Crop Diversity Surprisingly Stable in Ethiopia Despite New Introductions

A new study published in Plants, People, Planet found that crop diversity has remained stable in Ethiopia despite introducing many new species over thousands of years. A team of scientists from Ethiopia and the UK conducted the research in the Ethiopian Highlands. Rampersad and colleagues write in their article, “The global expansion of a handful of major crops risks eroding indigenous crop diversity and homogenising agroecosystems, with significant consequences for sustainable and resilient food systems.” The study’s findings are a surprising but welcome result for ecologists seeking to preserve biodiversity.

Ethiopia has been a centre of crop domestication and diversity for thousands of years. Many edible plant species originated in the region or were locally adapted over generations, resulting in a wealth of crop biodiversity uniquely suited to the local climate and conditions. These include coffea, teff and enset.

Over time, movements of people and trade introduced many new crops to Ethiopia. Some arrived centuries ago, like maize, which arrived in the late 1600s. More recent introductions include rice, which started growing in the 1970s. There were concerns that newcomers, which often receive more research investment, could displace the local varieties that smallholder farmers relied upon. This could potentially reduce crop diversity and resilience.

There have been longstanding concerns that introduced crops could displace native varieties, reducing agricultural diversity and resilience in the process. If new arrivals outcompete local crops, it could impact food security that relies on well-adapted indigenous crops. It may also undermine local climate adaptation and agricultural sustainability built on diverse traditional knowledge and practices.

To investigate this issue, the scientists surveyed over 1300 smallholder farms across elevation and climate gradients in the Ethiopian Highlands. This region is a hotspot of crop diversity, with hundreds of locally adapted edible plant species supporting millions of subsistence farmers.

The researchers took a comprehensive census of all crops cultivated on each farm. This included measuring the area allocated to 83 different edible species. By consulting historical and genetic records, they categorised each crop as either native to Ethiopia or introduced.

This extensive dataset enabled the team to test whether farms relying more heavily on introduced crops had less overall crop diversity. They also looked for signs that long-cultivated native species were being displaced.

The study findings paint a more optimistic picture of crop diversity:

• The team found no difference in the frequency of native versus introduced crops grown on farms
• Introduced crops were well integrated into farm systems alongside indigenous crops
• More diverse farms with higher overall crop richness contained more introduced crops, not less
• There was no sign that long-cultivated native crops were being displaced
• Crop diversity has remained stable despite introductions over thousands of years

The results suggest that introduced crops have successfully supplemented indigenous varieties in Ethiopia. They appear to be adding to local crop richness rather than reducing diversity.

Even recently arrived crops seem to be rapidly incorporated into traditional agroecosystems. The study found crops introduced at different times were equally well integrated across farms.

The findings indicate that diverse smallholder farms can harness both native and introduced crops to maintain resilient food production. Ethiopian agriculture has so far avoided a homogenisation of crop diversity despite adding many new options over millennia.

The study findings have several important implications. First, they suggest that introduced crops can expand diversity at the local farm level, not just increase national crop richness. This highlights the potential for new arrivals to complement indigenous varieties when successfully integrated into traditional agroecosystems.

Second, the rapid integration of useful introduced crops points to an inherent resilience and adaptability of smallholder agriculture in Ethiopia. Incorporating well-suited newcomers may even increase the flexibility and food security of subsistence farming systems built on indigenous knowledge.

Third, agricultural policies could promote sustainable intensification by encouraging knowledge-sharing around integrating introduced crops alongside time-tested indigenous staples. Enabling farmers to harness diversity in this way may be an important path to maintaining productive and resilient agroecosystems.

However, it is important to note that the study is limited to Ethiopia, where introduced crops were not driven by colonial export markets. Findings may differ significantly in regions where cash cropping led to widespread specialisation and homogenisation.

Maintaining diverse agroecosystems with a mix of locally adapted and useful introduced crops will be critical to sustaining food production amid mounting pressures like climate change. The Ethiopian example provides an encouraging case study on the potential for smallholder farmers to successfully incorporate new options while retaining indigenous varieties that provide the foundation for lasting food security.

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Rampersad, C., Geto, T., Samuel, T., Abebe, M., Gomez, M.S., Pironon, S., Büchi, L., Haggar, J., Stocks, J., Ryan, P., Buggs, R.J.A., Demissew, S., Wilkin, P., Abebe, W.M. and Borrell, J.S. (2023) “Indigenous crop diversity maintained despite the introduction of major global crops in an African centre of agrobiodiversity,” Plants, People, Planet. Available at: https://doi.org/10.1002/ppp3.10407.