Differences in top-soil features between beech-mixture and Norway spruce forests of the Šumava Mts.

Top-soil samples were taken from four mountain forest ecosystems in the Bohemian Forest to compare the processes in European beech-mixture (Fs) and Norway spruce (Pa) dominating ecosystems. Selected plots can be grouped into two types of forest ecosystems which are conditioned by position on the natural altitudinal gradient. Several chemical features (content of organic matter, properties of humic and fulvic acids, releasable P, Ca, Mg, Fe and Al content) were compared with the species structure of oribatid mite communities in the same samples. Strict differences between both ecosystem types were discovered. Statistically significant differences were detected in Mg content (0.42 mg/g in Fs ecosystems compared to 0.30 mg/g in Pa ecosystems) and in organic matter quality (the ratio of carbon content in humic acids to carbon content in total humus acids was 0.53 in Fs ecosystems and 0.66 in Pa ecosystems) and quantity (e.g. content of humic acid carbon was 59 and 86 mg/g in Fs and Pa ecosystems, respectively). Different dynamics of organic matter decomposition and nutrient movement lead to some opposite correlations among the soil chemical features: correlation between total ash and soluble ash (r = +0.96 and -0.86 in the Fs and Pa ecosystems, respectively) and total ash - P content correlation (r = +0.76 and -0.92 in the Fs and Pa ecosystems, respectively) can be mentioned as examples. The oribatid mite communities are markedly distinct in both ecosystem types, although parameters of species diversity and abundance are similar. Different correlations were revealed between the parameters of mite community structure (e.g. species diversity and total mite abundance) and top-soil chemical features. The correlation structure is different in both ecosystem types. It indicates differences in leading variables determining the oribatid community structure in the beech mixture ecosystem or in the Norway spruce one.