Perennial alternative crops for biogas production increase arthropod abundance and diversity after harvest – results of suction sampling and metabarcoding

Abstract

The effects of novel perennial energy crops on arthropod abundance and diversity were tested using three fi eld trials in Bavaria. Established cup plant (Silphium perfoliatum), Virginia mallow (Sida hermaphrodita) and tall wheat grass (Thinopyrum ponticum) plots were sampled in autumn using a modifi ed leaf blower and their arthropod faunas compared with that recorded in maize plots. At the time of sampling, maize, cup plant and Virginia mallow had already been harvested and samples from the remaining stubble were compared with those from open ground. Collembola were the most abundant group. The highest abundance and diversity of arthropods was recorded in tall wheat grass, with Hemiptera and Aranea especially benefi tting from the green and taller vegetation. Post-harvest cup plant and Virginia mallow plots harboured a more diverse and more abundant arthropod assemblage than maize plots. Stubble was identifi ed as a suitable habitat for arthropods in agricultural fi elds. In conclusion, the integration of perennial energy crops into existing biogas production systems could play an important role in supporting arthropods in agricultural landscapes by providing crucial structures and resources, such as the grassy vegetation of tall wheat grass in autumn and the long-lasting stubbles of cup plant and Virginia mallow.