Weed seed predation in arable crops relates to semi-natural habitats in European landscapes

Greening policies require increased knowledge about interactions between semi-natural habitat (SNH) and ecosystem services such as pollination and pest control that are supported by these habitats at the landscape scale. The EU-FP7 project QuESSA (Quantification of ecological services for sustainable agriculture), aims to quantify how SNH composition and configuration affect weed seed predation levels in arable fields in Germany, Estonia, Switzerland, England, Hungary, Italy, in French vineyards and in Dutch orchards. In each case study (country-crop species combination), 18 fields were selected on separate farms. Landscape context around each focal field was digitized, characterizing all landscape elements wider than 3 m in a 1 km circle. Fields were selected to represent a gradient in the proportion of SNH in the surrounding landscape sectors. Fields had either a woody, herbaceous or no field margin adjacent to the transects, with 6 fields of each type. In each field, eight seed cards covered with a 1-cm wire mesh, containing 20 Poa trivialis and 20 Chenopodium album seeds were exposed for 7 days on two transects, 10 m apart, at four distances from the field margin. We used GLMs to model the expected seed predation in the fields as a function of variables characterizing the landscape, the margin habitat and distance from the margin. To link habitat and seed predation, a modelling approach was used that assumes that the amount of seed predation at a given target site is the sum of contributions from different sources in the surrounding landscape, according to their area and distance from the target. Semi-natural habitats in the landscape had significant effects on seed predation, but the size and direction of effect varied between studies, species of seed, and habitat type. This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration.