Piotr Skubała

Heavy metal sensitivity and bioconcentration in oribatid mites (Acari, Oribatida): Gradient study in meadow ecosystems

In this study we aimed to identify different reactions of oribatid species to heavy metal pollution and to measure concentrations of cadmium, zinc and copper in oribatid species sampled along a gradient. Oribatid mites were sampled seasonally during two years in five meadows located at different distances from the zinc smelter in the Olkusz District, southern Poland. Oribatids were shown to withstand critical metal concentration and established comparatively abundant and diverse communities. The highest abundance and species richness of oribatids were recorded in soils with moderate concentrations of heavy metals. Four different responses of oribatid species to heavy metal pollution were recognized. Heavy metals (Zn, Pb, Cd, Ni) and various physical (bulk density, field capacity, total porosity) and chemical (K(av), P(av), N, C, pH) factors were recognized as the structuring forces that influence the distribution of oribatid species. Analysis by atomic absorption spectrophotometry revealed large differences in metal body burdens among species. None of the species can be categorized as accumulators or non-accumulators of the heavy metals - the pattern depends on the metal. The process of bioconcentration of the toxic metal (regulated) and essential elements (accumulated) was generally different in the five oribatid species studied.

Do Decaying Logs Represent Habitat Islands? Oribatid Mite Communities in Dead Wood

Abstract. Oribatid mites are a characteristic element of soil fauna, but they are also found in decomposing wood. However, they are often absent from publications dealing with dead wood. A core question of our study was how much the mite fauna differs between dead wood and the forest floor and at different locations on dead wood. Three dead, fallen beech logs (in the third stage of decay) in the “Góra Chełm” Reserve (Jura Krakowsko-Czçstochowska, Silesian province, south Poland) were examined for log-inhabiting species of mites. Samples were collected at seven microhabitats from the logs and the ground surface adjacent to each log was also sampled. Forty-nine oribatid species (44%) were obligate members of the intra-log community. Our study revealed strong differentiation between oribatid fauna in different microhabitats of decaying logs. No statistically significant differences in oribatid communities in beech logs of the same stage of decay were observed. It may be concluded that oribatid mites are using logs as a separate habitat rather than as an extension of the forest floor.

Succession of oribatid fauna (Acari, Oribatida) in fallen spruce trees: Deadwood promotes species and functional diversity

The purpose of this study was to contribute to our understanding of oribatid mites inhabiting fallen logs, and to studysuccessional patterns in Oribatida associated with deadwood. This research was carried out in the spruce forest in theBabia G‘ora National Park, Carpathian Mountains. Per season, five samples of decaying wood were taken from fivedowned spruce logs of similar size. Forty soil and litter samples were additionally collected around logs. Overall 55,723specimens of oribatid mites belonging to 131 species were collected in 140 samples. Spruce deadwood is settled by arich mite fauna. It becomes a more rewarding food resource for mites as they tend to increase with log age, althoughthe maximum density was observed in log IV (i.e., the last but one decay class). It was both surprising and interestingto find that oribatid mite fauna in deadwood is not depauperated in comparison with forest soil. For oribatid miteslogs are a separate habitat rather than simply an extension of the forest floor. Some mite species may specialize ondeadwood, because 55 species (of 131 in total) were obligate members of the intra-log community. The structuringforces that influence the oribatid communities in their successional stages of decaying wood were variable anddependent on the stage of wood decay. Against our expectations wood feeders did not prefer deadwood over soilhabitat, whereas eurytopic and parthenogenetic species did not constitute a major part of the oribatid community inpioneer stages of wood decay.

Invasive giant knotweed (Fallopia sachalinensis) alters the composition of oribatid mite communities.

Abstract Plant invasions are a serious global threat to biodiversity and ecosystem stability. The invasive giant knotweed Fallopia sachalinensis (synonym: Reynoutria sachalinensis) is one of the most aggressive plant invaders in many countries. It forms dense stands that prevent other species from growing. To assess the impact of the knotweed, oribatid mite communities were studied under Fallopia-free native vegetation and at Fallopia-infested sites (2 types: 90-100% and 30% of coverage) with similar soil. All the sites are located in mixed forest in the Kraków-Częstochowa Upland (Jura Krakowsko-Częstochowska) in south Poland. Species composition and functional group composition of oribatid mite communities were compared. In total, 1540 specimens belonging to 70 oribatid species were collected from 90 soil samples. This successful exotic invasive species had a moderate influence on species richness (20% less species at the totally invaded site than at the Fallopia-free site) and a profound effect on soil oribatid mite community composition. Several oribatid species characteristic of a particular site were observed. Shifts were detected in proportions of groups with different habitat specificity (e.g. higher proportion of eurytopic mites at invaded sites), ecomorphological groups (e.g. lower proportion of litter-dwelling mites at invaded sites), trophic groups (e.g. lower proportion of macrophytophagous mites at invaded sites) and zoogeographical groups (e.g. higher proportion of mites with broad geographical distribution at invaded sites). These observations prove the radical negative change of environmental conditions for soil oribatid mites as a result of Fallopia invasion. The increase in sexually reproducing oribatid mites at invaded sites suggests that this way of reproduction is preferable when resources are in shortage.

Taxonomy of European Damaeidae (Acari: Oribatida) V. Redescription of Epidamaeus bituberculatus (Kulczynski, 1902)

ABSTRACT Epidamaeus bituberculatus (Kulczynski, 1902) – type species of the genus Epidamaeus Bulanova-Zachvatkina 1957 (Damaeidae) – is redescribed and illustrated in detail based on adult specimens collected in dead wood and tree hollows in natural forest in Upper Silesia, Poland. The species is characterized mainly by a single pair of postbothridial tubercles (Ba) on prodorsum; comparatively strong sensillus with slightly indicated subterminal expansion and blunt tip; fully developed propodoventral (E2a, E2p) and ventrosejugal (Va, Vp) enantiophyses. The neotype is designated, because the original type series is lost. The species seems to be comparatively rare and remained poorly known until present. At least part of the published records is probably based on confusion with other species of the genus.

