Plant sociological table
In a plant-sociological table , vegetation images are compiled in tabular form. It is the descriptive , comparative and synthetic working tool of the plant sociology , with which the comparison of the vegetation, which is represented by vegetation photographs, is carried out in order to work out plant societies and higher plant sociological units .
Vegetation illustration
The vegetation is determined by the species involved in building up the population. These in turn form identifiable features with which they can characterize vegetation stands. The real vegetation stocks are mapped using plant-sociological vegetation recordings. Vegetation surveys consist of a list of the species found, which are provided with information on cover and sociability. If there is a sufficient number of vegetation photographs, they can be entered in a plant-sociological society table in order to compare the vegetation photographs.
Social table
Structure of the table
The table enables a comparison of the combinations of characteristics, i.e. the types involved in the stock build-up. The table consists of a table header, which includes the upper lines with information on the recording code, coverage, number of species, etc. and a table field in which the information on the species listed on the left edge of the table is entered.
Raw table
First, a raw table is created in which all vegetation images are entered. The raw table is unordered and its picture follows the order in which the recordings are entered. In order to arrange the raw table roughly, the order of the species is arranged in descending order after all recordings have been entered according to the frequency of their occurrence. This means that the species that are represented in most of the vegetation surveys are listed at the top and the species that are rarely found are listed in the lower section of the table. The frequency of a species in the table is called continuity . The parts table is then created from the types of medium continuity, usually types that are represented in 60% to 20% of the recordings, so that the recordings can be easily sorted.
Parts table
The partial table includes all vegetation surveys but only a few species and forms the central instrument of the actual plant-sociological table work . Now the species (in the horizontal lines) and the vegetation photographs (in the vertical columns) are arranged in such a way that, after repeated adjustments, types of the same species combination are gradually identified. Since the table picture changes every time the table is rearranged and certain recordings and species find each other, the old master of plant sociology Reinhold Tüxen described this typification of vegetation according to species set as the crystallization of plant communities. The plant sociological table work is not very complicated if you can, nevertheless it is demanding even for the plant sociologist trained in it.
Pure table
As soon as the part table is arranged so that the vegetation units are clearly delimited and floristically describable, the pure table is created from the part table. The pure table again includes all species from the raw table, only in a different order of the species and arrangement of the vegetation recordings. With the help of columns and boxes that mark groups of species, the vegetation units are clearly highlighted.
Synthetic table
The synthetic table reduces the plant communities from the society table to summarized information on the continuity of the species involved in the plant community. In this way, several vegetation recordings are combined to form a synthesized plant community, which enables an overview of the sociological relationship of plant communities. Synthetic overview tables bring together many society tables and can thus include up to several thousand vegetation photographs and compare them as a type. This reduction of vegetation surveys to synthetic types is accompanied by a loss of information with regard to coverage and sociability of the species involved.
The synthesized types are created from the society tables via the continuity of the types involved. To do this, it is necessary to calculate the continuity of the species and convert it into continuity classes. It's pretty easy. First the number of vegetation recordings that belong to a plant community is counted and then the frequency of the individual species is counted and finally the proportion of the frequency of the individual species in the number of vegetation recordings is calculated and expressed as a percentage. Ultimately, the percentage is assigned to a continuity class, which is expressed in Roman numerals, and this is entered in the synthetic table.
Continuity classes
| symbol | continuity |
|---|---|
| r | once only |
| + | several times up to 5% |
| I. | 5% to 20% |
| II | 21% to 40% |
| III | 41% to 60% |
| IV | 61% to 80% |
| V | 81% to 100% |
Quotes
- "The table remains the 'touchstone for the young', but also for the old 'sociologist', in order to repeat a remark by Braun-Blanquet in a slightly modified form" (Tüxen, 1974: 6).
literature
- Josias Braun-Blanquet (1964): Plant Sociology. Vienna 1964.
- Reinhold Tüxen (1974): The Plant Societies of Northwest Germany. Apprenticeship 1974.
- Hartmut Dierschke, Karl-Heinrich Hülbusch, Reinhold Tüxen (1973): Ash and alder spring forests on the southwestern edge of the Bückeberge near Bad Eilsen, at the same time a contribution to the local plant-sociological approach. In: Communications of the Erich floristic-sociological working group. Vol. 15/16, pp. 153-164.
- Otti Wilmanns (1989): Ecological Plant Sociology. Heidelberg, Wiesbaden 1989.