Plant-mediated effects of soil invertebrates and summer drought on above-ground multitrophic interactions

摘要: 1. We conducted a large-scale field study to determine how the interactive effects of earthworms (Aporrectodea caliginosa) and summer drought affected plant communities containing barley (Hordeum vulgare), shepherd’s purse (Capsella bursa-pastoris) common groundsel (Senecio vulgaris), such then influenced populations aphid Rhopalosiphum padi its parasitoid, Aphidius ervi. 2. Total biomass decreased by around 25% with drought, but was increased presence earthworms over 11%. The on H. vulgare differed in monocultures mixed communities. In monocultures, earthworms had biggest impact, increasing biomass, had effect multi-species communities, causing decrease biomass. 3. Drought an extremely negative impact on S. vulgaris shoot root this was ameliorated roots when were present. Capsella bursa-pastoris was not significantly affected or earthworms. caused significant increase nitrogen concentrations all plants, including H. (from19.2 23.8 mg g)1). 4. total, 35 234 aphids recorded, which 3936 parasitized. conditions reduced aphid abundance 50%. interaction moderated earthworms, further declines R. under conditions, most notably monocultures. 5. plant-mediated (negative positive, respectively) on R. cascading parasitoid, ervi, declined with reduced numbers padi. addition, A. ervi abundance beyond its impacts density, suggesting reduced prey quality as well quantity. 6. Synthesis. This demonstrated predicted climate change (i.e. summer rainfall) interactions between above-ground multitrophic groups. These seen differ multi-species communities, suggesting that changes above-ground–below-ground linkages response may influence future.