Holocene high-altitude vegetation dynamics in the Pyrenees: A pedoanthracology contribution to an interdisciplinary approach

Quaternary International 289 (2013) 60e70

Contents lists available at SciVerse ScienceDirect

Quaternary International journal homepage: www.elsevier.com/locate/quaint

Holocene high-altitude vegetation dynamics in the Pyrenees: A pedoanthracology contribution to an interdisciplinary approach Raquel Cunill a, d, *, Joan Manuel Soriano a, Marie Claude Bal b, Albert Pèlachs a, Josep Manel Rodriguez c, Ramon Pérez-Obiol c a GRAMP (Grup de Recerca en Àrees de Muntanya i Paisatge), Departament de Geografia, edifici B, Facultat de Filosofia i Lletres, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain b GEOLAB, Départament de Geógraphie, Faculté des Lettres et des Sciences Humaines, 39E Rue Camille Guérin, 87036 Limoges, France c Unitat de Botànica, Facultat de Biociències, Departament de Biologia Animal, de Biologia Vegetal i d’Ecologia, Edifici C, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain d Laboratoire GEODE, UMR 5602 CNRS, Université Toulouse Le Mirail, 5 allées A. Machado, 31058 Toulouse Cedex, France

a r t i c l e i n f o

a b s t r a c t

Article history: Available online 4 May 2012

Using an interdisciplinary methodology based on pedoanthracology, palynology and sedimentary charcoals, landscape transformation in the Pyrenees mountains during the Holocene is analyzed, with special attention to altitudinal variation in the treeline. The data sources were eight soil profiles on a transect at 2000e2600 m a.s.l. and a sedimentary record extracted from a very nearby peat bog at 2247 m a.s.l. The combination of three different proxies permits a more viable and qualitatively complementary data set, making it possible to better interpret the vegetation dynamic in this space through the Holocene. Analysis of the data showed that the Pyrenees landscape has undergone important changes during this period. The changing treeline is a good example. There is evidence of the decisive role of fire in the configuration of this landscape. Finally, this study shows that herding and agricultural uses over thousands of years in the study area have had a determining influence on the current configuration of the territory, equal to or more important than climatic factors. Ó 2012 Elsevier Ltd and INQUA. All rights reserved.

1. Introduction Among the key defining characteristics of mountain areas, the verticality of their slopes and the height of their profile certainly stand out. The sharp altitudinal gradients put numerous habitats and ecosystems, responding to different environmental characteristics, in contact with each other. An important element of the study is the variation between habitat boundaries, the ecotone. Its sensitivity in the face of environmental transformations allows use of this variation as an early indicator of environmental change (Hansen and di Castri, 1992; Kullman, 1998). One of the most visible and best-studied ecotones in these mountain systems is the treeline, or the zone of contact between the subalpine forest and alpine meadows without arboreal vegetation (Holtmeier, 2003).

* Corresponding author. GRAMP (Grup de Recerca en Àrees de Muntanya i Paisatge), Departament de Geografia, edifici B, Facultat de Filosofia i Lletres, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain. E-mail address: [email protected] (R. Cunill). 1040-6182/$ e see front matter Ó 2012 Elsevier Ltd and INQUA. All rights reserved. doi:10.1016/j.quaint.2012.04.041

The present study focuses on the changes in composition and the altitudinal variation of the high mountain landscape (>2000 m a.s.l.) and on one specific ecotone, the treeline. The research described here is based on the idea that throughout the Holocene diverse bioclimatic inductive forces have modified the landscape of the Pyrenees Mountains (Ninyerola et al., 2007). In the same way, however, changes in human activity and territorial uses of these spaces have modified its geosystem (Rull et al., 2011). Since prehistoric times, the human species has modified its surroundings in various ways to take advantage of available resources (Mercuri et al., 2010; Sadori et al., 2010), and European high mountain areas are a good example (Galop, 1998; Rendu, 2003; Walsh et al., 2006; Gassiot et al., 2009). The use of mountain meadows for grazing is the most obvious example, although there is evidence of agricultural or mining-metallurgical uses of these spaces. In summary, the landscape dynamic is influenced by multiple factors, both bioclimatic and social, that have varied considerably during the Holocene. Confronting this complexity requires taking advantage of multidisciplinary approaches that permit the use of

