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This paper presents a multidisciplinary summary of the most recent discoveries and hypotheses concerning factors driving the human subsistence economy and landscape shaping in Sicily during the Holocene. A number of scientific papers have recently pointed out the key role played by paleogeography, resource (water, food) availability and natural disturbances (volcanic eruptions, tsunamis) in local human activities. Modern anthropology and archaeology increasingly use biological remains (e.g. soils, bones, wood, plant macroremains, pollen) to better understand how human communities managed to survive and spread. Likewise, refined reconstructions of past human demographic fluxes and socio-economic structures may enable a better understanding of landscape dynamics. Specifically, this historical perspective on the management of natural resources allows the finding of past episodes of unsustainable land use (e.g. forest destruction, overgrazing), thus providing a useful basis for future nature protection and maintaining sustainable ecosystem services.

International audience; The future of PAGES is in the construction of a more global and diverse paleoscience community, expansion of links with other, complementary initiatives, and in the support of community-driven science. PAGES should challenge itself with bold new initiatives, lean administration, a smaller carbon footprint, and open and inclusive activities, with the central theme of time threaded through the effort.

1. Tree lines are supposed to react sensitively to the current global change. However, the lack of a long-term (millennial) perspective on tree line shifts in the Pyrenees prevents understanding the underlying ecosystem dynamics and processes. 2. We combine multiproxy palaeoecological analyses (fossil pollen, spores, conifer stomata, plant macrofossils, and ordination) from an outstanding ice cave deposit located in the alpine belt c. 200 m above current tree line (Armeña-A294 Ice Cave, 2, 238 m a.s.l.), to assess for the first time in the Pyrenees, tree line dynamics, and ecosystem resilience to climate changes 5, 700–2, 200 (cal.) years ago. 3. The tree line ecotone was located at the cave altitude from 5, 700 to 4, 650 cal year bp, when vegetation consisted of open Pinus uncinata Ramond ex DC and Betula spp. Woodlands and timberline were very close to the site. Subsequently, tree line slightly raised and timberline reached the ice cave altitude, exceeding its today''s uppermost limit by c. 300–400 m during more than four centuries (4, 650 and 4, 200 cal year bp) at the end of the Holocene Thermal Maximum. After 4, 200 cal year bp, alpine tundra communities dominated by Dryas octopetala L. expanded while tree line descended, most likely as a consequence of the Neoglacial cooling. Prehistoric livestock raising likely reinforced climate cooling impacts at 3, 450–3, 250 cal year bp. Finally, a tree line ecotone developed around the cave that was on its turn replaced by alpine communities during the past 2, 000 years. 4. Synthesis. The long-term Pyrenean tree line ecotone sensitivity suggests that rising temperatures will trigger future P. uncinata and Betula expansions to higher elevations, replacing arctic–alpine plant species. Climate change is causing the rapid melting of the cave ice; rescue investigations would be urgently needed to exploit its unique ecological information.

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La plurimillenaria azione dell'uomo sugli ecosistemi sudalpini, e mediterranei in particolare, ha fortemente alterato i consorzi vegetali e spesso cancellato le specie arboree che in natura dominerebbero nelle attuali condizioni ambientali. Tale lacuna rende molto difficile pronosticare quali specie sarebbero le meglio adattate a eventuali futuri cambiamenti climatici.

Want a glimpse at past vegetation? Studying pollen and other plant remains which are preserved for example in lake sediments or mires for thousands of years allows us to document regional occurrences of plant species over radiocarbon dated time series. Such vegetation reconstructions derived from optical analyses of fossil samples are inherently incomplete because they only comprise taxa that contribute sufficient amounts of pollen spores macrofossil or other evidences. To complement optical analyses for paleoecological inference molecular markers applied to ancient DNA (aDNA) may help in disclosing information hitherto inaccessible to biologists. Parducci et al. (2013) targeted aDNA from sediment cores of two lakes in the Scandes Mountains with generic primers in a meta barcoding approach. When compared to palynological records from the same cores respective taxon lists show remarkable differences in their compositions but also in quantitative representation and in taxonomic resolution similar to a previous study (Jørgensen et al. 2012). While not free of assumptions that need critical and robust testing notably the question of possible contamination this study provides thrilling prospects to improve our knowledge about past vegetation composition but also other organismic groups stored as a biological treasure in the ground.

High-resolution pollen, macrofossil and charcoal data, combined with accelerator mass spectrometry 14C dating and multivariate analysis, were used to reconstruct Holocene vegetation and fire dynamics at Urio Quattrocchi, a small lake in the supra-mediterranean belt in the Nebrodi Mountains of Sicily (Italy). The data suggest that after 10 000 cal a BP increasing moisture availability supported closed forests with deciduous (Quercus cerris, Fagus sylvatica and Fraxinus spp.) and evergreen (Quercus ilex) species. Species-rich closed forest persisted until 6850 cal a BP, when Neolithic activities caused a forest decline and affected plant diversity. Secondary forest with abundant Ilex aquifolium recovered between 6650 and 6000 cal a BP, indicating moist conditions. From 5000 cal a BP, agriculture and pastoralism led to the currently fragmented landscape with sparse deciduous forests (Quercus cerris). The study suggests that evergreen broadleaved species were more important at elevations above 1000m a.s.l. before ca. 5000 cal a BP than subsequently. Despite human impact since Neolithic times, deciduous supramediterranean forests were never completely displaced from the Nebrodi Mountains, because of favourable moist conditions that persisted throughout the Holocene. Reconstructed vegetation dynamics document the absence of any pronounced mid- or late-Holocene ‘aridification’ trend at the site, an issue which is controversially debated in Italy and the Mediterranean region.

