Farming should be as high-yield as possible so it can be limited to relatively small areas, allowing much more land to be left as natural habitats while still meeting future food targets, according to new research.
Most species fare better under this “land sparing” approach than if farming tries to share land with nature – as wildlife-friendly agriculture still damages most biodiversity and requires far more land to produce the same amount of food.
This is the conclusion of University of Cambridge researchers, who took into into account over 2,500 individually assessed plant, insect and vertebrate species from five continents.
The review, conducted by Professor Andrew Balmford, also suggests that “land sparing” sequesters more carbon.
“Figuring out how to feed, clothe and power 11 billion people without causing mass species extinction and wrecking the climate is this century’s greatest challenge,” he said.
“Preserving diverse life while meeting humanity’s needs will mean enormous trade-offs, but the evidence is starting to point in one direction.”
In a paper published in the Journal of Zoology, he lays out the case for securing the highest levels of production from land already farmed, in order to spare remaining wilderness from cows and ploughs.
He added: “Most species fare much better if habitats are left intact, which means reducing the space needed for farming. So areas that are farmed need to be as productive as we can possibly make them.”
Some species thrive on traditional farmland, particularly in Europe, where light grazing by livestock can imitate “disturbance” once caused by large prehistoric mammals, creating habitats for many species that otherwise struggle.
As such, some low-yield farming should be factored in, the researchers explained, but at a low level.
The UK government-commissioned National Food Strategy (NFS), published in the summer, recommended that his “three-compartment” model – harnessing high-yield farming in order to leave space for many more protected habitats, with pockets of traditional agriculture to preserve farmland-associated species – should form the basis of a new “Rural Land Use framework”.
The NFS points out that around 21% of farmed land in England will need to be re-wilded to some extent or used for biofuel if the UK is to meet its net zero targets, and that the entire bottom third of farmed land produces just 15% of English agricultural output.
Cambridge University's latest paper summarises a decade of global research on trade-offs between crop production and biodiversity.
This includes Cambridge-led studies on bird and tree species in India and West Africa, finding that – while all species are “losers” if mid-century food targets are met – more species “fare least badly” under extreme land sparing: concentrated farming that allows for more natural habitat.
“Colleagues have replicated these findings in field sites ranging from Mexico and the Pampas to Colombia and Kazakhstan,” said Professor Balmford.
“Most species are specialized to particular environments. Even minor disruptions reduce their populations. This is why so many species decline even with gentler farming.”
Retaining and increasing habitats to create patchwork landscapes of nature and mostly high-yield farming will not just preserve species in isolated areas but allow them to “seed” and repopulate entire regions and nations.
Professor Balmford highlights the success of just four square kilometres of restored wetland near Lakenheath in the east of England.
Covered with carrot fields as recently as 1995, the site is now a launchpad for egrets spreading northwards under climate change, and home to the first breeding cranes seen in The Fens for over 300 years.
In addition to biodiversity benefits, emerging evidence from areas including the Andes, the US and the UK suggests “land sparing” is an ally in the fight against climate change, as carbon storage levels are higher if high-yield production allows for more natural vegetation.
Previous research suggests that if 30% of UK land was spared for woods and wetlands, it could store enough carbon to offset almost all emissions from UK farming by 2050 – and provide a boost to wildlife.
Support for “land sparing” is not a whole-hearted endorsement of industrial production, says Professor Balmford. Driving up farm yields also means supporting smallholder farmers and adopting nature-based agricultural science.
Farming systems can only be usefully compared when they’re actually meeting society’s food needs. “You can’t convince people to save nature if they are hungry.
"We need to ensure we can harvest enough from the biosphere while preserving the planet,” he added.
“Conservation has to be pragmatic if we are to interrupt an ecological catastrophe.”
