Phytoliths in paleoecology: Analytical considerations, current use, and future directions

Abstract

Phytoliths, microscopic plant silica bodies, are often preserved in modern and fossil soils and sediment, as well as in archaeological contexts. They record unique characteristics of past vegetation and, unlike palynomorphs and macrofossils, are commonly found in direct association with fossil vertebrates, providing vital paleoecological data. Within pre-Quaternary paleoecology, phytolith analysis has so far elucidated Cretaceous-Cenozoic grass evolution, vegetation change including the spread of grasslands, plant-animal co-evolution, and diets of extinct animals. Because deep-time phytolith analysis is a young field, many methodological aspects are not standardized, preventing comparisons among studies and calibration using published modern analogs. On the other hand, the plethora of novel approaches in recent literature points to the potential of phytolith-based paleoecology. Here, we review the present state of phytolith analysis, focusing on pre-Quaternary applications. We discuss the nature and known biases of the phytolith record, current methods, and examples of when phytoliths contributed substantially to knowledge of past ecosystems, and highlight important future avenues of research.