Truck drops

One of the problems facing the introduction of novel crops is the concerns about their spread into the natural environment. A long-term study of oilseed rape (canola) growing on the verges of one of Britain’s busiest motorways provides some encouragement that at least some crops find the going tough outside the field environment in which they are sown. Michael Crawley at Imperial College London and Susan Brown at the Winfrith Technology Centre in Dorchester (published in the Proceedings of the Royal Society online) have studied populations of oilseed rape growing in more than 3,500 quadrants at the side of London’s M25 motorway for ten years. The researchers found oilseed rape showed a wide range of temporal dynamics over the study period (decreases, increases, cycles, extinction, re-colonization and stasis). The most frequently observed pattern, however, involved classic ‘casual’ dynamics with populations lasting for just 1 or 2 years before local extinction. Part of their apparent persistence was due to spillage of seed from lorries taking oilseed rape to a processing plant. The crop was much less evident on the opposite carriageway leading away from the plant. The work suggests some crop plants may find it much tougher than is apparent when they go wild. Truck drops