High-resolution ecosystem changes pacing the millennial climate variability at the Middle to Upper Palaeolithic transition in NE-Italy.

Observation of high-resolution terrestrial palaeoecological series can decipher relationships between past climatic transitions, their effects on ecosystems and wildfire cyclicity. Here we present a new radiocarbon dated record from Lake Fimon (NE-Italy) covering the 60-27 ka interval. Palynological, charcoal fragments and sediment lithology analysis were carried out at centennial to sub-centennial resolutions. Identification of the best modern analogues for MIS 3 ecosystems further enabled to thoroughly reconstruct structural changes in the vegetation through time. This series also represents an "off-site" reference record for chronologically well-constrained Palaeolithic sites documenting Neanderthal and Homo sapiens occupations within the same region. Neanderthals lived in a mosaic of grasslands and woodlands, composed of a mixture of boreal and broad-leaved temperate trees analogous to those of the modern Central-Eastern Europe, the Southern Urals and central-southern Siberia. Dry and other grassland types expanded steadily from 44 to 43 ka and peaked between 42 and 39 ka, i.e., about the same time when Sapiens reached this region. This vegetation, which finds very few reliable modern analogues in the adopted Eurasian calibration set, led to the expansion of ecosystems able to sustain large herds of herbivores. During 39-27 ka, the landscape was covered by steppe, desert-steppe and open dry boreal forests similar to those of the modern Altai-Sayan region. Both Neanderthal and Sapiens lived in contexts of expanded fire-prone ecosystems modulated by the high-frequency climatic cycles of MIS 3.

Life on a hilltop: vegetation history, plant husbandry and pastoralism at the dawn of Bergamo-Bergomum (northern Italy, 15th to 7th century bc).

Cores and trenches drilled or dug in religious and secular buildings in the hilltop town of Bergamo (northern Italy) were investigated by means of micro/macrobotanical and pedochemical analysis to unravel the cultural vegetation history of the area during ca. seven centuries across the Bronze-Iron Ages. We explore the predictive power of biological proxies, nutrients, and coupled 14C datings to reveal early phases of human settlement and activity in a modern urban context with low visibility and difficult accessibility. Our records suggest that a farming centre was active on the Bergamo hilltop as early as the 15th century bc. Crop and animal husbandry reached a high point between the 11th-8th century bc. Plant and biogeochemical proxies predict extensive and diversified cereal cropping, flax and grapevine cultivation, as well as herd stalling at a watering pond, free range livestock growing in woodlands, and pastoralism, shown by hay making and overgrazing evidence. The suggestive hypothesis of carding wool is mentioned but is currently untenable. Furthermore, we identified a possible phase of abandonment starting from the 8th century bc, to be further investigated, and in agreement with archaeological data suggesting settlement decline in the 8th-6th century bc. Our research highlights the dedication to pastoralism of the Bergamo hill since prehistoric times. The settlement position was strategic for pastoralists to exploit biological and water resources in space, season and elevation, i.e. from the plain to higher Alpine pastures. Ethnographic examples and Middle Age written sources strongly support this picture.

Early life of Neanderthals.

The early onset of weaning in modern humans has been linked to the high nutritional demand of brain development that is intimately connected with infant physiology and growth rate. In Neanderthals, ontogenetic patterns in early life are still debated, with some studies suggesting an accelerated development and others indicating only subtle differences vs. modern humans. Here we report the onset of weaning and rates of enamel growth using an unprecedented sample set of three late (∼70 to 50 ka) Neanderthals and one Upper Paleolithic modern human from northeastern Italy via spatially resolved chemical/isotopic analyses and histomorphometry of deciduous teeth. Our results reveal that the modern human nursing strategy, with onset of weaning at 5 to 6 mo, was present among these Neanderthals. This evidence, combined with dental development akin to modern humans, highlights their similar metabolic constraints during early life and excludes late weaning as a factor contributing to Neanderthals' demise.

The fast-acting "pulse" of Heinrich Stadial 3 in a mid-latitude boreal ecosystem.

A 3800 year-long radiocarbon-dated and highly-resolved palaeoecological record from Lake Fimon (N-Italy) served to investigate the effects of potential teleconnections between North Atlantic and mid-to-low latitudes at the transition from Marine Isotope Stage (MIS) 3 to 2. Boreal ecosystems documented in the Fimon record reacted in a sensitive way to millennial and sub-millennial scale Northern Hemisphere atmospheric circulation patterns. The high median time-resolution of 58 years allows the identification of five abrupt event-boundaries (i.e., main forest expansion and decline excursions) synchronous with the sharp stadial/interstadial (GS/GI) transitions within dating uncertainties. During Heinrich Stadial 3 (HS 3) we reconstruct more open and dry conditions, compared to the other GS, with a dominant regional scale fire signal. Linkages between local fires and climate-driven fuel changes resulted in high-magnitude fire peaks close to GI/GS boundaries, even exacerbated by local peatland conditions. Finally, palaeoecological data from the HS 3 interval unveiled an internal variability suggesting a peak between 30,425 and 29,772 cal BP (2σ error) which matches more depleted δ18O values in alpine speleothems. We hypothesise that this signal, broadly resembling that of other mid-latitudes proxies, may be attributed to the southward shift of the Northern Hemisphere storm tracks and the associated delayed iceberg discharge events as documented during other HS.