Holarctic
The Holarctic ( ancient Greek ὅλος holos , German “whole” and ἀρκτικός arktikos , arctic) is a biogeographical region and represents both a flora kingdom and a fauna kingdom . It covers most of the northern hemisphere of the earth and is the largest of the regions. The southern border of the Holarctic runs in northern Mexico (but extends further south in the highlands than on the coast), includes the Cape Verde Islands , runs along the northern edge of the Sahara and the Arabian Peninsula , along the Himalayas to southern China, excludes Taiwan and Japan a.
Florentine
Characteristic representatives of the Holarctic are the pine family (Pinaceae), birch family (Betulaceae), beech family (Fagaceae), willow family (Salicaceae) and mostly the buttercup family (Ranunculaceae) and rose family (Rosaceae). Furthermore, the cruciferous family (Brassicaceae), carnation family (Caryophyllaceae), the rush family (Juncaceae) and the genus of sedges ( Carex ) have their focus here.
A certain differentiation within the flora resulted from the ice ages of the Pleistocene : In Europe a large part of the Pliocene flora died out, so that the flora of Europe is now impoverished. Some families such as the magnolia family , Hamamelidaceae and Styracaceae therefore only occur in North America and Asia, but no longer in Europe.
The floral kingdom of the Holarctic is subdivided into the arctic, boreal, atlantic, south eurosiberian, mediterranean and irano-turanic floral regions. The flora regions are determined according to the taxonomic plant species occurring in the region:
- arctic
- Main distribution in the treeless arctic tundra, reaching into the coniferous forest zone, also in the Alps, only need a very short vegetation period with a daily average below 10 ° C
- boreal
- An essential part of the large coniferous forest zone, the character tree is the spruce - Picea abies . Many of these floral elements reach far into Central Europe and some subboreal species, e.g. B. Pinus sylvestris, even far south.
- atlantic
- A group of floral elements, which are strongly linked to the oceanic climate, partly in Central Europe, but hardly represented in Eastern Europe
- eu Central European
- Essentially species that make up the deciduous forest zone. They are Central European species in the narrower sense, the distribution of which does not extend into Eastern Europe. Central European species in the broader sense, however, still reach all of Central Russia, but sometimes as far as the Urals.
- Mediterranean
- Geo-elements that form the Mediterranean hard-leaf zone. They are typical of areas with winter rain and a pronounced summer drought.
- Pontic
- - Species of the treeless Eastern European steppes, in which the summers are hot, but in contrast to the Mediterranean area, the winters are much colder than in Central Europe.
- south siberian
- These species have their distribution center in the transition zones between the West Siberian steppes and the taiga.
- turanic-central asian
- Species of the southeast European semi-desert, in Central Europe rarely on salt soils and sometimes on the coast of the sea.
Faunal
The fauna kingdom of the Holarctic is divided into two regions, the Nearctic (Greenland and North America) and the Palearctic . The border of the fauna kingdom runs further to the south, or a broad transition area to the other fauna kingdoms is partially defined here. The border in America is either drawn as in the Florentine Empire (H. J. Müller) or a transition zone that includes all of Central America and the Caribbean is assumed. In Africa, the border runs south of the Sahara, or the Sahara is assumed to be a transition area, the same applies to Arabia, although the southern edge of the Arabian Peninsula is not included.
Characteristic mammals are the elk (Alcinae), real deer (Cervinae), the lynxes ( Lynx ), the goats and sheep ( Caprinae ), the beavers ( Castoridae ), the pigeon hares (Ochotonidae), among the insectivores the moles (Talpidae) and Shrews (Soricidae) and among the rodents the bouncy mice (Zapodinae) and voles (Arvicolinae). Typical bird families are the grouse (Tetraoninae), alkenbirds (Alcidae) and waxwings (Bombycillidae). Among the insects, the butterfly families Hesperiidae , Lycaenidae , Noctuidae , Notodontidae , Nymphalidae , Pieridae and Sphingidae .
literature
- HJ Müller: Ecology. 2nd edition, Gustav Fischer, Jena 1991, ISBN 3-334-00398-1 , p. 133 f.
- P. Sitte, EW Weiler, JW Kadereit, A. Bresinsky, C. Körner: Strasburger - textbook of botany for universities . 35th edition, Spektrum Akademischer Verlag, Heidelberg 2002, ISBN 3-8274-1010-X , p. 986.
- H. Walter, S.-W. Breckle: Ecology of the Earth. Volume 1: Basics. 2nd edition, Gustav Fischer, Stuttgart 1991, ISBN 3-437-20454-8 , p. 11 f.
- Dieter Heinrich, Manfred Hergt, Rudolf Fahnert: dtv-Atlas Earth . Physical geography. Deutscher Taschenbuch Verlag, Munich 2006, ISBN 3-423-03329-0 , pp. 266-267 .
Web links
Individual evidence
- ^ Heinrich Walter: General geobotany . 3rd edition, Ulmer, Stuttgart 1986, p. 38.
- ↑ Nentwig, Bacher, Beierkuhnlein, Brandl, Grabherr: Ökologie. Spektrum Akademischer Verlag, Heidelberg 2004, ISBN 3-8274-0172-0 .