R. Cunill et al. / Quaternary International 289 (2013) 60e70

a variety of sources that contribute different and complementary information. The research design for this study employs a group of methodologies that allow us to pursue a common objective using various sources, covering different time and space scales and resolution. Their complementarities have been fundamental to accomplishing the proposed objectives: Pedoanthracology permits analysis of vegetation dynamics around the treeline, with great spatial precision. Use of this proxy made it possible to precisely locate the dynamics assessed with other techniques such as palynology. This discipline, based on soil analysis, opens a wide window of potential areas of application that could include the highest peaks of the Pyrenees or other places where it is often difficult to apply other paleobotanical methodologies. Although extensive studies in the French and Swiss Alps (Carcaillet and Thinon, 1996; Talon et al., 1998; Carnelli et al., 2004; Talon, 2010) and also in the equatorial Andes (Di Pasquale et al., 2008) have used pedoanthracology for the aim of studying the evolution of the treeline, this research represents the first application of soil charcoals analysis in the Pyrenees to accomplish this research objective. The methodology of this discipline has also been applied extensively in other zones, such as the study of pasture lands, forest spaces, or abandoned crop areas (Quilès et al., 2002; Goepp, 2007; Touflan and Talon, 2008, 2009; Dutoit et al., 2009; Bal et al., 2010; Henry et al., 2010; Novák et al., 2010; Poschlod and Baumann, 2010; Touflan et al., 2010; Morales-Molino et al., 2011). Sedimentary record analysis allows a temporal continuity that cannot be achieved using pedoanthracology, producing a continuous curve for the past 11 000 years for the study area. With respect to fires, sedimentary information is useful for sequencing burns to complement the time-point information provided by pedoanthracology. Pollen analysis delivers data on very diverse taxa that go beyond the information limited exclusively to woody plants that pedoanthracology provides. Therefore, the use of palynology acquires a general, overall context of the vegetation that allows delving into the causes of change in the treeline registered by pedoanthracology

61

as well as assessing the impact of fires on the landscape. The Estanilles sequence is a new register for a south slope of the Pyrenees with a broad temporal range that includes data from the Younger Dryas until the present (Pérez-Obiol et al., 2011; Riera and Turu, 2011; Rodríguez et al., 2011). Sedimentary charcoals, the third methodology used in this research, contribute information on the frequency and intensity of the fire events over time (Carcaillet, 1998; Tinner et al., 2005; Walsh et al., 2008). More recently, this approach has also shown its usefulness as a complement to the pollen studies on the south slope of the Pyrenees (Bal et al., 2011). Finally, all of these methodologies provide information from the Late Glacial until the contemporary era, resulting in a coherent temporal relationship between all three proxies. Examples of interdisciplinary paleobotanic studies exist for the Pyrenees (Galop, 1998; Rendu, 2003; Ejarque et al., 2009, 2010; Mazier et al., 2009) and in other European mountain areas (Miras et al., 2004; Walsh et al., 2006; Jouffroy-Bapicot et al., 2007). Pedoanthracology has only been used in the context of interdisciplinary studies of the high mountain landscape and the treeline in the Alps (Tessier et al., 1993) and Sudetes (Novák et al., 2010). The goals of this study were: 1) to analyze the transformation of the Pyrenees mountain landscape above 2000 m during the Holocene, as well as altitudinal and composition variations in the treeline during this same period; 2) to explore the natural and anthropic causes of landscape changes in the Pyrenees mountains; and 3) to demonstrate the value of integrating data drawn from different paleobotanic methodologies. 2. Study area The Plaus de Boldís-Montarenyo area (42
37040.500 42
380 2000 N; 1
16’1200 1
180 30.900 E) is located in the axial Pyrenees in the upper Cardós river valley (Fig. 1) on the south slope of the study area, which extends from 2000 m to 2600 m, approximately. The Estanilles peat bog (42
370 34.300 N, 1
17046.500 E) is located at 2247 m a.s.l. Lithologically, this part of the valley is formed by CambroOrdovician quartz schists and phyllites. Estanilles peat bog is in

Fig. 1. Location of the study area.

62

R. Cunill et al. / Quaternary International 289 (2013) 60e70

a basin formed by overdeepening of the glacial excavation of a cirque (2328 m2). The basin at this site is currently filled with sediment and functions as a fen with seasonal water level fluctuations. Climatically, these paleoenvironmental sites are located at an area of both Mediterranean and Atlantic influences. Present-day climatic data are obtained from the Certascan lake weather station (2240 m a.s.l.) located in the same valley. The climatic conditions are humid with annual values around 1352 mm, with a summer minimum (51 mm) and spring maximum (166 mm). The mean annual temperature of 2.6
C decreases in winter to a mean minimum temperature of around 4.3
C and increases in summer to a maximum temperature of around 11.1
C. The distribution of vegetation is differentiated by altitude and by the orientation of the slopes. South and southeast slopes are formerly cultivated zones; further up, subalpine pastures overlap with zones of supra-forest pastures. Therefore, the subalpine stage is currently either nonexistent or at least not well represented. In its place, from 1600 to 2300 m are dense shrublands (Genista balansae (Boiss.) Rouy subsp. europaea (G. Lopez et C.E. Jarvis), O. Bolos et Vigo [¼Cytisus oromediterraneus Rivas Martinez et al.]). On the north- and west-facing slopes, where the sampling sites are located, the low altitude and montane stage of the floor of the principal valley is occupied by Quercus petraea, covering the first few hundred meters of the slopes and mixed with Betula pendula. Mountain pine (Pinus uncinata Ramond ex DC. in Lam. & DC.), accompanied by Rhododendron ferrugineum L. and whortleberry (Vaccinium myrtillus), is found in the subalpine stage up to 2000 m a.s.l. Higher up, where the first vegetation is a 150 m wide swath of G. balansae, followed by Festuca spp. alpine meadows to the peak, are small clusters or sparse trees of P. uncinata up to 2300e2400 m a.s.l. In the upper areas, the altitudinal limit of the forest is clearly modified by human influence, including livestock activities and land management. Use of these zones for grazing implies a burn every few years to maintain the pastures in good condition for the cattle (Métailié and Faerber, 2003). If grazing activity diminishes, and with it the intensity of pasture maintenance, the brush and

