Earthworm communities in the Austrian biodiversity hotspot region Waldviertel: Effects of site vs landscape factors

Biodiversity monitoring programs often focus on aboveground organisms but ignore soil organisms. Among soil organisms, earthworms (Lumbricidae) are vital macrofaunal components of soil ecosystems and serve as bioindicators of soil health due to their significant ecological functions and interactions with above – and below-ground organisms. Moreover, earthworm species richness is crucial for biodiversity monitoring because of its manageable diversity and ease of sampling. This study aims to investigate the distribution of earthworms in the open landscape and potential site- and landscape-level factors influencing their distribution.

The study was conducted in the Waldviertel region of Austria, bordering to Czech Republic and Slovakia. The region is characterized by a dense network of Natura 2000 nature conservation areas and is known for its high biodiversity and fragmented landscape with many semi-natural structures. Additionally, the identified threats and pressures to Natura 2000 sites in the region, such as eutrophication, intensive grassland management, and landscape simplification are considered in terms of their impact on earthworms. In particular, we focused on the effects of semi-natural landscape elements, such as hedgerows or grass strips, on earthworm abundance and diversity. Hedgerow soils, characterized by high organic matter content, litter cover, and structural complexity, provide ideal habitats for earthworms.

The objectives of this study were to (1) assess earthworm communities (biomass, abundance and species richness) in grasslands and arable land, (2) investigate the influence of soil chemical and physical parameters, and intensity of agricultural management, and (3) examine the extent to which landscape structures at different scales influence earthworm communities. Preliminary analyses suggest that earthworms are influenced by both site-level and landscape-level. By linking earthworm communities to landscape features, this study aims to contribute to a better understanding of soil life and its role in sustainable land management. Additionally, promoting earthworm populations may have benefits for other soil organisms, soil health and overall biodiversity.

The study was conducted as part of the Austrian soil biodiversity monitoring project “BodenBiodiv” funded by the Austrian Biodiversity Fund and the Next Generation EU.