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.

Amazonian Dark Earths (ADEs) are fertile anthropic soils found throughout Amazonia, resulting from long-term occupation by pre-Columbian societies. Although the chemistry of these soils is well known, their biodiversity, particularly soil invertebrate communities have been neglected. To address this, we characterised soil macroinvertebrate communities and their activities in ADEs, comparing them with adjacent reference soils under forests and agriculture, at nine archaeological sites. We found 667 morphospecies and a tenacious pre-Columbian biodiversity footprint, with 40% of species found exclusively in ADEs. Soil biological activity was higher in ADEs than in adjacent soils, and associated with higher biomass and richness of organisms known to engineer the ecosystem. We show that these habitats have unique species pools, but that contemporary land-use causes nutrient loss and threatens their diversity. Both past and present human activities alter biodiversity and its distribution in Amazonia, and further efforts are needed to recognize and preserve these ADEs and their biodiversity.

Earthworms are often related to fertile soils and are also frequently used as environmental quality indicators. However, to optimize their use as bioindicators, earthworm populations must be evaluated together with the environmental and anthropogenic variables regulating their communities. This review sought to identify the earthworm-sampling, soil chemical and physical, and environmental and anthropogenic attributes evaluated in 124 published studies that quantified earthworm abundance (>7,300 samples) in 765 sites with different types of climate, soils, land use, and management systems in Brazil. Soil chemical and physical attributes (except pH) were less reported (≤50% of studies) than other environmental variables such as sampling date, altitude, temperature, precipitation, climate and soil type, and land use (>50% of studies). Earthworms were rarely identified (24%) and few studies (31%) measured their biomass, although most provided adequate information on sampling protocol. Based on their importance in regulating earthworm populations, a set of variables is proposed to be evaluated when studying earthworm communities and other macrofauna groups. This should help guide future studies on earthworms in Brazil and other countries, optimize data collection and replicability, allow comparisons between different studies, and promote the use of earthworms as soil quality bioindicators.

The Campos Gerais region of Paraná are on an ancient plateau of sandstone origin and are covered with a diverse vegetation including mainly grasslands and various types of Atlantic Forest (particularly Araucaria forest). The region represents an important natural capital for biodiversity conservation as well as for agricultural and forestry production. However, little is known of the species richness and diversity of soil macroinvertebrates in this region. In the present study we evaluated earthworm species occurrence and richness in five land use systems (LUS) in the southern part of the Campos Gerais in Lapa county. Earthworms were handsorted from up to 18 soil monoliths on five occasions over three years (Feb. 2014, Feb., Mar., Nov. 2015, Jul. 2016) in the following LUS: old native forest, native grassland, young regenerating forest and grass lawn in the Uru Reserve and annual crop fields (soybean) in neighboring private farms (not all systems were sampled on all occasions). Nine earthworm species belonging to four families and five genera were found, of which six were native and three exotic species (Dichogaster gracilis, Amynthas gracilis, A. corticis). Of the native species, Urobenus brasiliensis and Andiorrhinus duseni (a large bodied-worm) are already well known from S and SE Brazil, while the remaining four were new species that require further description (Fimoscolex n.sp.1 and n.sp.2, Glossoscolex n.sp.1 and n.sp.2). In general, more species were found in February (summer) than March and November. The cropping system (soybean) had the lowest abundance and species richness in relation to other sites, although in the young and old forests no earthworms were found on some sample dates. Given the several new species found in this small reserve, and the relatively few sites studied thus far in the Campos Gerais, further efforts are needed to adequately characterize the earthworm fauna of the region, from which many other species are expected.