From cropland to alpine meadows: Earthworm diversity in agroecosystems across Austria

Soil is among the most species-rich habitats on Earth and soil organisms - especially earthworms - are important for sustaining and enhancing soil quality. Monitoring earthworm communities is thus crucial, both for using earthworms as a measure of soil quality, and to assess the status of earthworm biodiversity as they are under a multitude of different pressures. Although Austria is a hotspot for earthworm diversity, there is a profound lack of recent field studies. Here we present the first systematic assessment of earthworms in agricultural open land in Austria. We collected earthworms from 412 sites (arable fields, field margins, grasslands, and alpine meadows) following an altitudinal gradient from 114 to 2440 m a.s.l. We found 33 different species representing more than 50 % of the known species for Austria. Land use was identified as the most important driver of earthworm species richness, abundance, and biomass. Grassland showed the highest earthworm species richness and abundance, harbouring 70 % of all species found, while alpine meadows showed the lowest at only 36 %, though these species were rarely found anywhere else. Field margins did generally not differ significantly from arable fields, except for species richness, as field margins on average contained one additional species. Several soil properties were also important drivers, such as soil texture, C/N ratio and pH, which are likely also linked with altitude. We conclude that earthworms are suitable organisms to be used in national and international soil monitoring schemes, e.g. the EU soil monitoring law.