Snow valley
Schneetälchen is a term Geobotany and ecology of the plant society snowy layers in oceanic to sub-continental high mountains above the tree-line designated, depending on the small topography and -relief usually between (1600) 2400 and 3000 meters NN (alpine and subnivale height level ) are and form the plant sociological associations of the snow valley vegetation (chionophytes) through their own character and identification species .
Geobotanical features
Due to the relief coverings, the snow valleys only slowly apper even in summer, so the snow-free vegetation period is shortened to a maximum of 4 months. The melt water, which lasts over large parts of the growth period, brings in nutrients in the form of soluble minerals , which largely originate from drifting dust (aeolian transport) and accumulate on the snow cover in winter. The plant communities are flora and vegetation adapted to the extreme conditions with the ability to cope with the short, snow-free time and the always cool environment. In general, the sites are well moistened by the long snow cover and the meltwater, but can dry out in summer due to the permeability of the carbonate rock if there is a lime base. In addition to the distinction between snow valleys on silicate and lime underlay , the snow valleys in the alpine mountains of the temperate and subarctic northern hemisphere from the Pyrenees to the Urals and from Scandinavia, the Balkan Peninsula and the Caucasus are characterized by creeping willows ( Salix ), which in the arctic areas with numerous societies in several associations achieve their greatest diversity through the characteristic silicole herb willow . Even the snow valleys in the Colorado Rocky Mountains are assigned to this as a separate order. Only in the high mountains of Asia Minor and East Asia were other associations eliminated. The snow valleys found on lime substrates often belong to vicarious units due to the abundance of species and endemics and in Europe they belong to two associations, while the silicate snow valleys have no subdivision and are characterized everywhere by uniform combinations of species.
etymology
The term snow valley goes back to the botanist Oswald Heer who took the name from the popular name of long snow-covered hollows in his homeland in the canton of Glarus.
Location conditions
According to Thorsten Englisch, little snow valleys are understood to mean " slightly sloping, flat or trough-shaped places soaked in meltwater, which are mainly found on northern slopes or in other shady places or on the sandy fields at the foot of the scree slopes and on glacier floors in the high alpine region " .
Snow valleys are widespread in the silicate mountains and lime in high-relief high mountains in hollows, depressions and flat to gently sloping slopes as far as the central Arctic. They are relatively humid and cool with comparatively little temperature fluctuations. Snow valley societies therefore have an oceanic character and are predominantly composed of hygrophilic species. The vegetation seasons (also aperzeit without snow cover ) last only a few weeks - one to a maximum of four months a year. During the short aperitif, however, the plants are exposed to full irradiation. In the silicate mountains, the soil moisture is very high all year round due to the low porosity of the subsoil and the accumulation of melt water, whereas lime deposits lead to drying out in midsummer. The waterlogging causes pseudogley soils with a pH value between 4.5 and 6.5 to form on the silicate . Formative location factors are the duration of snow cover, noticeable meltwater influence and, in addition to the long-lasting water saturation of the soils, often also cryoturbation and solifluction . These location factors favor bryophytes more than phanerogams or lichens, the societies are uniform from the southern and central Arctic and Scandinavia to central Europe and the southern European high mountains. While snow soils shape the landscape in the north, they are becoming increasingly rare in the south and are only "snow valleys" developed over small areas in southern Europe.
In the limestone mountains, communities of snow valleys often form at the foot of coarse rubble heaps and are therefore more difficult to colonize. Wherever fine earth is brought in between the coarse stones, plants gain a foothold in the rubble. Since the limestone rubble is much more permeable than the soil above silicate rock, it becomes much drier in summer. In addition, the snow stays in hollows, dents on slopes and hollow forms in the Glaziokarst and carts longer than average. This is particularly the case at the foot of rubble heaps. A transition from rubble corridors to snow-soil herbaceous corridors is possible here and both are usually systematically combined as an association Arabidion caeurleae in the class Thalspietea rotundifolii. In general, snow soils over limestone are characterized by greater soil mobility than in comparable locations over silicate rocks, which leads to a greater variety of locations. The subsoil is often rich in debris, and meltwater quickly seeps into the crevices. Rock and rubble heaps prevail in the main distribution area of the limestone snow valleys, which are absent in silicate mountains.
