J 2000

Towards unification of national vegetation classifications: A comparison of two methods for analysis of large datasets

BRUELHEIDE, Helge and Milan CHYTRÝ

Basic information

Original name

Towards unification of national vegetation classifications: A comparison of two methods for analysis of large datasets

Authors

BRUELHEIDE, Helge and Milan CHYTRÝ (203 Czech Republic)

Edition

Journal of Vegetation Science, Uppsala, Opulus Press, 2000, 110-9233

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10600 1.6 Biological sciences

Country of publisher

Sweden

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

RIV identification code

RIV/00216224:14310/00:00003421

Organization unit

Faculty of Science
Změněno: 19/8/2003 09:51, prof. RNDr. Milan Chytrý, Ph.D.

Abstract

V originále

In European phytosociology, national classifications of corresponding vegetation types show considerable differences even between neighbouring countries. Therefore, the European Vegetation Survey project urgently needs numerical classification methods for large datasets that are able to produce compatible classifications using datasets from different countries. We tested the ability of two methods, TWINSPAN and COCKTAIL, to produce similar classifications of wet meadows (Calthion, incl. Filipendulenion) for Germany (7909 relevés) and the Czech Republic (1287 relevés) in this respect. In TWINSPAN, the indicator ordination option was used for classification of two national datasets, and the extracted assignment criteria (indicator species) were applied crosswise from one to the other national dataset. Although the datasets presumably contained similar community types, TWINSPAN revealed almost no correspondence between the groups derived from the proper classification of the national dataset and the groups defined by the assignment criteria taken from the other national dataset. The reason is probably the difference in structure between the national datasets, which is a typical, but hardly avoidable, feature of any pair of phytosociological datasets. As a result, the first axis of correspondence analysis, and consequently the first TWINSPAN division, are associated with different environmental gradients; the difference in the first division is transferred and multiplied further down the hierarchy. COCKTAIL is a method which produces relevé groups on the basis of statistically formed species groups. The user determines the starting points for the formation of species groups, and groups already found in one dataset can be tested for existence in the other dataset. The correspondence between the national classifications produced by COCKTAIL was fairly good. For some relevé groups, the lack of correspondence to groups in the other national dataset could be explained by absence of the corresponding vegetation types in one of the countries, rather than by methodological problems.

Links

GA206/99/1523, research and development project
Name: Parametrizace fytocenologického systému pomocí velkých souborů dat
Investor: Czech Science Foundation, Parameterization of the phytosociological classification using large datasets