EFFECTS OF SHEEP TREADING ON PLANT COVERING AND SOIL ORIBATIDA (ACARI) IN A WOODED HAY MEADOW IN SOGN (NORWAY)

Effects of sheep treading on plant covering and soil oribatid mites in a traditionally maintained wooded hay meadow in Sogn (Norway) were investigated. Samples were taken under the elm trees in 2 zones, situated 1m from the elm trunks, heavily treaded by sheep, and 5m from these trunks. The sheep treading decreased the plant covering, especially mosses, and the density of Oribatida, but increased the participation of their juvenile stages. The Oribatida occupied mainly the upper soil layer and the density distinctly decreased with the soil depth, but the sheep treading appeased the differences of density of mites in soil layers, comparing to the zone situated 5m from the elm trunks

Jordlevende midd - jordas glemte nyttedyr

Ingress: Midd er mest kjent for å gjøre skade på planter eller kunne gjøre mennesker og dyr syke. Mange arter midd i norsk jordbruksjord er helt ufarlige og har viktige oppgaver i jordas økosystem. Midd som finnes i jord spiser planterester, bakterier og sopphyfer, inkludert plantepatogene bakterier og sopp. Mange jordlevende midd er rovdyr og spiser spretthaler, nematoder, bladlus, insektegg og larver. Midd som gruppe utgjør et stort mangfold av fasonger, farger og funksjoner på overflata og nede i jorda

Morphological ontogeny of Galumna flagellata Willmann (Acari: Oribatida: Galumnidae)

The morphological ontogeny of Galumna flagellata Willmann, 1925 is described and illustrated. The juveniles of this species are light brown, with prodorsal setae of medium size or long and barbed, and bothridial seta clavate. The larva has 12 pairs of gastronotal setae, most of the medium size and barbed, of which seven (d-, l-series, h1) are located on gastronotal shield, nymphs have 15 pairs, mostly short setae, of which 10 (d-, l-, h-series, p1) are located on the gastronotal shield, setae of c-series are inserted on individual sclerites. In all juveniles, the typical galumnid humeral organ is absent, but a porose area is present in this location, which is unique in Galumna.Spanish Ministry of Economy and Competitiveness CGL-2013-46665-REuropean Commissio

Seasonal dynamics of mites (Acari) in pastures and meadows in Poland, with species analysis of Oribatida

The study involved three pastures, grazed by geese, goats and fallow deer, and three nearby meadows (control plots) situated in north-central Poland. Samples of 150 cm3 each (6 cm of soil and 3 cm of lower parts of plants) were collected in spring, summer and autumn 2016 and 2017 in 10 replications, 360 samples in total. This material included 22.561 mites, among which Oribatida accounted for 69%, Mesostigmata for 21%, and other mites for 10%. At most study sites, both pastures and meadows, no significant seasonal differences in the abundance of Oribatida and Mesostigmata were seen. Such differences were only observed for the third category of other mites that were the most abundant in spring and usually the least abundant in autumn. Also species diversity of Oribatida differed between the seasons – in all pastures it was the highest in summer and the lowest in spring, while in all meadows it was the highest in spring and decreased towards autumn. Oribatid species were more affected by the habitats than by seasons, as some species were strongly associated with pastures (Platynothrus peltifer), other with meadows (Achipteria coleoptrata, Liebstadia similis, Metabelba pulverosa, Scheloribates laevigatus and Sellnickochthonius immaculatus), and some (Eupelops occultus and Tectocepheus velatus) were abundant in both habitats. Although the effect of seasonality was weaker than that of the habitat, it was still perceptible. Platynothrus peltifer was most associated with autumn, T. velatus with spring, E. occultus with spring and summer and L. similis with summer.publishedVersio

Morphological ontogeny, distribution of Hermannia scabra (Acari: Oribatida: Hermanniidae) in Svalbard and descriptive population parameters

