Oribatid Communities Research Articles

Vertical distribution of edaphic oribatid mites (Acari: Oribatida) in two artificial forests planted on temperate grasslands

Context Oribatid mites are the most abundant taxon in forest soils that rely on porosity and organic matter availability. Exotic forests of Pinus radiata and Eucalyptus globulus planted over native grasslands in the Pampas region of Argentina have produced modification in soil properties, which can affect the composition and structure of native oribatids communities. Aims To compare oribatid communities in soils under artificial woodlands of pine and eucalyptus and to assess the vertical distribution of oribatids in relation to edaphic variables. Methods In each forest, oribatids were collected from three levels of the A horizon: (1) litter layer; (2) 0–5 cm; and (3) 5–10 cm. Edaphic variables measured were penetration resistance, bulk density, total porosity, pH and water content and luminosity at soil level. Density, species richness, diversity and evenness of oribatids were calculated in each level of each forest. Comparisons were made through multivariate analyses. Key results Edaphic variables showed no significant differences between plots but litters were structurally different. Richness and diversity showed no differences between plots whereas evenness was significantly higher in plot P. Density had higher values in the litter layer of both forests. Canonical Analysis of Principal Coordinates (CAP) showed that Pine plots had a more defined vertical distribution. Conclusions The structure and composition of litters promoted differences in the vertical distribution of oribatids. In Pinus, thick unaltered litter showed a marked vertical gradient of mites along levels while in Eucalyptus, thin and easily decomposing litter, showed no vertical patterns. Implications Assessment and management of soil biodiversity in artificial woodlands.

Impacts of garlic mustard (Alliaria petiolata, Brassicaceae) invasion on oribatid mites in urban forest soils vary with the size of the invaded patch

Investment in non-native species management should be informed by knowledge of impact, including on native biodiversity and ecosystem function. Oribatid soil mites may be useful to evaluate the impacts of plant invasions since they are bioindicators of disturbance and soil ecosystem health. Still, more research is needed to characterize their responses to plant invasion, especially at the species level. Our objective was to determine the effect of invasion of urban forest understories by an allelopathic weed (garlic mustard, Alliaria petiolata (Brassicaceae)) on belowground oribatid mite species and communities. At two sites in central Alberta (Canada), over two years, we examined adult oribatid (≥ 300 µm) community assemblages, species richness, evenness, diversity, and abundance in plots invaded with garlic mustard and uninvaded plots with native vegetation. Environmental covariates known to be associated with soil invertebrate communities were also evaluated. Results suggest that the spatial extent of the garlic mustard invasion (patch area) mediates its impact on oribatid mite communities. However, there were no community-level impacts when considering invasion as binary (garlic mustard vs. native vegetation). Garlic mustard patch area influenced oribatid community composition and was positively related to species richness and several abundance metrics. The oribatid species we observed benefiting from garlic mustard invasion have been previously associated with disturbed soils. The mechanisms driving these patterns need more research, but we hypothesize they may relate to patch-specific resident times. Site was also a dominant factor influencing oribatid mite communities, and impacts of year, litter depth, and canopy cover were also detected at the species and/or community level. These findings contribute to our understanding of the impact of an invasive weed on bioindicating soil mite communities and species and highlight the importance of considering invasion context, including spatial extent when evaluating the impacts of invasive species on belowground invertebrate communities.

Taxonomic and ecological structure of oribatid mites (Acari: Oribatida) of mesophilic grasslands on the Transcarpathian lowland

