Consequences of Spiraea tomentosa invasion in Uropodina mite (Acari: Mesostigmata) communities in wet meadows.

Vegetation cover has been consistently reported to be a factor influencing soil biota. Massive spreading of invasive plants may transform native plant communities, changing the quality of habitats as a result of modification of soil properties, most often having a directional effect on soil microorganisms and soil fauna. One of the most numerous microarthropods in the litter and soil is Acari. It has been shown that invasive plants usually have a negative effect on mites. We hypothesized that invasive Spiraea tomentosa affects the structure of the Uropodina community and that the abundance and species richness of Uropodina are lower in stands monodominated by S. tomentosa than in wet meadows free of this alien species. The research was carried out in wet meadows, where permanent plots were established in an invaded and uninvaded area of each meadow, soil samples were collected, soil moisture was determined and the mites were extracted. We found that Uropodina mite communities differed in the abundance of individual species but that the abundance and richness of species in their communities were similar. S. tomentosa invasion led primarily to changes in the quality of Uropodina communities, due to an increase in the shares of species from forest and hygrophilous habitats. Our results suggest that alien plant invasion does not always induce directional changes in mite assemblages, and conclude that the impact of an alien species on Uropodina may cause significant changes in the abundance and richness of individual species without causing significant changes in the abundance and diversity of their community.

Overwintering Culex torrentium in abandoned animal burrows as a reservoir for arboviruses in Central Europe.

Culex pipiens s.s./Culex torrentium belong to the most widespread mosquito taxa in Europe and are the main vectors of Sindbis, West Nile and Usutu virus. The adult overwintering females can act as reservoir for these arthropod-borne viruses (arboviruses), thus contributing to their local persistence when transmission cycles are interrupted during the winter. However, the main overwintering sites of Cx. torrentium are unknown. In a study from 2017, 3455 Cx. pipiens s.s./Cx. torrentium specimens were collected from abandoned animal burrows in Poznan, Poland. These specimens were retrospectively identified to species-level with a PCR assay, which revealed Cx. torrentium as dominant species (> 60%). Motivated by these results, we conducted a field study from February to July 2022 to systematically analyse the overwintering site patterns of Cx. pipiens s.s./Cx. torrentium. Mosquitoes were sampled using pipe traps in abandoned animal burrows (n = 20) and with aspirators in nearby anthropogenic overwintering sites (n = 23). All Cx. pipiens s.s./Cx. torrentium were screened for Flaviviridae RNA. In total, 4710 mosquitoes of five different taxa were collected from anthropogenic sites. 3977 of them were identified as Cx. p. pipiens/Cx. torrentium (Cx. p. pipiens: 85%, Cx torrentium: 1%, pools with both species: 14%). In contrast, only Cx. p. pipiens/Cx. torrentium (1688 specimens) were collected from animal burrows dominated by Cx. torrentium (52%), followed by pools with both species (40%) and Cx. p pipiens (8%). A single pool of 10 Cx. torrentium specimens collected from an animal burrow was positive for Usutu virus. The detection of Usutu virus demonstrates that Cx. torrentium can act as winter reservoir for arboviruses. Abandoned animal burrows may by the primary overwintering site for the species and should be considered in future surveillance programmes, when sampling overwintering mosquitoes.

Badger Meles meles as Ecosystem Engineer and Its Legal Status in Europe.

The European badger plays an important role as a natural factor shaping species diversity in forests. Its extensive setts can be used by many other animals as shelters. Soil perturbations in their setts support plant communities that differ from the matrix landscape. The badger is also an effective seed disperser. We investigated its role as an ecosystem engineer in preserving species diversity and discussed its legal status across Europe. In most European countries (69.3% of the continent), the badger is hunted, sometimes year-round. The hunting season lasting through winter until early spring may have a negative effect on badger populations, especially when cubs are born in February. Although this species is Red Listed in 19 European countries (with categories ranging from LC to EN), the badger is strictly protected by law in 30.7% of its European range. A reduction in badger populations may limit its ecosystem services (seed dispersal, topsoil disturbances, microhabitat creation). Much new data on the importance of badgers in ecosystem engineering has allowed us to reconsider how we manage badger populations.

Pollen morphology and variability of invasive Spiraea tomentosa L. (Rosaceae) from populations in Poland.

The aim of this study was to investigate the pollen morphology and the ranges of intraspecific and interindividual variability of the North American steeplebush-Spiraea tomentosa L., an invasive species in Poland. Steeplebush inflorescences were collected randomly from 30 localities of S. tomentosa in Poland. In total, 900 pollen grains were analysed with both a light and a scanning electron microscope. Nine quantitative and three qualitative pollen features were studied. The diagnostic features were: exine ornamentation (size and direction of the muri), operculum and perforation size. For the first time, the intraspecific and interindividual variability of the pollen grains of the highly invasive S. tomentosa were investigated. Pollen grain features were so similar, that they did not allow to differentiate individual samples of S. tomentosa and only groups of samples were recognized.