Is Biodiversity of Uropodina Mites (Acari: Parasitiformes) Inhabiting Dead Wood Dependent on the Tree Species?

The article presented here is the continuation of a study on the importance of dead wood for the biodiversity of the Uropodina (Acari: Parasitiformes) communities inhabiting dead wood. The major aim of this study is to check whether the species of tree can have any impact on the species composition and abundance of uropodine mite communities inhabiting dead wood. The next aim of the study is to test the following hypotheses: (1) Uropodina exhibit preferences for certain tree species; and (2) communities differ depending on the region and time of the samples collection. The material for the analysis consists of samples from different types of dead wood merocenoses and 37 species of trees, and were collected across the whole area of Poland. More Uropodina species were collected from the dead wood of broadleaved species than from coniferous species. The tree species in which communities of the studied mites were the richest were beech, oak, pine, spruce, linden, and hornbeam. The analysis of habitat preferences of Uropodina mites for particular tree species has revealed that none of the analyzed mite species did not occur in the dead wood samples from all tree species. Another important result is that the mite communities found in the samples from the same tree species remained similar in each decade of the research. The results also show that the communities of Uropodina inhabiting dead wood of the same tree species in different regions of Poland had different species composition, which stems from differences in the range of occurrence of these mites species.

A Forest Pool as a Habitat Island for Mites in a Limestone Forest in Southern Norway

Forest water bodies, e.g., pools, constitute ‘environmental islands’ within forests, with specific flora and fauna thus contributing considerably to the landscape biodiversity. The mite communities of Oribatida and Mesostigmata in two distinctive microhabitats, water-soaked Sphagnum mosses at the edge of a pool and other mosses growing on the medium-wet forest floor nearby, were compared in a limestone forest in Southern Norway. In total, 16,189 specimens of Oribatida representing 98 species, and 499 specimens of Mesostigmata, from 23 species, were found. The abundance and species number of Oribatida were significantly lower at the pool, while the abundance and species richness of Mesostigmata did not differ. Both the communities of Oribatida and of Mesostigmata differed among the microhabitats studied and analysis showed significant differences between the community structures in the two microhabitats. The most abundant oribatid species in Sphagnum mosses was Parachipteria fanzagoi (Jacot, 1929), which made up over 30% of all Oribatida, followed by Atropacarus striculus (C.L. Koch, 1835) and Tyrphonothrus maior (Berlese, 1910) (14% and 12% of Oribatida, respectively). Among Mesostigmata Paragamasus parrunciger (Bhattacharyya, 1963) dominated (44% of Mesostigmata), followed by P. lapponicus (Trägårdh, 1910) (14% of Mesostigmata). Most of these species, except P. lapponicus, were either absent or very uncommon in the other microhabitat studied. The specific acarofauna of the forest pool shows the importance of such microhabitats in increasing forest diversity. In addition, a quarter of the mite species found had not been reported from Norwegian broadleaf forests before, including five new species records for Norway and four new to Fennoscandia, all found in the medium-wet microhabitat. Most of these species are rarely collected and have their northernmost occurrence in the studied forest.

Predatory mite instars (Acari, Mesostigmata) and decomposing tree leaves in mixed and monoculture stands growing on a spoil heap and surrounding forests

In the past, ecological research mainly omitted the sexual and developmental variability of mite communities, and therefore could not fully reflect the actual state and function of mite communities in the ecosystems studied. The aim here was to analyze how habitat conditions (mixed vs. monoculture stands) and single-species litter of 14 tree species (in mixed stands) affect the sex and developmental stages of Mesostigmata mites living on the decomposing litter. The research was conducted in 2011–2016, at the Bełchatów Lignite Mine external spoil heap (Central Poland) in mixed stands growing on the spoil heap, as well as in pine and birch monoculture stands growing on the spoil heap and an adjacent forest area. We found significant influences of habitat on females, males and juveniles. Additionally, we found that soil mean temperature had a significant effect on males and juveniles, but not on females. Moreover, despite the insignificant influence of litter species on mite communities, we found that percentage litter mass loss significantly affected female and juvenile mites. Taking into account habitat type, the percentage litter mass loss significantly affected female and male mites, but not juveniles. The mite abundance calculated per dry litter mass usually gradually increased during decomposition. Interestingly, the highest mean female, male and juvenile abundances were recorded in birch stands growing on the adjacent forest area; however, juvenile mites were also very numerous in mixed stands on spoil heap. Therefore, our results confirm that mixed stands on post-mining areas are a potentially better habitat for development of mesostigmatid communities compared to monocultures, among others by relatively higher humidity and lower temperatures.

Type of broadleaf forest matters most for ptyctimous mite communities (Acari, Oribatida) in Norway

We studied ptyctimous moss mites, which are characteristic of forest habitats, in Norwegian broadleaf forests considered as biodiversity hotspot areas in Fennoscandia. The study aimed to evaluate the effect of different factors (regional locality, annual precipitation, mean annual temperature, forest type, forest wetness and microhabitat) on the ptyctimous mites and on discovering their richness in broadleaf forests. Samples were collected from nine broadleaf forests in Western, Southern and Eastern Norway, in different climatic conditions, six forest types, three forest wetness states and eight microhabitats. Overall, 3341 ptyctimous mites were collected and their abundance differed significantly among the regions, forest types and microhabitats. Forest type turned out to be the most important factor, responsible for 24.5% of the total variation in the abundance of the ptyctimous mites. Other important factors were forest wetness and microhabitat. In total, 27 species, i.e., 87% of all ptyctimous mites known from before in Norway were found and the species richness was highest in the east and lowest in the west of the country. Atropacarus (Atropacarus) striculus was most common and most abundant; it made nearly 30% of all ptyctimous mites collected. On the other hand, a quarter of the species were represented by less than 10 specimens; most of these were new records for Norway. Among ten species discovered as new to Norway, four were also new to Fennoscandia. These findings confirm the unique character and high biological diversity of Norwegian broadleaf forests.

