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During the Last Glacial Maximum (LGM, 30 to 16.5 ka ago), the Great Adriatic-Po Region (GAPR) was deeply affected by the spread of glaciers from the Alps to the southern foreland and by the dropping of the sea level to ~ -120 m amsl. The combination of these two events triggered the aggradation of the Great Po Plain (GPP), a vast flat area between the Alpine chain, the Italian Peninsula and the north-western Balkan Peninsula, physically and ecologically featured through a range of palaeogeographic and palaeoecological conditions. The low-elevated Prealpine sectors and the Alpine foothills supported more extensive forest stands, due to increased orographic rainfall. These were open boreal forests which persisted throughout the LGM, while open woodlands, steppes, semideserts and wetlands occupied the lowlands. A complex ecogradient, including both an Alpine and a continental timberline, is documented by the fossil records at the NE Alpine border, with a larch-pine forest-steppe belt, in contact with steppes and loess areas extending in the plain, on the dry extreme of the gradient. Still, edaphic wetlands occupied the waterlogged silty soils in the lowlands. Other areas, marked by active geodynamic processes, supported semideserts, i.e. grooves of xerophytic herbs and shrubs. Enhanced aridity and the development of deflation areas, prompted the accretion of loess cover at the northern and southern margins of the GPP. Fauna recorded the gradual disappearance of mammoth, woolly rhino and giant deer, together with cave bear. Gravettian and Epigravettian hunter-gatherer groups inhabited the GPP, although their presence and settlement dynamics at the margins and across this region has long been questioned. As a matter of fact, a handful of archaeological sites composes a patchy record of the peopling of the plain itself. At the northern rim of the GAPR, characterized by a well-developed karst region, several caves and rock shelters record the presence of hunters of bisons and horses at the margins of the GPP and ibexes and cave bears in some hilly landscapes. Nonetheless, evidence of contacts across this area is provided by the exploitation of chert sources and by stylistic and technical similarities in the lithic industries. The work resumes the currently available multidisciplinary data and adds new petroarchaeological evidence for reconstructing the settlement dynamics of the Gravettian - Epigravettian hunter-gatherers in this vast region up to the early Late Glacial, when the Prealpine and the Apennine foothills, along with the Dinarids, were persistently settled.

During the Last Glacial Maximum (LGM), the Adriatic Sea basin was deeply affected by considerable geomorphological and sedimentological processes mainly due to the extension of the alpine glaciers to the plain and dropping of the sea level to -120 a.s.l. The combination of these two processes contributed to the formation of the Great Adriatic Plain (GAP), a vast area covering the center of the Great Adriatic Region (GAR) between the Alpine chain, the Italian Peninsula and the north-western Balkan Peninsula. The GAP has been physically and ecologically featured through a range of palaeogeographic and palaeocological data. Within the lower prealpine belts of the Lombardy, Veneto and Friuli some lake and fine-grained alluvial successions provided palaeocological data. These indicate the persistence of boreal forests of boreal forests throughout the LGM in moist habitat on stable areas and wetland margins, while open woodlands, steppe and semideserts occupied the uplands. Here, a tree cover persisted until the Late-glacial. Extensive wetlands occupied the water-satured silty soils in the lowlands. Other ecozones, marked by active geodynamic processes, got extensive semideserts, i.e. sparse grooves by xerophytic herbs and shrubs. The low mountain belt of the Forealps supported more extensive forest stands, in reason of increased orographic rainfall. Increased aridity and wind intensity prompted the accretion of widespread loess cover throughout MIS 2 at the northern and southern margins of the Po Plain and along the foothills bordering the Adriatic Plains, as documented by the occurrence of loess layers dating to the LGM in several localities. During this period, the Great Adriatic Plain was inhabited by Gravettian and Epigravettian hunter-gatherer groups although their presence and settlement dynamics at the margins and across this region raised up questions for decades. Actually, a handful of archaeological sites compose a patchy record of the peopling of the plain itself. Nonetheless, evidence of contacts across this area is provided by the exploitation of common chert sources and by stylistic and technical similarities in the lithic industries documented in northern and central eastern Italy, Slovenia, Istria and Dalmatia. At the northern rim of the GAR, characterized by a well developed karstic region, a handful of caves and shelters yielded evidence of the presence of these Gravettian hunter-gatherers.

