Holocene environmental change on the Atlantic coast of NW Iberia as inferred from the Ponzos wetland sequence

Abstract

The intertidal environment of the Ponzos beach (NW Iberian Peninsula) hosts a sedimentary sequence (including large wood fragments) deposited during the first half of the Holocene in a hygrophilous continental wetland. Pollen and macrofossil data alongside radiocarbon dating allow reconstruction of the changes that occurred during the Early and Middle Holocene in the landscape of the NW Iberia coastal lowlands, aswell as the local wetland plant communities, in response to the climate variations and the eustatic sea-level oscillations. The sequence represents the evolution of a coastal wetland from its initial phases as a hygrophilous wetland towards the subsequent installation of a freshwater lagoon. Pollen data show the dominant role of Atlantic (mainly deciduous) woody taxa, the scarcity of conifers and the lackof Mediterranean elements in the coastal landscapes around the Ponzos site. The presence and abundance of some taxa such as deciduous Quercus, Castanea, Fagus, Tilia and Ulmus during the Early Holocene provides further support for the occurrence of glacial refuges in the Cantabrian-Atlantic area during the Last Glaciation. The diverse vegetation that characterizes the modern landscapes in this territory established later, spreading from these glacial reservoirs of biodiversity. In this sense, the notable and early presence of Fagus at the beginning of the Holocene, a tree also previously recorded during several phases of the Last Glacial Cycle on the NW Iberia coasts, is noteworthy. In addition, during the Early and Middle Holocene are recorded other trees that are currently extirpated as natural taxa in the area, such as Pinus, Tilia and Carpinus.

Aeolization on the Atlantic coast of Galicia (NW Spain) from the end of the last glacial period to the present day: Chronology, origin and evolution of coastal dunes linked to sea‐level oscillations

“…The erroneous interpretation of coastal sands as present‐day marine formations (Alonso & Pagés, 2010; Gómez‐Orellana et al, 2007, 2014) ignores the most logical sequence of aeolian accretion. This is the case of the 7 ky woody macrofossils found on the north coast of Galicia (Table 2), subjectively interpreted as materials removed from the seabed and moved by the waves to the intertidal (see figure 2 of Gómez‐Orellana et al, 2021), although they are represented by fossil roots and trunks in a living position (Figure 10). It is the waves stirring up the sands that uncover all these macrofossils and even the organic soil of the palaeo‐forest (Vidal‐Romaní & Grandal‐d'Anglade, 2018), some of them buried by aeolian sands 25 ky ago (García‐Amorena et al, 2007; Granja & Soares de Carvalho, 1995) (Table 2, Figure 10) when the sea level was at −120 m bmsl (Waelbroeck et al, 2002) and the coastline was displaced more than 20 km to the west (Figure 7).…”

The Roman Legacy on European Chestnut and Walnut Arboriculture

“…In fact, prior to classical antiquity, Juglans and Castanea may occur in European pollen records, but usually as sporadic finds. Exception comprise sites close to the glacial refugia, where pollen abundances were higher (Torri 2010;Lazarova et al 2011;Tonkov and Possnert 2014;López-Sáez et al 2017;Pollegioni et al 2017;Krebs et al 2019;Gómez-Orellana et al 2021).…”