Autori: Ruprecht, E., Botta-Dukát, Z.

Editorial: Acta Botanica Hungarica, 42, p.263-281, 2000.

Rezumat:

Our main question discussed in this paper is whether changes of environmental factors can be supported by changes reflected in vegetation texture using the species indicator values. A case study is presented on the statistical analysis and interpretation of changes in vegetation texture in some rich fen associations: Carici flavae-Eriophoretum latifolii, Junco obtusiflori-Schoenetum nigricantis and a Cladietum marisci association using the species indicator values for moisture (W), acidity (R) and nutrients (N). The social behaviour type (SBT) and coenological status of the species is used, too. The changes of vegetation are evaluated on the basis of releves made in the beginning of 1940s, in 1956, 1961 and 1998 of non-permanent plots with varying numbers among the years. Data were collected by different people in the mentioned years in the 7 fen patches in Malom Valley (Romania). The pattern of indicator values was analysed by concentration analysis. This procedure was suggested by Précsényi (1995) instead of the calculation of average indicator values, which from a mathematical point of view is incorrect inspite of the fact that the results can often be interpreted well. Significant correlation was found between the coordinates calculated from indicator values for moisture and acidity. Similar behaviour was found in vegetation textural changes indicated for moisture, acidity and nutrient status of the two rich-fen associations, but the rate of coenological groups and social behaviour types changed differently. The Cladietum marisci association presented completely different behaviour.

Cuvinte cheie: chronosequence, non-permanent plot, indicator values, annual precipitation, calcareous ground-water