The morphological ontogeny and distribution of Hermannia scabra (L. Koch, 1879) in Arctic Svalbard and descriptive population parameters were investigated. All instars of H. scabra are stocky, as in other species of Hermannia Nicolet, 1855, and have the same gastronotal setal ontogeny (12 pairs in the larve and 16 pairs in the nymphs and adults). In this species, the prodorsal setae are similar to other species of Hermannia, except for the bothridial seta which is clavate, as in H. reticulata Thorell, 1871. In other species of Hermannia the bothridial seta is setiform. Most prodorsal and gastronotal setae of H. scabra are phylliform whereas in other Hermannia species they are thickened. The number of epimeral setae in the nymphs and adults and the ontogeny of leg setae are characteristic for H. scabra. This species has a holarctic distribution and in Svalbard is not as common as H. reticulata, but it achieves higher density than the latter species, mainly due to the abundance of juveniles. Hermannia scabra prefers moist and wet localities, and in Svalbard the highest density is achieved in vegetation class 8 (wet vegetated flats, beaches, slopes and river fans with some exposed Dryas vegetation and graminoids Luzula sp.)

WPŁYW WYDEPTYWANIA GLEBY PRZEZ OWCE NA POKRYCIE ROŚLINNOŚCI I GLEBOWE MECHOWCE (ACARI, ORIBATIDA) ZADRZEWIONEJ ŁĄKI W SOGN (NORWEGIA)

Effects of sheep treading on plant covering and soil oribatid mites in a traditionally maintained wooded hay meadow in Sogn (Norway) were investigated. Samples were taken under the elm trees in 2 zones, situated 1m from the elm trunks, heavily treaded by sheep, and 5m from these trunks. The sheep treading decreased the plant covering, especially mosses, and the density of Oribatida, but increased the participation of their juvenile stages. The Oribatida occupied mainly the upper soil layer and the density distinctly decreased with the soil depth, but the sheep treading appeased the differences of density of mites in soil layers, comparing to the zone situated 5m from the elm trunks.Zbadano wpływ wydeptywania gleby przez owce na roślinność i glebowe mechowce na tradycyjnie utrzymywanej, zadrzewionej łące w Sogn w Norwegii. Próby pobrano z łąki pod wiązami w 2 strefach, oddalonej 1m od pni drzew, silnie wydeptanej przez owce oraz 5m od pni drzew, jako strefie kontrolnej. Wydeptywanie łąki przez owce zmniejszyło pokrycie roślinności, zwłaszcza mchów, a także liczebność mechowców, ale zwiększyło udział ich stadiów młodocianych. W obu strefach liczba gatunków mechowców była zbliżona. Mechowce skupiały się głównie w górnej warstwie gleby, a ich zagęszczenie zmniejszało się wraz z głębokością. Wydeptywanie łąki przez owce złagodziło różnice w zagęszczeniu roztoczy w profilu glebowym w porównaniu do strefy odległej 5m od pni drzew

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.publishedVersio

Mites (Oribatida and Mesostigmata) and vegetation as complementary bioindicators in peatlands

Vegetation is widely used in the assessment of the quality of peatlands, while the invertebrate fauna of peatlands is relatively poorly studied. We compared the bioindicator values of vegetation with two arthropod groups widespread in peatlands, saprophagous Oribatida (Acariformes) and predatory Mesostigmata (Parasitiformes) mites. Samples were collected from ecotones at the edges of peatland ponds in Poland, including four in near-natural condition (i.e., peatlands unaffected by human activity) and three in previously disturbed but now recovering peatlands. A set of abiotic parameters was measured at each site: pond area, mean annual temperature, annual precipitation, and water parameters (pH, conductivity, colour, total nitrogen, phosphorus, calcium, and organic carbon). Overall, 63,635 specimens of Oribatida and 448 of Mesostigmata were recovered in the sampling. Species richness of Oribatida (56 species) was higher than that of flora (46) and Mesostigmata (15). Vegetation was significantly associated with annual precipitation in the years 1998–2007 which accounted for 29.1 % of the variation in vegetation communities. Oribatida variability was significantly associated with the content of organic carbon in water accounting for 32.4 % of variation. In contrast, variation in the Mesostigmata was not significantly associated with any of the abiotic parameters. Vegetation at ponds in previously disturbed and now recovering peatlands had higher bush cover than at near-natural ponds and the pond in the cutaway peat had lowest moss cover and the highest number of associate species (i.e., species with wide tolerance not characteristic of the certain community). Mite communities did not differ consistently between near-natural and recovering peatlands. Sphagnum divinum Flatberg et Hassel was recorded from Poland for the first time.publishedVersio

