Ladislav Háněl

Soil biota and upper soil layer development in two contrasting post-mining chronosequences

Abstract Density and community composition of a wide spectrum of soil organisms (fungi, algae, testate amoebae, nematodes, enchytraeids, lumbricids, oribatid mites, diplopods, terrestrial isopods, collembolans and dipteran larvae), direct counts of bacteria, rate of cellulose decomposition and microstructure of upper soil layers were studied in two chronosequences of plots reclaimed from open-cast coal mining near Cottbus (Germany) and near Sokolov (Czech Republic). German plots were characterized by acidic sandy soils and afforested with pine, while the Czech plots possessed alkaline clay soils and were afforested with alder. In both chronosequences, density and species richness in most of investigated groups of soil biota gradually increased with increasing succession age. Typical pioneer species were found in initial stands of both chronosequences. Nevertheless, the initial stands supported poorer assemblages of soil biota in the Cottbus area than did those in the Sokolov area. The Cottbus area was characterized by a moor type of humus and by gradual uniform increase of abundances and species numbers of most studied groups of soil biota. On the contrary, moder type of humus and a more variable pattern of soil biota development during the course of succession were found in the Sokolov area. Slower development of soil biota in initial stages of succession in Cottbus is caused by unfavourable physical and chemical conditions of heap substrates, and by lower input and poor quality of litter in pine plantations.

Recovery of soil nematode populations from cropping stress by natural secondary succession to meadow land

The spectrum and densities of soil nematode species were studied in an extensively managed sub-thermophilous meadow and in conventionally managed and abandoned fallow fields left to natural succession. In the meadow, 115 species and 71 genera of soil nematodes were found and the total mean nematode abundance was 1019×103 individuals/m2. The dominant feeding groups were root-fungal feeders (31%, mainly Filenchus), bacterivores (26%; variety of genera, mainly Panagrolaimus, Rhabditis, Acrobeloides, Bursilla, Plectus, Anaplectus, and Eucephalobus), and fungivores (16%, Aphelenchoides). The cultivated field had 66 species and 41 genera of nematodes and a mean nematode abundance of 546×103 individuals/m2. The eudominant trophic group was bacterivores (53%; mainly Panagrolaimus and Acrobeloides) accompanied by fungivores (28%, Aphelenchoides). During 2 years of natural succession in an abandoned field, the total mean nematode abundance rose to 938×103 individuals/m2, and the number of species and genera increased to 73 and 46, respectively. Omnivores (25%, Aporcelaimellus and Eudorylaimus), fungivores (24%, Aphelenchus) and bacterivores (21%, Eucephalobus and Panagrolaimus) became the leading trophic groups, and the values of the Shannon Index of diversity and the Maturity Index increased. The development of soil nematode populations in the early successional stages of abandoned cambisol fields in Central Europe is discussed.

Development of soil nematode communities on coal-mining dumps in two different landscapes and reclamation practices

Soil nematodes were studied in two chronosequences of plots from open-cast coal-mining dumps near Cottbus (Germany, acidic tertiary sandy spoils afforested with pines) and near Sokolov (Czech Republic, alkaline tertiary clays afforested with alder). Nematodes at Sokolov developed more abundant and diverse communities with a high proportion of omnivores and plant parasites than those at Cottbus. The pH and spoil texture, amount of precipitation, litter accumulation and colonisation of dumps by plants and soil biota were probably important factors for different development of nematode assemblages in the regions compared.

Soil Food Web Changes during Spontaneous Succession at Post Mining Sites: A Possible Ecosystem Engineering Effect on Food Web Organization?

