Soil Mites Research Articles

Distribution pattern and driving factors of mite communities in karst cave ecosystems.

Mites are among the most abundant invertebrates in subsurface ecosystems, and their community assemblages and distributions are often significantly influenced by the diversity of habitat resources. The cave ecosystem encompasses drastic changes in nonbiological factors, such as changes in lighting conditions from bright to extraordinarily dark and habitat gradients of surface plant resources from abundant to scarce or even disappearing, providing an ideal unique environment for evaluating the assembly mechanism of soil animal communities. Nevertheless, there still needs to be a sufficient understanding of the biodiversity patterns and drivers of mite communities across environmental gradients in karst caves. We conducted a comprehensive survey on the composition and diversity of soil mites in three photometric zones (dark, twilight, and light) of a typical karst cave and its adjoining extractive environments (forest scrub and farmland). Our research aimed to investigate the ecological relationships of mite communities between above- and below-ground habitats and the effects of abiotic factors on mite communities. We collected 49 families, 86 genera, and 1284 mites. In the external cave environment, we captured 1052 mites from 72 genera and 45 families; in the internal cave environment, we captured 232 mites from 46 genera and 29 families. The abundance, richness of genera, and diversity parameters of the mite community decreased from the cave entrance to the cave interior with decreasing light intensity. Oribatid mites dominated the mite community. Protoribates and Scheloribates were the dominant genera, along with Tectocepheus and 11 other genera, which primarily distinguished the mite communities among different habitats. Forty endemic taxa were found in the external cave environment, compared to 14 endemic taxa in the internal cave environment. The mite community showed a strong preference for the cave ecosystem habitat. Temperature, humidity, and soil nitrogen content significantly influenced the distribution pattern of mite communities (VIP > 0.8, p < 0.05).

Cyclobutrifluram (TYMIRIUM® technology): Low risks of a soil applied nematicide and fungicide to non-target soil invertebrates and bees

Cyclobutrifluram (TYMIRIUM® technology) is a seed- and soil-applied nematicide and fungicide which protects the plant root mass. Cyclobutrifluram acts by inhibiting mitochondrial complex II electron transport and succinate dehydrogenase inhibition (SDHI). Concerns over the potential adverse effects on non-target species were addressed by assessing whether recommended field application rates of cyclobutrifluram would result in adverse impacts on soil invertebrates or honeybees. Studies conducted under laboratory conditions with the active ingredient and two formulations provided No Observed Effect Concentrations for earthworm (Eisenia andreii) reproduction of 71–171 mg a.i./kg dry soil with no effects on soil mite (Hypoaspis aculifier) reproduction. There were no effects on honeybee (Apis mellifera) adults or larvae following chronic exposure to doses up to 400 and 160 mg/kg diet respectively. Using Brazil as a target market (soybean seed treatment and in-furrow application in fruiting vegetables), our laboratory studies indicate that the risk to two species of soil invertebrates and honeybees of the use of cyclobutrifluram either in-furrow or as a seed treatment was orders of magnitude below any levels of concern.

Free-living mites (Acari) of the Shokalsky Island, off the northern Gyda Peninsula, Kara Sea, High Arctic

The fauna of free-living mites of the Shokalsky Island, off the Gyda Peninsula, Kara Sea, totals at least 81 species belonging to 36 families. The suborder Prostigmata includes 38 species, vs 18 of Oribatida, 17 of Mesostigmata, 5 of Endeostigmata, and 3 of Astigmata. The most species-rich families are Ascidae (9 species), Eupodidae (7), Tarsonemidae (4), and Ceratozetidae (4). However, most genera (77%) are represented by one species only. Among mites identified to the species level, the Holarctic species prevail which show mainly arctic, arctic-montane, and arctic-boreal distribution patterns. The abundance of soil mites varies with 10160–299440 ind./m&lt;sup&gt;2&lt;/sup&gt;, being the maximum in the soil of both dryad tundra and in a polar fox den on a hillock. Prostigmata are the most diverse mite group throughout, but the dominant species include either prostigmatic or endeostigmatic, or oribatid mites. The rare species, Charadracarus hurdi Newell, 1960, hitherto known only from Point Barrow, Alaska, has been found for the first time since its original description. Some features of the acarofauna of the Shokalsky Island are transitional between those characteristics of the polar desert and tundra zones.