Inclusion of juvenile stages improves diversity assessment and adds to our understanding of mite ecology – A case study from mires in Norway

Arachnid orders, Mesostigmata, Trombidiformes, and Sarcoptiformes, commonly known as ‘mites’, are abundant in mires, both as adults and as juveniles. However, due to the challenges of identification, the juvenile forms are often excluded from analyses. This is the first study in mires that included all three mite orders identified to the species level, including juvenile instars. We aimed to compare how diversity and the response to ecological variables differed if only the adults (ad) vs. the total number of specimens (ad+juv) are considered. Samples of 20 Sphagnum species (five subgenera) were collected and mites were extracted using Berlese funnels. Overall, nearly 60,000 mites were analyzed; of these Mesostigmata made up 1.87% of the total, Trombidiformes −0.27%, and Sarcoptiformes −97.86%. The study revealed 154 species (33 Mesostigmata, 24 Trombidiformes, and 97 Sarcoptiformes), the highest diversity of mites ever reported from mires. The inclusion of juveniles increased observed species richness by 6%, with 10 species (one Mesostigmata, six Trombidiformes, and three Sarcoptiformes) represented only by juvenile forms. Seventeen species are new to Norway (four Mesostigmata, one Sarcoptiformes, and 12 Trombidiformes, including five undescribed species of Stigmaeidae and Cunaxidae). Four of these were represented in the samples only by juveniles. Including the juveniles explained a greater amount of the variability of Trombidiformes (explanatory variables account for 23.60% for ad, and 73.74% for ad+juv) and Mesostigmata (29.23% − ad, 52.91% − ad+juv), but had less of an impact for Sarcoptiformes (38.48% − ad, 39.26% − ad+juv). Locality, Sphagnum subgenus and species, wetness, and trophic state significantly affected the mite communities and should be taken into consideration when studying mires. Since juvenile stages contribute significantly to mite diversity in mires, they should also be included in mite studies in other habitats.publishedVersio

Diversity and Distribution of Mites (Acari: Ixodida, Mesostigmata, Trombidiformes, Sarcoptiformes) in the Svalbard Archipelago

Svalbard is a singular region to study biodiversity. Located at a high latitude and geographically isolated, the archipelago possesses widely varying environmental conditions and unique flora and fauna communities. It is also here where particularly rapid environmental changes are occurring, having amongst the fastest increases in mean air temperature in the Arctic. One of the most common and species-rich invertebrate groups in Svalbard is the mites (Acari). We here describe the characteristics of the Svalbard acarofauna, and, as a baseline, an updated inventory of 178 species (one Ixodida, 36 Mesostigmata, 43 Trombidiformes, and 98 Sarcoptiformes) along with their occurrences. In contrast to the Trombidiformes and Sarcoptiformes, which are dominated in Svalbard by species with wide geographical distributions, the Mesostigmata include many Arctic species (39%); it would thus be an interesting future study to determine if mesostigmatid communities are more affected by global warming then other mite groups. A large number of new species (42 spp.) have been described from Svalbard, including 15 that have so far been found exclusively there. It is yet uncertain if any of these latter species are endemic: six are recent findings, the others are old records and, in most cases, impossible to verify. That the Arctic is still insufficiently sampled also limits conclusions concerning endemicity.publishedVersio