The Mompos Depression (N Colombia) is one of the largest flooding areas of South America and one of the largest perennial Neotropical wetlands. Pre-Columbian populations of the Mompos Depression modified the flooding-prone areas through the construction of earthworks such as raised fields, platforms and canal-camellón systems. The ancient inhabitants of this area successfully managed the territory as a complex society by exploiting the area for food production and adapting their agroforestry practices to the changing hydrological regime. After 13 th century, this land was abandoned and the canals were progressively filled up with sediment. The present work aims to present for the first time in the region preliminary data on past diatom community assemblages of the canal- camellón systems through time and space. We analysed samples from 3 different locations in order to evaluate the diatom diversity and distribution, as well as the community changes through the recent past, to see if is there any signal related with the ancient human settlements in the area. We found single species dominance among space and time (Diadesmis confervacea) followed by several abundant genera (Eunotia, Pinnularia and Gomphonema). A large portion of the species found indicate warm and acidic conditions, similar to present conditions.

Spanish Council of Science and Innovation (ref. PID2022-138059NB-I00). We would like to thank all the local people who welcomed and helped us, the field work assistants, and the Instituto Colombiano de Antropología e Historia (ICAHN) for the permits (ref. 8793).