Өсімдік қауымдастықтарының өсімдіктердің өсуін зерттеуі

The empirical study of plant growth in communities
Phytosociology, also known as phytocoenology or simply plant sociology, is the study of groups of species of plant that are usually found together. Phytosociology aims to empirically describe the vegetative environment of a given territory. A specific community of plants is considered a social unit, the product of definite conditions, present and past, and can exist only when such conditions are met. In phyto sociology, such a unit is known as a phytocoenosis (or phytocoenose). A phytocoenosis is more commonly known as a plant community, and consists of the sum of all plants in a given area. It is a subset of a biocoenosis, which consists of all organisms in a given area. More strictly speaking, a phytocoenosis is a set of plants in area that are interacting with each other through competition or other ecological processes. Coenoses are not equivalent to ecosystems, which consist of organisms and the physical environment that they interact with. A phytocoensis has a distribution which can be mapped. Phytosociology has a system for describing and classifying these phytocoenoses in a hierarchy, known as syntaxonomy, and this system has a nomenclature. The science is most advanced in Europe, Africa and Asia. In the United States this concept was largely rejected in favour of studying environments in more individualistic terms regarding species, where specific associations of plants occur randomly because of individual preferences and responses to gradients, and there are no sharp boundaries between phytocoenoses. The terminology 'plant community' is usually used in the US for a habitat consisting of a number of specific plant species. It has been a successful approach in the scope of contemporary vegetation science because of its highly descriptive and predictive powers, and its usefulness in nature management issues.

Modern phytosociology for largely follows the work of Józef Paczoski in Poland, Josias Braun Blanquet in France and Gustaf Einar Du Rietz in Sweden. also sometimes called the Braun Blanquet approach.

The first step in phytosociology is gathering data. This is done with what is known as a relevé, a plot in which all the species are identified, and their abundance both vertically and in area are calculated. Other data are also recorded for a relevé: the geographic location, environmental factors and vegetation structure. Boolean operators and (formerly) tables are used to sort the data. As the calculations needed are difficult and tedious to do manually, modern ecologists feed the relevé data into software programs that use algorithms to crunch the numbers. Braun Blanquet's method uses the scientific name of its most characteristic species as namesake, changing the ending of the generic epithet to " etum" and treating the specific epithet as an adjective. Thus, a particular type of mesotrophic grassland widespread in western Europe and dominated only by the grass Arrhenatherum elatius becomes "Arrhenatheretum elatioris Br. Bl.". To distinguish between similar plant communities dominated by the same species, other important species are included in the name, but the name is otherwise is formed according to the same rules. Another type of mesotrophic pasture dominated by black knapweed (Centaurea nigra) and the grass Cynosurus cristatus, which is also widespread in western Europe, is consequently named Centaureo Cynosuretum cristati Br. Bl. & Tx If the second species is characteristic but notably less dominant than the first one, its genus name may be used as the adjective, for example in Pterocarpetum rhizophorosus, a type of tropical scrubland near water which has abundant Pterocarpus officinalis and significant (though not overwhelmingly prominent) red mangrove (Rhizophora mangle). Today an International Code of Phytosociological Nomenclature exists, in which the rules for naming syntaxa are given. Its use has increased among botanists. In Anglo American ecology, the association concept is mostly linked to the work of the mid twentieth century botanist Henry Gleason, who set it up as an alternative to Frederic Clement's views on the superorganismic framework. The philosophical parameters of the association concept have also come under study by environmental philosophers as to how it values and defends the natural environment.

Modern phytosociologists try to include higher levels of complexity in the perception of vegetation, namely by describing whole successional units (vegetation series) or, in general, vegetation complexes. Other developments include the use of multivariate statistics for the definition of syntaxa and their interpretation.

Phytosociological data contain information collected in relevés (or plots) listing each species cover abundance values and the measured environmental variables. This data is conveniently databanked in a program like TURBOVEG allowing for editing, storage and export to other applications. Data is usually classified and sorted using TWINSPAN in host programs like JUICE to create realistic species relevé associations. Further patterns are investigated using clustering and resemblance methods, and ordination techniques available in software packages like CANOCO or the R package vegan.