The method of Josias Braun-Blanquet is used when creating a vegetation survey, usually briefly referred to as a survey, at least in Central Europe . For this purpose , the occurring plant species are listed on a homogeneous surface, arranged according to layers (tree, shrub, herb layer) and evaluated according to the degree of coverage , i.e. the soil area that their leaves cover, and the growth behavior (sociability). For this purpose, the classic or the extended Braun-Blanquet scale are used (estimates of species thickness).
Other, less frequently used scales are the Londo scale , presence / absence, ordinal scales , the Barkman, Doing & Segal scale , the Doing scale , the Domin scale , the Colin scale , the Tansley scale or the Didukh scale . Scale .
Plant-sociological vegetation survey
To record the vegetation, the first step is to select the recording area which should include a homogeneous plant population and which should not fall below a certain minimum size, the so-called minimum area . To determine the minimum area, the increase in species as a function of the increase in area is noted and graphically represented in a species number-area curve. The minimum area is reached when this curve is flattened depending on the scale, see species-area relationship . Usual sizes vary between less than one square meter in the case of step turf and up to over 100 square meters in the case of forest surveys, depending on the homogeneity of the stand, the biodiversity of the plant community and the distribution of vegetation in the area.
In Central Europe, the following area sizes can be used as guidelines:
|Vegetation stock||Recording area|
|Step turf||0.5 to 1 m²|
|Meadow and pasture||5 to 25 m²|
|Ruderal corridor and fallow land||10 to 50 m²|
|Arable herb layer||20 to 80 m²|
|Forest and forest||100 to 500 m²|
In the recording area, the header data (recording location, data on the terrain, vegetation cover and stratification, soil and use, geographical coordinates, sea level) are first collected. These may be supplemented later with data from maps and other data collections. The recording area should be documented photographically (situation in the area, demarcation, special species). Then the recording area is searched, all of the species represented in it are noted and then the species thickness and sociability of each species are assessed individually using assessment scales.
The Artmächtigkeit is after a combined Abundanz- / domination scale, of the Braun-Blanquet scale indicated. For plant species with low coverage, the number of individuals ( abundance ) is estimated, for those with coverage of 5% or more, the degree of coverage (dominance):
|symbol||Number of individuals||cover|
|r||rare, one copy||(well below 1%)|
|+||few (2 to 5) copies||(up to 1%)|
|1||many (6 to 50) copies||(until 5 %)|
|2||very many (over 50) copies||(until 5 %)|
|(or any)||5 to 25%|
|3||(any)||26 to 50%|
|4th||(any)||51 to 75%|
|5||(any)||76 to 100%|
In order to specify the estimate 2 (coverage 5 to 25%), Reichelt & Wilmanns proposed an extended Braun-Blanquet scale in 1973, which is often used. Deviating estimated values according to this scale:
|symbol||Number of individuals||cover|
|2m||very many (over 50) copies||(until 5 %)|
|2a||(any)||5 to 15%|
|2 B||(any)||16 to 25%|
In the sociability , the growth behavior of the individual species and their distribution in the recording area is assessed. The following estimated values are used:
|2||growing in small groups or clumps|
|3||growing in small spots or pads|
|4th||growing in small colonies to extensive patches (carpets)|
|5||growing in large herds|
Vitality (VIT) of the species:
|oo||very weak, accidentally germinated, not multiplying|
|O||weakened, meager from visible damage|
Example of a vegetation survey according to the Braun-Blanquet scale:
Step turf at the roadside, recording area 0.15 × 1.00 m, coverage 20%, vegetation height 1–5 cm, silty sand substrate.
2.3 Poa annua
The specification +.1 is often shown in abbreviated form as +. Many authors only indicate the degree of coverage and do not indicate sociability.