Relazione scientifica che illustra le attività di ricerca svolte dal gruppo di lavoro IGAG nel'ambito del Progetto Scorluzzo.

The potential of quantitatively reconstructing climate from modern pollen assemblages from high mountain environments has been widely debated but seldom tested. We analysed the pollen deposition in 53 surface samples (mosses) in relation to July temperature in two elevational transects in the European Alps. Each surface-sample site was assigned climate data derived from the local-scale climate. We compared our results with a larger calibration set extracted from the European Modern Pollen Database (EMPD) and centred on the European Alps. This also was assigned local climate data. The main calibration set (234 pollen samples) had Alnus harmonized at genus level; in contrast, a second set was selected (174) that retained the taxonomic resolution of Alnus viridis, which is one of the main climate indicators in the timberline ecotone. The overall and individual pollen responses to July temperature were inferred by canonical correspondence analysis (CCA), generalized linear regression (eHOF) and weighted averaging (WA). Quantitative climate reconstructions for each sample site of the two elevational transects were obtained using transfer functions, that is, WA and WA partial least squares (WA-PLS) regressions. In each calibration set, around 30% of the pollen taxa show a relationship with July temperature through monotonic or unimodal functions. The best transfer function obtained has a good statistical performance, with a determination coefficient ( r2) of 0.74. We propose new calibration procedures formulated to include the full climate space of the modelled taxa, as well as to account for uphill pollen transport in the high mountains and for human activity.

Montane vegetation is traditionally known to be particularly sensitive to climate changes. The strong elevational climatic gradient that characterizes mountain areas results in a steep ecological slope, with several ecotones occurring in a small area. Modern pollen deposition is significantly predicted by both vegetation cover and pollen production; in turn, each predictor is significantly predicted by elevation and climate. Analyses of modern pollen deposition are essential to calibrate fossil pollen sequences accounting for site topography and depositional process, and thus for pollen-based palaeoenvironment and palaeoclimate reconstructions. This study analyzes the relationships among modern pollen assemblages, vegetation and climate along an elevational gradient in the outer belt of the European Alps. Results of Canonical Correspondence Analysis (CCA) demonstrated a general good agreement with previous studies, which identified elevation as the main gradient in the variation of modern pollen and vegetation assemblages in elevational transects. Modern pollen assemblages have been studied in pollen traps and moss samples from different vegetation communities along an elevational transect (stretching from 1240 to 2390 m asl), as well as the vegetation using the Braun-Blanquet system up to the 10 m radius scale, field vegetation surveys and aerial photographs for plant cover of the main species for larger surfaces. Moss samples are assumed to record an average of several years of pollen deposition and can be profitably used as analogues for fossil pollen assemblages; while pollen traps can be expressed as Pollen Accumulation Rates (PAR) and used as a modern reference to estimate past plant population densities. Alnus viridis, the main woody species forming dwarf forests in the oceanic-type timberline ecotone, shows a specific elevational PAR arrangement under modern climate conditions. Strong pollen producers (e.g. Pinus sylvestris/mugo, Picea, Castanea, Corylus and Ostrya) display enhanced uphill wind-transport to subalpine and alpine zones leading to wider pollen belts with less defined boundaries than vegetation. To overcome these limitations, potential indicator pollen taxa of alpine/subalpine belts (Vaccinium, Rhododendron, Loiseleuria) documented in this study and PAR of timberline species (e.g. Alnus viridis) could be useful. Thus, if it is possible to identify the major vegetation types and ecotones by means of their modern pollen deposition (e.g. timberline ecotone), other limits, poorly marked by changes in pollen dispersal (e.g. treeline) are not resolved by pollen proxies alone.