The pH values are significantly higher here at 6.5 to 7 due to the lime content. The calcareous snow valleys generally show transitions to grass communities ( Festuca pumila , Carex curvula ), hollows with spongy mineral fine earth are locations of the blue cress corridor, on coarse debris the trellised willow Salix retusa is a characteristic species.
Flora and vegetation
Snow soils are characterized by characteristic vegetation of the alpine (more rarely the upper subalpine or subnival) level. Their structure is one-layer (in the case of pure moss snow floors) or two-layer. In the Alps, the plant-sociological units of Arabidion caeruleae and Salicion herbaceae, with emanations in the Thlaspion rotundifolii, Androsacion alpine and Drabion hoppeanae (rubble over lime, silicate or base-rich slate rocks), Nardion (here in particular the naturally forest-free subalpine grasslands of the upper alpine grasslands and lower alpine level), Poion alpinae and Alchemillo-Poion supinae (milkweed willows, "fax lawn") are included.
Snow valleys of the silicate soils
The plant associations (association) of the snow valleys over silicate belong to the plant sociological class of Salicetea herbacea Br.-Bl. et al. 47. These are moss, dwarf grass and creeping shrub communities that are covered with snow for seven to ten months a year. Year after year, they don't wipe out at all, i. i.e. they will not be free of snow. If the snow-free time becomes too short, only mosses develop . Flowering plants need to be snow-free for at least eight weeks.
The Krautweidenflur (Salicetum herbacea Rübel 12) is an acidic snow-soil society, especially of the alpine level, with an average of eight to nine months of snow cover. The species-poor society includes plants with very small growth. Floristically and ecologically, the characteristics of this society in the Alps are very similar to the snow-soil societies in Northern Europe and the Arctic . The herb willow ( Salix herbacea ) is characteristic of this association . Other species are the Alpine yellow fling ( Sibbaldia procumbens ) and the dwarf dysentery ( Gnaphalium supinum ). The dwarf soldanelle ( Soldanella pusilla ) occurs here as a lawn-like spring aspect. It is able to grow through the last thin layer of ice in order to get to the surface.
The hornwort-snow- soil -society (Poo supinae-Cerastium cerastioides (Söyr. 54) Oberd. 57) is a society of flat, very wet alluvial soil and snow hollows and is often in contact with the Salicetum herbaceae. The fine earth and humus that have been washed in lead to nutrient enrichment and a soft, swampy soil. The characteristic species of this society is the three-fluted hornwort ( Cerastium cerastoides ). Furthermore, the Alpine bluegrass ( Poa alpina ) and the Läger bluegrass ( Poa supina ) grow here as nutrient indicators. Society occurs in the Alps.
The Widertonmoos Society (Polytrichetum sexangularis Frey 22) marks an initial, moss-rich snow floor settlement phase of very long, nine to ten months snow-covered hollows. The characteristic of the association consisting almost entirely of moss is the Widertonmoos ( Polytrichum sexangulare ). The society is found in the Scandinavian mountains as well as in the Central Alps.
The Lebermoos-Schneeboden (Anthelietum juratzkanae Rübel 11) inhabits locations that are snow-covered for most of the year, but for at least 10 months. The society mostly consists only of moisture-loving mosses like Widertonmoos ( Polytrichum sexangulare ) and lichens like the saffron lichen ( Solorina crocea ). The dwarf soldanelle ( Soldanella pusilla ) and the dwarf dysentery herb ( Gnaphalium supinum ) occur in flowering plants . The association forms the first pioneering stages on glacier forelands. The company can be found in the Central Alps, the Carpathian Mountains , the Pyrenees and also in Scandinavia .
