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.” |
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