Since the time of the Middle Pleistocene Revolution, the increased magnitude of glacial cycles and unstable climatic conditions deeply influenced human environment adaptive strategies and lifestyle. This occurred also during the Upper Palaeolithic, when hunter-gatherers experienced dramatic turnovers, as attested by discontinuous biological and archaeological records [1, 2]. The timing and pattern of multiscalar shifts that occurred from the Last Glacial Maximum (LGM ; 30-16.5 ka sensu [3]) to the onset of the Late Glacial (LG) interstadial are considered to be among the most important events. This period was characterized by largescale climatic oscillations triggered by changes in insolation degree that led to the build-up of boreal ice sheets and emersion of major continental shelves along the coast of North, Southwest and South Europe as a consequence of the lowering of sea level up to -120 m a.s.l. [3]. Human groups reacted to ecological turnovers by increasing their resilience, as shown by a large array of evidence revealed by sites persisting at middle latitudes. Anyhow, also large migrations took place through the corridors connecting European and Mediterranean regions, and pronounced changes in demography and behaviour occurred, resulting in the synchronic and diachronic development of a variety of archaeological cultures in different regions and at different times [1]. Lastly, these events deeply contributed to shaping our present genetic ancestry [4]. In Mediterranean Europe, the combination of the sea-level dropping with the extension of alpine glaciers contributed to the aggradation of the Great Po Plain (GPP) in the Great Adriatic-Po Region (GAPR). The GPP is largely known as the largest alluvial plain ever existed which connected the Italian and Balkan Peninsulae. Geomorphological, sedimentological and ecological processes led to the persistence of boreal forests in moist habitats on stable areas and wetland margins, while open woodlands, steppes and semideserts occupied the uplands and part of the plain, where tree cover persisted until the LG. This offered suitable environmental conditions for several mammal species, while large part of their former distribution range, in Central and Northern Europe, was covered by ice sheets. South of the Alps, the more favourable environmental conditions also allowed the survival and delayed extinction of important consumers like cave bears. The presence of a rich mammal fauna in this southern glacial refugia provided subsistence to hunters-gatherers groups and enhanced their capability to maintain large-scale networks. Gravettian and Epigravettian hunter-gatherer groups inhabited the GPP, although their presence and settlement dynamics at the margins and across this region have raised questions for decades. Actually, a handful of archaeological sites outlines a patchy record of the peopling of the plain itself. Nonetheless, evidence of contacts across this area is provided by the exploitation of common chert sources and by stylistic and technical similarities in the lithic industries documented in northern and central-eastern Italy, Slovenia, Istria, and Dalmatia. Thanks to its peculiar geographic setting and climatic and ecological variability, GAPR is supposed to have represented a paradigmatic case which supported vast movements of populations [5]. Settlement dynamics, mobility, subsistence and symbolic thought as reflected by multidisciplinary data are here reviewed to assess the role of human adaptive flexibility and population turnover as recorded by genetic discontinuity (Fu et al., 2016). As an alternative the possibility of a concurrence of both factors in drawing distinct biological and cultural ancestries is also explored. This study is a contribution to the CNR-IGAG research line DTA.AD001.112 – Quaternary paleoenvironments and palaeoclimate. Studies and analyses were supported by the Ferrara University (FAR2019) and by the Croatian Science Foundation (grant no: IP-2019-04-7821). References: [1] Djindjian, F., Kozłowski, J.K., Otte, M., 1999. Le Paléolithique supérieur en Europe. Colin ed. Paris. [2] Bocquet-Appel, J.P., Demars, P.Y., Noiret, L., Dobrowsky, D., 2005. Estimates of Upper Palaeolithic meta-population size in Europe from archaeological data. J. Archaeol. Sci. 32, 1656-1668. [3] Lambeck, K., Rouby, H., Purcell, A., Sun, Y., Sambridge, M., 2014. Sea level and global ice volumes from the Last Glacial Maximum to the Holocene. Proc. Natl. Acad. Sci. USA 111, 15296-15303 [4] Fu, Q., Posth, C., Hajdinjak, M., Petr, M., Mallick, S., et al., 2016. The genetic history of Ice Age Europe. Nature 534, 200-205. [5] Peresani, M., Monegato, G., Ravazzi, C., Bertola, S., Margaritora, D., Breda, M., Fontana, A., Fontana, F., Janković, I., Karavanic, I., Komšo, D., Mozzi P., Pini R., Furlanetto G., De Amicis M.G.M., Perhoč Z., Posth C., Ronchi L., Rossato S., Vukosavljević N., Zerboni A., in press. Hunter-gatherers across the Great Adriatic-Po Region during the Last Glacial Maximum: environmental and cultural dynamics. Quaternary International, special issue LGM in Europe.

