Exploring the use of wild cereals at Takarkori (Central Sahara, southwestern Libya) through stable carbon and nitrogen isotope analysis of prehistoric desiccated seeds

Stable isotope analyses of archaeological plant material have increased in the last few decades with questions arising about climate, environment, and subsistence strategies. While the available studies are of great interest in the field, they are still a minority compared to other types of organic material, especially from African contexts. Desiccated plant material in particular has only sporadically been investigated, partly because archaeological contexts suitable for its conservation are extremely rare and potentially diagenetically altered. Here we provide stable carbon and nitrogen isotope data from prehistoric C4 wild desiccated cereals from Takarkori (central Sahara, southwestern Libya). To our knowledge, this is the first study on uncharred African archaeological seeds and one of the few examples of stable isotope analysis applied to desiccated cereals. Results show that the stable nitrogen isotope values are likely diagenetically altered. The stable carbon isotope values are uniform across the different species analysed except for Panicum, likely linked to its photosynthetic subpathway. Although the response to environmental constraints is difficult to assess using stable isotope analysis applied to C4 plants, the multidisciplinary studies available from Takarkori suggest some kind of adaptation/resilience of the wild cereal species alongside human exploitation over several millennia.