Over the last millennia, the land between the Alps and the Mediterranean Sea, characterized by extraordinary habitat diversity, has seen an outstanding cross-cultural development. For the first time, this paper reports on the census of the Holocene archaeological sites that have been studied as part of archaeobotany in Italy (continental Italy, the Italian peninsula and islands) over the last quarter in a century. Pollen, non-pollen palynomorphs, seeds and fruits, woods/charcoals and other plant remains have all been analysed in multidisciplinary researches. A list of 630 sites has been provided by more than 15 archaeobotanical teams. The sites are located across the 20 regions of Italy, and in the Republic of San Marino (356 sites in northern Italy, 118 in central Italy, 156 in southern Italy and on the islands). They belong to several cultural phases: 321 sites are only pre-Roman, 264 are Roman/post-Roman, and 45 sites cover a broader range of time, present in both time spans. Site distribution is plotted in maps of site density according to geographical districts and the main chronological phases. The reference list helps to find analytical data referring to the descriptive papers that may be scattered throughout monographs and specific books on the matter

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Aim High‐elevation forest line or tree line is an ecological ecotone representing the upper elevation thermal limit for forest development. The current tree line position is the result of the past human activity interacting with climatic and topographic conditions. In this study, we investigate how climate, local topographic factors and anthropogenic disturbance currently affect tree line distribution. Location Apennine Mountains, 900 km latitudinal gradient along the Italian Peninsula. Methods Overall, 302 mountain peaks were studied, comprising 3,622 km of measured tree lines. The position of the Fagus sylvatica tree line in all peaks was assessed and correlated with 58 selected variables representing climate, topography and human disturbance. Results The mean tree line elevation was 1,589 m a.s.l., with considerable variability among peaks. Contrary to our expectations, the tree line elevation was lower in the warmer southerly exposed slopes compared to north‐facing aspects, where we found the highest tree line (2,141 m a.s.l.). Correlation analysis indicates that both climatic and human density variables are associated with tree line elevation, with the climate having more influence in high elevation mountains, while human impact plays a prominent role in low elevation mountain peaks. Specifically, we found negative correlations between density of the resident population around each peak and tree line elevation at all examined dates (1861, 1921, and 2011), suggesting a pervasive negative impact of human activity on tree lines. As regards climatic variables, tree line elevation showed a stronger negative correlation with winter and spring months temperature than with mean annual temperature. Noteworthy, climatic variables had stronger effect on high elevation peaks (>1,900 m a.s.l.) compared with low elevation ones (<1,900 m a.s.l.). Main Conclusion Our data provide evidence that the current position of the F. sylvatica tree line in the Apennines is heavily depressed as a result of a complex interaction between climatic factors and the past human pressure.

In Mediterranean countries, in the year 2017, extensive surfaces of forests were damaged by wildfires. In the Vesuvius National Park, multiple summer wildfires burned 88% of the Mediterranean forest. This unprecedented event in an environmentally vulnerable area suggests conducting spatial assessment of the mixed-severity fire effects for identifying priority areas and support decision-making in post-fire restoration. The main objective of this study was to compare the ability of the delta Normalized Burn Ratio (dNBR) spectral index obtained from Landsat-8 and Sentinel-2A satellites in retrieving burn severity levels. Burn severity levels experienced by the Mediterranean forest communities were defined by using two quali-quantitative field-based composite burn indices (FBIs), namely the Composite Burn Index (CBI), its geometrically modified version CBI (GeoCBI), and the dNBR derived from the two medium-resolution multispectral remote sensors. The accuracy of the burn severity map produced by using the dNBR thresholds developed by Key and Benson (2006) was first evaluated. We found very low agreement (0.15 < K < 0.21) between the burn severity class obtained from field-based indices (CBI and GeoCBI) and satellite-derived metrics (dNBR) from both Landsat-8 and Sentinel-2A. Therefore, the most appropriate dNBR thresholds were rebuilt by analyzing the relationships between two field-based (CBI and GeoCBI) and dNBR from Landsat-8 and Sentinel-2A. By regressing alternatively FBIs and dNBRs, a slightly stronger relationship between GeoCBI and dNBR metrics obtained from the Sentinel-2A remote sensor (R2 = 0.69) was found. The regressed dNBR thresholds showed moderately high classification accuracy (K = 0.77, OA = 83%) for Sentinel-2A, suggesting the appropriateness of dNBR-Sentinel 2A in assessing mixed-severity Mediterranean wildfires. Our results suggest that there is no single set of dNBR thresholds that are appropriate for all burnt biomes, especially for the low levels of burn severity, as biotic factors could affect satellite observations.

