Farming intensity and field margin complexity affected post-dispersal weed seed predation by arthropods in sunflower crops

MOONEN, ANNA-CAMILLA; MOLINA, GONZALO A R; BOCCIO, GIONATA; POGGIO, SANTIAGO L

Poznan

Simposio; IOBC/WPRS Working Group ?Landscape management for functional biodiversity?; 2014

Weed seed predation can be considered as a special type of biological pest control. Farming intensity and complexity of field margins adjoining to crop fields are expected to affect seed predation levels in the regularly cropped area. Impact of both factors was determined in six sunflower fields in the Pisa Plain (Italy). Arthropod seed predation was measured above- and below-ground by comparing the seed removal of two common weeds differing in seed size (small: Amaranthus retroflexus L.; large: Lolium multiflorum Lam.). Farming system intensity defined the largest difference in weed seed predation for both species. The presence of a complex, undisturbed margin adjoining to fields increased seed predation only when conventionally managed. Unlike the prediction, seed predation was higher in field centres than close to field margins. In organic fields, seed predation for both weed species was lower below-ground than above-ground, whereas the opposite was observed in the other farming systems. Arthropod predation levels of weed seeds could be encouraged within regularly cropped fields by managing both farming intensity and field margin complexity.