Plant communities and soil phytolith assemblages relationship in native grasslands from southeastern Buenos Aires province,Argentina

This study has compared the phytolith production and soil phytolith assemblages of two native grass communities typical in Argentina, namely the monospecific Paspalum quadrifarium community or “pajonal”, and the Stipa-Piptochaetium community or “flechillar”. Five sites – three of which had been unmanaged while other two had been submitted to fire and fire-grazing management activities – were selected for study. The results show that in these sites a) phytolith production of the plant communities differed due to their diverse floristic composition, b) it was possible to define the type of management or the type of community based on soil phytolith assemblages, c) there were differences between plant communities and soil phytolith assemblages. These results suggest that modern phytolith assemblages are composed not only of local and present vegetation but also of extralocal/regional and probably past vegetation. Hypotheses about the probable processes involved in phytolith incorporation to soil have emerged during the investigation.