Pollen assemblages are increasingly used for quantitative reconstructions of past climate parameters. Estimated tempera-tures and precipitations can be coupled with palaeoecological records to make their interpretation more robust. Although the potential of numerical techniques is suggested by published and ongoing researches, improvements in the calibration datasets used to compare fossil and modern pollen spectra are needed. Current limitations within the European Modern Pollen Database concerning data quality and density are discussed. Attention is given to altitudinal training sets of modern pollen rain - vegetation - climate - terrain parameters, allowing a better understanding of pollen dispersal and deposition across elevational gradients.

Durante l'ultimo periodo glaciale le calotte dell'emisfero Nord (ed anche l'ice field alpino) si sono più volte espanse e contratte assumendo configurazioni diverse (Ivy-Ochs et al., 2008; Lambeck et al., 2010; Monegato et al., 2017) e raggiungendo la massima estensione intorno a 22 mila anni fa (Hughes et al., 2016) durante l'Ultimo Massimo Glaciale (UMG). A queste maggiori oscillazioni climatiche e glaciali, si sono sovrapposte variazioni climatiche a scala millenaria: i cicli Dansgaard-Oescheger (DO cycles). Tale instabilità climatica, i cui picchi caldi e freddi sono detti, rispettivamente, Greenland Interstadials (GIs) e Greenland Stadials (GSs), è documentata a scala globale. Alla scala dell'emisfero boreale, record paleoclimatici ad alta risoluzione mostrano un marcato raffreddamento durante i GSs a cui sono associati Heinrich events (HEs) (Guillevic et al., 2014; Darfeuil et al., 2016). Per meglio comprendere i meccanismi che regolano tale variabilità climatica e le risposte degli ecosistemi terrestri agli HEs, verrà preso in considerazione il record pollinico del lago di Fimon all'interno della cerchia dei Colli Berici (Vicenza), che documenta la storia ambientale della Pianura Veneta e del margine prealpino a partire dalla Penultima Glaciazione (Pini et al. 2010). Nuove indagini stratigrafiche, geocronologiche e polliniche ad alta risoluzione (media di 1 campione/80-120 anni), hanno evidenziato fasi di apertura forestale con espansione di ecosistemi di semideserto a sud delle Alpi durante il MIS 3. In particolare, fra circa 27 e 35 mila anni fa, dati biostratigrafici e datazioni radiocarboniche restituiscono un robusto quadro cronologico per l'intervallo che precede, documenta e segue il GS 5.1-HE3 (30,6- 28,9 mila anni fa, cronologia GICC05, Rasmussen et al., 2014). Pinete dominate da Pinus sylvestris con betulla erano diffuse fra 35-30 mila anni fa nel settore prealpino sud-orientale. Il lago di Fimon era un bacino con acque poco profonde soggetto a oscillazioni del livello lacustre fino a 25505±99 anni fa (età 14C BP, median probability: 29599 anni cal BP), quando si sviluppa una torbiera a Cyperaceae che si mantiene per circa 2500 anni. All'inizio di questa fase, con un cambio centrato a circa 29,5 mila anni fa, le foreste subiscono una brusca contrazione (percentuali polliniche della componente arborea si riducono dal 70 al 30%), accompagnata dalla riduzione del segnale degli incendi a scala locale. Si espandono praterie (Gramineae, Asteraceae, Cichorioideae) con arbusti xerici e piante erbacee di ambiente steppico (Hippophae, Artemisia, Chenopodiaceae, Ephedra). Tale evento, di durata millenaria, può essere correlato alla fase freddo-arida dell'HE3, visibile in altri record pollinici continui in Nord Italia (Azzano decimo; Pini et al., 2009) e area mediterranea (Lago Grande di Monticchio, Tenaghi Philippon; Wulf et al., 2018). La fase successiva: interstadiali GI 4 e GI 3 (rispettivamente 28,9 e 27,78 mila anni fa, cronologia GICC05, Rasmussen et al., 2014), è caratterizzata da una nuova espansione di pinete con larice, betulla e ginepro, e dall'intensificazione di incendi a scala locale.

