Palaeogeography, Palaeoclimatology, Palaeoecology 441 (2016) 811–822 Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Early Holocene vegetation in the Ayllón Massif (Central System Range, Spain) based on macroremains. A paleoecological approach Mar Génova ⁎, Fernando Gómez-Manzaneque, Felipe Martínez-García, José Mª. Postigo-Mijarra Departamento de Sistemas y Recursos Naturales, Escuela de Ingeniería de Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, 28040 Madrid, Spain article info abstract Article history: We present a palaeoecological study of well-preserved vegetal macroremains in Spain, which age range (10,025– Received 25 May 2015 5371 cal yr BP) confers it an outstanding interest, because for the first half of the Holocene, palaeobotanical data Received in revised form 13 October 2015 are extremely scarce in the Iberian Central System Range. We found, for the first time in the easternmost zone of Accepted 16 October 2015 the Central System Range, macroremains belonging to the genus Pinus; these have specifically been identified as Available online 24 October 2015 Pinus cf. sylvestris and Pinus gr. sylvestris. These findings provide valuable information on the role of the genus Keywords: Pinus, regarding the natural character of these pine forests in this relatively unknown region. Palaeobiogeography In the larger wood samples we measured tree rings and cross-dated growth series, which represent a 75% increase in Macroremains the number of floating fossil chronologies and increase the time span by almost 1750 years, in the centre of the Dendrochronology Iberian Peninsula. Remarkably, this is the firsttimeinSpainandinsouthernEuropethatsomeofthefloating chro- Spain nologies have been successfully crossdated, creating four composite chronologies. Furthermore, we discuss some Pinus cf. sylvestris palaeoclimatic inferences comparing with different sites in southern Europe and provide new data for best knowing Bos primigenius the palaeoecological characteristics of the first half of the Holocene in Spain. Likewise, we found two bones belonging to aurochs (Bos primigenius), one of these also dating from the first half of the Holocene, with Valdojos constituting the only site with this taxon for this period in the Central System Range and surrounding areas. © 2015 Elsevier B.V. All rights reserved. 1. Introduction et al., 2012). Interestingly, all this research provides only information on the recent past (the last 4000 yr BP), and no study addressing the Inthelastfewdecades,therelevanceofthegenusPinus and the role it Ayllón Massif gives any information on the palaeovegetation existing played in the Iberian ecosystems throughout the Holocene has aroused in the area for the first half of the Holocene. The scarce palaeobotanical intense debate and given rise to abundant research (e.g. Carrión et al., information has contributed to generate different interpretations on 2000a, 2010; Franco-Múgica et al., 2000, 2001a; Rubiales et al., 2010; the natural vegetation, especially with regard to the role played by García-Antón et al., 2011). In areas presenting notable anthropic activity, pine forests in this region (Martínez-García and Costa Tenorio, 2001; such as the Central System Range, palaeobotanical research is necessary Martínez-García, 2002). In fact, besides the mentioned palynological in- to understand the nature of changes in the anthropogenic landscapes. formation, different authors have discarded the presence of natural for- Thus, although abundant palynological studies have referred to the Cen- mations of these species in the area, being interpreted the current pine tral System Range, fundamentally in the Estrela, Béjar, Francia, Gredos forest in the region only as a result of recent afforestations (De la and Guadarrama mountains (López-Sáez et al., 2013) the eastern sector Fuente, 1985; Monje-Arenas, 1987; Peinado-Lorca and Martínez Parras, of this large mountain range, known as the Ayllón Massif, remains rela- 1987; Rivas-Martínez, 1987; Rivas-Martínez et al., 2011). On the other tively unexplored in the palaeobotanical sense. hand, any particular species belonging to the genus Pinus has been de- To date, the scarce available information on these mountains consists termined by means the palynological studies. Macroremains studies in of a few palynological studies presenting no accurate chronology the eastern area of this Range may significantly help to know which spe- (Hernández-Vera and Ruiz-Zapata, 1984; Jiménez-Ballesta et al., 1985; cies occurred in these pre-anthropic forests. The only studies conducted Ruiz del Castillo, 1993) and some others dated by radiocarbon to date addressing vegetal macroremains in the Central Range refer to (Gil-García et al., 1994; Franco-Múgica et al., 2001a, 2001b; Currás the western sector — the Gredos mountains, Fig. 1 — (Rubiales et al., 2007; Génova et al., 2009; Rubiales and Génova, 2015). Our study of the Valdojos site, in the eastern sector, therefore greatly broadens the ⁎ Corresponding author at: Departamento de Sistemas y Recursos Naturales, Universidad geographical range of research on vegetal macroremains in the centre Politécnica de Madrid, 28040 Madrid, Spain. Tel.:+34 91 3367669. of the Iberian Peninsula. Additionally, the only dendrochronological E-mail addresses: [email protected] (M. Génova), [email protected] (F. Gómez-Manzaneque), [email protected] (F. Martínez-García), studies on macroremains in Spain also involved the above mentioned [email protected] (J.M.ª Postigo-Mijarra). research for the Gredos mountains. Although these constitute a very http://dx.doi.org/10.1016/j.palaeo.2015.10.027 0031-0182/© 2015 Elsevier B.V. All rights reserved. 812 M. Génova et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 441 (2016) 811–822 Valdojos site Estrela Francia Ayllón Somosierra Guadarrama Gata Béjar Gredos Fig. 1. Situation of the Central and Iberian System Ranges inland on the Iberian Peninsula. The enlarged box on the right shows the different mountains making up the Central System Range, and the location of the site studied is indicated in red. important milestone for the creation of multimillenial chronologies in forests of Quercus pyrenaica Willd., which comprise a belt of deciduous Spain, they involve mainly short floating sequences (Rubiales and trees between 1200 and 1500 m asl. Around this elevation, the oaks Génova, 2015). give way to forests of Scots pine (P. sylvestris L.), which form forests up Consequently, we have pursued the following aims in this work: to approximately 2000 m asl. These pine formations are currently well represented in the more continental sections of the Range (Guadarrama), – To identify the taxa of the remains found and to evaluate their becoming scarcer towards the east (Ayllón) and west (Gredos). Above biogeographical role (spatial and temporal) in the eastern Central 2000 m asl the woody vegetation is represented by a bushy stratum of System Range. Leguminosae (Cytisus, Genista, Echinospartum)orEricaceae(Erica, Calluna, – To study the palaeoecological information provided by the tree ring Arctostaphylos), which at higher altitudes gives way to alpine grassland growth sequences from the dendrochronological perspective. (Luceño and Vargas, 1991; Costa et al., 1997). The E/W and N/S gradients – To analyse the data we have obtained, comparing them with other give rise to local variations in the distribution of the plant communities, pre-existing palaeobotanical information in order to contribute to such as the presence of relict forests. This occurs, for instance, in the designing a vegetation evolution model for the region. Ayllón Massif, with the beech forests of Fagus sylvatica L. The Ayllón Massif makes contact with the Iberian System Range, a mountain range running through the east of the peninsula in the NW– 2. Regional setting SE direction. From the climatic perspective, the Ayllón Massif represents the least Mediterranean zone of the Central System Range, The Central System Range of the Iberian Peninsula constitutes a large it provides refuge for numerous boreal and boreo alpine species mountain range over 500 km long (one of the longest in the Mediterra- (Luceño and Vargas, 1991; Martínez-García, 2001; Ruiz-Labourdette nean Basin), running from West to East. It comprises a succession of et al., 2010) and also explain the presence of P. sylvestris forests and mountain ranges originating in central Portugal (Estrela mountains) the relict forests of beech (F. sylvatica)(Costa et al., 1997). and continuing in Spain: the Gata, Francia, Béjar, Gredos (presenting The Valdojos site (41° 14′ N, 3° 11′ W, 1320 m asl) is located in the the highest point — Almanzor peak, 2592 m asl–), Guadarrama, Ayllón Massif, within the municipality of Campisábalos (Guadalajara Somosierra and Ayllón ranges (Fig. 1). This mountain chain is so long, Province) (Fig. 1) and it comprises a marshy system covering an area with such a broad altitudinal gradient, that it ranges from 300 to over of approximately 5.5 ha. This site is located at the bottom of a valley 2500 m asl; it is highly heterogeneous from the climatic point of view filled with alluvial materials from the Holocene. It is located within a (Ruiz-Labourdette et al., 2010). To simplify, it could be said that the geological context of stratified limestone and dolomites of cretaceous more Mediterranean environments are located on the southern slope origin. In the surrounding