Naming

[Current editors: Miquel De Cáceres]

Phytosociological nomenclature

[Taken from Dengler et al. 2008]

In phytosociology, abstract vegetation units defined by floristic–sociological criteria are termed syntaxa. They are positioned in a hierarchy of different ranks, called syntaxonomy, among which the association is considered as the basic unit, comparable to species in taxonomy. Ranks below the association level are often used to express edaphic, climatic, geographic, structural, and successional variation. Like other fields of biological systematics, syntaxonomy is an open-ended process that is carried out by a large community of independent researchers and requires unequivocal rules for naming classification units. Therefore, the Nomenclature Commission of the International Association for Vegetation Science (IAVS) and the Féderation Internationale de Phytosociologie (FIP) have established the International Code of Phytosociological Nomenclature (ICPN) (Weber et al. 2000).

The ICPN regulates the scientific nomenclature of four principal and four supplementary ranks of syntaxa. Neither synusial nor symphytosociological units (see below), nor informally named syntaxa fall under the ICPN. The ICPN provides precise instructions for the formation of syntaxon names, their valid publication, and the decision about which of several available names from the earlier literature to apply. According to the ICPN, every syntaxon of a certain circumscription and rank has only one correct name. However, the ICPN only regulates the nomenclature and does not define rules for proper delimitation and classification of syntaxa. Aiming to provide unambiguity and stability of syntaxon names, the ICPN is based on two major principles: (1) among several names for a syntaxon, the oldest valid (published) name is the correct one (priority); (2) each syntaxon name is connected to a nomenclatural type (a single relevé for associations, a validly described lower-rank syntaxon for higher syntaxa), which determines the usage of the name when this syntaxon is split off, merged with others, or otherwise changed in its delimitation.

Syntaxon names are formed of the scientific names of one or two (in the case of subassociations, up to three) plant species or infraspecific taxa, which usually are, but need not be, characteristic in the respective vegetation type. The formation of the scientific syntaxon names involves connecting vowels, the declination of the taxon epithets, and addition of terminations indicating syntaxonomic rank. An ‘author citation’ (i.e., the author(s) and year of the first valid publication) also forms part of the complete syntaxon name.

Naming conventions in the US NVC

[From Jennings et al. 2009]

The most basic units of the NVC hierarchy are associations and alliances. The association is the primary unit of vegetation, reflecting patterns of plant species occurrence and frequency. The alliance is the next broader unit of vegetation and is composed of one to many associations. Each association and each alliance is assigned a scientific name based on the scientific names of plant species that occur in the type. The scientific name will also have a standard translated English name from the vernacular plant names listed in the PLANTS database. Finally, each association and alliance is assigned a globally unique identifier. Dominant and diagnostic taxa are used in naming a type and are derived from the tabular summaries of the type. Names of associations and alliances should include one or more species names from the dominant stratum of the type. Among the taxa that are chosen to name a type, those occurring in the same strata (tree, shrub, field, ground, floating, submerged) are separated by a hyphen (-), and those occurring in different strata are separated by a slash (/). Species that may occur with low constancy can be placed in parentheses. Taxa occurring in the dominant stratum are listed first, followed successively by those in other strata. Within one stratum, the order of species names generally reflects decreasing levels of dominance, constancy, or diagnostic value of the taxa. Where a dominant herbaceous stratum is present with a scattered woody stratum, names can be based on species found inthe herbaceous stratum and/or the woody stratum, whichever is more characteristic of the type. Association or alliance names include the term association or alliance as part of the name to indicate the level of the type in the hierarchy, as well as a descriptive physiognomic term, e.g., forest or grassland.

Discussion

Bibliography

    • Dengler, J., Chytry, M. & Ewald, J. (2008) Phytosociology. Encyclopedia of Ecology (eds S. E. Jørgensen & B. D. Fath), pp. 2767-2779. Elsevier, Oxford.
    • Grossman, D. H., Faber-Langendoen, D., Weakley, A. S., Anderson, M., Bourgeron, P., Crawford, R., Goodin, K., Landaal, S., Metzler, K. & Patterson, K. (1998) International classification of ecological communities: terrestrial vegetation of the United States. The National Vegetation Classification System: Development, Status, and Applications, 1.
    • Jennings, M. D., Faber-Langendoen, D., Loucks, O. L., Peet, R. K. & Roberts, D. (2009) Standards for associations and alliances of the US National Vegetation Classification. Ecological Monographs, 79, 173-199.
    • Weber, H. E., Moravec, J. & Theurillat, J. P. (2000) International code of phytosociological nomenclature. Journal of Vegetation Science, 11, 739-768.