Soil mite communities (Acari: Gamasina) from different ecosystem types from Romania

The study aimed to characterize the distribution of soil mite populations (Acari: Gamasina) from several terrestrial ecosystems, some of them little studied in Romania as well as in Europe. We studied the Gamasina communities in seven ecosystem types from the Doftana Valley, Prahova County: Luzulo-Fagetum beech forest; Medio-European limestone beech forest of the Cephalanthero-Fagion; Pannonic woods with Quercus petraea and Carpinus betulus; Galio-carpinetum oak – hornbeam forests; Alpine rivers and their ligneous vegetation with Myricaria germanica; alluvial shrub, characteristic for a hilly-mountain area, with Salix purpurea; adjacent area to an inland cliff ecosystem. A total of 240 soil samples, 63 species and 475 individuals were analysed. The samples were taken from May 2006 till September 2010. The highest numerical abundance and species diversity was found in the area located nearby to an inland cliff, which is an early succession stage ecosystem. Considering the dominance and constancy indices quantified for mites from all investigated areas, the highest percent was recorded by the recedent-subrecedent and accessory-accidental species. Based on similarity index two different characteristic groups of gamasid populations were delimited: one for deciduous forests and one for shrubs. DCA ordination successfully handled the variation in soil mite species communities taking account of the soil type.

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.

Impact of land use history and soil properties on soil mite communities (Acari, Mesostigmata) inhabiting stands growing on post‐agricultural land

AbstractDecades of agriculture in a former—type of ecosystem, for example, deciduous forests—result in severe habitat degradation. The planted tree species encounter harsh conditions due to physically and chemically transformed soil environments. In addition, afforestation itself significantly modifies the upper soil horizons. It may impact the soil fauna communities, including mites from the Mesostigmata order (Mesostigmata = Gamasida). Due to their sensitivity, mesostigmatid mites are good bioindicators of changes in the soil. A decrease in the density, species richness, and diversity of mites indicates disturbances in the soil environment and may confirm the impact of agricultural practice on the soil environment. Our research aim was to examine the impact of soil properties and land use history on the mesostigmatid mite communities in stands growing on forest and post‐agricultural lands. These sites were afforested with different tree species (Betula pendula Roth., Fagus sylvatica L., Pinus sylvestris L., and Quercus robur L.). Thus, 21 research plots were established on forest and post‐agricultural land, each on rusty soils considered to be one of the most common in Central European forests. We collected a total of 567 soil samples during three sampling sessions in spring and autumn for soil Mesostigmata investigation. We also described the soil profile on each plot and collected soil and litter samples to measure pH, litter thickness, soil organic matter, bulk density, soil moisture, soil organic carbon, and elements content. Our study revealed that 16 out of 30 environmental parameters differed between habitat types. A total of 1355 mites were classified into 58 taxa (50 species and 8 genera). The most numerous species were Veigaia nemorensis (165 ind.; 12.2% of all mesostigmatid mites), Zercon peltatus (156; 11.5%), and Paragamasus conus (141; 10.4%). The highest abundance was recorded in birch stands on forest land, whereas the lowest abundance for oak stands growing on post‐agricultural land. Interestingly, in oak stands we recorded both the highest diversity of mite communities (forest land) and the lowest on post‐agricultural land. Furthermore, our study showed that post‐agricultural land and Na content in forest litter affected the abundance, species richness, and diversity of mesostigmatid mite communities. Species richness was additionally affected by tree species, that is, pine and oak. Our research indicated that long‐term agricultural practice negatively affected the density, species richness, and diversity of Mesostigmata communities 20 years after afforestation.

