Integrative approach needed to protect crop biodiversity, researcher says

Karl Zimmerer, professor of geography at Penn State, talks in 2016 with farmers who grow high-biodiversity Andean maize in Huánuco in the Andes of Central Peru.  Credit: Penn StateCreative Commons

UNIVERSITY PARK, Pa. -- While studying ways to protect and strengthen the biodiversity and social accessibility of food plants, Karl Zimmerer, professor of geography, often finds simple solutions.

Sometimes growers have simply run out of seed for a unique strain of crop or garden plant. That food source could be gone forever, or quickly replenished if a seed bank is operating in the region.

Other solutions, said Zimmerer, are far more complex. 

In a commentary in the April issue of Nature Plants, he argues that a comprehensive approach to protecting the human use of biodiversity of agricultural crops is vital to a sustainable food future that addresses global hunger, increasing populations and changing climate.

Biodiversity and human systems of use and knowledge are needed to steer the future of food crops, according to Zimmerer. The more biologically diverse and socially accessible a plant is, the better a robust suite of growers is able to adapt crops to combat pests, diseases and climate variations. Increased biodiversity also allows growers to produce foods with higher nutritional value.  

For example, when severe storms threaten food-growing, as they did when Hurricane Mitch struck Central America in 1998, the growers with more biodiversity in their farming systems were able to withstand this shock and respond with more resilience. The more biodiversity in a farm landscape, the more likely a problem can be mitigated. Within the individual crop this raw genetic material is routinely used to strengthen the crop’s resistance to stressors.

Since the 1900s, about 75 percent of plant biodiversity within both major and minor crops has been lost as farmers worldwide shifted from local varieties to genetically uniform, high-yielding varieties, according to the Food and Agriculture Organization of the United Nations.

“This topic is really important to a sustainable future," Zimmerer said. “For a long time we recognized that, and beginning with the Green Revolution of the 1970s, people started to take notice of accelerated loss and to care about the biodiversity of food plants as a human-environment issue. Still, a lot of it is at risk.”

Zimmerer, who is also director of the Geographic Syntheses for Social-Ecological Sustainability (GeoSyntheSES) Laboratory at Penn State, says protecting agrobiodiversity requires integrative research and policy in four areas: genetic resources and agroecology, government policy and local initiatives, food nutrition and health, and social-ecological interactions in response to global changes. In his commentary, Zimmerer describes how these four areas connect and can be used to strength science and build better policy.

Smallholder and indigenous farmers, about 2.2 billion people, are responsible for the bulk of food biodiversity and hold the key to its future, said Zimmerer. He works in areas such as Peru, Africa and Asia, where food biodiversity is widespread among growers and consumers. For instance, Peru has thousands of varieties of potatoes eaten on a daily basis.

In the area of agrobiodiversity, Zimmerer said seed initiatives can continue to help farmers grow these diverse foods by offering a backup in case they run out. In the field, Zimmerer says he often hears stories of farmers faced with drought or price shocks eating their seed supply to keep from becoming malnourished. In such cases, vast amounts of biodiversity might be lost if seed banks aren’t in place and functioning well.

Gene banks, where genetic material can be stored for prolonged periods, are used to protect those plants and also can be used to return them to smallholder and indigenous farmers, which has occurred in the Potato Park in Peru and more recently in Brazil and India.

Government policy at both the local and global scale also play a role.

These initiatives require coordinated government policy and approaches that benefit small-scale farmers and involve the role of larger agricultural and consumer groups, Zimmerer said.

He said global policies, which are largely crafted by developed nations, often fail to strengthen biodiversity improvement systems in developing nations. Policies that benefit biodiverse areas in the tropics and subtropics are key to strengthening biodiversity worldwide.

“Benefits sharing is very important and in principle might seem easy to do but it’s really hard to put these systems into effect,” Zimmerer said. “The global governance systems in particular have been really challenged in this regard. We would certainly benefit from advances in understanding and especially being able to apply governance approaches in this area.”

Nutritional value of the crops is also important.

Opting for high-yield, easy-to-grow crops, Zimmerer said some regions are producing foods that don’t meet the nutritional needs of the community. In developed nations, that’s contributed to a rise in issues such as obesity and diabetes. But it’s worse in developing nations.

“We have some real challenges in the U.S., but in various places where I work there’s also a tragic combination of noncommunicable diseases — obesity, Type 2 diabetes — people being overweight but at the same time being malnourished. It’s bad enough to have one of those issues, but for those to be co-existing is really tragic. There are many ways that needs to be addressed but biodiversity in food systems is one of the main ways.”

For instance, the amount of iron found in potatoes grown in the Andes Mountains varies wildly, depending on the variety. The same is true for other staple crops such as rice, wheat or corn. Having a diverse group of varieties at hand enables us to tailor and grow crops that meet our production and nutritional needs as well as our cultural preferences.

How biodiversity is used and maintained across the globe is Zimmerer’s final point in the commentary. He concludes that the interdisciplinary is deeply inherent to agrobiodiversity because it is intimately connected to humans across consumption and production activities that are vitally important to who we are.

“This is a complex human environmental system,” said Zimmerer. “What we were able to do over a period of a few years in this research synthesis, generally supported through the Ernst Strüngmann Foundation, is to wrap our minds around this rather huge and interdisciplinary constellation of identifiable areas. Then we can think about research and policy coalescing in each of the four areas while examining how they’re connected and globally impacting people.”

Stef de Haan, a genetic resources expert and program management officer at the International Center for Tropical Agriculture, co-authored the commentary. Zimmerer and de Haan will present their new work in early May at the meeting of the European Association for Research on Plant Breeding (EUCARPIA) in Montpelier, France, and early next month at the international meeting of the Society for Economic Botany in Portugal.

Last Updated July 28, 2017