As Nazis stormed Leningrad in 1941 and cut off food supplies, a team of scientists defended their laboratory deep in the city, boarding doors and windows to bar soldiers and starving citizens from entry. Their protected treasure was a collection of over 200,000 seeds gathered by Russian scientist Nikolai Vavilov, who had traveled over five continents to collect samples from local farmers. The seeds would have offered temporary relief for the rampant hunger during the siege, but the team refused to release them to the city. Several scientists starved to death during the defense. Vavilov joined their fate two years later while in prison.1
Why did Vavilov and his group of scientists choose death over the sacrifice of a seed collection? They believed that understanding the genetic diversity hidden within those tiny capsules of life was the key to ending worldwide hunger.2
Today, Vavilov’s vision lives on through the science of plant biodiversity. Botanists, geneticists, climate scientists, and wildlife ecologists continue his quest to understand how diversified genetic portfolios in plants increase crop yields, prevent soil degradation or destruction from pests, and provide stability against global warming. The story of this science takes us from the farms of the Great Plains to the Arctic Circle, and the stakes are no less than the future of the global food supply and its resilience against unpredictable environmental changes.
When humans first domesticated crops around 12,000 years ago, farmers preserved seeds from the crops with the best yield each year to plant during the next season.3 This practice altered the genetic makeup of the crops from year to year and allowed them to slowly adapt to selective pressures from the environment, such as climatic changes or new pests.
Farming methods have changed over the last century to try to feed 9 billion people by 2050.4 The birth of corporations in the 20th century has centralized food production to a few large companies.5 To maximize yield and profits, these megafarms genetically modify plants that provide more food but require that the same seeds be planted each year, dramatically reducing genetic diversity. These monocultures have improved yields, but seventy five percent of the world’s food supply now comes from only 12 plant species.6 Eighty percent of the world’s almonds come from a single crop in California with a uniform genetic code.7
These monocultures may provide high yields now to satisfy global food demands, but times are changing. Global surface temperatures have increased by 0.15-0.20 degrees Celsius per decade since 19758 and the genetic tailoring of monocultures will not be able to withstand resulting environmental changes. Monocultures have also been groomed to combat specific groups of pests native to a specific region. But pests change with climate. A new fungal disease in 1971 already wiped out a year’s harvest of a common, genetically unifrom pearl millet crop in India, hinting at disasters to come.9 Global food security depends on only a small number of farms, so any of these events could bring famine around the world.
Progress in the science of plant biodiversity is the answer to these dangerous trends. Scientists in the field provide quantitative evidence of connections between climate change, genetic diversity, and crop yields to push policymakers away from monocultures that are vulnerable to environmental changes.10 Crops on the rear edge of temperature shifts to higher latitudes have also been found to be especially at risk because they have the least time to adapt.11 The discipline has already informed policymaking in Canada, where farms have become too specialized with genetically uniform crops despite calls for better adaptation to climate change.12
As one arm of biodiversity science uncovers information to inform decision-making, the other arm is already providing concrete solutions. Following in the footsteps of Vavilov, a scientific collaboration has constructed a seed bank half-buried in a glacier in the Arctic tundra. Seeds donated from a host of countries sit comfortably at -18 degrees Celsius, waiting for their moment to rescue our civilization from a particularly brutal locust swarm or drought.13 Similar seed banks are now popping up around the world.
The fruits of these seed-saving efforts are already ripening. In the 1990s, a particular type of yucca in Thailand was eroding soil and threatening the major export of the Thai economy. Colombian scientists identified a sample of cassava seeds collected from Venezuela 40 years ago that did not impact soil quality to the same degree.14 The scientists crossbred this variety with the Thai crops, leading to sustainable yeids that have allowed Thailand to lead exports in Yucca today.
A future society applying the science of biodiversity will look quite different. Monocultures will be replaced with many smaller farms, each with a diverse collection of genotypes resistant to a variety of pests and ready to adapat to changing temperatures and weather conditions. If droughts or other disasters threaten a particular region, seed banks supplied around the world would be ready with the necessary seeds to prevent famine and alleviate suffering. These precautions will be the difference between a world in danger of the next food shortage and one with the security to adapt to changing times.
Beyond the benefits to food security, understanding the benefits of diversity may begin to move global trends away from expansion and towards conservation, leave domination for cohabitation, emphasize the local instead of the global. This is the true transformation – to allow the science to transform how our global society interacts with the world we are overloading. And if Vavilov were alive today, he would surely be traveling the world to preach the message.
- Pringle, P. The murder of Nikolai Vavilov. JR Books: London, 2009.
- Nabhan, GP. Where our food comes from: retracing Nikolay Vavilov’s quest to end famine. Island Press: Washington D.C., 2009.
- Olsen, KM and Gross, BL. “Detecting multiple origins of domesticated crops.” PNAS, 105(37), 13701-2, 2008.
- U.S. Census Bureau. International database, June 2011 update. http://www.census.gov/population/international/data/idb/worldpoptotal.php. Accessed June 16, 2015.
- Nye, DE. Consuming Power. The MIT Press: Cambridge, 1999.
- FAO. “What is happening to agrobiodiversity?” http://www.fao.org/docrep/007/y5609e/y5609e02.htm. Accessed June 16, 2015.
- Pollan, M. “Our decrepit food factories.” The New York Times Magazine. December 16, 2007.
- Hansen, J et al. “Global surface temperature change.” Reviews of Geophysics, 48, RG4004, 2010.
- Thakur, RP et al. “Pearl millet downy mildew research in India: progress and perspectives.” ICRISAT, 2(1), 2006.
- Hooper, DU et al. “A global synthesis reveals biodiversity loss a major driver of ecosystem change.” Nature, 486, 105, 2012.
- Hampe, A and Petit, RJ. “Conserving biodiversity under climate change: the rear edge matters.” Ecology Letters, 8, 461-7, 2005.
- Bradshaw, B et al. “Farm-level adaptation to climatic variability and change: crop diversification in the Canadian prairies.” Climatic Change, 67, 119-41, 2004.
- Goldenberg, S. “The doomsday vault: the seedds that could save a post-apocalyptic world.” The Guardian, May 20, 2015. Accessed June 16, 2015.
- Utsumi Y et al. “Transcriptome analysis using a high-density oligomicroarray under drought stress in various genotypes of cassava: an important tropical crop.” DNA Research, 19(4), 335-45, 2012.