Türkiye'den Yeni Kaydedilen bir Gymnodamaeid Akar (Acari, Oribatida, Gymnodamaeidae)

The knowledge of the oribatid mite fauna of Türkiye is very limited. In order to make contribution to the Turkish soil mite fauna samples were collected from Kocaeli province and the Gymnodamaeid mites systematically evaluated. Gymnodamaeid mites are cosmopolitan except Australia and Antarctica and they tend to live in dry habitats like alpine, tundra and grasslands. Members of this family usually inhabit in soil but some tend to live on moss, algae and lichen and so they supposed as phytophagous. The taxonomy of the Gymnodamaeid mites is difficult because of incomplete descriptions or misinterpretations. This is due to the fact that some authors try to dissolve the cerotegument layer or prefer newly molted samples for study. However thick, ornamented cerotegument provides useful in species recognition in undamaged, mature adults. So the scanning electron microscopic investigation is almost mandatory in the study of Gymnodamaeid mites. The number of Gymnodamaeid species previously recorded from Turkiye is just restricted to five. The samples are collected in May 2019 from pine forest in Sarıcaali town of Kocaeli province of Turkey. The Gymnodamaeid mite species Adrodamaeus striatus (Aoki, 1984) is newly recorded from Turkey by this study. This species previously known from South Eastern Palearctic and North of Oriental. Scanning electron microscopy images of the species is firstly presented by this study.

The Influence of Land Management on Soil Mite (Acari: Oribatida, Prostigmata, and Mesostigmata) Communities as Bioindicators for Environmental Conditions

As a soil-living organism, soil mite presence is important for ensuring the sustainable land. Intensive management practices in forest land drive a change in its community structure. A field study was conducted in Wanagama Education and Research Forest I, Gunungkidul District, Yogyakarta Special Region Province, Indonesia, to assess the role and impact of the different forest management practices on the soil mite community. Soil samples from 15 representative soil sites were taken from the agroforestry, mixed-forest, and pioneer community forest. Collected individuals from August to October 2021 were taken by Berlese-Tullgenn Funnel and identified to morphospecies level. A total of 758 individuals of soil mites were recorded during the study period. Out of these, 21 individuals from agroforestry, 288 individuals from mixed-forest, and 449 individuals from pioneer community forest. Results of the study revealed the occurrence of 3 taxa from 36 morphospecies of oribatid mites occurred in the areas. The Shannon diversity indices of oribatid mites were 1.831, 1.424, and 0.867 in mixed-forest, agroforestry, and pioneer community, respectively. The similarity indices showed there was a similar diversity in agroforestry and mixed-forest, either in pioneer community. Through one-way ANOVA analysis, we stated that differences between of three management practices significantly affected soil mites, especially oribatida rather than prostigmata and mesostigmata.

Responses of taxonomic and functional diversity of soil mites to altitudinal changes in forest ecosystems of Lyuliang Mountains, Shanxi, China

The altitudinal gradient pattern of mountain biodiversity and its formation mechanism are hot topics in ecological research. The altitudinal variations of belowground invertebrates are less understood than aboveground plants and animals. With soil mites as the model soil animals, we investigated their distribution patterns from 1318 m to 2500 m above sea level in three mountains of Lyuliang Mountains based on species diversity and functional diversity. We used soil pH, total N, total P, total K, and organic matter content to identify potential drivers of soil mite communities and diversity along the altitudinal gradient. A total of 715 soil mites were collected, belonging to 3 orders, 27 families, 28 genera, and 29 species. Phthiracarus clemens, Geolaelaps praesternalis and Diapterobates humeralis were dominant mites. Non-metric multidimensional scaling showed that soil mites community composition varied significantly among different altitudes due to Epilohmannia ovata predominated in high altitude and P. clemens predominated in middle altitude. There were significant differences in individual density of soil mites among different altitudes. The Margalef, Shannon, and Simpson indices followed a unimodal distribution pattern along the altitudinal gradient. Functional richness and functional evenness showed a unimodal distribution pattern along the altitudinal gradient, while other functional diversity indices changed little with altitude. The RDA results indicated that total K and soil pH were the major drivers for the variations in soil mite communities. The Pielou index of soil mites was significantly positively correlated with soil pH, while functional evenness was negatively correlated with altitude. Individual density, species number, Margalef, Simpson and Shannon indices were significantly positively correlated with functional richness index. Species diversity and functional diversity of soil mites varied differently with altitude. In the future, we should strengthen long-term monitoring and dynamic functional properties of soil mites and the community assembly to deeply understand the relationship between biodiversity and ecosystem functions.

