Comparing diagnostic species combinations of Carpathian calcicolous beech forests using different approaches
Ujházyová, Mariana; Ujházy, Karol
The aim of the study was to differentiate calcicolous beech forests within beech-dominated forest communities using a formalised approach and to compare classifications obtained by commonly used methods (approaches). Relevés with beech dominance (cover > 25 %) were extracted from the Slovak national database and 951 relevés were selected within the geographical stratification. A formalised selection of relevés on a suballiance and alliance level was carried out according to the extended lists of the diagnostic species excerpted from Central European literature and restricted by Ellenberǵs indicator values. A divisive TWINSPAN method and an agglomerative cluster analysis were performed and the resulting classifications were compared with the original author's assignment. The number of diagnostic species, average positive fidelity, sharpness (calculated according to phicoefficient) and average Euclidean distance were used as the measures of the classification effectivity. The formalised selection of relevés was found to be highly effective, especially in the case of the calcicolous beech forests; it is therefore recommended that it be more widely used in the Central European scale. The approach is consistent with the traditional classification and can be used as a method of the same rank as the numerical classification methods for the delimiting of higher syntaxonomical units - although the most contrast units were obtained by TWINSPAN method. Here we present a diagnostic species combination of the calcicolous beech forests in the Slovak Carpathians, and a unified list of diagnostic species confirmed by all approaches is defined as well.Sorbus aria agg. was found to be the best diagnostic species. The calcicolous beech forests form a well differentiated and homogenous unit within beech dominated forest communities.