Czech National Phytosociological Database: basic statistics ofthe available vegetation-plot data

Abstract

Electronic vegetation releves available in the Czech National Phytosociological Database are reviewed. The database was established in 1996, with a central database managed in the Department of Botany, Masaryk University in Brno (www.sci.muni.cz/botany/database.htm). On 15 November 2002 the central database contained 54,310 releves from the territory of the Czech Republic, sampled by 332 authors between 1922-2002. Ca. 54 % of the releves have been taken from published papers or monographs, 21 % from theses and the rest from various unpublished reports and field-books. These releves include 1,259,008 floristic records of individual plant species. Territorial coverage of the country with releve-plot data is irregular due to more intensive sampling in the areas with attractive natural or semi-natural vegetation; on the other hand some gaps still exist in less attractive or poorly accessible areas. Most releves are of broad-leaved deciduous forests (Querco-Fagetea), meadows (Molinio-Arrhenatheretea), dry grasslands (Festuco-Brometea), and marsh grasslands (Phragmito-Magnocaricetea). Data quality issues are discussed, such as researcher bias in field recording, preferential selection of sampling sites, spatial autocorrelation, and missing values of some data elements.