Soil mite (Acari: Oribatida) communities in the limestone quarry of Saskhori (Gerogia)

Abstract The present publication provides a review of the soil mite (Acari; Oribatida) community’s structure and the connection between changes in environmental factors and oribatid mite diversity in the limestone quarry of Saskhori and its adjacent areas. Overall, 52 species were recorded during the study. The most abundant oribatid mite species were Steganacarus carinatus, Aleurodamaeus setosus, Xenillus tegeocranus, Ceratoppia bipilis, Oribatula tibialis, and Punctoribates punctum. Interestingly, 23 species of oribatid mites were recorded for the first time from the limestone quarry of Saskhori, and one species (Liacarus oribatelloides) was a new record for the Caucasus fauna. The following indices were analyzed: abundance (N), species diversity (S), Shannon’s diversity index (H), and Pielou’s evenness index (J’). Regarding the obtained results, the highest density of oribatid mites was recorded in the habitat with Shibliak shrubbery (332 inds/m2), while the forest habitat was characterized with the highest value for Shannon’s diversity index (2,64). In the publication, we also provide a detailed morphological description of the newly recorded species L. oribatelloides, with the respective illustration, as no figures are given in its original description.

Effects of yak and Tibetan sheep grazing on soil arthropods community in an alpine meadow on the Qinghai-Tibet Plateau, China.

We investigated the responses of community structure of soil arthropods to yak and Tibetan sheep grazing based on a manipulated grazing experiment at the alpine meadow livestock Adaptive Management Platform, which locates in Haiyan County, Qinghai Province. The results showed that the obtained soil arthropods belonged to 26 families, 8 orders, and 4 classes, with Acaroidae and Oribatida as the dominant groups. Yak and Tibetan sheep grazing decreased the abundance but increased Shannon index, Margalef index and Pielou index of soil arthropods. Yak grazing significantly increased the quantity of the predatory soil arthropod groups. Yak and Tibetan sheep gra-zing significantly increased the quantity of the detritivore soil arthropod groups, but did not affect the quantity of the omnivorous and phytophagous soil arthropod groups. Yak and Tibetan sheep grazing significantly reduced the abundance of soil mites. Soil bulk density, available potassium, and available nitrogen were the main abiotic factors affecting soil arthropods community composition.

Impact of forest disturbance on microarthropod communities depends on underlying ecological gradients and species traits.

Windstorms and salvage logging lead to huge soil disturbance in alpine spruce forests, potentially affecting soil-living arthropods. However, the impacts of forest loss and possible interactions with underlying ecological gradients on soil microarthropod communities remain little known, especially across different environmental conditions. Here we used DNA metabarcoding approach to study wind-induced disturbances on forest communities of springtails and soil mites. In particular, we aimed to test the effect of forest soil disturbance on the abundance, richness, species composition, and functional guilds of microarthropods. We sampled 29 pairs of windfall-forest sites across gradients of elevation, precipitation, aspect and slope, 2 years after a massive windstorm, named Vaia, which hit North-Eastern Italy in October 2018. Our results showed that wind-induced disturbances led to detrimental impacts on soil-living communities. Abundance of microarthropods decreased in windfalls, but with interacting effects with precipitation gradients. Operative Taxonomic Units (OTU) richness strongly decreased in post-disturbance sites, particularly affecting plant-feeder trophic guilds. Furthermore, species composition analyses revealed that communities occurring in post-disturbance sites were different to those in undisturbed forests (i.e., stands without wind damage). However, variables at different spatial scales played different roles depending on the considered taxon. Our study contributes to shed light on the impacts on important, but often neglected arthropod communities after windstorm in spruce forests. Effects of forest disturbance are often mediated by underlying large scale ecological gradients, such as precipitation and topography. Massive impacts of stronger and more frequent windstorms are expected to hit forests in the future; given the response we recorded, mediated by environmental features, forest managers need to take site-specific conservation measures.

