Mervyn Piesse, Research Manager, Global Food and Water Crises Research Programme – Biodiversity: An Integral Part of Food Security
Biodiversity provides an insurance policy for the global food system. If disease or other changes in the natural environment occur, different species can provide a source of genetic material that can be harnessed to protect against these threats.
The role of biodiversity in preserving food security is well established. Botanists are able to utilise genes from wild relatives of domesticated food crops to develop new varieties that are able to survive more hostile environments. This process is often cheaper and less controversial than genetic modification, but it is dependent on having access to thousands of different species to find the required genetic material.
Several food crops have been protected by selecting genes from wild relatives of domesticated species. For instance, Australian scientists have recently utilised genes from wild plant species to further the development of wheat resistant to UG99, a form of wheat rust fungus that emerged in Uganda in 1999. Winds carried the disease from East Africa into Southern Africa and the Middle East. From there it could spread into South Asia. If left unaddressed, it is believed that up to 30 per cent of global wheat production could be threatened. Finding and developing natural resistance to the fungus will help protect the world’s most widely grown food crop. Without a wide array of wheat varieties, however, the chance of finding resistant genes becomes much lower.
Over the past century, according to The Economist, about three-quarters of global crop genetic diversity is believed to have been lost. As the level of biodiversity decreases the potential for solutions to future crop diseases and changing environmental conditions becomes narrower.
Modern agricultural practices have downplayed the importance of biodiversity by concentrating on a few, mainly high-yielding, varieties. As a result, the world is highly dependent on a small number of plant and animal species for its food supply. Currently, about 30 crops provide 95 per cent of the world’s food, with five cereal crops – rice, wheat, maize, millet and sorghum – accounting for 60 per cent of the world’s food. These food crops are composed of a relatively small number of domesticated varieties.
A heavy reliance on a small number of crop species increases the vulnerability of the food supply. Reduced biodiversity increases the risk of diseases spreading through the international agricultural system. There is concern about the potential for a global sixth mass extinction that could damage food security. While extinction is a natural process, it appears to be occurring at a much greater rate than usual. Many of these concerns lean towards alarmism and will take centuries to become apparent. Almost 70 per cent of plant species are currently threatened with extinction, but the likelihood of them all dying out at the same time is remote. As plants are the basis of the global food system and wild species are a useful repository of genetic material, a loss of diversity would pose considerable problems for future food security.
International efforts have been made to store and preserve a wide range of plant genetic material. Seed banks are costly to establish and maintain and in addition to unstable financing, many face numerous challenges, such as civil unrest, urban encroachment and natural disasters. These efforts require continued international co-operation and funding.
Preserving a wide array of genetic material provides an insurance policy for future problems. While this policy is costly it helps ensure the security of the global food system, an assurance that ultimately increases the resilience of the global food system.