The article analyzes the taxonomic diversity, dominance structure, spectra of morpho-ecological types, biotope complexes and groups of oribatid mites of mesophilic grasslands on Transcarpathian lowland. Prior to our works, there were almost no studies of the oribatid communities of the studied area. The research plots located on the sorrounding areas of the city of Mukachevo and the village of Kalnyk of the Mukachevo district. Soil samples selected for 2013-2014. The geographical coordinates of the first meadow are: 48º22.79' N, 22º40.14' E, and the second one is 48º30.86' N, 22º34.65' E. The total area of the first biotope is 0.45, and the second is 37.5 hectares. In relation to the humidity of the substrate, this type of biotope is characterized by mesophilic conditions. Extraction of mites from soil was carried out using Tullgren funnel method. Permanent preparations were prepared. Identification of the specimens was carried out using a microscope (Olympus BX 51). Oribatid mites of the investigated mesophilic grasslands are represented by 26 species from 22 genera and 16 families. The families Oppiidae and Scheloribatidae are the most represented. The average density of oribatid mites of the mesophilic grasslands on Transcarpathian lowland has relatively small values (3.7 thousand specimens per m2). The dominant species include Punctoribates punctum (C. L. Koch, 1839) and Ceratozetes mediocris Berlese, 1908. They together make up 44% of the total density of oribatids. Margalef, Menkhinik, Simpson, Shannon and Berger-Parker indices were calculated. 10 morpho-ecological types of oribatid mites were found on mesophilic grasslands. Oribatids - inhabitants of small soil crevices – predominate. Representatives of five biotope complexes (euryoecic, hygrophilous, hygro-mesophilous, mesophilous and xerophilous) and four biotope groups (eurytopic, forest, forest-meadow, meadow) were identified in the structure of ecological groups of Oribatids. Mesophilous and meadow species of oribatid mites have the largest share.

Patterns and drivers of soil surface-dwelling Oribatida diversity along an altitudinal gradient on the Changbai Mountain, China.

Distribution patterns of biodiversity and environmental interactions are dominant themes in ecology. In montane ecosystems, biodiversity is closely associated with altitudinal gradients. However, studies of biodiversity in montane ecosystems are focused on plants and vertebrates, with relatively less on invertebrates. Here, the present study used a Vortis arthropod suction sampler to explore the biodiversity patterns of soil surface-dwelling Oribatida and their drivers along an altitudinal gradient (600, 800, 1600, 2000, and 2300 m) from typical temperate forests, evergreen coniferous forests, subalpine birch forests to alpine tundra on the north slope of Changbai Mountain, Northeast China. Trichoribates berlesei, Platynothrus peltifer, and Oribatula tibialis were the dominant soil surface-dwelling species on Changbai Mountain. Generally, alpha diversity and beta diversity of soil surface-dwelling Oribatida decreased with the rising altitude, with a peaking density value at 2000 m. The result of beta diversity showed that the structures of community were more influenced by the species turnover component than the nestedness component. Nonmetric multidimensional scaling (NMDS) ordination showed that the community structure of soil surface-dwelling Oribatida varied significantly along the altitudinal gradient. The variance partitioning showed that the elevation and climatic conditions determined the soil surface-dwelling Oribatida community. Spatial filtering represented by geographic and elevation distances was particularly associated with soil surface-dwelling Oribatida community variation between altitudes on Changbai Mountain. However, the variation of the Oribatida community between adjacent altitudes was only associated with geographic distance. Our study provides supportive evidence for the biodiversity analyzing of soil surface-dwelling Oribatida in montane ecosystems along an altitudinal gradient.

Quantitative assessment of the dispersal of soil-dwelling oribatid mites via rodents in restored heathlands.

Heathland restoration using topsoil removal requires the re-colonization of above- and belowground communities. Oribatid mites play a key role in the comminution of organic matter and are frequently early colonizers during succession despite their limited mobility. Whereas the assembly of their communities may take decades, passive dispersal likely dominates colonization processes, but especially dispersal via other animals (phoresy) remains poorly studied. Compared to other potential hosts, movement habits and ecology of small rodents may provide dispersal advantages to oribatid communities. We studied dispersal of oribatid mites via small rodents in restored heathland sites of different age. We measured movement patterns of small rodents and extracted mites from their pelts and nests to estimate annual contributions of these rodents to the dispersal of oribatids. We also discussed phoretic estimates reported on other host groups as a reference. Probability estimates of oribatids in pelts and nests showed lower occurrence frequencies compared to other reported phoretic hosts. However, local rodent communities may aid the dispersal of up to 41,000 oribatid mites per year. We highlight the high diversity of oribatid species mounting rodents, unlike strong species-specific filters reported in other passive pathways. We found that over half (58%) of the oribatid species reproduced asexually and over a third (32%) had a soil-dwelling lifestyle. We also observed that rodents often travel short distances below 40 m, but occasionally reach distances of up to 100 m, especially in earlier successional stages. Synthesis and applications. Our results suggest that rodents may contribute to assembly processes of soil-dwelling oribatid communities given the slow turnover rate of this group in heathlands. This is accomplished through short-distance dispersal, and especially in sites at early stages of succession. To our knowledge, we are the first to quantitatively assess the potential dispersal of oribatid mites via rodents.

