Several studies have characterized and delimited subterranean ant assemblages. Soil extraction, one of the methods employed to access this fauna, employs the removal of monoliths. One of the most widely used methods for the extraction of soil sampling is called TSBF (developed by the Tropical Soil Biology and Fertility Programme). This method provides relevant data about the species associated with the soil. In the present study we characterized assemblages of subterranean ants using the TSBF method in different subtropical areas of the Neotropics. We considered two sampling designs in different localities. The first design resulted in 315 TSBF samples obtained from layers at distinct depths. The second design resulted in 270 TSBF samples and 270 epigaeic pitfall trap samples. This material was used to delimit the species that occur exclusively in the subterranean stratum (TSBF) and that are not found on the soil surface. A total of 281 species were recorded. Of these, 57 can be considered subterranean, based on their occurrence in subterranean strata. We also verified that the highest occurrence of ants was in the first 10 cm of soil depth. Due to the importance of using methods that efficiently extract the subterranean ant fauna in studies, we suggest the TSBF method should be used to sample ants or to associate this method with epigaeic pitfall traps to delimit strictly subterranean assemblages in specific community stratification studies.

No-tillage (NT) agriculture represents a great advance in soil conservation in tropical and subtropical zones, occupying more than 32 million ha in Brazil in 2017. No-tillage systems can promote earthworm populations, which can improve soil physical and chemical properties, thus enhancing the benefits of NT for soil conservation and ecosystem services. Furthermore, earthworms can be used as indicators of the quality of NT systems. Here, we summarize the studies that evaluated earthworm populations in NT systems between 1986 and 2016 in Brazil, highlighting important gaps in knowledge. The studies were highly skewed geographically, with most data from southern and southeastern Brazil, and had very little information from the two states with the greatest NT area (Mato Grosso and Rio Grande do Sul) which together represent 43% of Brazilʼs NT area. Abundance values ranged from 0 to 660 ind. m −2 , with a mean of 91 ± 129 ind. m −2 (±SD), and at least 33 species were identified in NT systems. However, 73% of sites were considered to have poor and moderate soil quality based on their earthworm populations, raising concern regarding soil quality levels in Brazilian NT systems. Climate, soil and management conditions are important drivers of earthworm populations in Brazilian NT systems and future earthworm surveys in NT systems should provide ample data on these attributes, as well as on earthworm species, in order to improve their use as soil quality bioindicators. Highlights

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Earthworm populations often increase with the adoption of no-tillage (NT) practices, but few studies have evaluated earthworm diversity in these agroecosystems. In the present study we assessed earthworm species richness in 40 sites under NT and six native Atlantic forest fragments in Western Paraná, Southern Brazil. At each site earthworms were sampled quantitatively (n=5) and qualitatively (n=5), by handsorting soil monoliths (20 x 20 cm width x 20 cm depth), totaling 460 samples overall. Earthworms were killed and fixed in 96% ethanol, counted and identified. Overall, 18 species were found, in the families Acanthodrilidae, Glossoscolecidae, Megascolecidae, Rhinodrilidae and Ocnerodrilidae, of which 10 were native and eight exotic. No-tillage agroecosystems had larger earthworm populations and higher species richness overall than native forests, although this was mainly due to colonization of these agricultural fields by exotic species. Mostly native species were found in the Atlantic forests, highlighting the importance of these habitats as refugia for native earthworm species conservation.

Abstract:The soil mesofauna plays a role in organic matter comminution and decomposition, and can be used as bioindicators, since they are sensitive to soil management, vegetation and climate changes. Hence, this study aimed to evaluate mesofauna density and diversity in different land use systems to identify faunal relationships with soil properties, management and seasonality. The study area included five land use systems in Ponta Grossa municipality, Paraná State: integrated crop-livestock (ICL), integrated crop-livestock-forestry (ICLF), grazed native pasture (NP), Eucalyptus dunnii plantation (EU) and no-tillage (NT) cropping systems. In each system, eight soil samples for mesofauna were collected with Berlese funnels of 8 cm diameter along a transect in three replicate plots of 50 m × 100 m. For physical and chemical analysis, soil was sampled at five points per plot in two seasons: winter 2012 and autumn 2013. Data were statistically analyzed using ANOVA and Duncan's test (P < 0.05), nonparametric statistics (when necessary) and redundancy analysis (RDA). Diversity was calculated based on the group richness and Simpson index. The main mesofauna groups found were: Acarina, Collembola and Hymenoptera. Diplopoda, Enchytraeidae, Isopoda, Collembola, Hemiptera, Hymenoptera and Coleoptera larvae were more abundant in autumn than winter. Soil moisture was the main factor responsible for higher mesofauna abundance in autumn. Integrated production systems, especially ICLF had similar invertebrate community abundance and composition with EU, while NT favored Oribatid mites, although the use of insecticides, herbicides and fungicides reduced total mesofauna density. Most correlations between mesofauna and physical-chemical attributes in the winter were not observed in the autumn and vice versa, revealing that there are more factors involved in regulating soil mesofauna distribution.