Afforestation can make an important contribution mitigating the effects of changing climate and provide structural and functional benefits. Afforestation also provides challenges for forest managers connected with past land-use history; therefore, there is an urgent need to summarize knowledge about such habitats and point out the gaps in knowledge for planning future studies. Although post-agricultural forests cover a large forest area in Europe, our understanding of the mechanisms governing the below-ground environment is still poor, especially when soil fauna is considered. In this study, we revised knowledge about the soil environment and the response of soil fauna to afforestation on former agricultural lands located in Europe based on research articles from the ISI Web of Science database. Data came from various but distinct locations, compared forests with different types of agricultural lands, and presented previous knowledge about soil chemistry and accompanying soil fauna communities. Finally, we selected 15 studies, investigating soil fauna communities on post-agricultural lands. The meta-analysis was based on response ratio (R) for available data, although in many cases the data were incomplete. Results indicated that post-agricultural forests differ from arable lands in reference to soil pH, but not for soil organic matter and carbon content. Different soil animal groups were represented by a similar number of studies: microfauna (seven studies) and mesofauna (nine), whereas macrofauna were represented by five studies. Meta-analysis revealed that the response of soil fauna to afforestation differed between soil fauna size classes. Additionally, in total, 18 tree species, 12 soil types, and 20 soil parameters were provided in the literature but only a few of them were presented in a single study. Future studies should include the impact of microclimate, detailed stand characteristics and soil conditions, which could help to clearly describe the impact of certain tree species growing on certain soil types. In future soil fauna ecological studies, the data should include mean values, standard deviation (SD) and/or standard effort of means (SE) for abundance, species richness, diversity indices and number of collected samples. Providing the above mentioned information will give the broad audience the opportunity to include data in future comparative analyses.

Afforestation of post-agricultural land is one of the most important challenges of modern forestry, posed by economic demand and climate protection. Unfortunately, stands introduced on such degraded soils are not sustainable and their productive value is limited. The present study tested the effects of two substances—Humac and Alginite—on the community structure of mesostigmatid mites colonizing plots overgrown by Platanus × acerifolia (Aiton) Willd, also comparing them with the mite communities of arable field and 64-year-old stands of Pinus sylvestris L. and Quercus robur L. growing on post-agricultural land. A total of 306 mite individuals were recorded, belonging to 45 taxa and 14 families. The results indicate a moderately positive effect of Humac fertilization on the mite communities studied. A similar impact has not been demonstrated for Alginite. In contrast, all parameters studied (density, species richness and diversity of mite communities) reached the highest values in the P. sylvestris stand. Humac application harmonizes Mesostigmata mite community structures between young and older stands and may be considered a beneficial practice for the afforestation of former agricultural land.

The European beech (Fagus sylvatica L.) is a dominant tree species in European forests and it has a huge ecological significance and high economic value. Due to its large dimensions, it can produce large amounts of decayed wood (CWD) which may be critical for maintaining the population of many rare species including mites. Many studies focused on mite (Mesostigmata) abundance, species richness, or diversity in CWD, however, our knowledge on mite biomass is still scarce. Therefore, the main aim of that study was to recognize the Mesostigmata biomass in logs and adjacent soil. In total, 90 samples (125 cm3, 5 cm depth) were collected from European beech logs and soil with litter thickness. Soil samples were collected from ecotone zone (soil near the log) and further three distances—0.5 m, 1.0 m, 1.5 m away from the log. Body length and width were measured for each individual of rare species and in the case of common species at least for 10 individuals. Our study revealed the highest mite biomass in CWD and soil near to the log (ecotone). Total male biomass was the highest in CWD and differed significantly from all other soil microhabitats. Female biomass did not differ between soil and CWD, whereas deutonymphs biomass differed between CWD and soil 1.0 m away from the log. Mean abundance, species richness, and diversity did not differ between the microhabitats. Decaying logs were dominated by Janietella pulchella whereas soil by Veigaia nemorensis. In conclusion, decayed European beech logs maintain the highest male and deutonymph biomass when compared to adjacent soil. Beech logs are important microhabitats for Mesostigmata mite communities, where they reached the highest abundance.