From alpine pastures to cropland – initial results from a country-wide earthworm monitoring initiative in Austria

Earthworms play a vital role in soil agroecosystems, representing a major part of the total soil fauna. Through their activities they provide essential ecosystem services, including improving soil structure, increasing nutrient availability for plants and ultimately supporting plant growth and boosting crop production. In a nutshell, they make a major contribution to maintaining soil health. However, while earthworms are generally regarded positively in agricultural settings, they are also threatened, e.g. by intensifying land use, certain agricultural practices and climate change. A British study has already found that earthworm abundances have declined significantly in recent decades, suggesting that earthworms are indeed under pressure. In addition, different earthworm species play different roles in the soil and maintaining their diversity is key to promoting soil health. Here we present the results of a recent field study in which 400 sites in Austria were sampled for earthworms in order to investigate the total earthworm biodiversity in arable land, grassland and field margins. The goal was (i) to describe the current state of earthworm biodiversity on agricultural land in Austria, (ii) to determine the most important factors driving earthworm biodiversity, and (iii) to investigate the geographic distribution of earthworms in the country and whether this is linked with future threats and opportunities. Preliminary results suggest that about 30 different species inhabit these agriculturally used fields, representing around half of the known earthworm biodiversity in Austria. While earthworm communities differed little between land uses, higher intensity farming was associated with lower earthworm abundance and biodiversity. This is likely due to a combination of management factors and environmental conditions. Further research will provide a more detailed understanding of these effects and their interactions and allow us to take steps to promote earthworm biodiversity and thus soil health in the future.