5. Conclusions

Archaeological and palynological studies carried out in Ahanve, south-western Nigeria, provided insights into the availability and utilisation of aquatic resources during the last 900 years. During the earliest phase of human occupation of Ahanve (9th-17th centuries), the people's diet included freshwater cat-fish (Clariidae) and bivalves (Anodonta sp.); they also engaged in the production of salt. Salt was produced by boiling brine from the Atlantic Ocean in large clay vessels. The archaeological evidence indicated that aquatic resources were supplemented with diverse terrestrial animals (African giant snails, bush meat [baboons?]) and plants (oil palm and kernels [Elaeis guineensis]). In the second occupation phase, aquatic resources such as cat-fish and bivalves declined and subsequently disappeared and salt production was discontinued. In contrast, at the topmost levels (0-20 cm) of the sediment core there was an increase in the pollen of herbaceous and weedy plants associated with human habitation and agriculture; this is an indication of a greater reliance on plant as opposed to animal resources. These developments coincided with the trans-Atlantic trade following the arrival of Europeans in Nigeria. During this period, the indigenous method of salt production in Ahanve was discontinued in favour of imported salt. Ethnographic data reveal ethnomedicinal uses of Acrostichum aureum, and the practice of using Typha australis and T. domingensis to produce mats and brooms continues to the present day. It is possible that the ancient Ahanve people used these plants for similar ethnobotanical purposes as they do now.