Earthworms in the state of Paraná, Brazil: State of the art

: 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.