Phytosociology

The plants Sociology ( Phytozönologie; . Engl phytosociology ) is a descriptive and systematic method of Geobotany ( phytogeography ) for the typing of vegetation and structure of the vegetation units. It can be seen as part of vegetation science, which deals in plant ecology with the vegetation cover.

Definition

The vegetation cover of the Earth consists of various plant species that occur in different types and recurrent combinations. The plants Sociology is the study of the socialization of plant species and vegetation of the customer. It describes individual plant communities and seeks to empirically based systematic arrangement of all plant communities on to represent their characteristics and their relationship. In plant sociology the Zurich -Montpellier school after Braun- Blanquet is predominant.

Plant sociology is a historically established but controversial term. While the resulting only after their sociology and their biological disciplines Animal sociology and Biosoziologie often only investigate intraspecific Socialization, there are the cases examined by the plant sociology plant communities of several species. Therefore, some authors refer by analogy to Zoozönologie and Biozönologie the doctrine of the association of plant species as Phytozönologie. But this usage is controversial because it abstracts from the historical development of plant sociology. Conversely, receives the use of the term "plant sociology " also popular by the sociologist Bruno Latour, She is not only the older term, but also pursues the goal to describe societies of heterogeneous components and understand. This was Augustin- de Candolle Pyrame as their creator also one of the founding fathers of sociology and the sociology plant a model for the social sciences.

Method

The phytosociological method is based on four steps: first the vegetation surveys, 2nd tabular typing of relevés according to floristic similarity 3, the Company Description of vegetation types and 4 the systematic classification of the vegetation types.

Vegetation surveys

The vegetation surveys carried out in the field and involves the transfer of real vegetation stands in a symbolic figure. → Main article: vegetation surveys

Tabular comparison

The vegetation surveys are collected and entered for comparison in a phytosociological table. The rows of the table list the species on which column the single frames. The rows and columns are sorted by similar species combinations and similar occurrences priorities. Here, phytosociological vegetation types can emerge, which are characterized by their floristic structure. This taxonomic rank loose phytosociological units are referred to as plant communities that meet fileformat in types of terrain combinations.

Company Description

If the vegetation units in the tabular comparison of the vegetation surveys and mapping typological been determined, the plant communities can be described, with the characteristic species combination of the respective plant community should be defined. Succeed the description of the floristic structure of the plant community, then other synthetic characteristics such as saturation, distribution, adjacency, substrate properties can be taken into account for the participating vegetation surveys to analyze geographical aspects, ecological site characteristics and anthropogenic conditions of vegetation units.

Scientific classification

By generalizing company description, the real cases are abstracted to an ideal type, which occurs as nowhere in the real vegetation, but many real-world vegetation stands in the characteristic species composition is similar. Is the plant community has been well typified and described, it can be compared with known phytosociological associations and assigned. Associations are clearly identifiable plant communities with syntaxonomical rank and ending in- etum. For example, a ranking the loose Matricaria discoidea Society would be allocated from the example described above, the Polygono arenastri - Matricarietum disco ideae.

System

The associations are the basic units of phytosociological nomenclature ( Synsystematik ). The associations are classified into a hierarchically ordered system of plant communities. Related associations are again combined to phytosociological associations to these regulations and to these classes. Thus, the phytosociological units of varying scope and syntaxonomischer stage are formed. The associations are based on socio- loyal character types that are typical for an association, ie occur disseminated here and missing in other societies. Here, the character types principle is applied only within its parent, defined mainly by growth forms over units, the formations ( so may be a grassland society a kind of characteristic species, even if it also occurs in various forest communities ). To character types in the ideal case only in the described association ( " true " ), but in this in all herds ( " stet " ) occur. In societies " medium " site conditions, since it is particularly not always possible to form associations based on character types, differential species are considered in addition. This limits a company against an adjacent, but come in other companies before ( are not " true "). The character and differential species principle is applied for the higher units in exactly the same way. Thus, class, order, association character types are defined.

Species combinations that are not classified by character or differential species are not described as plant communities according to the phytosociological system. Will they retain (for practical reasons ), they are neutral as "Company", but not described as an association. A company may normally a higher level (eg, an association or an order ) to be assigned if the corresponding character types occur. The naming of the phytosociological syntaxa is governed by the International Code of Botanical Nomenclature Sociology ( ICPN ). The company names consist of one or two species names and a suffix that identifies the syntaxonomic level:

History

Been The plant sociology comes from the vegetation geography, such as the national heritage vegetation descriptions of Linnaeus and Alexander von Humboldt, and is developed in the first decades of the 20th century and eventually expanded by Josias Braun- Blanquet (1928 ) to a scientific and practical in the field method. This is called the Zurich -Montpellier school of plant sociology and has over other schools enforced as the Uppsala School of Du Rietz. The plant according to Braun- Blanquet sociology was significantly promoted in Germany by Reinhold Tüxen and the floristic - sociological study group. In southern Germany, Erich Oberdorfer has significantly contributed to the breakthrough of this method. In addition to specialist scientists were and are many interested lay people involved in the development of plant sociology. The phytosociological method is used as a tool in various scientific disciplines (eg, geography, biology, agronomy, forestry, landscape design). After the phytosociological system was largely developed in the early 1970s for Central Europe, the academic interest in plant sociology of the production-oriented scientific disciplines of ecology and nature conservation shifted. At the same time quantitative approaches have been used in plant sociology, who tried with statistical significance analysis, the phytosociological method to approximate the exact sciences. Such approaches are controversial, because the basis of plant sociology is the vegetation recording, which is a qualitative step, and with significance analysis and homogeneity calculation would introduce an ultimately pseudo -scientific precision.

Sigma sociology

The Sigma sociology is a special form of plant sociology, which examines the socialization of plant communities, as the vegetation complex ( Sigma Company, Sigmetum ) are referred to. For this, the plant communities of a region are first described and classified synsystematisch to create a recording key or a Mapping with which the vegetation complexes are then mapped. The recurring combination of plant communities can be determined nomenclaturally then analogous to the classification society ( see above). The synsystematische structure consists of the characteristic plant communities with an appropriate additive, which indicates the level in the scheme:

Precursor of Sigma sociology have been developed by the vegetation geography to describe landscapes, for example the formations.