Taxonomic lists are crucial elements of vegetation-plot databases and provide the links between original entries, reference taxon views and different taxon concepts. We introduce the R package taxlist in the context of object-oriented modelling for taxonomic lists. This package provides a data structure based on species lists in Turboveg, which is a software broadly used for the storage of vegetation-plot databases and implements functions for importing and handling them prior to statistical analysis. We also present a schema for relational databases, compatible with taxlist objects and recommend its use for handling diversity records.

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Introduction Vegetation-plot databases are increasingly gaining importance, not only as a way to host historical vegetation data or to store data collected in ongoing research projects, but also for storing vegetation-plot observations including types of syntaxonomical classifications in the context of the Braun-Blanquet approach (). Several software applications are suitable for storing and handling this kind of database. For instance, Turboveg () is one of the most widespread software used for storage of vegetation-plot databases and for data sharing in Europe (, ) and was therefore recognised in 1994 as the official software for storing vegetation data by the Working Group Council of the European Vegetation Survey (). Taxonomic lists (i.e. Species lists) are crucial components of vegetation-plot databases and several authors have raised concerns about the consequences of inconsistent nomenclatorial applications in downstream statistical analyses (,, ).

Milleduemila un mondo al plurale 1 pdf. Many applications attempt to standardise nomenclatures comparing custom species lists with on-line databases. Many of those applications are available in R ().

Some examples are the packages Taxonstand () that compares lists with the Taxonomic Resolution Services (e.g. And ), taxize () which uses the same sources as Taxonstand but some additional ones (e.g. And ) and vegdata () which imports tables from Turboveg databases as well as data from the German database 'VegetWeb', providing some functions for handling data previous to statistical analysis. These packages assume that retrieved accepted taxonomic names replace (overwrite) the names from the input data according to a standard synonymy. However, a universal consensus on the delimitations of a taxon is frequently not achieved and taxonomy is either a static discipline (,,, ).

When working with historical data, the links between old taxa names (see Table for basic definitions) and the current accepted name have to be traceable, allowing tracking back inconsistencies in the data. This is also in agreement with, who remark that even uncertain information should be stored as in the source, since expert opinions or access to collected specimens, for instance, may allow the resolution of these uncertainties that otherwise will not be available for the statistical analysis. Film mahabharata.

Accepted name: The name used for designating a taxon. According to the International Code of Botanical Nomenclature (), its description could be vouchered by a type, while its taxonomic circumscription may vary according to different taxon views (, ). Combination: The name of a taxon at the species level or below, which includes the name of the genus and further epithets (). A combination should also indicate the respective author for differentiation amongst homonyms. Potential taxon: Proposed by as a technical solution for taxon- and name-based databases in cases where the same taxon name could have different taxonomic circumscriptions (e.g. When a taxon gets split or when divergent views are applied in the databases). The potential taxon indicates the taxonomic circumscription of an accepted name according to a reference (taxon view).