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Biodiversity Loss Is Threatening Our Food Supply

At its heart, it's a matter of economics.
Holstein cows make up the vast majority of the US dairy herd. Image via F.d.W./Flickr

We're in the middle of a mass extinction worldwide, which will make the world's ecosystems more susceptible to drastic change. But biodiversity loss isn't limited to wild species. According to the head of a UN panel on biodiversity, domesticated plants and animals are also seeing diversity declines.

Dr. Zakri Abdul Hamid, which was elected in January to head a new UN panel on biodiversity, didn't pull any punches in his first public remarks. There is mounting evidence, he said, that "we are hurtling towards irreversible environmental tipping points that, once passed, would reduce the ability of ecosystems to provide essential goods and services to humankind.”

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The decline in domesticated species diversity is not a new concern. According to a 2010 paper in Animal Genetics, high tech breeding and feeding processes (think artificial insemination and custom feed blends) have enabled agricultural scientists and farmers to develop breeds that produce more milk, meat, or grain than ever before. But than means highly productive breeds have replaced local ones across the world.The UN's Food and Agriculture Organization has noted that up to 30 percent of the world's 4,500 or so livestock breeds are at risk of extinction; Zakri put the latest number at around 22 percent.

At its heart, it's a matter of economics. We need more food grown more cheaply to feed a growing world, and developing animal and plant breeds that can do so is a major part of the puzzle. The problem lies in how homogenous our food supply has become.

According to Hamid's panel, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), about 75 percent of genetic diversity was lost in crops worldwide in the last century. Of the tens of thousands of edible plant species out there, around 60 percent of plant calories consumed by humans come from just rice, maize, and wheat.

On the livestock front, more than 80 percent of dairy cows in the US are Holsteins. Three breeds of beef cattle—Angus, Hereford, and Semmental—make up 60 percent of the US beef cattle herd. Three breeds make up three quarters of our pig stocks. And two dozen breeds of poultry are listed as critical or threatened (including the wonderfully named Dorking), according to the American Livestock Breeds Conservancy.

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Like wild ecosystems, a more homogenous human food supply is more susceptible to drastic change. Imagine if a superlethal version of mad cow disease cropped up and started attacking Holstein cows—the US milk supply would be in grave danger. Or if low genetic diversity in corn crops started producing runaway anomalies. They're not immediate threats, but ones that become potentially more catastrophic as diversity declines.

What's the answer? The Animal Genetics paper cited above suggests that even low-production breeds have high value as sinks of genetic diversity, which is true. But calculating (and monetizing) the value of a cow whose value lies in being genetically different, not producing more milk, isn't easy to sell.

“In theory, however, the undoubted value of these natural treasures should be reflected in their price, which should rise steeply as they become scarcer," Hamid said. "In practice, natural assets are often hard to price well, if at all."

Instead, Hamid argues that the way we quantify production needs to be thrown out altogether. He suggested that as the world continues to strive towards the Millennium Development Goals, biodiversity should play an important part, perhaps modeled after the CDC's Aichi biodiversity targets. That the CDC is already focused on biodiversity should come as no surprise, for without a diverse food supply, we're all more susceptible to the supply chain breaking down.

@derektmead