What are sustainable limits to ruminant food production? Exploring biodiversity.

Livestock are important food sources and means of livelihood for millions, but production also puts considerable pressure on our planet. Many have argued that using global grazing areas for food production is sustainable, for example because grazing animals can have positive effects on biodiversity.

But all grazing everywhere is not automatically good for biodiversity.

In a new study, published in Nature Sustainability, researchers from among others the Centre have explored limits to ruminant food production from a biodiversity perspective.

“The overarching question we looked at is where and how grazing could take place if we set up certain boundaries for production based on biodiversity. And, if we do so, how much meat and milk would theoretically come from such production,” explains Centre researcher Kajsa Resare Sahlin, who is the lead author of the article.

In their study, they explore biodiversity-based limits from two perspectives.

Firstly, some grazing areas globally are recently converted for animal production, while other areas have ancient legacy of grazing. Using presence of historical grazing as a requirement in their study, the researchers explore a new way of thinking about what lands could be considered available for meat and milk production.

Secondly, past research has found that low-intensity grazing often has positive effects on biodiversity while overgrazing can cause of biodiversity loss. So, the researchers set a cap to the number of animals on the grazing areas.

So, how much meat and milk would this land use and low-intensity production theoretically provide? Based on comparison with what is currently produced on global grasslands, it corresponds to around 10% of milk, and 26-40% of meat.
One factor impacting the amounts of production is that the researchers have mirrored the current mix of cows, sheep and goats in every country.

“Many countries currently put all available feed into only producing beef in specialised systems. But if more production was dairy-based, providing both milk and meat, there would be more food production from the same amount of feed and land,” explains Kajsa Resare Sahlin.

The study also discusses that ‘biodiversity-friendly’ grazing can be interpreted in different ways.

“This is one take on animal production that might be better for biodiversity, and we hope there will be more research on what ‘biodiversity-limits’ could be. But more than anything, I think the study really contrasts the reality that current trends are pushing production in quite the opposite direction – that worries me,” says Kajsa Resare Sahlin.