Parameters characterizing the structure of the decomposer food web, biomass of the soil microflora (bacteria and fungi) and soil micro-, meso- and macrofauna were studied at 14 non-reclaimed 1– 41-year-old post-mining sites near the town of Sokolov (Czech Republic). These observations on the decomposer food webs were compared with knowledge of vegetation and soil microstructure development from previous studies. The amount of carbon entering the food web increased with succession age in a similar way as the total amount of C in food web biomass and the number of functional groups in the food web. Connectance did not show any significant changes with succession age, however. In early stages of the succession, the bacterial channel dominated the food web. Later on, in shrub-dominated stands, the fungal channel took over. Even later, in the forest stage, the bacterial channel prevailed again. The best predictor of fungal bacterial ratio is thickness of fermentation layer. We argue that these changes correspond with changes in topsoil microstructure driven by a combination of plant organic matter input and engineering effects of earthworms. In early stages, soil is alkaline, and a discontinuous litter layer on the soil surface promotes bacterial biomass growth, so the bacterial food web channel can dominate. Litter accumulation on the soil surface supports the development of the fungal channel. In older stages, earthworms arrive, mix litter into the mineral soil and form an organo-mineral topsoil, which is beneficial for bacteria and enhances the bacterial food web channel.

Species and genera of soil nematodes in forest ecosystems of the Vihorlat Protected Landscape Area, Slovakia

SummaryFauna of soil nematodes was studied in three main forest types of the Vihorlat Mountains, Querceto-Fageto-Aceretum at Remetské Hámre (RH), Fagetum at Morské oko (MO), and Fageto-Aceretum at Sninský kameň (SK). Each forest type was represented by five sites. In total 198 species and 98 genera of soil nematodes were distinguished. Most species belonged to rare taxa with the frequency of occurrence lower than 50 %. The number of species and genera decreased from RH (167 species and 86 genera) through MO (115 and 68) to SK (87 and 51). Species and generic richness was significantly positively correlated with soil pH(H2O), negatively with altitude, soil moisture and Cox. Greater part of nematode species and genera belonged to microbivores and to the taxa with higher cp values of 3 – 5. We can conclude that rich nematode fauna indicated undisturbed forest soil condition, nevertheless, the richness decreased with increasing altitude.

Diversity of soil nematodes in meadows of the White Carpathians

SummarySoil nematodes were studied in 11 meadow sites in the White Carpathians. In total, 155 species and 86 genera were found but the composition of nematode assemblages in eastern and western side of the mountains differed. Most nematode species belonged to the orders Tylenchida (52), Dorylaimida (35) and Rhabditida (16), and to the trophic groups bacterivores (47), plant parasites (29) and omnivores (25). In individual sites and sampling dates the number of species varied in range 18–68, genera 18–52, H’spp 1.32–3.50, H’gen 1.31–3.21, T 1.79–5.70, MI 2.32–3.63, PPI 2.03–2.98, and ΣMI 2.20–3.50. Composition of nematode assemblages and their matrix classification indicated a low degree of anthropogenous disturbance to the meadows.

Soil nematodes inhabiting an original dry meadow and an abandoned vineyard in the National Park Seewinkel, Eastern Austria

SummaryNematode communities of cultivated vineyards showed characteristics typical for cultivated ecosystems, e.g. predominance of plant parasitic nematodes followed by bacterivores. The abandoned vineyard showed a reverse trophic structure: bacterivorous nematodes with short life cycles (cp 2) predominated and the population of plant parasites was small. The nematode trophic structure of the dry meadow was similar to the abandoned vineyard. Nevertheless, Principal Component Analysis (PCA) showed that differences in nematode communities were still detectable at the generic level, with some genera occurring solely in one or the other site (e.g. Xiphinema). Thus, soil nematodes indicated a recovery of primary production and decomposition processes in the formerly cultivated vineyard soil, because plant parasites consuming plant tissues decreased, and organic matter breakdown was slower, as in low-input grasslands. Communities of soil nematodes were also compared with intensively cultivated vineyards previously surveyed in Eastern Austria.

Composition and vertical distribution of free living and plant parasitic nematodes in hop gardens in the Czech Republic.