Oribatida in New Zealand alpine environments

New Zealand’s soil biota is diverse and unusual, and has high levels of species endemism. Soil microarthropods are the major (and least studied) part of NZ land fauna, yet changes in their biodiversity are often difficult to quantify, because the baseline data are lacking. Data on alpine fauna and flora are a priority in preserving NZ biological heritage, as they are vulnerable to range contraction and higher-altitude displacement due to climate warming. In this presentation we briefly summarize the gaps and challenges in our knowledge of NZ alpine invertebrate biodiversity. The patterns in diversity and community structure of soil Oribatida in the alpine zone vs. upland forests are discussed using spatially-explicit data from several alpine regions of the South Island. Focusing on environmental and spatial analysis, we answer several questions: 1) is alpine plant diversity a significant driver for oribatid species diversity in the high alpine, and if not, what is? 2) Did limited dispersal and habitat fragmentation during Pliocene mountain building and Pleistocene glaciation produce regionally unique alpine communities, or is the alpine fauna a generic depauperate fragment of communities below treeline? 3) What is the scale of species turnover patterns across the alpine landscape? There is also an interesting opportunity to compare oribatid communities of alpine New Zealand with those bearing similar ecophysiological challenges in the Northern Hemisphere.

Soil-biological methods in monitoring the processes of turning the steppe into a meadow near lake ecosystems of Khakassia

The article analyzes the results of the study of microbiological and zoological components in the soils of lake territories in the steppe zone of the Khakassia Republic. It is shown that the transformation of the zoo-microbial complex of the southern chernozem in the process of turning the steppe into a meadow occurs along the way of reducing the biomass of soil microorganisms and a sharp increase in the total and specific metabolic activity of this biomass. At the same time, a sharp decrease in the number of oribatids occurs in the process of turning the steppe into a meadow, with the practical immutability of species richness. At the same time, the composition of the oribatid community is undergoing a radical transformation. These changes in the zoo-microbial complex are associated with changes in the level of soil moisture. The conducted research demonstrated that the identified features of the studied biological and soil indicators (microbiomass, respiration of biomass and metabolic coefficient, the number and species richness of oribatid mites) can be successfully used in the practice of monitoring the process of turning the steppe into a meadow on lake territories in the steppe zone of the Khakassia Republic.

High Diversity of Mites (Acari: Oribatida, Mesostigmata) Supports the High Conservation Value of a Broadleaf Forest in Eastern Norway

