Mites (Acari) of the shores of forest lakes and ponds in northern Poland, with species analysis of Oribatida

Peatlands harbour a large number of specialized plants and animals. In many European countries more than 90% of the peat bogs have been destroyed through drainage for agriculture and forestry. The knowledge on the consequences for soil animals restricted to peatlands is scarce. The current study presents a comparison of the oribatid mite assemblages recorded in 1987 and 2012 from a Sphagnum bog being part of a large peatland complex that has suffered from drainage between the two periods. Furthermore, the oribatid mite fauna of the Sphagnum bog is compared to the fauna of adjacent peatland habitats of different soil moisture, shadowing and vegetation (Molinia meadow, spruce afforestation, birch wood). The study addresses the following questions: 1) which environmental factors determine the oribatid species composition in the peatland complex? 2) how do anthropogenic desiccation and afforestation influence the oribatid mite assemblage? CCAs were calculated using the species abundances recorded in 2012 and the parameters soil moisture, vegetation temperature index, pH, cover of the tree-, herb- and moss layer, cover of herbleaf-litter and needle litter as well as C/N ratio. In total, 87 oribatid mite species were recorded in the Dubringer Moor in 2012. Species distribution was most closely related to cover of herb-leaf-litter and needle-litter, soil moisture and vegetation temperature index. However, all sampling sites in the spruce forest contained similar sets of common species despite of differences in moisture and vegetation cover. The species composition of the two birch wood sites differed slightly from that of the spruce forest sites. In contrast, the Sphagnum bog was characterized by five tyrphophilic species (Pergalumna nervosa, Pilogalumna tenuiclava , Malaconothrus monodactylus, Mainothrus badius, Nothrus pratensis) that occurred almost exclusively here. The Molinia meadow as a degenerated part of the Sphagnum bog contained almost no species that were characteristic for the Sphagnum bog site. However, species richness was higher in the Molinia meadow, because a large number of species characteristic for forest habitats occurred. In the Sphagnum bog, species richness was heavily reduced from 1987 to 2012 from 37 to 10 species and also density was reduced from 164 individuals/100 cm³ to 9 individuals/100 cm³ due to ongoing desiccation. Several bog-specific species such as Hoplophthiracarus illinoisensis, Trhypochthoniellus longisetus and Trhypochthonius nigricans have apparently disappeared from the Sphagnum bog today. Characteristic bog species still occurring in the Sphagnum bog in 2012 might be less sensitive to dryer periods and strong water level fluctuations than the species that disappeared since 1987. The results indicate that desiccation in Sphagnum sp. reduces oribatid species richness. However, after vegetational changes to, e.g., a Molinia meadow, oribatid species richness increases again due to immigrating species that are characteristic for forest habitats and euryoecious species. The oribatid mite community composition and densities of tyrphophilic and hygrophilic species appeared to be closely related to Sphagnum bog desiccation and peatland habitat characteristics. Oribatid mites therefore obviously offer the opportunity to evaluate the ecological conditions and degeneration of a peatland.

The oribatid mite community of a German peatland in 1987 and 2012 - effects of anthropogenic desiccation and afforestation

Oribatid mites (Acari, Oribatida) and their seasonal dynamics in a floating bog mat in Jeziorka Kozie Reserve, Tuchola Forest (Poland) The oribatid mite community from the edge of the Sphagnum mat of dystrophic K1 pond (Jeziorka Kozie Reserve, Poland), and its seasonal dynamics was studied in 2006 (29 May, 6 August and 22 October). In all seasons, Limnozetes foveolatus dominated, followed by L. ciliatus; abundant were also L. lustrum, Trhypochthoniellus longisetus, Trhypochthonius nigricans, and Trimalaconothrus foveolatus. In autumn, the mean density of Oribatida was significantly higher than in spring. The percentage of juvenile stages was generally low, but highest in summer (22%), while in the other seasons it was about half as high. Metabelba sphagni is new to the Polish fauna.

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Oribatid mites (Acari, Oribatida) and their seasonal dynamics in a floating bog mat in Jeziorka Kozie Reserve, Tuchola Forest (Poland)

Species composition and abundance of the oribatid fauna (Acari, Oribatida) at two lakes in the Fløyen area, Bergen, Norway Oribatid communities from the edges of two lakes in the Fløyen area, Bergen, Norway, were compared in June 2005. The lower lake, Blåmansvannet (412 m a.s.l.), is surrounded by spruce forest, while the ‘Higher Lake’ (513 m a.s.l.), is above the tree line. Both lakes have a low pH and their edges are dominated by Sphagnum mosses. The abundance of total mites, as well as of Oribatida, were almost 2-fold higher at the ‘Higher Lake’ (51 510 and 51 160 ind./m2, respectively), while species diversity was lower than at Blåmansvannet. On the shore of Blåmansvannet, the eudominant (20% < D ≤ 40%) species was Trimalaconothrus maior, while Liochthonius peduncularis, Limnozetes ciliatus, and Nanhermannia cf. coronata were dominant (10%< D ≤ 20%). At ‘Higher Lake’, the eudominant species was Limnozetes ciliatus, which reached a 4-fold higher abundance (15 930 ind./m2) than at Blåmansvannet, and dominant species were Liochthonius alpestris, Nanhermannia cf. coronata, and Platynothrus punctatus. At both lakes, juveniles made up about 30% of all oribatids. Four species are new to Norway: Ceratoppia sexpilosa, Liochthonius alpestris, Liochthonius peduncularis, and Trhypochthoniellus longisetus.

