Copenhagen, Denmark
March 12, 2009

Changes to agricultural geography – brought about by climate change – require us to change our approach to the use and conservation of agricultural biodiversity. Toby Hodgkin, Principal Scientist and Director of the Global Partnership Programme at Bioversity International, told the Climate Congress in Copenhagen that four areas needed to be re-examined.

• Ex-situ conservation in genebanks must expand dramatically.
• Diverse farming systems do adapt and help poor farmers to survive change; more use should be made of biodiversity as an adaptive strategy.
• The relationship between on-farm conservation and genebanks must change.
• Access to genetic diversity, by farmers and by breeders, becomes of paramount importance.

“Increasing, or even maintaining, food production to meet expected demand will require greater use of genetic resources, the diversity present within the plants we depend on,” Hodgkin said. Much of that diversity resides within the varieties grown by poor rural farmers and the wild relatives of crop plants.

Much agricultural biodiversity is stored ex-situ. Over the past 60 years some 6.5 million accessions have been stored in genebanks worldwide. And more recently efforts have been made to promote the wider use and conservation of diversity by farmers in-situ in their fields. Climate change raises the stakes.

“It adds to the forces already threatening farmers' varieties and it puts new pressures on crop wild relatives,” Hodgkin said. He urged a massive increase in collecting, targeted to those areas and those crops and wild relatives that geographical information systems identify as most in danger.

But at a lower level – what precisely to collect in the target areas and of the target crops – Hodgkin urged no targets.

“What you need to collect is diversity,” he said, “precisely because you can't predict what you will need in future.”

One reason to collect diversity now is that diverse agricultural systems have been shown to buffer farmers against changing circumstances. Hodgkin pointed to a study by colleagues who have looked at how farmers in the Sahel belt of Niger use pearl millet. The number of different named varieties more than doubled from 1976 to 2003 as farmers selected plant types that performed better under lower rainfall.

“This is something we need to recognize and promote. Diverse crops and diverse systems allow farmers to adapt and to meet their own needs often more rapidly than more specific scientific breeding programmes.” Hodgkin said.

This changes the way scientists should view the relationships between genebanks and in-situ or on farm conservation, according to Hodgkin. In the past, researchers have tended to focus on the genetic identity of the entities being grown in farmer's fields, concerned with questions such as whether the same name always refers to the same genetic population, or how much diversity is present in a variety.

More important is that being in fields exposes diverse systems to changing conditions and selection by farmers.

“It allows them to evolve, that's the crucial point,” said Hodgkin. Genebank samples remain important, but if conditions have changed then they may well no longer be relevant in the specific places where they were collected. Diversity that remains in the open and shifted around by farmers in response to shifting growing conditions will be crucial in adapting to climate change.

“And that makes access absolutely vital,” said Hodgkin. Access, in this sense, ranges from the international flows to local informal seed systems. The International Treaty on Plant Genetic Resources for Food and Agriculture is beginning to ease the movement of material among genebanks and breeders, but far more robust national and regional systems are needed. The informal systems that enable farmers to exchange material and knowledge are also important to allow them to adapt to climate change, and national policies must recognise this.

“As climate change continues to change the geography of agriculture, we have to mimic natural systems ourselves and use a diversity of approaches to ensure that farmers and breeders have the ability to get hold of and make use of as much diversity as possible,” said Hodgkin. “That way, we might stand a chance of creating secure food systems.”

Website: http://www.bioversityinternational.org

Published: March 12, 2009