Organic farms increase biodiversity on nearby conventional farms

photo credit; Angelia Sims photo credit; Angelia Sims

Many studies have demonstrated that organic farms harbor higher biodiversity than conventional farms. However, until now, few studies have examined whether the presence of organic farms influences the amount of biodiversity on surrounding conventional farms. A recent study, published in the Proceedings of the Royal Society of London B – Biological Sciences, has shown that plant biodiversity in conventional farming fields increases when organically farmed fields are present in the surrounding landscape. Researchers sampled weed species in 465 French wheat fields in which included organically and conventionally managed fields. Samples were collected over a four-year period and were taken from the field core (center of the crop) and field margin (the land between the field border and first row of crops). The study found that similar to previous studies, organic farming fields harbored higher weed diversity than conventional farms and that diversity was higher in field margins rather than the field core. They also found that when organic farms were in the landscape, conventional farms were more likely to have higher levels of weed diversity—suggesting that the benefit of having an organic farm nearby, outweighed the negative effects of conventional farming methods, such as herbicide applications, on weed diversity. Because wild plants provide food and habitat for beneficial insects, pollinators and other animals, maintaining weed diversity is important for all biodiversity. While organic farms provide the most benefit to biodiversity, the presence of even some organic farms among conventional farms benefits biodiversity across the entire landscape.