This paper presents the results of the explorations carried out in the western sector of the Iberian Central System (western Gredos, Béjar, Gata and Estrela mountain ranges). The macroremains found ...allow detailing the model of the landscape transformation, the composition and extension of their vegetal formations throughout the Holocene.
Ninety-nine woody macroremains, 3 bark remains and 8 pinecones were located from eight sites between 875 and 1860 m above sea level, among which 15 radiocarbon dates were made. The taxonomic identification of two trunks found in Estrela allows us to document the local presence of Pinus cf. sylvestris ca. 6600 cal BP in this site. The same taxon also appears at the western end of Gredos between ca. 1700–2800 cal BP at approximately 1300 m. These remains expand the Holocene distribution of P. cf. sylvestris in the Central System known to date, both temporally and geographically.
In parallel, the macroremains analysed document the composition of high mountain scrub (Cytisus type, Erica cf. arborea) in Béjar (ca. 1860 m), as well as mixed scrub-woodland formations in Gata (975–1180 m), which included deciduous Quercus, Betulaceae and Ericaceae. The presence of P. pinaster at ca. 6200 cal BP and 1180 m in this mountain range constitutes the earliest palaeobotanical evidence of this species recorded in Gata.
The main results support the continuous persistence of plant formations in which P. sylvestris, P. nigra, and P. pinaster would have formed part throughout the Iberian Central System during the Holocene in a wide altitudinal range (1100–1840 m).
•Above one hundred Holocene macrofossils from eight different sites were analysed.•Pinus sylvestris recently disappeared from the western Central System.•P. gr. sylvestris remained in Serra da Estrela until ˜6650 years ago.•First evidence of Pinus pinaster has been found in Gata ˜6200 years ago.•Betula, Quercus, Alnus and Ericaceae Holocene macroremains were found in Gata.
Palaeoecological evidence indicates that highland pines were dominant in extensive areas of the mountains of Central and Northern Iberia during the first half of the Holocene. However, following ...several millennia of anthropogenic pressure, their natural ranges are now severely reduced. Although pines have been frequently viewed as first-stage successional species responding positively to human disturbance, some recent palaeobotanical work has proposed fire disturbance and human deforestation as the main drivers of this vegetation turnover. To assess the strength of the evidence for this hypothesis and to identify other possible explanations for this scenario, we review the available information on past vegetation change in the mountains of northern inland Iberia. We have chosen data from several sites that offer good chronological control, including palynological records with microscopic charcoal data and sites with plant macro-and megafossil occurrence. We conclude that although the available longterm data are still fragmentary and that new methods are needed for a better understanding of the ecological history of Iberia, fire events and human activities (probably modulated by climate) have triggered the pine demise at different locations and different temporal scales. In addition, all palaeoxylological, palynological and charcoal results obtained so far are fully compatible with a rapid human-induced ecological change that could have caused a range contraction of highland pines in western Iberia.
Paleoenvironmental and archaeological data show that Mediterranean landscapes result from long-term socio-environmental interactions. Mediterranean islands constitute a place of passage where the ...creation of cultural landscapes can be traced through colonization and anthropization histories. Palynological studies carried out in the Balearic Islands highlight a deep vegetation change from the mid- to late-Holocene, but the climate-environmental-human interactions are not fully understood yet. In this study, we aim to disentangle the causalities of landscape changes during the last six millennia using a multi-proxy approach on an off-site core for the first time in Minorca island. We find that, during the mid-Holocene, the climate was wetter than today with less rainfall seasonality than in the current Mediterranean. This climate, favoured the expansion of box formations and the predominance of forested formations with minimal anthropized conditions. First agropastoral activities appeared in the sequence between ca. 3500–2650 cal BCE in north-eastern Minorca, coinciding with other sporadic archaeological evidence (Cova dels Morts rock-shelter) which support the possibility of a pre-Chalcolithic discovery and frequentation of the island. We record deep environmental change during the third millennium cal BCE, reflected in the substitution of the former mesophytic vegetation by Mediterranean maquis formations dominated by wild olive trees, heathers, mastic and Cistaceae. We propose that maquis, garrigues and open-land vegetation were favoured by human action in a context of increasing climatic dryness and seasonality, promoting vegetation flammability and substitution of former mesic communities to more adapted termophilous vegetation. The comparison of our new record from Addaia with other pollen studies from the Balearic Islands highlights the resilience of mesic vegetation to climate change. This is shown by the survival of box formations to the increased aridification initiated at ca. sixth–fifth millennium cal BCE (ca. 7–6 cal kyr BP) in the Western Mediterranean which culminated at ca. fourth–third millennium cal BCE (ca. 5–4 cal kyr BP). Additionally, whilst sporadic human presence versus stable occupation are difficult to detect in archaeological records, the coupling with paleoenvironmental studies may offer new scenarios and information for human arrival in the Balearic Islands.