Phenological vegetation survey
For the description of the appearance of a stand and the seasonal change, a phenological mapping can be created, which can also be combined with plant-sociological vegetation recordings.
|number||Monocots , dicots||Notes for woody plants|
|1||Without inflorescences||Rosette stage|
|2||Beginning of ear / panicle emergence / inflorescence emergence||elongated shoots without buds|
|3||Ears / panicles / inflorescence slide||elongated shoots with buds|
|4th||Completion of spikes / panicles / inflorescences||Buds just before flowering begins|
|5||Beginning of flowering||Beginning of flowering|
|6th||Full bloom||Full bloom|
|7th||End of flowering||End of flowering|
|8th||Fruit set||Fruit set|
|10||Seed failed||Seed failed|
When carrying out a vegetation survey, in addition to identification literature that should be tailored to the area, aids may be required to e.g. As in studies of grassland stake out the exact size and location of the study area. If recurring examinations are planned, it is advisable to mark the area e.g. B. using stakes or magnets in the ground, the area should be mowed by machine.
When recording, it should be noted that the appearance of the existing species depends on the annual weather and the time of recording as well as depending on uses e.g. B. depends on mowing frequency.
Other methodological approaches
One of the most common methods used in North America to estimate the dominance of individual plant species on the basis of point-shaped test areas is the point-intercept method (point-contact method).
- Norbert Knauer: Vegetation Science and Landscape Ecology (= university pocket books. Volume 941). Quelle & Meyer, Heidelberg 1981, ISBN 3-494-02109-0 .
- Klaus Dierßen: Introduction to Plant Sociology. Knowledge Buchgesellschaft, Darmstadt 1990, ISBN 3-534-02151-7 .
- Peter Frankenberg : Vegetation and Space. Concepts of ordination and classification (= UTB. Volume 1177). Schöningh, Paderborn / Munich / Vienna / Zurich 1982, ISBN 3-506-99311-9 .
- Hartmut Dierschke : Plant Sociology . Basics and methods. Eugen Ulmer, Stuttgart 1994, ISBN 3-8252-8078-0 .
- Otti Wilmanns : Ecological Plant Sociology. An introduction to the vegetation of Central Europe. 6th, revised edition. Quelle & Meyer, Wiesbaden 1998, ISBN 3-494-02239-9 ( full text ).
- Matthias Schaefer: Dictionary of Ecology. 4th edition. Spectrum Academic Publishing House, Heidelberg / Berlin 2003, ISBN 3-8274-0167-4 .
- Matthias Schaefer: Dictionary of Ecology. 4th edition. Spektrum Akademischer Verlag, Heidelberg / Berlin 2003, ISBN 3-8274-0167-4 , p. 366.
- Options offered in the Turboveg software by SM Hennekens and JHJ Schaminée.
- Norbert Knauer: Vegetation Science and Landscape Ecology. Heidelberg 1981, p. 36f.
- Peter Frankenberg: Vegetation and Space. Concepts of ordination and classification. Paderborn 1982, pp. 32-33.
- Günther Reichelt, Otti Wilmanns: Vegetationsgeographie. Westermann, Braunschweig 1973, ISBN 3-14-160241-7 (quoted from Dierschke 1994).
- Otti Wilmanns: Ecological Plant Sociology. 4th edition. Quelle & Meyer, Heidelberg 1989, ISBN 3-494-02168-6 .
- Hartmut Dierschke: Fringing societies in the vegetation and location gradient at forest edges. In: Scripta Geobotanica. Volume 6, Göttingen 1974.
- Hartmut Dierschke: Plant Sociology . Basics and methods. Eugen Ulmer, Stuttgart 1994, ISBN 3-8252-8078-0 .
- Ernst Klapp, Adolf Stählin: Agricultural yearbooks . In: Scientific Archive for Agriculture . 1929, ISSN 0365-544X .
- Horst Tremp: Recording and analysis of vegetation-ecological data (= UTB. Volume 8299). Eugen Ulmer, Stuttgart (Hohenheim), ISBN 3-8001-2815-2 , pp. 31-32.