Earthworm functional groups respond to the perennial energy cropping system of the cup plant ( Silphium perfoliatumLinnédeL. )

Biodiversity is a major issue in the sustainable production of bioenergy from biomass, since it is threatened by land use change and intensification. Functional biodiversity in soils is a major contributor to ecosystem services, essential for human well-being. We assessed the long term development of earthworm communities in a chronosequence of the perennial bioenergy plant Silphium perfoliatum L. and compared them to traditional biomass production from maize. The cultivation period covered by the chronosequence was 1-9 years. Abundances of anecic and endogeic earthworms increased with the age of the fields. Endogeic earthworms exhibited significant differences to younger stages later than anecic earthworms. A successive increase in biodiversity was observed with endogeic species of the genus Octolasion and epigeic species. They occurred in cup plant fields after 3 and 5 years, respectively. Overall, maize fields had decreased earthworm biomass and population densities as well as less functional diversity. Cropping systems of S. perfoliatum have positive ecological implications for soil biodiversity and according ecosystem services. Due to the facilitation of functional diversity, soil processes, such as water infiltration, erosion resistance and nutrient cycling, are expected to increase. Hence we suggest a potential for remediation of formerly intensively managed soils. S. perfoliatum is considered to be well suited for the diversification of bioenergy farming landscapes.