Mite communities (Acari: Mesostigmata, Oribatida) in the red belt conk, Fomitopsis pinicola (Polyporales), in Polish forests

The fruiting bodies of bracket fungi are a specific microhabitat colonized by various invertebrates of which mites (Acari) are rarely studied, and if they are, the study is usually faunistic. The aim of the research was to determine whether the diversification of mite assemblages (Mesostigmata, Oribatida) inhabiting the fruiting bodies of Fomitopsis pinicola (Sw.) P. Karst. (Polyporales) are connected with the character of the forests and/or the degree of decay (DD) of the fruiting bodies. The research was conducted at Białowieża National Park (BNP), in forests close to natural ones and in Karkonosze National Park (KNP) which was affected by a large-scale forest dieback in the 1980s. Eighty fruiting bodies (40 at each study site) of F. pinicola belonging to four DD categories were collected. In total, 4,345 individuals of 120 mite species were recorded at BNP, and 13,912 individuals of 96 species were recorded at KNP. Analyses revealed that the sample dispersion at each study site was comparable, nevertheless the samples from each study site were clearly grouped into slightly overlapping sets which allow observation of the differences between them. In the less decayed fungi (DD 1 and 2) there were fewer mite species and individual mites than in the more decayed samples (DD 3 and 4). There were also significant differences between the fauna of the fungi in each particular DD: the fauna of DD 1 differed from all others, whereas the fauna of heavily decayed fungi (DD 3 and 4) was more comparable.

Immediate Effects of Prescribed Burning on Soil Mite (Acari: Oribatida) Communities in a Scots Pine (Pinus Sylvestris) Forest, Latvia

Prescribed burning is used to maintain and restore habitats, to protect and increase species bio-diversity. Knowledge about soil fauna is limited, especially on community responses to fire disturbances. The aim of this study was to determine the immediate effects of prescribed burning on soil armoured mite (Acari: Oribatida) communities, vegetation cover and soil physiochemical properties in a boreal Scots pine forest in Latvia. Soil samples were collected on the day of the prescribed burning in the protected landscape area “Ādaži” and 16 days after. No significant changes in abiotic factors were found. Fire significantly decreased the vegetation cover. After the burning, the total number of oribatid mites decreased by 93%, and the number of species by 77%. Changes in oribatid mite communities were significantly influenced by fire severity. The number of individuals decreased among all taxa, except Brachychthonioidea spp. and Cosmochthonius lanathus. A significant decrease in abundance was observed in previously abundant species — Suctobelbella spp., Oppiella nova and Tectocepheus velatus. After the burning, Suctobelbella spp. was an eudominant and Tectocepheus spp. was a dominant genus.

Soil mite communities (Acari: Mesostigmata) as indicators of urban ecosystems in Bucharest, Romania

The aim of the present study was to establish the effect of management type and of environmental variables on the structure, abundance and species richness of soil mites (Acari: Mesostigmata) in twelve urban green areas in Bucharest-Romania. Three categories of ecosystem based upon management type were investigated: protected area, managed (metropolitan, municipal and district parks) and unmanaged urban areas. The environmental variables which were analysed were: soil and air temperature, soil moisture and atmospheric humidity, soil pH and soil penetration resistance. In June 2017, 480 soil samples were taken, using MacFadyen soil core. The same number of measures was made for quantification of environmental variables. Considering these, we observed that soil temperature, air temperature, air humidity and soil penetration resistance differed significantly between all three types of managed urban green area. All investigated environmental variables, especially soil pH, were significantly related to community assemblage. Analysing the entire Mesostigmata community, 68 species were identified, with 790 individuals and 49 immatures. In order to highlight the response of the soil mite communities to the urban conditions, Shannon, dominance, equitability and soil maturity indices were quantified. With one exception (numerical abundance), these indices recorded higher values in unmanaged green areas compared to managed ecosystems. The same trend was observed between different types of managed green areas, with metropolitan parks having a richer acarological fauna than the municipal or district parks.

Communities of predatory mites (Phytoseiidae and Stigmaeidae) in different environments of the Brazilian Pampa

The Brazilian Pampa presents a high diversity of fauna and flora within a mosaic of environments. The aim of this study was to evaluate the assemblages of predatory mites (Phytoseiidae and Stigmaeidae) in three different Pampa environments: Grassland shrub vegetation, Grazing Exclusions fenced for six years and Riparian Forest with tree vegetation. Phytoseiidae and Stigmaeidae were evaluated with a total of 324 plant sampled from nine sites in three environments. Twenty-two Phytoseiidae species and six Stigmaeidae species were found. Riparian Forest presented the highest abundance of predatory mites (243) and the greatest species diversity. Mites were more abundant in Grazing Exclusions (64) than in Grassland (25) environments, but species diversity was similar. In Riparian Forest, the most abundant species were Amblyseius tamatavensis Blommers, Amblyseius herbicolus (Chant) and Agistemus floridanus González-Rodríguez. Arrenoseius gaucho Ferla, Silva and Moraes and Zetzellia malvinae Matioli, Ueckermann and Oliveira were the most abundant in Grassland environment. Our results demonstrate that the Brazilian Pampa has a high diversity of predatory mites and mite communities seem to be affected by the type of environment, showing the importance of this ecosystem as a reservoir of natural enemies.