Snow valleys of the limestone soils
Unlike the snow valleys on silicate, the plant sociological associations on lime break down into regional units. In general, lime snow soils are outsourced due to their different landscape-ecological features and the differently directed hierarchy and significance of individual processes in the landscape budget and their spatial distribution. In their ecosystem processes, they are characterized by seepage regimes which, due to the water-permeable limestone subsoil, do not allow any adhesive storage of soil water over clayey-loamy substrates, such as occur over soils on silicate subsoil.
Limestone snow valleys in the Alps
In Central and Southern Europe, the Salix retusa willow is the characteristic of the snow valley flora on lime . Due to the location factors, Kalkschnetälchen are less common and not as constant in socialization as the snow valleys over silicate. Salix retusa is also one of the arctic-alpine species with a Eurasian-montane distribution that does not occur in the Arctic.
The espalier willow lawn (Salicetum retuso-reticulatae Br.-Bl. 26) is a pioneering society that lives on sites with seven to eight months of snow cover. It is one of the most biodiverse societies. The association characteristic is the stump-leaved willow ( Salix retusa ). The net willow Salix reticulata , the lime blue grass ( Sesleria albicans ), the small-flowered sedge ( Carex parviflora ) and numerous other species also grow here .
The Schneeampfer -Flur (Arabido-Rumicetum nivalis (Jenny-Lips 30) Oberd. 57 nom. Invers.) Grows in the Alps on locations with ten months of snow cover. Association characteristic is the snow dock ( Rumex nivalis ). The stocks are supplemented primarily by the Alpine Speedwell ( Veronica alpina ), the Bavarian gentian ( Gentiana bavarica ) and the Alpine dandelion ( Taraxacum alpina ). The society occurs in the Alps and is more common in Switzerland.
The rock cress corridor (Arabidetum caeruleae Br.-Bl. 18) grows in eight to nine months of snow-covered sinkholes or sinkholes . Association identifier is the blue rockcress ( Arabis cearulea ). The Mannsschild saxifrage ( Saxifraga androsacea ), the Alpine buttercup ( Ranunculus alpestris ) and the black-rimmed yarrow ( Achillea atrata ) also grow here . The society occurs in the Alps with a focus on the Swiss Alps.
Limestone snow valleys of the Dinarides and Southeast Europe
In Southeastern Europe, too, the stump-leaved willow is a characteristic species of the snow valleys above carbonate soils. The association Salicion retusae was eliminated for this purpose. Originally it was eliminated in two associations:
- Soldanello-Salicetum retusae Horvat 33 (= Salix retusa-Carex nigra -Ass.) On coarse-block heaps that attach to limestone rocks (e.g. in Čvrsnica, Bjelašnica, Vranica and Durmitor)
- Saxifrago sepervivi-Salicetum reticulatae (Horvat 1936) Mucina et al. 1990 (Basionym Salicetum retusae-reticulatae macedonicum Horvat 36) from Macedonia (Jakupica and Šar Planina). Common to the association are among others: Soldanella alpina ; Anemona baldensis , Carex nigra , Ranunculus montanus , Polygonum viviparum , Carex kitaibelliana u. a.