Broadleaf forests are critical habitats for biodiversity and this biodiversity is in turn essential for their proper functioning. Mites (Acari) are a numerous and functionally essential component of these forests. We report the diversity of two important groups, Oribatida and Mesostigmata, in a broadleaf forest in Eastern Norway which is considered to be a biodiversity hotspot. Eighteen samples, each 500 cm3, were collected from diverse microhabitats (moss on ground, lichens on tree twigs lying on ground, moss on tree trunks at ground level, moss on tree trunks 1.5 m above ground, moss on decaying stump, moss on decaying log, and decaying wood from trees) from which 10,843 specimens and 95 species from 32 families of Oribatida, and 655 specimens of 34 species from 14 families of Mesostigmata were found. Only 30% of the species were previously recorded in broadleaf forests in Western Norway. Oribatid communities on decaying stump and in lichens were distinct from the other communities, while mesostigmatid communities on tree trunks (both at ground level and 1.5 m above ground) and in lichens differed most from other communities. Over 30% of the species were found in only a single microhabitat. Twenty-three species and the genus Zerconopsis are reported from Norway for the first time. Six records are also new to Fennoscandia, including (Oribatida) Coronoquadroppia monstruosa, Eueremaeus valkanovi, Ramusella furcata, and (Mesostigmata) Dendrolaelaps rectus, D. multidentatus, and D. tenuipilus. In addition, several rare species were detected, e.g., Achipteria magna, Oribotritia berlesei, and Subiasella quadrimaculata, and two were found in their northernmost locality (O. berlesei, E. valkanovi). These results confirm the unique character and high conservation value of the studied forest in Norway, Fennoscandia and at a European scale.

Soil microarthropods respond differently to simulated drought in organic and conventional farming systems.

In Central Europe, summer droughts are increasing in frequency which threatens production and biodiversity in agroecosystems. The potential of different farming systems to mitigate detrimental drought effects on soil animals is largely unknown. We investigated the effects of simulated drought on the abundance and community composition of soil microarthropods (Collembola and Oribatida and Meso‐, Pro‐, and Astigmata) in winter wheat fields under long‐term conventional and organic farming in the DOK trial, Switzerland. We simulated drought by excluding 65% of the ambient precipitation during the wheat‐growing season from March to June 2017. The abundance of Collembola and Oribatida declined more consistently in conventionally managed fields compared to organically managed fields under simulated drought. The abundance of Collembola as well as Meso‐, Pro‐ and Astigmata, but not the abundance of Oribatida, increased in deeper soil layers due to simulated drought, suggesting vertical migration as a drought avoidance strategy. The species composition of Oribatida communities, but not of Collembola communities, differed significantly between drought treatments and between farming systems. Soil carbon content was a major factor structuring Oribatida communities. Our results suggest that organic farming buffers negative effects of drought on soil microarthropods, presumably due to higher soil carbon content and associated higher soil moisture and improved soil structure. This potential of organic farming systems to mitigate consequences of future droughts on soil biodiversity is promising and needs further exploration across larger climatic and spatial scales and should be extended to other groups of soil biota.

The changes in ecological structure of oribatid mites (Oribatida) communities under the influence of anthropogenic factors on Transcarpathian Lowland

The peculiarities of changes in the ecological structure of oribatid communities under the influence of anthropogenic factors (grazing and hydromelioration) in the conditions of the Transcarpathian Lowland are considered in the work. In particular, the changes in the structure of mopho-ecological types (adaptive types), biotope groups and complexes according to the hygropreferendum, which occur due to the transformation of biotopes, are analyzed. It is established that hydromelioration and grazing leads to various tendency changes, which in turn are related to the peculiarities of the biology of specific species of oribatids and the specifics of the action of the studied factors.

The first report on the oribatid mites (Acari: Oribatida) in tundra of the Chunatundra Mountains on the Kola Peninsula, Russia