•First off-site multiproxy study in Minorca island•Mid- and late-Holocene socio-environmental interaction•Causalities for the mid- to late-Holocene environmental change•Human activities and aridification promotes a patchy landscape.•Potential new scenarios for human arrival in the Balearics
Integration of a diverse set of data from pollen, wood, macrofossils and dendrochronological studies from the Sierra de Ayllón, a mountainous region in central Spain, enables one of the most complete ...palaeoecological vegetation reconstructions for almost the whole Holocene on the Iberian Peninsula. Previously, the absence of pollen data for the early Holocene in the eastern part of the Sistema Central mountains had been a gap in the information needed for correctly reconstructing palaeoenvironmental change there. Our pollen study on the Valdojos site finally allows this issue to be resolved. This analysis highlights the crucial role played by pine woodlands throughout the first half of the Holocene in this region. The importance of the pine woods in the region enables us to show the clear difference in vegetation between the western and eastern parts of the Sistema Central mountains for the early to mid Holocene. Moreover, the
Fagus
pollen found at Valdojos, dating to ca. 7,000–6,600 cal years
bp
, is the oldest beech record for the central and eastern part of this chain of mountains during the Holocene. This supports the hypothesis of the existence of beech refuges in the Sistema Central for this time span. Furthermore, we used the tree-ring series from the
Pinus
cf.
sylvestris
subfossil wood from the Sandria site to extend the previous data from the Sierra de Ayllón to almost the entire Holocene. This tree-ring record is the most complete data set from the Iberian Peninsula and southern Europe and it also provides data on some aspects of the palaeoenvironment.
Unravelling the precise Holocene altitudinal fluctuation of the highland vegetation communities (>1800 m asl) in the Gredos Range (Central System, Spain) is challenging owing to the complexity of the ...long-term human-environmental interactions in the area. Aiming at improving the knowledge of these highland dynamics, a pedoanthracological analysis was conducted on six soil profiles located on the northern slope of the central sector of the Gredos Range, following an altitudinal transect between 2200 and 1700 m asl in the Las Pozas valley. The soil charcoal analysis revealed the long-term stability of the Leguminosae shrublands, which have dominated the landscape over 1800 m asl since the Early Holocene. The highest ancient timberline was stimated to be at approximately 1700 m asl in this valley, from the Early Holocene until the beginning of the Late Holocene. This ancient forest contained Pinus gr. sylvestris, with significant numbers of deciduous Quercus. However, scattered individuals or small groves of pioneer deciduous taxa (Betula sp., Populus sp., Salix sp., Maloideae and Prunus sp.) were found to have thrived over the timberline during the Early and Middle Holocene, especially between 1900 and 2000 m asl. The highest treeline was marked by Betula at 2100 m asl. Elevated values of charcoal concentration reflect the intense fire regime of the area. The pattern of fire events accumulation periods that can be inferred from the 23 dated charcoal samples is consistent with previous data, which supports an increase in fire frequency around 2000 cal yr BP, during the first reported period of significant human influence.
The study of well-preserved archaeological charcoals in the pre-Roman Iron Age settlement of Castillejos II (Badajoz, Spain) is used to reconstruct environmental conditions and land-use practices in ...vegetation landscapes in the southwest of the Iberian Peninsula before the arrival of Roman civilization. The results support that, while evergreen Quercus forests dominated during the Holocene, Pinus pinaster existed as a natural element of southwestern Iberian Peninsula vegetation. Although its presence could be linked to anthropogenic disturbance or fire history, it is suggested that P. pinaster populations survived during the Holocene in the region, mixed with oaks or in monospecific stands in mountain enclaves. This hypothesis contrasts with previous assumptions that P. pinaster was not autochthonous in the area.