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Questions: Pollen data for Abies alba Mill., a key European tree species, show broad occurrence in the Italian peninsula in the early to mid-Holocene diffusion (until ca. 6000 yr ago) along the Italian peninsula and a strong decline/local extinction starting ca. 5000 yr ago. This decline has been attributed to climate change. Recently, high-resolution pollen studies, mainly in northern Italian sites claim that A. alba disappearance was mainly due to human impact. We examined the presence of A. alba in archaeological sites of southern and central Italy in order to trace the late Holocene history (last 3000 yr) of this tree and enhance understanding of its role in pre-anthropic vegetation and of human involvement in its decline.Location: Central and southern Italy.Methods: Anthracological analysis was conducted in six archaeological layers at the archaeological site of Trebbio-Spinellina (800-600 BC, Sansepolcro, Tuscany). A critical analysis of wood/charcoal literature relevant to Abies in central and southern Italy was used to corroborate the results of Trebbio-Spinellina. Charcoal records from archaeological sites have been compared with the current distribution of A. alba.Results: At Trebbio-Spinellina, A. alba charcoal is present in all contexts examined, together with mesophilous broad-leaf taxa (Quercus deciduous, Carpinus betulus, Ostrya carpinifolia, Corylus avellana). A low charcoal percentage of Fagus sylvatica and Taxus baccata is also found; evergreen taxa are mainly represented by Quercus ilex with occasional shrubs (i.e. Viburnum, Cistus, Erica). In the literature, we identified several peninsular and insular Italian archaeological sites showing charcoal evidence of Abies, accompanied by deciduous oaks, mainly Q. cerris, and other broad-leaf mesophilous trees, dating from the Iron Age to the Middle Ages. All sites, except one, lie at less than 600 m a.s.l., and far from present-day A. alba communities. Conclusion:Results call for a reworking of the prevailing paradigm of A. alba as a relic mountain species. Indeed, A. alba once grew at lower altitudes than currently and was associated with deciduous oaks, mainly Q. cerris, and other mesophilous broad-leaf trees. This evidence calls into question the suitability of the Potential Natural Vegetation (PNV) concept usually applied in the floristic approach. The recent population decline is attributable to human activity rather than to climate change. Finally, the persistence of A. alba until the late Holocene calls into question the assumptions that it is a relic species with no potential to expand its spatial range.

During the glacial episodes of the Quaternary, European forests were restricted to small favourable spots, namely refugia, acting as biodiversity reservoirs. the Iberian, Italian and Balkan peninsulas have been considered as the main glacial refugia of trees in Europe. In this study, we estimate the composition of the last glacial forest in a coastal cave of the Cilento area (SW Italy) in seven time frames, spanning from the last Pleniglacial to the Late Glacial. Charcoal analyses were performed in seven archaeological layers. Furthermore, a paleoclimate modelling (Maxent) approach was used to complement the taxonomic identification of charcoal fragments to estimate the past potential distribution of tree species in Europe. Our results showed that the mesothermophilous forest survived in this region in the core of the Mediterranean basin during the Last Glacial Period (LGP, since ~36 ka cal BP), indicating that this area played an important role as a reservoir of woodland biodiversity. Here, Quercus pubescens was the most abundant component, followed by a wide variety of deciduous trees and Pinus nigra. Charcoal data also pointed at the crucial role of this coastal area, acting as a reservoir for warm temperate trees of genera Tilia, Carpinus and Sambucus, in LGP, in the Mediterranean region. Our modelling results showed that P. nigra might be the main candidate as a “Pinus sylvestris type” in the study site in the Last Glacial Maximum (LGM). Furthermore, we found that P. nigra might coexist with Q. pubescens in several European territories both currently and in the LGM. All models showed high levels of predictive performances. Our results highlight the advantage of combining different approaches such as charcoal analysis and ecological niche models to explore biogeographic questions about past and current forest distribution, with important implications to inform today’s forest management and conservation.

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