‘An ancient seed bank captures people’s efforts to save plants during invasions’

Shanti Morell-Hart is Associate Professor of Anthropology at Brown University. Speaking with Srijana Mitra Das at Times Evoke , she discusses how ancient food held power — and sustainability:
What is the core of your research?
I am an anthropological archaeologist. I’m interested in questions of human relationships and activities — I look at these in the past and sometimes, in the deep past. The two planks of my research are linked to foodways and cuisine and ethnoecological relationships. My specialisation is in the study of ancient plant residues — I use this to understand what people were consuming in terms of different plant foods and the relationships they had with their environments and crops.

Which geographical areas do you study?
I work mostly in Mesoamerica, which encompasses parts of North America and regions of Central America. My work is largely in the Maya area, which includes Mexico, Guatemala and Honduras. I’ve also done research in Oaxaca, mostly with ancient Mixtec and Zapotec societies. Some of my research stretches back to 10,000 years ago, when people were just beginning to tinker with crops and cultivate different plants, up through the colonial period and the first moments of European contact.

Can you describe some important agricultural practices you’ve found?
One of the findings I’ve had, in collaboration with Stacie King at the University of Indiana, was discovering evidence of an ancient seed bank dating from between 400 to 700 years ago, in mountains near a contemporary community in Oaxaca. There were many colonial incursions then and people in the Nejapan Sierra Sur collected over a hundred different species of seeds. They put them in a bin close to where they retreated when colonial invaders — Zapotecs, Aztecs, later, the Spaniards — came sweeping through the area.

Part of what King and I found with this seed bank was that people were not only collecting varieties of maize and beans, they were storinga huge suite of diverse plant foods that featured in their cuisines, which they could perhaps replant after a colonial incursion. People had collected this large store of culinary elements — grains, fruits, vegetables, pungent leaves, herbs, seasonings — to make a very complex cuisine, instead of just survival food.

How was food, as you write, ‘media, medium and messages’?
Food isn’t just calories — it’s an edible medium which conveys messages with deliberation. In the ancient Maya era, murals and representations on ceramic vessels show courtly scenes ( see below ) and feasting imagery with rulers entertaining other rulers or vassals coming to their courts — in such paintings, we see tamales and chocolate beverages with other foods in jars and bundles by the ruler’s throne. What we don’t see is atole — corn porridge that’s very commonly consumed in Mesoamerica. There are tamales though, corn dumplings that often have rich fillings and sauces. Tamales are repeatedly shown, so we can think about the messages consuming or presenting these to guests at court conveyed — a ruler could be giving visitors these or maybe, they’d just sit on their throne, eating them, watching penitents make requests like asking to provide less tribute. Different foods conveyed diverse messages, alongside a ruler’s robes, the opulence of their palace, the carvings on their throne.

What archaeological evidence does food leave?
Every few years, a new innovative techniquelets us get at different kinds of data we once thought were inaccessible. Over time, we’ve been able to access both larger and smaller kinds of evidence, going from things you see with the bare eye to things you can view microscopically. Part of what I study is the seeds that get left behind in residues of foods and agricultural activities. I can now look at starch grains using microscopy 400 times the power of the bare eye to see things like phytoliths or when silica gets deposited in plant cells.

Recently, we’ve been able to extract DNA and identify food and plant residues, chemical signatures of lipids or fats, plant waxes, etc. We also have a powerful new tool in LiDAR, where, using laser technology, you can penetrate jungle canopy and develop a ground surface map without vegetation — hence, we can now identify cities and settlements of the past with terraces and channels, places where people grew foods. We can see a macro view of farming, with enormous channels carved into a landscape or very elaborate terrace systems built onto a hillside.

What learnings does palaeobotany offer for food and sustainability today?
When we look at the past, two key themes emerge around diversity and flexibility. First, such research unearths diverse agriculturalpractices people engaged in, from the development of terraces, channels and fields to rotating crops or growing different kinds of plants together. Alongside, there were diverse food practices, like learning how to process certain foods that might not necessarily seem like ‘food’ at the outset — this might be people eating famine foods, not just maize, beans and squash, but bitter roots or the inner bark of certain trees, which required special preparations. So, having diversity in practices of collecting and preparing foods, and in the kinds of foods we have, helps buffer people against risk and provides more sustainable foodways.

Flexibility is the other important lesson — we find people were very flexible on the landscape here and used different agricultural techniques, crops and foods across time. They did this to optimise their diets and agricultural techniques — but also for other reasons. Some were political — they often provided food for tribute. Some were spiritual — they grew certain crops which were more aligned with their spiritual practices.

In contemporary times, there are many chokepoints where we’ve become overly reliant on certain foods, set ways of acquiring these and rigid food practices. When we look at deep time, the places that had the most trouble were large cities that relied on a few food crops which arrived through tribute or trade, serving people who had developed fixed ideas of food. The places with the greatest resilience were where people had access to more kinds of foods — and developed diverse ideas of what composed food. Another aspect which emerges in our work focuses on the seed bank and buffering against risk by conservation through collecting different seeds — that helps diversity and flexibility and, over time, it preserves biodiversity.