The aim of this research was to obtain initial data on the fauna and abundance of the oribatid mites from the main types of the mountain tundra habitats of the Chunatundra Mountains. Four plots, including two lichen tundra plots, one dwarf shrub tundra plot and one sphagnum bog in the belt of mountain tundra were investigated. Multidimensional scaling and discriminant function analysis were used to identify trends in the fauna and abundance of oribatid species through the explored plots. A total of 70 species and one subspecies from 37 genera and 24 families were found during the course of this investigation. Nine species, one subspecies, one genus and one family of oribatid mites have been added to the fauna of the Kola Peninsula. The families Brachychthoniidae, Oppiidae and Suctobelbidae are the most diverse in the discovered local fauna. According to literature data, the first two families are characteristic of the low tundra communities, the third family is more common for the boreal zone. The discovered oribatid fauna is similar to the fauna of other tundra sites of the Kola Peninsula studied previously and is significantly different to the local oribatid mite faunae of the Scandinavian Peninsula. The abundance of the adult oribatid mites reached 39 080 ind./m2 in the lichen tundra and 56 200 ind./m2 in the dwarf shrub tundra. The minimum abundance of oribatid mites, 18 640 ind./m2 was found in the sphagnum bog. Differences in the oribatid mite complexes of lichen tundra, dwarf shrub tundra and the sphagnum bog were found. The species Carabodes labyrinthicus, Nothrus borussicus, Sellnickochthonius immaculatus, Mycobates sarekensis, and Tectocepheus velatus were associated with the lichen tundra habitats. Nanhermannia sellnicki, Chamobates borealis and a few species of Oppiella and Suctobelbella were associated with the dwarf shrub tundra. Mucronothrus nasalis, Limnozetes ciliatus, Platynothrus peltifer, Trimalaconothrus foveolatus, Limnozetes cf. rugosus, and Trimalaconothrus maior are most characteristic of the sphagnum bog. The family Suctobelbidae was represented by a large number of species, while the families Ceratozetidae and Camisiidae were much less diverse. The low diversity of Ceratozetidae, a high diversity of Suctobelbidae and relatively high abundance of oribatid mites in the explored tundra habitats may be explained by an ambivalent nature of the oribatid community, which combines boreal and arctic features due to marine climate. Also, this result may be a feature of a local mountain tundra which is surrounded by the underlying belts of the mountain forests that are a source of the increasingly diversity of species.

The first report on oribatid mites in tundra belts of the Lovozersky Mountains on the Kola Peninsula, Russia

The fauna of oribatid mites (Acari, Oribatida) in the mountain tundra on the Kola Peninsula (Russia) is still poorly studied. The main aim of this research is to obtain initial data on the fauna and abundance of oribatid mites of the Lovozersky Mountains. We investigated five plots, including three lichen tundra plots, one dwarf shrub tundra plot and one wetted tundra plot in one of the largest mountain massifs of the Kola Peninsula — the Lovozersky Mountains. Multidimensional scaling and discriminant function analysis were used to identify some trends in the fauna and abundance of species on the explored plots. The abundance of oribatid mites in the lichen tundra reached 23,680 ind./m2. In the dwarf shrub tundra, this value is over three times higher — up to 81,160 ind./m2, which is comparable with the oribatid mite abundance of forest habitats. The minimum values were discovered in wetted tundra (6,200 ind./m2). A total of 71 species, 38 genera, and 24 families of oribatid mites were found during the course of this study. Eight species of Oribatida have been added to the fauna of the Kola Peninsula. A significant difference was observed in the structure of oribatid faunas of the explored habitats. The occurrence in samples and relative abundance of Mycobates sarekensis, Oribatula amblyptera, Tectocepheus velatus and Carabodes labyrinthicus increased in lichen tundra compared to dwarf shrub tundra. Species of Suctobelbidae and Oppiidae were higher in occurrence and relative abundance in dwarf shrub tundra compared to lichen tundra. The occurrence and relative abundance of Trimalaconothrus angulatus, T. maior and Platynothrus peltifer prevailed in wetted tundra as compared to automorphic tundra habitats. The family Suctobelbidae was represented by a large number of species, while the family Ceratozetidae showed a small number of species in the discovered fauna. According to the literature, these features of the fauna are unusual for tundra. A low diversity of Ceratozetidae, a high diversity of Suctobelbidae and high abundance of oribatid mites in dwarf shrub tundra may be explained by the ambivalent nature of the oribatid community in the explored region, which combines boreal and arctic features due to marine climate.