The special location of Lake "Specchio di Venere" on Pantelleria Island in the Sicily Channel (Mediterranean Sea) between Tunisia and Sicily offers a unique terrestrial archive recording atmospheric changes, which are otherwise difficult to decipher in the marine records from this area. The lake is an endorheic saline basin with a maximum depth of 12.5 m. As the water input depends on rainfall, precipitation variations influence changes of the lake's water chemistry. In summer 2008, Lake Venere was cored with a modified Livingstone corer revealing a composite sedimentary sequence of 10.29 m length. Two radiocarbon dates form a preliminary age model indicating a very high sedimentation rate ~80 cm/100 years. Therefore, the recovered sequence allows the analysis of the last 1,200 years in high resolution. The sedimentology of the core alternates between intervals with carbonate laminations, and sections rich in organic matter with variable amount of detrital influence. The carbonate was likely precipitated during dry climatic periods, when the ratio evaporation/precipitation was high. Carbonate content is especially high in the lower part of the core between 800 and 950 years AD. The carbonate content stays low for about 3 centuries, before several intervals of intermediate carbonate content separated by nearly carbonate free sediment occur. In the last 130 years, the carbonate content increases. The carbonate curve closely follows the general European climate evolution of the last millennium. Intervals rich in carbonate in the lower part of the Venere core coincide with the medieval warm period (WMP), whereas during the little ice age (LIA) (1250 - 1850 years AD) little or no carbonates were deposited. Pollen analysis suggests vegetation responded to the climatic changes we inferred from litho-stratigraphical properties. During the period 800-1050 AD, drought and disturbance-adapted, evergreen-broadleaved trees (e.g. Olea, Q. ilex), shrubs (e.g. Pistacia), and heliophilous herbs (e.g. Artemisia) dominated the vegetation of the island, and conifers were moderately abundant (on average 20-30% of the pollen sum). Afterwards conifers (Pinus pinaster) expanded, while Olea, Q.ilex, and open environments declined. From 1800-2000 AD Quercus ilex and Olea re-expanded and conifers became less abundant. Today dense Pinus pinaster forests are restricted to higher altitudes of the island, where moisture is more abundant. The pronounced negative correlation between evergreen broadleaved and conifers is also registered at decadal scales, with rather strong and abrupt oscillations during and after the LIA period. However, vegetational changes were certainly co-determined by land-use, which was quite intense in the past, as also shown by widespread stone-terrace constructions for crop cultivation. This initial analysis shows the potential of the Lake Venere sedimentary record as a valuable climatic and environmental archive for the Central Mediterranean.

We used a new sedimentary record to reconstruct the Holocene vegetation and fire history of Gorgo Basso, a coastal lake in south-western Sicily (Italy). Pollen and charcoal data suggest a fire-prone open grassland near the site until ca 10,000 cal yr BP (8050 cal BC), when Pistacia shrubland expanded and fire activity declined, probably in response to increased moisture availability. Evergreen Olea europaea woods expanded ca 8400 to decline abruptly at 8200 cal yr BP, when climatic conditions became drier at other sites in the Mediterranean region. Around 7000 cal yr BP evergreen broadleaved forests (Quercus ilex, Quercus suber and O. europaea) expanded at the cost of open communities. The expansion of evergreen broadleaved forests was associated with a decline of fire and of local Neolithic (Ficus carica–Cerealia based) agriculture that had initiated ca 500 years earlier. Vegetational, fire and land-use changes ca 7000 cal yr BP were probably caused by increased precipitation that resulted from (insolation-forced) weakening of the monsoon and Hadley circulation ca 8000–6000 cal yr BP. Low fire activity and dense coastal evergreen forests persisted until renewed human activity (probably Greek, respectively Roman colonists) disrupted the forest ca 2700 cal yr BP (750 BC) and 2100 cal yr BP (150 BC) to gain open land for agriculture. The intense use of fire for this purpose induced the expansion of open maquis, garrigue, and grassland-prairie environments (with an increasing abundance of the native palm Chamaerops humilis). Prehistoric land-use phases after the Bronze Age seem synchronous with those at other sites in southern and central Europe, possibly as a result of climatic forcing. Considering the response of vegetation to Holocene climatic variability as well as human impact we conclude that under (semi-)natural conditions evergreen broadleaved Q. ilex–O. europaea (s.l.) forests would still dominate near Gorgo Basso. However, forecasted climate change and aridification may lead to a situation similar to that before 7000 cal yr BP and thus trigger a rapid collapse of the few relict evergreen broadleaved woodlands in coastal Sicily and elsewhere in the southern Mediterranean region.

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