Climax vegetation

As a climax vegetation, a relatively stable final state of the vegetation is referred to in ecology, is emerging in the course of succession (after the Latin Klimax "ladder", or " end point", top of the ladder, transferred " climax "). From a phytosociological point of view is called the adjusting himself in the climax plant community also climax community ( the forest on well final forest community ).

Determinants of climax vegetation

The special climax vegetation of a particular site is derived from the abiotic site factors, in particular of the soil factors such as soil moisture and base content and the local climate. The location factors themselves are Klimaxstadium this profoundly over, may determine through the vegetation and its influences and been changed. For example, can have a powerful humus originally open, raw floors, which were mainly determined by the properties of the parent material, now. This humus increases the storage capacity for water and nutrients. Lime -and base- rich soils are shifted toward acidic soils in the climax by the leaching action of rainfall (at least in humid Central Europe). Therefore, there is a natural tendency that in the climax vegetation leveled the originally existing site-specific differences and all extremes are moderated.

The actual composition of the climax vegetation is determined and regulated primarily by the interaction of the involved animal and plant species. As time factors ( developmental age, immigration of species ), by definition, no longer matters is the essential process that determines the composition of the vegetation, the competition between plant species with each other. Therefore, " win " in the climax vegetation in the rule tree species to light- loving herbs and shrubs as they provide shade and this can displace thereby. Koike could, for example, the tree species composition of Southeast Asian forests well of only two factors ( shade tolerance and maximum plant height ) predict Wherever climate and location factors allow tree growth, therefore form the climax vegetation forests. Forest Free Klimaxstadien can be found where the climate does not allow tree growth, particularly in low rainfall to ( steppes and deserts ) or low temperature ( Tundra ). In Central Europe, forest-free Klimaxstadien exist only in very extreme location factors. Here it is for the forest to the ground wet ( Moore) or ground dry / shallow (rock Gentiles ).

Influence of the fauna

It is known that there are vegetation stocks where the absence or withdrawing from tree species not on the abiotic conditions, but to influence the wildlife (especially the phytophagous ) is based. This is, for example, assumed for the subtropical savannas with their Huftierfauna. Even examples with invertebrate species are known, mostly in climatic boundary layers ( boreal spruce and birch forests). The controversial Megaherbivorenhypothese balances the influence of herbivores in the intermediate warm periods in Central Europe for so large that it holds large, contiguous and homogeneous forest areas are not likely. The influence of phytophagous insects is often neglected or hidden in vegetation science and is not included in the traditional definition of climax vegetation (mainly because the scientists involved were looking at him usually as negligible).

Properties of the climax vegetation

Biomass

Klimaxstadien of vegetation are widely believed plant communities with the greatest possible production of biomass; according to the theoretical principles of ecology seeks the succession for the most effective use of resources. The theoretical prediction was confirmed in an intensively studied ecosystem ( the beech forest of the Solling project). In achieving the Klimaxzustandes a self regulatory system has developed, which remains stable with unchanged external influences, so no major changes in the composition of biocenosis permits ( steady state ).

Number of species

As for the number of species in the climax, there are different views. Usually the Klimaxwälder poorer in species than some pioneer companies or " semi-natural " cultural formations at the same location (eg Magerrasen ). This is explained by the importance of the factor competition: Under certain environmental conditions is always a kind of all other competitive superior to and can displace the location. This can climax even as "natural monocultures " arise, for example, Reed beds or under grew free beech forests. Studies of wildlife have shown that under certain circumstances the number of animal species may also increase, as the number of plant species decreases. In most cases, it is believed, however, that not the climax vegetation, but an "intermediate " stage of succession is the most biodiverse.

Climax vegetation in Central Europe

Due to the large climatic influence large parts of Central Europe ( euozeanisch to subcontinental ) the final forest communities would be significantly influenced by the beech as a collection or stock. The most common climax vegetation of Central Europe would be the beech forests. Oak forests and mixed oak forests were on very poor sandy soils instead more widespread in eastern Central Europe and pine forests. In a very base-rich soils, forests are the " precious hardwoods " ( ash, maple species, Linde species), mostly mixed with beech. In the higher mountain ranges form coniferous forests of fir and spruce up the climax vegetation (see also: forest communities in Central Europe). Mostly it is assumed that more natural production forests managed the climax vegetation are very close in spite of human impact already, at least in terms of plant species.

Term use, criticism

The use of the Klimaxbegriffs in vegetation science in its present form dates back to the American botanist Frederic Edward Clements. According to Clements ' concept is available for every climate zone only a climax vegetation ( " Monoklimax "). He understood these vegetation units as highly organized organisms -like individuals with a personal history of growth and decay, which spans at least thousands of years. Thus, the Klimaxbegriff is the history of ideas based on the organicist and conservative worldview. Many scientists react to this idea-historical reference so that they avoid the concept of climax and replace it with more neutral circumlocutions or neologisms. Modernized versions of the Klimaxbegriffs but are used in science today, especially in connection with the succession concept. Also important is the juxtaposition of " pioneer species " and " climax species " each with its own characteristics. In Clement 's original version, the term only of historical interest.

Regarding the use of the term is to be noted that there are by no means at the climax vegetation to a final state in geological time, but rather from a human perspective very long periods. Already from the original use was clear that the climax vegetation changes due to climate change.

It is also important to note that many ( as a theoretical reference state ) dynamic factors are hidden for the determination of the climax vegetation; this applies z.T. also for natural-looking factors. With regard to the Klimaxzustand all dynamic factors are known as " fault" defined. Even in natural ecosystems but countless animal and plant species (eg all pioneer species ) depend on the action of such " interference " for their survival.

To what extent the climax itself may be dynamic and can be characterized by dynamic processes with, is controversial in research. The mosaic - cycle concept is, for example, of a continuous, non-linear development of ecosystems in different subspaces of. These cyclically repeating states would together form the Klimaxzustand.

Relation to the Final Society

Within the framework of the concept of potential natural vegetation is used for the most highly developed plant community of a site, the term " Final Society", which is the concept of climax vegetation closely related. The main difference is the location- altering effects of succession, which is not taken into account for the final society.