Bottom-up effects of nematode prey on soil predatory mites (Acari: Mesostigmata)

Pest suppression is one of the desirable functions of a healthy soil. Predatory Mesostigmata soil mites, with their high degree of omnivory, are one of the most remarkable groups performing this beneficial role. Food web bottom-up effects are important for the fitness of these predators, which ultimately affects their potential as biocontrol agents. In below-ground systems, free-living nematodes (FLN) are an important diet for mites, providing essential nutrients such as omega 3 long-chain polyunsaturated fatty acids (ω3-LC PUFAs). Here we assess the food quality of nematodes for the maintenance of predator fitness, i.e. development, reproduction and lipid content. We selected two mite species, different in size and morphology, collected from vegetable crops in Israel. Additionally, five species of FLN were isolated from the same fields. Additionally, one plant-parasitic species, common across arable sites in Israel, and maintained on tomato as host, was tested. Depending on species and trophic group, nematodes varied in fatty acid profile, and both mite species generally reflected the fatty acid pattern of their diet. All nematode species were able to produce ω3-LC PUFA de novo, except the bacterial feeder Acrobeloides bodenheimeri, which had the highest proportion of ω6-PUFA. Interestingly, the latter lacking ω3-LC PUFA, was the best diet for both mites. Macrocheles aff. scutatus, a medium-sized mite with a holodorsal shield, fed and developed on all nematodes except the entomophilious Oscheius tipulae. It was able to complete its development feeding on the plant parasitic Meloidogyne incognita, yet the reproduction was almost zero. The smaller and slender Protogamasellopsis zaheri, with a split dorsal shield, developed and reproduced with all nematodes, with M. incognita as an intermediate diet. Our results demonstrate that nematode species vary in their nutritional quality as prey. However, food quality is predator species dependent, likely affecting biocontrol efficacy. Besides ω3-LC PUFA, ω6-PUFA can play an important role in the reproductive and developmental parameters of mesostigmatid mites; yet, other factors such as nematode size and behaviour have to be considered.

Small-scale genetic structure of populations of the bulb mite Rhizoglyphus robini.

Bulb mites are an economically significant pest of subterranean parts of plants and a versatile laboratory animal. However, the genetic structure of their populations remains unknown. To fill this gap in our knowledge of their biology, we set up a field experiment in which we allowed mites to colonize onion bulbs, and then determined the genetic structure of colonisers based on a panel of microsatellite loci. We found moderate but significant population structure among sites separated by ca. 20m (FST range 0.03-0.21), with 7% of genetic variance distributed among sites. Allelic richness within some bulbs was nearly as high as that in the total population, suggesting that colonisation of bulbs was not associated with strong population bottlenecks. The significant genetic structure we observed over small spatial scales seems to reflect limited dispersal of mites in soil.

Effect of Grazing Management on Predator Soil Mite Communities (Acari: Mesotigmata) in Some Subalpine Grasslands from the Făgăraş Mountains-Romania.

For the first time in Romania, a complex study was conducted on soil mite communities from two types of managed grasslands: ungrazed and intensively grazed. The study was accomplished in August 2018, in the Făgăraş Mountains. Within the soil mite communities (Mesostigmata), 30 species were identified, from 80 soil samples. The following population parameters were investigated: species richness, numerical abundance, dominance, Shannon index of diversity, evenness and equitability. Eight environmental variables were also measured: soil and air humidity; soil and air temperature; soil pH; resistance of soil to penetration; soil electrical conductivity; and vegetation coverage. The results revealed that species richness, Shannon index of diversity, evenness and equitability indices had higher values in ungrazed grasslands, whereas in intensively grazed areas, the numerical abundance and dominance index had significantly higher values. The species Alliphis halleri was dominant in the ungrazed grasslands. Each type of managed grassland was characterised by specific environmental conditions, which had an important influence, even at the species level.