Morpho-ecological structure of oribatid mite (Acariformes, Oribatida) communities in the forest litter of recultivated areas

The study of morpho-ecological organization of oribatid mite communities (Acariformes, Oribatida) inhabiting forest litter of recultivated areas in steppe zone conditions of Ukraine was performed. The role of the forest and forest floor litter in optimization of the ecological situation on degraded lands was demonstrated. The function of environment creation by oribatids, as primary destructors of dead plant matter, supporting such ecosystem services as soil fertility improvement and nutrients turnover was highlighted. The research was performed within different stratigraphic types of bulk edaphotops in the recultivated plot of “Pavlogradskaya” colliery (Pavlograd, Dnipropetrovsk region, Ukraine) planted with red juniper (Juniperus virginiana L.). Withdrawal and collection of mites was performed with thermoeclector. For determination of the domination structure in the mite communities, the Engelmann scale was used. Adaptive (morpho-ecological) groups of oribatid mites were diagnosed by Krivolutsky. It was established that the number of species of oribatid mites in the forest litter of the studied red juniper plantation varied from 16 to 25. Average density of oribatid mites varied from 4,720 to 25,327 ind./m2. Among such morpho-ecological groups as soil surface inhabitants, small soil pore inhabitants, deep soil forms, floor litter inhabitants and unspecified forms, identified in the coniferous litter, the share of unspecified forms increased from loess-like loam type (21% of total amount) to Calcic Chernozem types with different stratigraphy (41.0%, 70.0% and 70.4% accordingly). Deep soil forms in the forest floor litter of the studied red juniper plots were not identified for any of recultivation types. The obtained results expand our understanding of the role of oribatid mites in the processes of ecological rehabilitation of disturbed ecosystems in the conditions of modern nature management.

Diverse Sphagnum Mosses Support Rich Moss Mite Communities (Acari, Oribatida) in Mires of Western Norway

A study of oribatid mites was carried out in six mires located in western, oceanic parts of Norway. Twenty Sphagnum species of five subgenera were collected from microhabitats representing trophic state and wetness gradients. In total, over 60,000 mites were extracted, including 58,000 Oribatida, representing 95 species (i.e. 30% of total species diversity of Oribatida in Norway). This is the highest number ever reported from mires, including 18 species new to Norway. The average density of the Oribatida was 54,126 ind./m2, but it differed among Sphagnum subgenera, being four times lower in the subgenus Rigida than in the other subgenera. Juveniles contributed nearly 40% of oribatids, in some species highly dominating in the age structure (up to 80% in Nothrus spp.), and two oribatid species were represented only by juveniles, so their inclusion is important in ecological studies. In some species the proportion of juveniles varied between the studied microhabitats. Localities, Sphagnum subgenera, and wetness gradient affected significantly the oribatid communities, so these factors should be taken into consideration in studies of the Oribatida in mires.

Trees in trimmed hedgerows but not tree health increase diversity of oribatid mite communities in intensively managed agricultural land

Hedgerows structure agricultural landscape worldwide but little is known on their soil communities. In the intensively managed agricultural landscapes of Ireland and the UK, hedgerows protect soil from degradation and are thought to provide a reservoir of soil biodiversity for the farmed fields. But hedgerows are currently threatened by emergent tree diseases spread with rising volumes of trade in plants. This study analysed the effect of the most dominant hedgerow tree species on the composition and diversity of soil communities, which we estimated with oribatid mites in the context of an imminent ash dieback outbreak in Northern Ireland. We hypothesised that the environmental heterogeneity created by different tree species and good tree health are beneficial to the abundance and diversity of these soil communities. We found that communities differ, both in terms of species composition and relative abundances, between different trees in the trimmed hedgerows, and between untrimmed and trimmed hedgerows. The presence of trees was associated with more variable species composition. The analysis of phospholipid fatty acids (PLFA) showed that pasture and adjacent hedgerows were dominated by bacteria but there was no clear relationship between bacterial biomass and oribatid abundance or richness. However, changes in bacterial PLFAs were correlated positively with changes in oribatid community composition. Soil under ash trees which were diseased supported a higher species richness and greater abundance of oribatids than healthy trees. We conclude that the presence of different tree species in hedgerows adds to the overall diversity of soil hedgerow communities and hypothesise that the structural heterogeneity created by tree canopy drives increased diversity. Ill health in ash trees is currently positively affecting oribatid communities, possibly due to the temporarily increase in organic matter in soil. The epidemic of ash dieback, however, is expected to kill and remove trees in the medium term and so reduce soil community diversity in the long term.

