The thought of weeds thriving in a farm’s arable crops is usually cause for concern, but it might be one way to help invertebrates to recover according to a new study by the Game & Wildlife Conservation Trust (GWCT). They found that as the number of arable weeds increased, so did the number and diversity of invertebrates. This means more food for farmland birds and may mean more food for pollinators and more natural control of crop pests (biological control).
Researchers were keen to unlock the best way to improve insect number, so they reviewed 18 years of research into winter wheat, the most widespread global crop, to investigate the link between weeds in crops and invertebrate numbers on farmland. With popular agri-environment options focusing heavily on the edges of the farm, such as hedgerows, woodland and headlands, the results suggest that the answer might lie closer to the crops.
By focusing on winter wheat, the study recognises farmers’ primarily role – providing food to a growing global population with good crop yields – whilst balancing increasing pressure to support and preserve biodiversity on their land.
The study showed that all groups of invertebrates increased as arable weeds increased. The relationship was stronger for invertebrates that eat plants, compared to those that are predatory, but both groups increased with weed cover. Increased weed cover also caused an upturn in chick food availability.