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The aim of this study was to describe the decomposition of litter along a successive series of sites developed at a post-mining overburden deposit over 12, 21 and 45 years, representing the early, mid and late stages of succession. Litter decomposition was largely dependent on the initial composition of the litters. The tree litter of the mid and late stages decomposed faster than the grass litter of the early stage, with 64, 60 and 35 % of mass lost over 2 years, respectively. The contents of hot-water-soluble C and N, which were the best predictors of litter decay rates, were relatively stable over time in all litters. Neither the nutrient content nor the plant biopolymer composition exhibited convergence during decay, indicating that the litter-derived soil organic matter most likely carries a legacy of the original vegetation. In contrast to the litter chemistry, the development of the microbial community was largely specific to the decay stage and consistent among the litters, showing decreasing fungal dominance in time. Extracellular enzymes were found to be of limited value in the prediction of litter decay rates, chemical transformation or microbial community composition.

Chemical composition of litter has previously been reported to affect in situ decomposition. To identify its effects on a single species level, the saprotrophic basidiomycete Hypholoma fasciculare was grown on 11 types of litter with variable chemical composition (N content of 3.4–28.9 mg g−1), and the mass loss of litter and lignin, production of extracellular enzymes and fungal biomass were followed. After 12 weeks, mass loss ranged from 16 % to 34 %. During early decomposition stages, litter mass loss, fungal biomass production (estimated by ergosterol content) as well as fungal substrate use efficiency all increased with increasing initial N content of the litter. The initial litter decomposition rate was significantly positively correlated with the activities of arylsulfatase, cellobiohydrolase, endoxylanase and phosphatase. Contrary to expectations, the lignin content did not affect litter mass loss, when covariation with N content was accounted for. The ratio of lignin loss to total mass loss depended on the litter type and did not reflect the activities of ligninolytic enzymes.

Y-chromosomal variation of Central European populations and the possible appearance of genetic isolates in these populations are of increasing interest to forensic and human population geneticists. Y-chromosomal data for the population of the Czech Republic is still fractional. Kracmarova et al published a short report on paleolithic and neolithic Y chromosomal haplogroups in the Czech population (1) and Luca et al performed a refined study of the same data (2). Zastera et al published a major study on Czech Y-chromosomal data (3). Other authors have also reported on Czech Y-chromosomal variation, usually with other population data from Europe (4-7). A recent study compared Czechs with other West Slavic populations (8). In this range of reports regarding, genetic variation of possible or confirmed genetic isolates within Central European populations is virtually absent. Here we present the intra-population diversity of such an isolated population, the Moravian Valachs. So far, a limited number of studies that illustrate the variety of Y-chromosomal polymorphisms in the countries and populations supposedly connected or similar to the Moravian Valachs – the supposed isolate – have been published. Rebala et al (9) focused on the Slavic population from Eastern and Central Europe. As historical sources suggest, immigration from Slavic populations was one of the major sources for the emergence of the Valach population of the Czech Republic, therefore the study of Rebala et al (9) is certainly of great interest to us, as well as other studies on southern European Slavic populations (10). Bosch et al (11) analyzed paternal (and maternal) lineages of the Aromuns and other surrounding Balkan populations, thus offering excellent material for their comparison with the Valachs. They clearly documented the differences between Aromuns (ie, isolated populations) and the major populations that surround them, not only in haplogroup and haplotype lineages, but also in intra-population genetic variability. The Valachs (or Wallachs/Vlachs as they are sometimes called) are one of the most distinct ethnographic and cultural subpopulations of Central Europe. Today, they can be found not only in the Czech Republic – in its eastern border mountain ranges and highlands (Beskydy in Moravia) – but also in south-southeast Poland and several parts of Slovakia (far western, northern, and central region). Originally, this group spread from the Maramures region of Romania, roughly following the Carpathian Mountain range. The arrival of the Valachs to the area of today’s Czech Republic took place at the very end of the 15th or beginning of the 16th century (12). The migration was not spontaneous, but rather encouraged and subsidized by the local nobility, and it lasted at least until the end of the 18th century, with immigrants supposedly coming not only from Romania, but also from Ukraine, Poland, and Slovakia (13). Until the beginning of the 20th century, the Moravian Valachs’ way of life was similar to other Romanian ethnic groups in the Balkans, especially the Aromuns (seasonal mountain sheep herding, production of cheese, wool, and leather products). An admixture of the newly-arrived Valachs with autochthonous (Slavic and German) Moravian population also began soon after the arrival of the first immigrants – so we can assume a steady genetic and cultural flow between these two populations. Nonetheless, the core of the Valach settlement was located in a previously uninhabited high altitude region, neighboring with the indigenous population from lowlands. The result of the admixture process was a complete merging of both populations, and the disappearance of any distinction between “new” Valachs and indigenous Moravians during the 18th century, and the creation of one ethnogeographic region with all its properties and people – the Moravian Valachs. Demographic data (13,14) show only a small increase in the Valach population during the 17-18th century. In combination with population depression during and after the Thirty Years' War (1618-1648), the conditions in the Valach population favored inbreeding, an effect reinforced by isolation-by-distance from the surrounding populations. To investigate how severe this isolation effect was on Y chromosomal polymorphisms in the Moravian Valachs and whether it is still detectable in modern Valach population is the main aim of our study. Another topic of interest was how the intra-population variability and the sampling bias can affect forensic and population analyses performed on these data.

Acid N depositions in the Bohemian Forest during the second half of the last century caused enormous soil acidification which led to the leaching of essential nutrients including nitrates. We investigated the effect of dissolved organic matter (DOM) and pH on the abundance of 16S RDNA, nirK and nirS gene copies in four spruce forest sites. Soil samples for molecular based quantification (qPCR) were taken from the organic litter and humus layers. The amounts of dissolved organic carbon (DOC) and dissolved nitrogen (DN) were much lower in highly acidified soils. We found a strong correlation between nirK denitrifiers and the amount of available P (r = 0.83, p

The role of litter composition and quality on the nutrient release was studied in three month laboratory experiment. Spruce needles and leaves of four species dominant in understorey vegetation of the Norway spruce forest were collected in early autumn and incubated at 5°C, 10°C and 15°C. C mineralization was measured every two weeks, concentration of NH4, NO3, dissolved organic N, dissolved organic C and oxalate extractable P at the beginning and end of incubation and decay rate and nutrient release was calculated. Freshly senescent leaves contained less N and P indicating nutrient reallocation. Effect of temperature on a decay rate and nutrient transformation was not significant while the effect of litter quality expressed by C/N ratio at the end of incubation was. The decay rate was the fastest for the fern (Athyrium alpestre) and decreased in order: Callamagrostis villosa > Vaccinium myrtillus > Avenella flexuosa > spruce needles. The critical C/N ratio bellow which mineral N was released in high amount was around a value of 32. The results indicte that an increase of coverage of understorey vegetation can increase a risk of nutrient release.