Earthworm and soil microbial communities in flower strip mixtures

Abstract

Aims Incorporation of flower strips is an agricultural measure to increase aboveground biodiversity and ecosystem services. Although soil communities are key components of terrestrial biodiversity and drive important ecosystem services, their abundance, diversity, and composition in flower strips remain largely unexplored. Here, we shed light on earthworms and soil microorganisms in flower strips. Methods We sowed a grassy field margin vegetation as well as two annual and two perennial flower strip mixtures in fully randomized plots of 9 × 28 m in three different types of soil in Germany. Two years following sowing, we determined earthworm communities using chemical extraction and investigated the soil microbiome using real-time PCR (archaea, bacteria, fungi, and soil-N-cycling genes) and amplicon sequencing (bacteria and fungi). Results Different plant mixtures (i.e. field margin, annual and perennial flower strips) harbored distinct earthworm and soil microbial communities. Earthworm density and biomass declined or remained unaffected in annual flower strips but increased in perennial flower strips as compared to the field margins. Arbuscular mycorrhizal fungi showed greater diversity and relative abundance in non-tilled (i.e. field margin and perennial flower strips) than in tilled plant mixtures (i.e. annual flower strips). Conclusions We attribute changes in earthworm and microbial communities mainly to the effect of tillage and plant diversity. Overall, we suggest that perennial flower strips serve as refugia. Future studies should compare soil biota in perennial flower strips to those in adjacent fields and investigate whether the promotion of soil communities extends into adjacent fields (‘spillover’).

Soil–Plant–Pollinator Relationships in Urban Grass and Meadow Habitats: Competing Benefits and Demands of Tall Flowering Plants on Soil and Pollinator Diversity

“…In their meta-analysis, Zhang et al [53] identified an average 10% increase in soil fauna diversity in more diverse plant mixtures, compared to corresponding monocultures. Soil fauna diversity has, however, been previously observed to decline in field habitats with annual flower planting (similar to the 'sown flower' habitat type surveyed here) but increase with perennial plant species mixes [54]. As annual plants need to be replanted, while perennial plants do not, our observed decline in soil fauna diversity from TG to SF habitats may reflect greater disturbance due to re-sowing annual seeds and removing woody debris which acts as a habitat and food resource [24].…”

Flower Strips as an Ecological Tool to Strengthen the Environmental Balance of Fields: Case Study of a National Park Zone in Western Poland

“…Interesting results concerning annual and perennial flower strips located in areas adjacent to Poland (Germany) were obtained by Bednar et al [60]. They showed that strips of flowers with different life cycles are habitats for distinct communities of earthworms and soil microorganisms.…”