Oribatid Mite Communities on Lichens in Heavily Contaminated Post-Smelting Dumps

In this study, we examined oribatid fauna of strongly contaminated post-smelting dumps (southern Poland) that exist in the substrate and are associated with the most frequent lichen, Cladonia rei. Due to artificial origin of the substrate and the extremely high contamination with heavy metals, the studied dumps are unique in Europe in terms of unfavourable life conditions. In total, 2,936 specimens of Oribatida, representing 50 oribatid species, were sampled on 10 dumps and a reference site. Thalli of C. rei act as an island for soil oribatid mites on extremely contaminated post-smelting dumps. Both abundance and species richness of oribatid fauna collected from C. rei thalli were significantly greater than those recorded in the dump’s substrate. The pool of oribatid species that was able to persist in extremely high doses of heavy metals was comparatively broad. However, only one species, Tectocepheus velatus, was able to achieve high abundances on all dumps. Three different responses of species (tolerant, sensitive, and indifferent) to heavy-metal contamination were recognised. Redundancy analysis indicated that highly increased levels of heavy metals, as well as K content, C/N ratio, and pH value, were the main factors that influence the composition and distribution of species. The concentrations of heavy metals (both essential elements (zinc) as well as xenobiotics (lead, cadmium) in T. velatus from the most contaminated dumps were not increased compared with those observed in moderately contaminated soils.

Communities of mites (Acari) in litter and soil under the invasive red oak (Quercus rubra L.) and native pedunculate oak (Q. robur L.)

Abstract Because of thoughtless decisions or unintentional introduction, alien species disturb native ecosystems. Red oak (Quercus rubra), among other alien woody plants, is still used to rehabilitate degraded land because of its better resistance to pollution and faster growth, as compared to native tree species. Soil mites, especially Oribatida, are good bioindicators of ecosystem disturbance, so the main goal of this study was to explore the influence of invasive and native oaks on mite communities. F orest stands dominated by 40-year-old Q. rubra or 35-year-old Q. robur were compared. Over 2300 soil mites were extracted from 20 soil and 20 litter samples. M ite densities in the communities were higher in red oak litter, which is probably a result of the thicker layer of shed leaves. Changes in species composition of oribatid communities were observed in litter, in contrast to a lack of differences in soil. These observations are consistent with other researches on invasive woody plants. W e expect that over time these changes will also be noticeable in the soil and will increase in litter.

Development of oribatid mite communities (Acari, Oribatida) on a mine dump

The oribatid mite fauna on the mine dump and in the adjacent mixed forest has been the subject of the study. Three study plots, differing in age and plant cover, have been chosen on the dump. A continuos increase in abundance of oribatids, species richness with successional stages was observed on the dump. After 20 years of the development the abundance and species richness on the mine dump was still 3–4 times lower than in the adjacent forest. The dissimilarity of species composition in the three communities on the dump was high. Many of the successional oribatid species have probably been transported from other biotopes than the neighbouring forest. The progressive importance of Sellnickochthonius immaculatus, S. cricoides, Liochthonius piluliferus in communities from the forest to the community at the youngest site indicates their special features that enable the mites to colonize unfavourable habitats. As indicated by Canonical Correspondence Analysis (CCA), the most important factor responsible for the development of the oribatid mite community on the mine dump was soil bulk density and available Mg content accompanied by water capacity. Graptoppia (Stenoppia) italica Bernini, 1973, Suctobelbella duplex (Strenzke, 1951), and Suctobelbella latirostris (Forsslund, 1941) were new species for the Polish fauna.

Oribatid communities and heavy metal bioaccumulation in selected species associated with lichens in a heavily contaminated habitat

The study examines oribatid communities and heavy metal bioaccumulation in selected species associated with different microhabitats of a post-smelting dump, i.e. three lichen species of Cladonia with various growth forms and the slag substrate. The abundance of oribatids collected from the substrate was significantly lower than observed in lichen thalli. The morphology and chemical properties of lichens, and to some extent varying concentrations of heavy metals in thalli, are probably responsible for significant differences in oribatid communities inhabiting different Cladonia species. Some oribatids demonstrate the ability to accumulate zinc and cadmium with unusual efficiency, whereas lead is the most effectively regulated element by all species. A positive correlation was found between Zn content in all studied oribatids and their microhabitats. Oribatids exploring different food resources, i.e. fungivorous and non-fungivorous grazers, show considerable differences in bioconcentrations of certain elements.

Nests of the harvest mouse (Micromys minutus) as habitat for invertebrates.

Abstract The nests of the harvest mouse (Micromys minutus) from an extensively used farmland in Western Poland were recognized as a place of occurrence of a large group of invertebrates. In total, from 42 nests 6,544 individuals of invertebrates were extracted. The number of invertebrates was positively correlated with mass of mouse nests. There were found arthropods belonging to the following groups: Arachnida: spiders, mites and pseudoscorpions; Entognatha: springtails; Insecta: Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, Psocoptera, Siphonaptera and Thysanoptera. The most numerous groups were mites (Acari, 5,800 individuals) and fleas (Siphonaptera, 415 individuals). Among mites Astigmatida, Mesostigmata and Oribatida were identified. One species, Tyrophagus curvipenis (Acari: Astigmatina), was found in Poland for the first time. The study clearly showed that nests of the harvest mouse are often inhabited by invertebrates, and looks like some of them are characteristic to this particular kind of habitat.