SummaryComposition and vertical distribution of soil nematode communities within soil profile were investigated in eight hop gardens in Czech Republic. In total, the presence of 78 nematode genera was confirmed. Genus Drilocephalobus (Coomans & Coomans, 1990) is new for fauna of the Czech Republic. The highest abundance of soil nematodes was found at a depth of 0–10 cm and declined with increasing depth of soil profile. The most dominant genus was Bitylenchus, followed by genera Acrobeloides, Ditylenchus, Chiloplacus and Cervidelus. Ten genera of plant parasitic nematodes were recorded: Bitylenchus (with prevalence of B. dubius), Helicotylenchus, Heterodera (with absolute prevalence of H. humuli), Geocenamus, Longidorella, Longidorus (only L. elongatus), Merlinius (with prevalence of M. brevidens), Paratylenchus and Pratylenchus. Low population densities of predators and omnivores, low values of the community indices (MI, ΣMI, SI, and CI), and high values of NCR, EI, and PPI/MI ratio indicated disturbed nematode communities in hop gardens and bacteria-dominated decomposition pathways in the soil food web.

Diversity and feeding strategies of soil microfauna along elevation gradients in Himalayan cold deserts

High-elevation cold deserts in Tibet and Himalaya are one of the most extreme environments. One consequence is that the diversity of macrofauna in this environment is often limited, and soil microorganisms have a more influential role in governing key surface and subsurface bioprocesses. High-elevation soil microfauna represent important components of cold ecosystems and dominant consumers of microbial communities. Still little is known about their diversity and distribution on the edge of their reproductive and metabolic abilities. In this study, we disentangle the impact of elevation and soil chemistry on diversity and distribution of rotifers, nematodes and tardigrades and their most frequent feeding strategies (microbial filter-feeders, bacterivores, fungivores, root-fungal feeders, omnivores) along two contrasting altitudinal gradients in Indian NW Himalaya (Zanskar transect from 3805 to 4714 m a.s.l.) and southwestern Tibet (Tso Moriri transect from 4477 to 6176 m a.s.l.), using a combination of multivariate analysis, variation partitioning and generalized additive models. Zanskar transect had higher precipitation, soil moisture, organic matter and available nutrients than dry Tso Moriri transect. In total, 40 species of nematodes, 19 rotifers and 1 tardigrade were discovered. Species richness and total abundance of rotifers and nematodes showed mid-elevation peaks in both investigated transects. The optimum for rotifers was found at higher elevation than for nematodes. Diversity and distribution of soil microfauna was best explained by soil nitrogen, phosphorus and organic matter. More fertile soils hosted more diverse and abundant faunal communities. In Tso Moriri, bacterivores represented 60% of all nematodes, fungivores 35%, root-fungal feeders 1% and omnivores 3%. For Zanskar the respective proportions were 21%, 13%, 56% and 9%. Elevational optima of different feeding strategies occurred in Zanskar in one elevation zone (4400–4500 m), while in Tso Moriri each feeding strategy had their unique optima with fungivores at 5300 m (steppes), bacterivores at 5500 m (alpine grassland), filter-feeders at 5600 m and predators and omnivores above 5700 m (subnival zone). Our results shed light on the diversity of microfauna in the high-elevation cold deserts and disentangle the role of different ecological filters in structuring microfaunal communities in the rapidly-warming Himalayas.

First description of the males of Aphelenchoides limberi Steiner, 1936 (Nematoda: Aphelenchina)

SummaryMales of Aphelenchoides limberi are described and illustrated for the first time from mushroom plate cultures of Botrytis cinerea. The original parthenogenetic population was extracted from the soil of a hop garden in Senice na Hané, Czech Republic. The males are characterized by a stylet about 11 μm long, a prominent spicula, with the dorsal limb longer than the ventral limb, and a ventrally curved tip. The tail is arcuate, conoid, ending with a short, mostly ventrally bent hook-shaped mucro, the lateral field appears to have four lines under light microscopy.