To reconstruct the historical biogeography of Pinus sylvestris in the Cantabrian Range (Iberian Peninsula) during the Holocene, and to consider the interactions between vegetation dynamics, climate ...change and the role of man in the present-day distribution of the species. The study site is a mire (1300 m a.s.l.) at Vega de Viejos, on a south-facing slope of the western Cantabrian Range, Spain. The region's present-day landscape is almost treeless, with the exception of some patches of Quercus pyrenaica and a few copses of Salix and Betula along stream banks. Tree macrofossils from Vega de Viejos were studied by transmitted light and dark-field reflection microscopy; strobili were subjected to comparative morphological analyses. Two Pinus macrofossils were dated by conventional ¹⁴C methods. The taxonomic accuracy achieved in the identification of the macrofossils provided new information regarding the Holocene history of Pinus sylvestris in this territory. Ninety-five cones of this species were identified; in fact, more than 80% of the 36 identified wood remains were of Pinus gr. sylvestris. Radiocarbon dating revealed that the forest to which the fossils belonged was present until at least 2170 ± 50 yr bp- its disappearance was therefore relatively recent. Pinus sylvestris suffered long-term isolation, and after the Würm glacial period tended to migrate towards the east. In western Iberia, a temperate climate and autogenic succession favoured broadleaved taxa at the expense of Pinus. Late Holocene human disturbances may have further accelerated the decline of P. sylvestris; in the Cantabrian Range, only a few stands on southern slopes have persisted until the present day. The history of the capercaillie (Tetrao urogallus), a bird characteristic of pure or mixed Palaeartic coniferous forests, was almost certainly affected by the demise of these forests in this area. Cantabrian capercaillies are the only members of this species that live in purely deciduous forests, perhaps a recent adaptation to the regional extinction of pines. Today's P. sylvestris and capercaillie populations are now highly fragmented and their future, given the predictions of global climate change, is uncertain.
Taxonomic differences in the needle epidermis characteristics of
Pinus sylvestris L. and
Pinus uncinata Ramond ex DC. from two Iberian populations were sought; such information could help identify ...these species when pollen analysis and the inspection of wood anatomy fails. The features of the cuticle are commonly well preserved in the fossil record. Although the epidermal patterns of the examined taxa were similar, qualitative differences were seen in the subsidiary and guard cells.
P. sylvestris showed small subsidiary cells homogenously arranged around the opening of the epistomatal chamber, while
P. uncinata showed small, lateral subsidiary cells and non-differentiated subsidiary cells in the polar position. The aperture of the epistomatic chamber of
P. uncinata was also larger in diameter (15.1
±
1.8 µm
P. sylvestris; 21.1
±
2.8 µm
P. uncinata). Principal components analysis and discriminant analysis was performed on the features of the guard cells characterising the size and shape of the cuticular thickenings — all the variables analysed can be measured in disperse stomata in microscope preparations for pollen analysis. Significant differences were found in the upper woody lamellae width and the coefficient associated with the shape of the medial lamellae borders (discriminant analysis weighting 0.739 and 0.826 respectively). Other significant parameters included the coefficient associated with the relative size of the medial lamellae border width of the guard cells with respect to the distance between the external limits of the medial lamellae borders, and the length of the upper woody lamella. Different light regimens appeared not to significantly affect the variability of the studied features.
The Mirambel woodland on the margins of the Millevaches plateau (Massif Central) is one of the few ancient broad-leaved woodlands in France. Historical sources show that it has occupied the same ...surface area for the past 250 years, despite being in a region that underwent considerable anthropogenic changes during this period. We explored the Mirambel's Holocene history and ancientness by means of soil charcoal analysis, chosen because of its high accuracy on a local scale. We excavated five pedoanthracological pits in the woodland and its open marginal spaces. The 29 radiocarbon dates ranged from the Atlantic (8700–5500 cal yr BP) – Subboreal transition to the Subboreal (5500–2800 cal yr BP) and Subatlantic (2800–0 cal yr BP, i.e. AD 1950) periods, revealing the existence of fire events corresponding to six contemporaneous cultural periods: Neolithic (ca. 3877–2991 cal yr BC), Neolithic-Chalcolithic transition (ca. 2528–2525 cal yr BC), Protohistory (ca. 147 cal yr BC), Roman period (AD 326–579), Middle Ages (AD 732–1187), and contemporary times (AD 1781 to present day). Three Tilia charcoal fragments dating from ca. 3717–2919 cal yr BC indicated the presence of a diversified Mid-Holocene deciduous woodland featuring Tilia and Acer nowadays-absent taxa in this area. Deciduous Quercus and Fagus sylvatica dominated most of the soil profiles, as they do nowadays in the woodlands. Other taxa (Salix, Corylus avellana, Betula) were identified, as well as in the current vegetation. The occurrence of Cytisus-type (Fabaceae) and Calluna vulgaris suggested that there were forest clearing phases at all the points sampled. Widely varying levels of abundances may reflect differences in the duration of these open phases.
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