands sown with species-poor commercial seed mixtures

All forest vegetation types are treated as natural, although some forests have been seeded or managed by man for centuries. Only Robinia pseudoacacia forests and Mediterranean plantations of Pinus halepensis and Pinus pinea are classified as Anthropogenic (tree plantations). Pasture is not considered for forests, although grazing has been an important component of management in some regions. Some types of steppe grasslands have been assigned both a natural origin (climatic control combined with grazing by wild animals and a semi-natural origin (through livestock grazing in deforested areas).

Data source and citation

Preislerová, Z. (2022). Origin. – www.FloraVeg.EU.