Regional phytoliths from the Coastal Cordillera of the Atacama Desert, Chile, and their potential for paleoecological reconstructions

Siliceous phytoliths are frequently used in archaeology and Quaternary paleoecology. In order to validate the potential of phytoliths to reconstruct the vegetation history in the Atacama Desert, Chile, we analyzed the occurrence and morphotypes of phytoliths in different organs of 97 plant species from 36 families living in the Coastal Cordillera of the Atacama Desert. Phytolith extraction was conducted by a new protocol using microwave digestion, which is rapid, provides clean and well preserved phytoliths and can be employed on plant material as well as sediments. Phytoliths were found only in Poaceae and Bromeliaceae. Although this limited occurrence restricts their value for the reconstruction of past vegetation diversity, their identification to sub-family and species levels provides detailed information on the occurrence of grasses and monocot flowering plants. These taxa are sensitive to environmental factors, such as climatic conditions, i.e. temperature and water availability. Comparisons of the phytolith morphotypes isolated here with those described in the literature suggest that the characteristics of the phytoliths in the Atacama Desert may not only depend on species and plant organs, but may also be dependent on the specific regional environmental conditions.