Modelling the effects of farmland food webs of herbicide management in the agricultural ecosystem Final report A R Eberst 1 , J. L. Bown 1 , D. Bohan 2 , D. Brooks 2 , R. Caldow 3 , G. Champion 2 , J. Cussans 2 , S.E.A. Le V. dit Durell 3 , L. G. Firbank 3 , A. Haughton 2 , C. Hawes 4 , M. Hill 3 , M. Heard 3 , M. May 2 , J. Perry 2 , S. Petit 3 , A. Qi 2 , P. Rothery 3 , R. Scott 3 , G. R. Squire 4 , R. Stillman 3 , I. Woiwood 2 and J. W. Crawford 1 . 1 University of Abertay Dundee 2 Rothamsted Research 3 Centre for Ecology & Hydrology 4 Scottish Crop Research Institute Objectives: 1 – Review and assess existing modelling approaches, and then to construct a new alternative modelling framework that can be used to predict the effects of herbicide and insecticide management systems on plant and invertebrate food resources and foraging birds in the breeding season and during winter. 2 – Propose a number of crop, field and farm management scenarios that would act as a driver of weed and insect population change and thus have implications for the scaling up processes. 3 – Review existing and new structures for a model that will forecast changes of weed populations in winter and summer with respect to herbicide regime and crop management systems. 4 – Evaluate arable weed and invertebrate species as resources for species higher in trophic levels, with special reference to breeding and wintering birds. 5 – Review existing and new structures for a model that will relate bird populations to food resources within arable fields. 6 – Propose methods of scaling up bird / food models to include other factors and a wider geographic range. 7 – Integration of results and development of recommendations for implementation of systems-based modelling approach for forecasting farmland bird populations using data from the Farm Scale Evaluations.