Then there are the following associations:
- Saxifragetum prenjae Horvat
- Saxifrago-Rumicetum nivalis Horvat 1936
- Geo-Oxyrietum digynae Horvat 1936
- Bartsio-Salicetum reticulatae Mucina et al. 1990 (in Bulgarian Pirin)
- Dryado-Salicetum reticulatae Beldie 1967 (from the Romanian Carpathians)
- Anemono-Salicetum retusae Horvat 1953
- Salicetum retuso-kitaibelianae Lakušić 1970
- Gentiano-Plantaginetum atratae Mucina et al. 1990 (from the Bulgarian Pirin)
- Trifolio-Plantaginetum angustifoliae Lakušić 1966
An association in subalpine locations and exclusively deep depressions of the karst plateaus of Slovenia is:
- Drepanoclado uncinati-Heliospermetum pusilli Surina & Vreš ( Snežnik and Trnovski gozd )
The last association is only described for deep glaciocarst depressions, which are characterized by strong temperature inversion and cool, humid, rainy climates. The deciduous moss Sanionia uncinata and the small radiant seed ( Helispemra pusillum ) as well as the stump-leaved willow are the character types of the association, which is faltering on solid periglacial rock heaps . Viola biflora , Carex capillaris , Chrysosplenium alternifolium , Carex atrata , Polygonum viviparum and Festuca nitida appear as other accompanying species , while among the mosses Oncophorus virens , Campylium stellatum , Polytrichum alpinum , Pohlia elongata subsp. elongata and Orthothecium rufescens are most common. Since the association settles extrazonally below the tree line, a shrub layer with spruce , lashed alpine rose and large-leaved willow can occur, but can also be completely absent due to the extreme climatic conditions.
Taurus Mountains
Snow valleys of southern Greece and the Mediterranean high mountains of Asia Minor are no longer represented by creeping willows ( Salix herbacea , S. reticulata , S. retusa , S. serpyllifolia ). Snow valleys are now only bound to the bottom of depression or north-facing, shaded slopes with long snow cover, as well as in the immediate vicinity of meltwater channels. In southern Greece and Turkey, the chionophytes are formed by special turf associations (including Allopecurus gerardii and Crocus sieberi ). The short-growing lawns are tightly closed and characterized by long drought in summer. All of these turfs are placed in a currently blurred Trifolio-Polygonetalia association and their regionally subdivided associations. The soils are generally influenced by melt water and lie either within melt water channels or at the bottom of leveling niches in larger depressions of the glacial karst.
The calcareous snow valleys in the eastern Mediterranean were examined especially for the Taurus. There are snow valleys and meltwater communities that are close to the rubble communities in the western and central Taurus Mountains in the high alpine and subnival regions in lower elevations to convey the order Trifolio-Polygonion. In the Western Taurus and the adjacent Pisidian and Isaurian Taurus, on the other hand, there is a separate association:
- Thlaspion papoillosi within the Trifolio-Plygonetalia.
Basically, the snow valleys of the Taurus have a large proportion of conspicuously blooming onion monocotyledons , including Muscai bourgaei , Ornithogalum brevidepicellatum , Fritillaria pinardii , Sclla pleiophylla . Thlaspi papillosum was chosen as the namesake species of the association Thlapion Papillosi. Floristically, the alternation between the spring and early summer blooming geophytes and the chamaephytes and hemicryptophytes of the summer blooming lawn species is striking.
ecology
The snow valley vegetation is characterized by a number of species with ecophysiological adaptations to this location. You need a more or less uniform microclimate. They show a low tolerance to cold and heat and assimilate ( photosynthesis ) even at low temperatures. Most perennial species overwinter with green leaves and reproduce vegetatively by creeping shoots.
Protection and exposure
Tourism is one of the greatest threats to mountain landscapes. The mountain regions are used by hikers, mountain bikers, mountaineers and skiers in both summer and winter. A direct hazard arises primarily from the associated structural measures. Through development of pathways such as rest areas and parking spaces, ski lifts and mountain railway stations, which also involve soil drainage, compaction and / or sealing measures, valuable biotope areas are deprived of the types of snow-soil societies or the entire population is permanently damaged.
In the Federal Republic of Germany, snow valleys are legally protected biotopes according to Section 30 of the Federal Nature Conservation Act (BNatSchG).
literature
- P. Merz: Plant Associations of Central Europe and the Alps - Recognize, Determine, Evaluate. ecomed, Landsberg / Lech 2000, ISBN 3-609-19380-8
- E. Oberdorfer: South German plant communities. Part I: Rock and wall communities, alpine corridors, water, silting and moor communities. 4th edition, Gustav Fischer, Jena, Stuttgart 1998. ISBN 3-437-35280-6
- Ladislav Mucina , Milan Valachovič, Ivan Jarolímek, Ján Šeffer, Anna Kubinská, Ivan Pišút, I. 1990. The vegetation of rock fissures, screes, and snow-beds in the Pirin Planina Mountains (Bulgaria) . Studia Geobotanica 10: 15-58.
