The palaeoenvironmental context of MIS 3 and the use of plants by Neanderthal groups in southern Italy: results from the Riparo l’Oscurusciuto site

• Phytolith and pollen allow reconstruction of vegetation over 12,200 ka. • Vegetation is shifting from forests to open areas along the studied sequence. • Siliceous aqueous microremains indicates moisture conditions within the site. • Use of Poaceae plants and ash scattering revealed by study of sediments and hearths. • High phytolith dissolution is due to calcium carbonate rich sediments. Neanderthal populations occupied caves and rockshelters across the Mediterranean, leaving behind evidence of their daily activities, including plant remains. By studying these remains, we can gain a better understanding of how these populations used plant resources and adapted to their environment. A critical period for studying Neanderthal behaviour is Marine Isotope Stage 3 (MIS 3) which was characterized in Europe by millennial-scale climatic instability involving fluctuations between warming and cooling events. These changes may have impacted the dispersal and dynamics of Neanderthal populations, prompting new behavioural, subsistence and settlement adaptations. A key site for studying Neanderthal groups in southern Italy during MIS 3 is Riparo l’Oscurusciuto in the Ginosa Ravine. The site’s long stratigraphic sequence and well-preserved faunal and material culture remains, including hearths, span the period from ∼55 ka to ∼42.8 ka BP. This makes the site central to our understanding of Neanderthal life and how they adapted to the environment until their disappearance from the region. Here, we present the results of a high-resolution study of plant microremains (phytoliths and pollen) and aquatic siliceous microremains (diatoms and chrysophyte cysts), alongside the mineralogical characterisation of their sedimentary contexts using Fourier Transform Infrared (FTIR) spectroscopy. The ∼12,200-year long reconstruction of the palaeoenvironment reveals a changing landscape starting with semi-open woodlands and forests at ∼55 ka and changing to more open woodland steppe environments starting sometime before ∼52 ka. The woody vegetation was composed of evergreen and deciduous oak woodlands with a continued presence of other mesophytes and Mediterranean woody taxa, including gymnosperms. The grasses (mostly C 3 Pooid), are associated with a wide range of herbaceous species, probably reflecting the opening up of the landscape. Neanderthals responded to these changes by adapting their activities to the surrounding vegetation, by for example using grasses for the hearths, the ashes of which were later spread around the site.