Disjunction (ecology)

from Wikipedia, the free encyclopedia

In ecology, the disjunction is a sub-area ( exclave ) that has been spatially separated from the rest of the distribution area of a plant or animal species and cannot be bridged with the usual means of distribution of this species, but still represents a habitat .

Disjunction is, for example, a result of inventory and area losses. Areas may have been separated from each other by ice advances during the ice ages . Conversely, after a new climate change, relic populations that are far apart from each other often remain, for example in mountains or cooler zones. In particular, the arctic-alpine disjunction is known , which is a direct consequence of expansive spreading during cold periods and isolation during warm periods. Originally, alpine and arctic tundras also spread to the periglacial tundras in the flat and hilly countries of Central and Southern Europe. After the end of the ice ages, these migrated to both higher latitudes and higher altitudes. In the space between the European mountains and the Arctic, the species died out. These species are therefore considered to be Ice Age relics in Central and Southern Europe, which are generally glacial relics. In the warmer mountains they only survived in microclimatic favored areas; many species also need landscapes that have periglacial morphodynamics due to frost effects.

For the (sub) population in such a disjunction, this separation can be the beginning of a new speciation . If the disjunction loses its habitat function (i.e. becomes uninhabitable), the population cannot migrate and inevitably dies out. Species formation takes place either through specialized adaptation to the local habitat with unchanged conditions or through necessary adaptation to changes in the disjunction.

With the stepping stone concept one tries to counteract a disjunction.

literature

  • Volker Storch, Ulrich Welsch, Michael Wink: Evolutionary Biology . 2nd edition, Springer 2007, ISBN 978-3-540-36072-8 , pp. 37-38.

Web links

  • disjoint distribution , keyword at Wissenschaft-Online, Spektrum der Wissenschaft Verlagsgesellschaft (accessed on July 31, 2013)