Enormous loss of crop diversity found in recent decades

Despite the fact that scientists have been aware of a decline in crop diversity in agriculture over the last 100 years, many questions remain unanswered regarding the causes, magnitudes, and implications. A new study from agricultural research centers across North America, South America, and Europe is the world’s largest review of declining crop diversity.

The experts reviewed hundreds of primary data sources regarding crop diversity loss over the last 80 years. They found that changes in diversity were reported in 95 percent of cases, while 80 percent of cases produced evidence of diversity loss. This is a result of climatic, political, technological, and agricultural changes over the last 100 years.

Study lead author Colin Khoury is a research scientist at the Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT).

“The global picture that emerges from our review is that of enormous loss over a relatively short period of time of traditional agricultural diversity, which was nurtured by many cultures around the world over the last 10,000 years,” explained Khoury. “Yet the picture also provides hope, as considerable crop diversity persists, and because it shows that agriculture can be re-diversified.”

“The good news is that while we found evidence of enormous diversity loss over the past decades in each of the environments we studied, we also saw significant maintenance of that diversity in some contexts, and even marked increases in specific instances,” noted study co-author Stephen Brush.

Crop diversity allows crops to remain productive when facing diseases, pests, and extreme weather. Genetic variation among crops also contributes to dietary diversity, nutrition, and food security.

 “The magnitude of crop diversity loss we have seen in some regions of the world underscores the importance of conserving this diversity outside of these ecosystems as well as within them,” said study co-author Luigi Guarino. 

”Collections of crop diversity such as those in agricultural genebanks and botanic gardens can mitigate local and regional losses, enable the future reestablishment of diversity on farms, and preserve the availability of crops for future use by all. We need to strengthen these repositories and duplicate unique collections in other locations to insure against the risk of loss.”

Across the globe, there are currently 1,750 genebanks, maintaining crop diversity with over seven million crop samples. Additional efforts are provided by botanic gardens, community projects, and universities. However, the recent study has concluded that a lot more work will be required to fully protect crop diversity.

 “For crop diversity to continue evolving alongside pests and diseases, in response to climate change, and to meet demands for improved crops that provide both economic products and ecological services, we need to redouble support for conservation efforts in situ, or in the field, as well as ex situ,” said study co-author Allison Miller.

The research is published in the journal New Phytologist. 

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By Calum Vaughan, Earth.com Staff Writer