How best to save biodiversity and protect agricultural yields? Should farmers integrate their land with natural features to attract wildlife, or farm intensively on sections of land while leaving designated wildlife habitat completely untouched?
This longstanding ‘sharing versus sparing’ debate has divided farmers, scientists, and NGOs for years. Now, a new study may have finally settled the argument: neither one nor the other is best overall. Instead, landscapes need to contain a mix of both in order to effectively protect biodiversity and feed the world.
“We wanted to show what the data is actually saying, trying to reconcile a debate that has become rather polarized,” says Eva Augustiny, a doctoral student in the Department of Food System Sciences at the Research Institute of Organic Agriculture in Switzerland, and a lead author on the new paper. Augustiny and colleagues also caution, however, that more evidence is needed still, to appropriately guide farmers’ activities.
In fact, a major concern the study authors have is that despite how loud the sharing vs. sparing debate has become, it rests on rather shaky empirical evidence. They know this because they trawled through the data, ultimately bringing together 57 peer-reviewed studies in their meta-analysis. Many of these studies were full of holes: for example some didn’t look at agricultural yields when exploring the issue. And most studies didn’t include criteria that would allow a comparison between sparing and sharing strategies.
But of the 57 studies, 17 did, and these became a focus for the researchers. After analyzing this subset of 17, the results showed something surprising: over half of the cases—52%—determined that a combination of sharing and sparing approaches at the landscape level was best for biodiversity. This means that according to those studies, biodiversity thrives best in landscapes that include farms which welcome in wildlife, but also contain areas of undisturbed habitat.
This majority finding blurs the clear fault lines of the ‘sharing vs. sparing’ debate, which usually implies that either one or the other is better for nature and yields.
There was, however, still a lot of variability in the 17 studies. Among them, 41% of the cases showed that land-sparing worked best, while 7% determined that land-sharing was the answer for maintaining production and biodiversity.
Meanwhile, the 40 remaining studies the researchers looked at lacked the basic criteria that would allow a comparison between the two approaches. But when their results were combined with the initial 17, the overall data played out roughly as follows: 34% found that a combination of sharing and sparing was best, 36% overall showed that sparing alone performed best, and 19% determined that sharing alone was the route to boosting biodiversity and better yields.
Across the general dataset, the varied results reflect the different contexts, metrics, and methodologies used in the 57 studies. And this is why it’s challenging to answer the question of whether we should get behind sparing or sharing: the data is patchy and uncoordinated, making it hard to draw clear conclusions on which strategy is best.
Something that makes this even murkier, the PNAS Nexus researchers say, is the focus of many studies on specialist and tropical species that require undisturbed, intact habitats and cannot thrive in shared farmland environments. This leads naturally to the conclusion that the only way to save those species is with a land-sparing strategy where food is intensively produced on constrained pieces of land.
Researchers worry that this side of the argument has taken hold as the best way to support biodiversity, when in fact land-sparing involves many caveats that are often overlooked, such as the wider ecosystem effects of more intensive pesticide and fertilizer use. “Studies from the land sparing fraction tend to be oversimplified, for example only focusing on maximizing yields, neglecting these adverse impacts of high-yield agriculture, and measuring biodiversity of species that tend to need large natural habitats,” says Augustiny. “Therefore, they seem to have strong arguments, however only for these very specific cases.”
This highlights the problem with drawing broad, global conclusions from individual studies or specific contexts, when the reality is so much more diverse and complex on the ground. So, instead of a polarizing ideological debate about whether sharing or sparing is better for biodiversity, what’s needed is for researchers to take their investigations to the regional scale, and build up more local data on how best to balance biodiversity with yields, the authors say.
“There is no universal solution,” Augustiny says. “Rather context-specific solutions are needed: biodiversity protection depends on both the presence of sustainable agricultural production areas and areas with least disturbed habitats in a landscape.”
Augustiny et. al. “Empirical evidence supports neither land sparing nor land sharing as the main strategy to manage agriculture–biodiversity tradeoffs.” PNAS Nexus. 2025.
Image: ©Anthropocene Magazine
