Methodological optimization for ecotoxicological community tests with Enchytraeids-extraction procedures and sampling...

Enchytraeids play important roles in ecosystems, contributing to the decomposition of organic matter, given the feeding activity in the litter and the interaction with soil microorganisms, affecting the regulation, flow, and cycling of carbon and nutrients in ecosystems. Despite their ecological relevance, enchytraeids are commonly neglected in soil biodiversity assessments. To develop a methodology to assess the effects of pollutants on natural communities of enchytraeids, some methodologies require optimization. This study aimed to evaluate the performance of the two extraction methods of the enchytraeid community to access their structural diversity, determine the sampling effort for each extraction method, and evaluate the survival of the specimens subjected in a post-extraction survival test. The samplings were collected in two municipalities in the South region of Brazil. In each area, two transects were established (one for the wet-hot extraction method and one for the wet-cold extraction method); each transect contained nine sampling points, and nine cores were collected. The nine cores were collected in a grid of 3 × 3 subpoints, spaced 0.3 m. The enchytraeids were identified until genus and morphospecies level. The extraction method did not influence the diversity accessed in the field. The sampling effort was positively related to the genus and morphospecies richness, with the cold extraction method requiring more samples to achieve a given fraction of species richness. Additionally, both extraction methods had similar effects on the survival of enchytraeids after extraction. These results contribute to the development of a methodology to assess the effects of pollutants on enchytraeids communities and help to fulfill the gap of knowledge about this important biological indicator.