Microhabitat distribution of arboreal oribatid mites (Oribatida), associated with the Siberian pine (Pinus sibirica) of Western Siberia.

The species composition of arboreal oribatid mites that live on Siberian pine trees (Pinus sibirica) in the forest-tundra of Western Siberia was examined, specifically of three Siberian pines from two distinct forest stands (six trees in total). Samples of litter were taken near the tree trunk, as well as samples of bark, branches and needles from the tree. In total 144 samples were taken, from which close to 5000 mites were extracted. From the arboreal samples, the mites were extract by heptane flotation. Three species of oribatid mites were recorded for the first time in Russia: Diapterobates brevidentatus, Eueremaeus trionus and Cultroribula berolina. The highest density and the highest dominance index of these species were recorded in arboreal microhabitats. Thirty-one species of oribatid mites were identified in total. No oribatid mites were recovered from the needles of Siberian pine. The density of oribatid mites did not significantly differ among various heights of the crown and trunk. The lowest density of mites was recorded on young branches without needles, whereas other branch hypothetical microhabitats did not significantly differ from each other in terms of oribatid density. The greatest Simpson diversity index was recorded in the plant litter near tree trunks. On trees, the diversity index decreased with the height of the trunk and with the distance of branch sections from the trunk. The dominant species and the degree of their dominance varied among microhabitats and forest stands. Additionally, a high level of dominance of a single oribatid species was observed on tree branches, as well as on the trunk bark located above the bole. In the two forest stands, these species were D. brevidentatus and Ameronothrus dubinini. Based on the analysis of oribatid communities, three microhabitats were identified in the first forest stand: the bole bark, the bark of the trunk above the bole, and the branches. In the second forest stand, bases of tree branches were identified as an additional microhabitat. Oribatids inhabit Siberian pine trees in the severe conditions of the forest-tundra. Arboreal oribatid communities of various microhabitats vary in their qualitative and quantitative characteristics. Also, arboreal and forest litter communities of oribatid mites vary significantly.

The impacts of forest clear felling on the oribatid mite fauna inhabiting Formica aquilonia nest mounds

The ubiquitous soil-dwelling oribatid mites have long been investigated as potential bioindicator agents for environmental changes, such as those resulting from forest management. However, the oribatid community composition often lacks detectable changes, mainly due to the difficulties of finding homogenous microhabitats from the landscape for investigation purposes. Red wood ant nest mounds in boreal forests, however, form uniform, moisture, and temperature regulated, microhabitats of which are also inhabited by a rather characteristic oribatid fauna. With this standardized microhabitat—the red wood ant Formica aquilonia nest mounds in Finland—we studied the impacts of forest clear felling on the oribatid mites inhabiting those nests. We compared the oribatid assemblages of altogether 41 ant mounds, located in three separate clear fell areas and in adjacent mature coniferous forest. A total of 16,499 specimens, representing 67 oribatid species, were observed. The ten most abundant species represented 90.9% of the total abundance. The oribatid species richness was significantly lower in clear fell mounds and was positively related to the surface moisture content of the mounds. Oribatid abundance or community composition did not markedly differ between clear fell and forest mounds. Despite the attempt to standardize the microhabitat of oribatid fauna, the use of oribatid mites as biological indicators of harvesting disturbance was limited with this study design due the lack of changes in community composition. Then again, the oribatid species richness of this characteristic microhabitat may provide useable quality measures about the harms of forest clear felling.

