ABSTRACT Paraná State has approximately 74 % of its territory destined for agricultural activities. Several agricultural management practices modify soil quality and biodiversity, including earthworm populations that can contribute to soil health. This study aimed to review the studies carried out in the state of Paraná, Brazil, focusing on earthworm populations (abundance, biomass, richness, proportion of native and exotic species) in different land-use systems. In total, 51 publications were compiled, including peer-reviewed papers, book chapters, dissertations and theses. We used studies that analyzed chemical and physical soil properties (n = 14) to perform a principal component analysis to explore the relationships between these properties and earthworm populations. In total, 90 earthworm species are known from Paraná, of which more than half (n = 46) may be new species that still must be formally described. Of the total, 24 are exotic and 66 are native species, though only 62 (16 %) of the 399 counties have earthworm records. Of the land-use categories sampled, the lowest abundance and biomass were recorded in annual crops under conventional tillage, and the highest populations were found in agroforestry systems. Higher earthworm abundance and species richness were related to higher chemical fertility (soil P and base contents), while biomass was related to higher silt and sand contents.

Resumo: As minhocas são frequentemente relacionadas a solos férteis e, também, bastante usadas como indicadores da qualidade ambiental. No entanto, para otimizar seu uso como bioindicadores, as populações de minhocas devem ser avaliadas juntamente com as variáveis ambientais e antropogênicas que regulam as suas comunidades. Esta revisão buscou identificar os atributos relacionados à amostragem de minhocas, físicos e químicos dos solos, e ambientais e antropogênicos avaliados em 124 estudos publicados que quantificaram a abundância de minhocas (>7.300 amostras) em 765 locais com diferentes tipos de clima, solos, uso da terra e sistemas de manejo no Brasil. Os atributos químicos e físicos do solo (exceto pH) foram menos relatados (≤50% dos estudos) do que outras variáveis ambientais, como data de coleta, altitude, temperatura, precipitação, tipo de solo e de clima, e uso do solo (>50% dos estudos). As minhocas foram raramente identificadas (24%) e poucos estudos (31%) mediram sua biomassa, embora a maioria tenha fornecido informações adequadas sobre o protocolo de amostragem. Com base na sua importância para a regulação das populações de minhocas, propõe-se um conjunto de variáveis que devem ser avaliadas no estudo de comunidades de minhocas e outros grupos da macrofauna do solo. Isso deve ajudar a guiar futuros estudos sobre minhocas no Brasil e em outros países, otimizar a coleta e a replicabilidade de dados, permitir comparações entre diferentes estudos e promover o uso de minhocas como bioindicadores da qualidade do solo.

Abstract: 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.

Resumo: Vários estudos têm caracterizado e delimitado assembleias de formigas subterrâneas. A extração de solo, um dos métodos utilizados para amostragem dessa fala, implica na remoção de monólitos. Um dos métodos mais utilizados na extração de monólitos é chamado TSBF (desenvolvido pelo Programa Tropical Soil Biology and Fertility). Esse método fornece dados extremamente relevantes sobre as espécies associadas ao solo. No presente estudo, nós caracterizamos as assembleias de formigas subterrâneas usando o método TSBF em diferentes áreas subtropicais do Neotrópico. Utilizamos dois delineamentos amostrais distintos. O primeiro delineamento resultou em 315 amostras de TSBF obtidas a partir da estratificação do solo. O segundo resultou em 270 amostras de TSBF mais 270 provenientes de armadilhas pitfall epigeicas. Esse material foi utilizado para delimitar espécies que ocorrem exclusivamente no estrato subterrâneo (TSBF) e não são encontradas na superfície do solo. Registramos um total de 281 espécies. Destas, 57 podem ser consideradas subterrâneas (baseado na ocorrência no respectivo estrato). Também verificamos que a maior ocorrência de formigas se deu nos primeiros 10 cm de profundidade. Devido à importância do uso de métodos que coletem eficientemente formigas subterrâneas, sugerimos o uso do método TSBF em estudos de estratificação de comunidades ou sua associação a armadilhas do tipo pitfall epigeica para delimitar assembleias estritamente subterrâneas.

Abstract: 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.