Ellenberg-type indicator values for the Czech flora

A new dataset of ecological indicator values for species, subspecies and some varieties, hybrids and infrageneric species groups has been compiled for the vascular flora of the Czech Republic. Indicator values for light, temperature, moisture, (soil) reaction, nutrient availability and salinity were assigned to 2275 species and 801 other taxa, using the nine-degree (or 12-degree for moisture and 10-degree for salinity) ordinal scales proposed by Heinz Ellenberg for the flora of Germany. The values are compatible with Ellenberg indicator values, which were used as a baseline, but extensively revised based on our own field observations, literature, comparison with indicator value systems of other countries and an analysis of taxon co-occurrences in vegetation plots from the Czech National Phytosociological Database. Taxa in the Czech flora missing in the original Ellenberg tables were added. Compared with the original Ellenberg's dataset of indicator values, smaller proportions of taxa were classified as extremely basiphilous, extremely oligotrophic or strictly avoiding saline habitats. The revised values were tested by regressing unweighted site mean indicator values against measured environmental variables. In most cases, prediction of environmental conditions was slightly more accurate with the new Czech indicator values than with the original Ellenberg indicator values. The full dataset of indicator values is available in an electronic appendix to this paper.