Community structure of soil mites under different crops and its response to environmental factors in the buffer zone of Shibing Karst World Natural Heritage

To reveal the differences in the community structure of soil mites under different crop environments in the buffer zone of the Shibing Karst World Natural Heritage Site, soil mites from corn fields (CF), pear tree lands (PL), tobacco fields (TF), grape fields (GF), and plum gardens (PG) were collected in the buffer zone in January 2022. Through the identification of mite specimens and data analysis, differences in the number of families, genera, individuals, individual density, diversity, similarity of communities, ecological groups of oribatid mites, and responses to environmental factors of soil mites under different crop environments were determined. The results showed that: (1) A total of 6941 soil mites were captured in the study area, belonging to 130 genera, 75 families, and 3 orders. The number of soil mite genera (CF and TF > PL > PG > GF) and number of soil mite individuals (PG > PL > GF > TF > CF) showed characteristics of differential distribution and surface soil aggregation in the five habitats. (2) Scheloribates, Protorobotritia, and Tectocepheus were the dominant genera in the study area. Lohmannia, Scheloribates, and Tectocepheus, representative species that indicate a good soil environment, were distributed in the sample plots of CF, PL, and PG to varying degrees, indicating that the ecological environment of these three crops was healthy. (3) The diversity index of PG was the highest, and similarity analysis of the five habitats revealed that they were at a medium level of similarity. (4) The ecological groups of oribatid mites in the different crop environments were dominated by the overall (O) type, which is a combination of Macropylina, Gymnonota, and Poronota. (5) The community structure of soil mites was sensitive to bulk density (BD), natural water content (NWC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available potassium (AK), and soil organic matter (SOM). Based on the above results, there were differences in the community structures of soil mites under different crop environments in the study area. The identification of the dominant mite genera can preliminarily indicate the environmental conditions of different crops, and a special correlation exists between the community structure of mites and environmental factors. Studying the community structure of mites in different crop environments in the Shibing Karst World Natural Heritage Site buffer zone is important in ensuring the ecological protection and sustainable development of the buffer zone. Furthermore, the results of this study support the role of the buffer zone as an ecological protection barrier for the heritage site.

Diversity of soil mites (Acari: Mesostigmata) in streamside mountain forests

AbstractHabitat loss and fragmentation are among the most influential factors responsible for recent biodiversity decline. The key to understanding the changes in ecosystem functioning is the analysis of the relationship between species diversity and environmental gradients such as those found near streamside forests. We used soil mites (Mesostigmata) as model species as they are predators in soil ecosystems, they occur in high relative abundance, their communities are species‐rich and are robust toward sampling and extraction methods. The main goals of this study were to (1) check how the plant community and associated environmental variables (light conditions, litter accumulation, and soil acidity) along mountain streams affect soil Mesostigmata abundance and diversity, and (2) to analyze the distance from mountain streams to which the ecosystem functions (Mesostigmata diversity) are affected, based on a distance gradient. We systematically established 31 study plots (500 m2) every 200 m along the watercourses, representing three habitat types along the stand composition gradient (ash‐sycamore [Fraxinus excelsior–Acer pseudoplatanus], European beech [Fagus sylvatica], and Norway spruce [Picea abies] forests) for measurements of soil litter thickness, soil acidity, and light conditions. We extracted soil Mesostigmata mites from samples in Tullgren funnels and identified them to the species level. We found that Mesostigmata abundance in forests decreased in the following order: Norway spruce forest &gt; European beech forest &gt; ash‐sycamore forest. Additionally, changes in Shannon diversity were associated with light conditions. In conclusion, streamside mountain forests maintained abundant, diverse and species‐rich Mesostigmata communities, which were associated with a plant community‐light condition gradient. Additionally, more abundant mite communities occurred in forests with higher soil pH values, and under higher light conditions.

Opening up new niche dimensions: The stoichiometry of soil microarthropods in European beech and Norway spruce forests.