Distribution of Oribatida (Acari) along a depth gradient in forested scree slopes

Mesovoid shallow substratum (MSS) of scree slopes constitutes a transition habitat between the soil and the network of voids in the vadose zone of a bedrock massif. In the present study, the vertical distribution of oribatid communities along a depth of 95 cm was studied at five forested MSS sites in the Western Carpathians, Slovakia. The sites differed in type of bedrock, topography and gradient of the microclimate and nutrients content. In all, 909 specimens were captured in subterranean traps exposed for one year. Most Oribatida represented edaphic forms, and their presence in the depth profile of the screes was accidental. Pantelozetes cavatica (Kunst, 1962) was the only species closely linked to deep subterranean environments found in the deeper part of the single limestone site studied. Species richness and the activity of oribatids along the scree profile at the sites clearly reflected the content of organic carbon in the soil substratum. The communities had very low numbers of individuals and low species richness at three sites with soil pH < 7 and organic carbon content in the upper soil layer ≤ 10%. However, they differed markedly in internal temperature dynamics. The other two sites, with a slightly alkaline soil pH and a higher carbon content, showed distinctly higher activity and a relatively uniform pattern of oribatid distribution across the depth profile. The soil pH and organic carbon content in the topsoil layer were substantial factors that determined the Oribatida diversity and vertical distribution in the forested screes.

Oribatida (Acari) communities in arable soils formed under waterlogged conditions: the influence of a soil moisture gradient

Oribatid mites make up a dominant group of soil mesofauna. These microarthropods are quite rarely researched in heavy clay soils, and their seasonal dynamics has never been studied thoroughly during the year in such an environment. The research was conducted in 1994–1995 at three sites along a small-scale moisture gradient, with the aim of describing the influence of different moisture conditions on this soil mesofaunal group and evaluating their seasonal dynamics regarding temperature and soil humidity fluctuations. The study area was characterized by a land depression in a field with clay soil, where waterlogged periods occurred, in the Eastern Slovak Lowland (Slovakia). The investigations were based on 24,890 oribatid adults from 72 species. The mean abundance and total species richness of Oribatida increased with increasing soil moisture towards the lower part of the land depression. The abundance and number of species reached a maximum at the bottom site (ca. 8000 ind.m−2 and 59 species) and was two-fold greater than at the summit site. The mean oribatid abundance and the mean species richness between the sites were compared, and significant differences were found on almost all sampling occasions, but the patterns of changes along the moisture gradient differed between study years. The seasonal fluctuations of oribatid abundance within the sites showed a pattern with spring and autumn maxima and a summer minimum only at moist depression bottom. Seasonal changes in the oribatid community composition were more pronounced at sites with lower soil moisture. Specific communities consisting of hygrophilous or eurytopic species and located at the bottom and slope sites of the depression clearly differed from those of the summit site, where xerotolerant species predominated. Ordination analysis confirmed the influence of temperature and precipitation on the species community composition. The bottom and slope site communities were dominated by the species combination of hygrophilous Microppia minus, Oxyoppia europaea and hygrotolerant Oppiella nova, while at the summit site these mites were replaced by more xerotolerant species: Ramusella insculpta, Oppiella obsoleta and Tectocepheus velatus.

Species diversity of Oribatida mite community (Acari: Oribatida) by soil types and habitats in the Red river delta, Viet Nam

Research was undertaken from 2013 to 2017, in eleven provinces and cities, in the Red river delta, Vietnam. Samples were collected from fives types of habitat as follow: natural forest, human – disturbed forest, grassland, cultivated land with perennial plants, agricultural land with annual plants. Samples were also taken from five types of soil: coastal saline - acid soil, acid alluvial soil, neutral alluvial soil, ferritic brownish soil derived from limestone and emaciated greyish soil. In this research, we recorded 283 oribatida species, beloning to 129 genus, 59 families. Among them, 49 species were not defined to species. In comparison with the recordes of Vu Quang Manh (2013) and Ermilov (2015), there are 108 species were for the first time recorded for research region fauna and 65 speciesare new for the Vietnamese fauna. Species diversity of oribatida community in each type of soil and in each habitat are different from each others. The species number in each soil type oscillated from 78 species to 178 species. The species number in each habitat oscillated from 95 species to 127 species. The rate of species which only were recorded in one type of soil or in one habitat is high. The results show that soil types and habitats are in close relationship with oribatida community. It is the scientific base for using oribatida community as a biodiversity for soil quality.