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Species composition and abundance of the oribatid fauna (Acari, Oribatida) at two lakes in the Floyen area, Bergen, 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.

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

The Oribatida is the most abundant and diverse group of mites and one of the most abundant groups of invertebrates in bogs, important for the decomposition of organic matter. These mites are relatively poorly studied in bogs and their seasonal dynamics have never been investigated in detail throughout the year. The study was performed on the periphery of a bog pond located in north-eastern Poland during four seasons. The analyses were based on 25,128 mites comprising 24,393 Oribatida from 66 species. The second most abundant group was Prostigmata, followed by Mesostigmata. The density of mites and of Oribatida reached a maximum in autumn (ca. 90,000 individuals/m2), and was nearly two-fold greater than in other seasons. In autumn, spring and summer the oribatid communities were dominated by the aquatic genus Limnozetes, while in winter these mites were replaced by species with lower water demands (e.g. Liochthonius alpestris, Mainothrus badius, Scheloribates laevigatus) or eurytopic ones (e.g. Oppiella nova). Oribatida reproduced in all seasons with the greatest proportion of juveniles (25%) observed in winter. Two species, Liacarus acutus and Dissorhina ornata peloponnesiaca are reported for the first time for the Polish fauna; both were found only in one season showing that sampling throughout the year is important to determine biodiversity.

Seasonal Dynamics of Oribatid Mites (Acari, Oribatida) in a Bog in Poland

Roztocze (Acari) strefy brzegowej dwóch jezior śródleśnych, o różnej jakości wody, w Borach Tucholskich = Mites (Acari) of the littoral zone of two midforest lakes with different water quality in the Tuchola Forest

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Mechowce (Acari, Oribatida) glebowe strefy ekotonowej pomiędzy borem sosnowym a brzegiem jeziora lobeliowego Wielkie Gacno w Borach Tucholskich = Oribatid mites (Acari, Oribatida) ef ecotone between Scots pine forest and lobelias Lake Wielkie Gacno in Tuchola Fores

Abstract Moss mites were investigated at the edges of 4 bodies of water located in bogs: 2 lakes in Brodnica Lakeland (O and S) and 2 pools in Orawa-Nowy-Targ Basin (K and LP). The lakes differed from the pools in most of the analysed physicochemical parameters of water and in plant associations growing at their edges. Consequently, the species richness of Oribatida and their species composition differed between lakes and pools, but the total abundance of mites was similar. Abundance of most species was low, and only 13 had dominance indices (D) exceeding 1%. The acarofauna of both lakes was similar, as most abundant in them was Limnozetes foveolatus (D > 80%), and relatively abundant were Hydrozetes longisetosus, Limnozetes ciliatus, Punctoribates sellnicki, and Trhypochthonius nigricans. These species were absent or rare at the edges of pools K and LP. In the pools, differences in species structure of Oribatida were observed. At pool K, Trimalaconothrus maior was most abundant, accompanied by Hydrozetes octosetosus, H. lacustris, and Limnozetes foveolatus. At pool LP, Trimalaconothrus foveolatus was most abundant, which tolerates a wider range of humidity than T. maior; relatively abundant were also T. maior, Hydrozetes lacustris, and several species that were not found in the other bodies of water, including a generalist like Oppiella nova. In this study, Liochthonius furcillatus and Cultroribula berolina were recorded for the first time from Poland.

https://www.sciendo.com/pdf/10.2478/biolet-2013-0010

Moss mites (Acari, Oribatida) at the edges of bog lakes and pools in Brodnica Lakeland and Orawa–Nowy-Targ Basin (Poland)

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Anna Nowicka

Papers

Seasonal Dynamics of Oribatid Mites (Acari, Oribatida) in a Bog in Poland

Roztocze (Acari) strefy brzegowej dwóch jezior śródleśnych, o różnej jakości wody, w Borach Tucholskich = Mites (Acari) of the littoral zone of two midforest lakes with different water quality in the Tuchola Forest

Mechowce (Acari, Oribatida) glebowe strefy ekotonowej pomiędzy borem sosnowym a brzegiem jeziora lobeliowego Wielkie Gacno w Borach Tucholskich = Oribatid mites (Acari, Oribatida) ef ecotone between Scots pine forest and lobelias Lake Wielkie Gacno in Tuchola Fores

Moss mites (Acari, Oribatida) at the edges of bog lakes and pools in Brodnica Lakeland and Orawa–Nowy-Targ Basin (Poland)

Roztocze (Acari) strefy brzegowej dwóch jezior śródleśnych, o różnej jakości wody, w Borach Tucholskich