Farming to help preserve nature, such as rewilding and organic schemes, may be worsening the biodiversity crisis, according to leading academics.
In an article published on 21 June, Professor Ian Bateman of the University of Exeter and Professor Andrew Balmford of the University of Cambridge said that rewilding and organic and 'nature-friendly farming' measures included in some government conservation policies risk reducing how much food is produced in a region, driving up food imports and increasing environmental damage overseas.
In the article, the academics urged policy-makers to consider an approach known as 'land sparing', which they suggest is cheaper, more impactful, and avoids the displacement of food production and loss of wildlife habitats overseas.
Land sparing involves finding lower-impact ways to boost yields in farmed areas in order to make space for larger, non-farmed areas of the landscape to be put aside for nature without increasing imports and damaging overseas wildlife.
The approach has been overlooked by policymakers, they say, because of a failure to consider the wider consequences of changes in land management, arguing that changes that boost wildlife locally seem superficially attractive, but if food production is reduced there are unavoidable knock-on effects elsewhere, which must also be taken into account.
They also cite the influence of the 'Big Farm' lobby in maintaining the status quo in agricultural policy, with land-sharing subsidies allocated using a flat rate per hectare, which disproportionately benefits the biggest farms – resulting in the largest 12% of farms taking 50% of all UK taxpayer subsidies.
Their article also debunks some of the benefits to biodiversity of three widely advocated green farming approaches. They argue that while policy-funded measures such as reducing the use of pesticides and fertilisers can sometimes increase populations of more common animals and plants on farms, it does little for endangered birds, invertebrates, plants and fungi species that need larger stretches of non-farmed habitat – and by lowering yields can also make matters far worse for biodiversity overseas.
Rewilding initiatives, where large areas of land are taken out of farming, can indeed benefit locally endangered species. But unless other areas see compensating increases in food output then this reduces local production, increases demand for food imports, and so damages biodiversity elsewhere.
They also argue that organic farming, where crops are produced without manufactured fertilisers and modern pesticides, is even more likely to be damaging. Relatively few species will benefit in the farmed area, and the substantially lower yields from this type of farming risk greatly increasing the need for food imports, and hence a country's impacts on biodiversity elsewhere.
Land sparing, in contrast, involves retaining or creating sizeable blocks of unfarmed land containing larger populations of the many species that depend on natural habitats, as well as boosting farm yields elsewhere in the region so that overall production is maintained or even increased.
Promising methods to boost crop and livestock yields more sustainably than current high-yield practices include genomic screening and gene editing to accelerate animal and crop breeding; using new advances in aquaculture to produce high-value foods with much lower environmental impacts; and, in tropical countries, greater access to improved pasture and veterinary care.
Professor Bateman, of the University of Exeter Business School, has advised seven UK secretaries of state for the environment in the past decade, and said: "The stakes are too high for policymakers to continue to ignore the promise of land sparing when so much research demonstrates that it is a far more effective approach than many of the strategies being deployed.
"Unless researchers and policymakers assess the overall, global effects of interventions aimed at addressing biodiversity loss and climate change, poor decisions that are unsupported by the data will at best under-deliver, and at worst exacerbate existential threats posed by the extinction and climate crises."
Balmford, A, & Bateman, I. 2023. Current conservation policies risk accelerating biodiversity loss. Nature. DOI: 10.1038/d41586-023-01979-x