How long does it take to establish a field boundary with a small proportion of weeds? An example in semi-arid conditions

Context Field boundary (FB) establishment and conservation have been promoted to enhance biodiversity in agroecosystems. However, weeds can colonize these areas during the revegetation process, which might be a problem for adjacent fields. Data is necessary to facilitate acceptance of these structures by farmers. Objectives This work takes advantage of a unique opportunity to describe the plants establishing in a set of new FBs. The main aims were to describe species composition in a six-year period and to detect if FBs can be a weed source for surrounding agricultural land. Methods Data was collected in ten FBs in a semi-arid environment in north-eastern Spain (eight metres in width) created from 2003 to 2007 in a farm owned by the CITA Research Centre. Vegetation was recorded in spring in years 2006-08 and 2011-13 covering a time sequence that ran from establishment until an age of 10 years. The same data was recorded in adjacent winter cereal field centres (FCs) and existing boundaries of neighbouring commercial farms (CFBs) established decades earlier. Results Plant ground cover and total species richness increased rapidly in the FBs, remaining stable after approximately the fourth year. Different analysis confirm that vegetation in the FBs was different from that found in the FCs and CFBs; 10 years was probably a too short period for the FBs to develop a similar vegetation composition to that of the CFBs. Conclusions Data of this example support that establishing new FBs can promote plant diversity without infesting the surrounding fields with weeds.