Phytolith analysis of selected native plants and modern soils from southeastern Uruguay and its implications for paleoenvironmental and archeological reconstruction

This paper presents a phytolith analysis of selected native plants and modern surface soils from southeastern Uruguay. A modern phytolith reference collection was established based on 60 Poaceae species, 22 non-Poaceae monocotyledonous species, 17 species of herbaceous dicotyledons, 9 woody dicotyledonous species, and 2 species of fern. Nine modern surface soil samples were analyzed from the most representative vegetation units of the region, including wetlands, wet prairies, upland prairies, riparian forest, and palm forest. Of the 50 non-Poaceae plant species analyzed, 25 contribute diagnostic phytoliths at different taxonomic levels corresponding to all the major ecological zones of southeastern Uruguay. Patterns of phytolith production and morphology were concordant with those observed in related taxa studied from other regions of the world. The modern soil analysis revealed significant patterns that differentiate a number of specific habitats, showing that distinct vegetational units may be discriminated by the phytolith signatures they produce. These results reinforce the utility of using phytoliths as significant indicators for vegetation units dominated both by monocotyledonous and dicotyledonous plant species, and demonstrate the potential of phytolith analysis for paleoecological and archeological reconstruction in this region.