Phytosociological Tables

In phytosociology, original data and classification results are presented as tables of species by releves or community types. There are two types of phytosocio-logical tables, releve tables (Table 4(a)) and synoptic tables (Table 4(b)). In both cases, species are listed in the lines and releves (in releve tables) or combined groups of releves (in synoptic tables) in the columns.

Both types of tables are normally presented in a structured manner. Lines and columns are arranged in such a way that 'species blocks' (i.e., groups of nonempty table cells) form more or less a diagonal from the top left to the bottom right. Therefore, the diagnostic species corresponding to the syntaxa ordered from left to right are to be found from top downward (except for the negatively differentiated syntaxa). In tables representing multi-layered woody vegetation, plant species of upper layers are normally listed at the top of the table to give an impression of stand structure. At the bottom of the table, those species are listed that have no diagnostic value within the respective table. These may be diagnostic species of superior syntaxa or 'companions', that is, species that have no diagnostic value for any syntaxon included in the table. Within blocks, species are sorted by decreasing constancy or decreasing fidelity. Species blocks or individual diagnostic species can be highlighted by frames or shadings in the tables; the criteria for doing so are related to species fidelity to syntaxa and should be clearly defined in particular studies.

In synoptic tables, all releves assigned to the same vegetation unit are represented by a single column with constancy values (i.e., the percentage proportion of releves in which the species is present). Constancy values are often presented as classes indicated by Roman numerals (I: 1-20%; II: 21-40%; ...; V: 81-100%), but the use of percentages has several advantages, for example, it does allow the application of modern fidelity concepts and merging of different synoptic tables without loss of accuracy. In addition to the constancy values, medians or ranges of the cover-abundance values or fidelity levels may be indicated. It is important to note (though long-neglected in phytosociology) that the calculation and comparison of constancy values does only make sense for plots of the same or similar size, because constancy values are strongly influenced by plot size.

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