- H. Reisigl & R. Keller: Alpine plants in their habitat - Alpine lawns, debris and rock vegetation . Fischer, Stuttgart 1994, ISBN 3-437-20516-1
Individual evidence
- ↑ Thorsten English: Multivariate analyzes of the syn systematics and site ecology of the snow floor vegetation ( Arabidetalia caerulea ) in the Northern Limestone Alps. In: Stapfia. Volume 59, Linz 1999, p. 9, ISSN 0252-192X, PDF on ZOBODAT
- ↑ a b Thorsten English 1999: p. 12
- ↑ a b c d Thorsten English 1999: p. 13
- ↑ Thorsten English 1999: p. 17
- ↑ Thorsten English 1999: pp. 16-17
- ↑ Heinz Ellenberg, Christoph Leuschner: Vegetation of Central Europe with the Alps in an ecological, dynamic and historical perspective . 6th completely revised and greatly expanded edition by Christoph Leuschner. Eugen Ulmer, Stuttgart. P. 715
- ^ Reisigl Herbert, Richard Keller 1994: Alpine plants in their habitat . 2nd edition, Gustav Fischer, Stuttgart. ISBN 3-437-20516-1 Here p. 72
- ↑ Heinz Ellenberg, Christoph Leuschner: p. 718
- ^ Reisigl Herbert, Richard Keller 1994: p. 72
- ↑ Thorsten English 1999: pp. 18-19
- ↑ H. Kürschner, G. Parolly, E. v. Raab-Straube 1998: Phytsociological studies on high mountain plant communities of the Taurus Mountains (Turkey). 3. Snow-patch and meltwater communities . Feddes Repertorium 109, 7-8, 581-616
- ↑ Vladmir Stevanović, Snežana Vukojičić, Jasmina Šinžar-Sekulić, Maja Lazarević, Gordana Tomović, Kit Tan: Distribution and diversity of Arctic-Alpine species in the Balkans . Plant Systematics and Evolution, December 2009, 283.219, (PDF)
- ^ Ivo Horvat, Vjekoslav Glavac, Heinz Ellenberg 1974: Vegetation Southeast Europe . Geobotanica Selecta (Ed. Reinhard Tüxen), Vol. IV, Gustav Fischer, Stuttgart. ISBN 3-437-30168-3
- ^ Ivo Horvat, Vjekoslav Glavac, Heinz Ellenberg 1974: p. 627
- ↑ Mucina, L., Valachovič, M., Jarolímek, I., Šeffer, J., Kubinská, A. & Pišút, I. 1990. The vegetation of rock fissures, screes, and snow-beds in the Pirin Planina Mountains ( Bulgaria). Studia Geobotanica 10: 15-58.
- ↑ Boštjan Surina & Branko Vreš 2009: The Association Drepanoclado uncinati-Heliospermetum pusilli ( Arabiedtalia caeruleae , Thlaspietea rotundifolii ) in the Trnovski gozd Plateau (Slovenia, NW Dinaric Mts). Hacquetia, 8/1, 31-40.
- ↑ H. Kürschner, G. Parolly, E. v. Raab-Straube 1998: p. 582
- ↑ H. Kürschner, G. Parolly, E. v. Raab-Straube 1998: pp. 583 and 587
- ↑ H. Kürschner, G. Parolly, E. v. Raab-Straube 1998: p. 584
- ↑ H. Kürschner, G. Parolly, E. v. Raab-Straube 1998
- ↑ H. Kürschner, G. Parolly, E. v. Raab-Straube 1998: s. 587