Niche theory fundamentally contributed to the understanding of animal diversity. However, in soil, the diversity of animals seems enigmatic since the soil is a rather homogeneous habitat, and soil animals are often generalist feeders. A new approach to understand soil animal diversity is the use of ecological stoichiometry. The elemental composition of animals may explain their occurrence, distribution, and density. This approach has been used before in soil macrofauna, but this study is the first to investigate soil mesofauna. Using inductively coupled plasma optic emission spectrometry (ICP-OES), we analyzed the concentration of a wide range of elements (Al, Ca, Cu, Fe, K, Mg, Mn, Na, P, S, Zn) in 15 soil mite taxa (Oribatida, Mesostigmata) from the litter of two different forest types (beech, spruce) in Central Europe (Germany). Additionally, the concentration of carbon and nitrogen, and their stable isotope ratios (15N/14N, 13C/12C), reflecting their trophic niche, were measured. We hypothesized that (1) stoichiometry differs between mite taxa, (2) stoichiometry of mite taxa occurring in both forest types is not different, and (3) element composition is correlated to trophic level as indicated by 15N/14N ratios. The results showed that stoichiometric niches of soil mite taxa differed considerably indicating that elemental composition is an important niche dimension of soil animal taxa. Further, stoichiometric niches of the studied taxa did not differ significantly between the two forest types. Calcium was negatively correlated with trophic level indicating that taxa incorporating calcium carbonate in their cuticle for defense occupy lower trophic positions in the food web. Furthermore, a positive correlation of phosphorus with trophic level indicated that taxa higher in the food web have higher energetic demand. Overall, the results indicate that ecological stoichiometry of soil animals is a promising tool for understanding their diversity and functioning.

Climate and topography rather than tree species affect mite communities (Mesostigmata) in severe conditions—Studies from sandstone rocky islands of the Szczeliniec Wielki Plateau (Poland)

AbstractRelationships between certain plant species and soil fauna assemblages in severe climatic conditions require scientific attention due to reported climatic changes. We investigated density, diversity, and community structure of soil mites (Mesostigmata) in tree biogroups of Betula pendula, Picea abies, and Pinus sylvestris with microhabitats represented by Calluna vulgaris, Dicranum scoparium, Vaccinium myrtillus, and Vaccinium vitis‐idaea plant patches and accumulated litter in humid and cold rock crevices a few meters deep. We analyzed the effects of climatic (light availability, precipitation, temperature) and environmental (litter pH, organic matter thickness, microhabitat type) conditions on mite communities based on 1080 samples collected during two vegetation periods (2004–2005). Results revealed that litter pH was shaped by microhabitat type (plant patches and rock crevices) whereas organic matter thickness depended on tree species and microhabitat type. Also, light availability differed between tree biogroups and microhabitats. This study documented that Mesostigmata abundance was shaped by maximum daily temperature while species richness was also affected by total monthly precipitation, tree species (P. sylvestris) and microhabitat (rock crevices). Results revealed that mite density ranged from 3001 ± 213 ind./m2 in the P. abies biogroup to 3310 ± 350 ind./m2 in P. sylvestris. On the microhabitat level, mite density ranged from 2571 ± 170 ind./m2 in V. myrtillus patches to 4137 ± 463 ind./m2 in rock crevices. Total number of recorded species was highest in rock crevices (41 species), and lowest in C. vulgaris (19). In conclusion, results indicated that climatic conditions modulate mite communities on an isolated rocky island. This study documented that maximum daily temperature during the vegetation period affected Mesostigmata abundance, whereas species richness and diversity were also shaped by total monthly precipitation and tree species (P. sylvestris). In addition, the community was also affected by litter acidity, organic matter and tree species.

Changes in diversity and functional groups of soil mite communities are associated with properties of food resources along a subalpine secondary succession

It is hypothesized that soil animal diversity is supported by environmental and food diversity. Mites are the most abundant microarthropods in soil communities that occupy several trophic levels in soil food webs and play important role in litter decomposition and nutrient cycling. However, it is not clear if diversity of mite communities is associated with diversity and quality in corresponding food resources across trophic levels. Here, we studied the influences of resource diversity (plants, fungi, and nematodes) and abiotic factors (litter and soil attributes) on taxonomic richness of detritivorous, fungivorous, and predatory mites (75 mite genera in total) in a subalpine succession (grassland, shrubland, secondary forest, primary forest) in southwestern China. Supporting our main hypothesis, diversity of the bulk mite community and individual functional groups was associated with the diversity and quality of resources across trophic levels. The total taxonomic richness was highest in the shrubland successional stage, where plant diversity was the highest, and decreased in late-successional stages despite a similar abundance. Diversity of predatory and fungivorous mites was positively associated with the diversity of nematode and fungal communities and reached maximum at the shrubland and grassland stages, respectively. Diversity of detritivorous mites was similar across different successional stages, being associated with litter quality. These findings provide empirical evidence that supports general ecological theory on the mechanisms that support multitrophic biodiversity in soils.