Relazione scientifica finale, luglio 2019

During his explorations in temperate and tropical mountains, Humboldt made crucial observations about the importance of elevational climate gradients as drivers for biodiversity. We show here that pollen deposition may be a suitable, and statistically robust proxy for climate-driven elevational eco-gradients, thus assisting in the interpretation of modern ecosystem dynamics as well as in past climate reconstructions from fossil records. Our specific challenges are: (1) to derive consistent pollen-climate relationships in complex mountain regions bearing differences in local climates and intensity of human impact; (2) to find potential indicator taxa useful for paleoclimate reconstructions; (3) to estimate the effect of local parameters on the relationships linking pollen percentages variations, elevation and climate and put forward new hints for calibration of fossil sites; (4) to obtain quantitative climate reconstructions and compare the results with instrumental modelled data and finally (5) to integrate the newly-obtained pollen spectra into larger modern pollen samples datasets. We analyzed pollen deposition in the European Alps and the Canaries, captured by surface samples (subsampling mosses, forest litter, surface soil in open ground land) and artificial traps both at the ground level and over it. To examine the variance explained by climate parameters, elevational training sets were equipped with site-specific climatologies, together with an array of environmental variables (i.e. proxies for fire, nutrients, pastoralism, terrain parameters, plant cover). The potential for a quantitative reconstruction of sensible climate parameters was tested by canonical correspondence analysis (CCA), enhanced hierarchical logistic regression (extended eHOF models), and weighted averaging (WA).

Atlante per l'identificazione del polline di oltre 50 fanerofite presenti nel territorio della Riserva Naturale "Bosco della Fontana" (Marmirolo, provincia di Mantova)

Microscopic remains (pollen, spores, algae, insect remains, etc.) stored and preserved in sedimentary sequences over geological time periods provide a wide spectra of "response variables" (Birks et al., 2010) of past terrestrial and aquatic habitats. But, while the suitability of paleoecological records for qualitative environmental reconstructions is widely accepted, their potential as quantitative climate predictors is still poorly explored. Within the CNR-DTA "Nextdata Project" we tested the feasibility of reconstructing past temperature and precipitation series using terrestrial fossil pollen records from lake and mires located in Northern Italy and nearby areas. Climate parameters are estimated through updated numerical procedures comparing fossil pollen spectra with modern datasets. We applied several modern calibration subsets, obtained from a recently issued version of the European Modern Pollen Database (EMPD, Davis et al., 2013) New altitudinal training sets, recording ecological and climate gradients in the Alpine region, are being sampled and integrated within the EMPD to obtain transfer function for paleoclimate reconstructions. Techniques of regression and calibration (Locally-Weighted Weighted-Averaging - LWWA, Weighted Averaging - WA; ter Braak & Barendregt, 1986; Juggins & Birks, 2012) and the assemblage approach (Modern Analogue Technique - MAT; Juggins & Birks, 2012) are applied to pollen assemblages and used to constrain model uncertainties and to validate the models. Pollen-inferred quantitative climate estimations of past climate variables (temperatures and precipitation) will be presented from: (i) a high-elevation site in the western Alps (Rutor Glacier foreland; Badino, 2016) bearing paleobotanical evidence of an Holocene climate optimum and the thermal decline at around 4000 yrs cal BP; (ii) the Last Interglacial at Lake Fimon (Pini et al., 2010) where the development of forest vegetation after the treeless-steppe phase of the penultimate glaciation is documented. Here, mixed deciduous woodlands of warm-temperate and dry climate are replaced by mixed Abies-Fagus-Carpinus betulus forests of oceanic-temperate signature chronologically constrained during a phase of insolation minima. This climatic pattern is captured in the pollen-based reconstructions so far obtained; (iii) pollen and macroremains from a continuous sediment record spanning most of the Last Glacial Maximum at the slovenian fringe of the Alps. Here, the pollen and charcoal record of open forests with boreal signature provides several predictors of cold-temperate continental ecosystems, extinct in the Alps but finding appropriate analogues along ecological gradients in Fennoscandia and Siberian ranges.