forest will gradually invade the pastures (Battlori and Gutiérrez, 2008; Batllori et al., 2009; Cunill, 2010), which is the current trend. Despite some attempts at synthesis, explaining the chronology of human occupation in the studied region is complex, due to limited environmental and archaeological data (Esteban et al., 2003; Marugan and Rapalino, 2005). Studies that integrate paleoenvironmental and archaeological data are now improving knowledge of landscape evolution on the southern slopes of the Pyrenees (Miras et al., 2007, 2010; Palet et al., 2007a, 2007b; Gassiot et al., 2008, 2009; Ejarque et al., 2009, 2010; Pèlachs et al., 2009a). The traditional economic system based on grazing and agricultural crops, is currently in a deep crisis because it is not competitive. This results in a replacement of the activities of this primary sector with an economy based almost exclusively on tourism (Aldomà et al., 2004). The environmental impact is a generalized abandonment of traditional management of these territories, with a drastic decline in pastures and cultivated land and spontaneous forest growth in these spaces (García-Ruiz et al., 1996; Lasanta-Martínez et al., 2005; Améztegui et al., 2010). 3. Materials and methods 3.1. Pedoanthracology The study of soil charcoals (i.e., pedoanthracology) allows assessment of the historical changes in woody plants of an area on the basis of the numbers, taxonomy and dating of the charcoals (Thinon, 1992; Carcaillet, 1998; Talon et al., 1998). To meet the project objectives, eight soil excavation sites were selected along a SW altitudinal transect from 1996 to 2593 m a.s.l. (Cunill, 2010) (Fig. 2). This resulted in soil charcoal analysis of 47 soil samples from the various sampling levels in each pit. From the plain of Udes (1996 m), the transect proceeds to the Montarenyo peak (2593 m), crossing the Plaus de Boldís and the high plain of Montarenyo (Fig. 2). The pattern of the sampling transect permits a global analysis of the mountain slope, with

Fig. 2. Sampling sites. Soil profiles and sedimentary record.

R. Cunill et al. / Quaternary International 289 (2013) 60e70

samples obtained approximately every 100 m altitude. The parameters of all sampling sites are shown in Table 1. Samples were extracted by digging a pit that revealed the complete profile of the soil, down to the bedrock. The depth of the pit varied from a maximum 70 cme50 cm. Description of the soil included the carbon horizons and possible bioturbation phenomena. Material extraction was done at homogeneous soil levels 10 cm thick. The quantity of soil extracted at each level ranged from 4 to 10 kg. Prior to identifying the charcoal fragments, they were isolated by flotation, using manual sorting with the help of a binocular lens. The fragments were sorted by size, using a column of three different screen sizes: 5 mm, 2 mm and 0.8 mm. Anthracomass is defined as the quantity of charcoal per kilogram of dried soil, and was calculated on the basis of the mass of charcoals larger than 0.8 mm (expressed in milligrams) and the total mass of the fraction of dry soil less than 5 mm (expressed in kilograms). Identification of charcoal fragments (n ¼ 2861) (Fig. 3) used an episcopic Zeiss Axio Imager A1 microscope with the following magnifications: 50x, 100x, 200x and 500x. Taxa were determined with the help of an atlas of the anatomy of woody plants (Schweingruber, 1990a, b) and the research group’s charred wood reference collection. From the group of isolated charcoals, 13 fragments possessed sufficient mass for 14C dating with Accelerator Mass Spectrometry (AMS) in the laboratories of Beta Analytic (Miami, Florida, USA). The data were calibrated with the Calib program, version 6.0.1, based on the Intcal09.14c database (Reimer et al., 2009) and with a standard deviation of 2s (95% probability). 3.2. Sedimentary records Sedimentary evidence contributes the temporal continuity that pedoanthracology lacks. Due to edaphogenic processes, an edaphic profile does not allow extrapolation of the age of samples based on their depth in the sedimentary record. The sedimentary material extracted from the Estanilles peat bog was used to conduct two types of analysis: pollen and sedimentary charcoal data. Five core samples were taken with a mechanical sampler with a percussion hammer; the sample in which the peat was most consolidated was selected for analysis. Eleven samples (6 of peat, 2 of wood and 3 of organic sediment) were selected (Pérez-Obiol et al., 2012) for 14C-AMS dating (Beta Analytic Inc.). An age-depth linear interpolation graphic was constructed using the CalPal2007_HULU calibration curve (Danzeglocke et al., 2012).

63

3.2.1. Palynology The selected core sample, from a depth of 275 cm (called ESTIV), was tested at every centimetre; pollen analysis was done every two cm. The sediment samples were prepared according to standard chemical procedures, including treatment with 10% HCl, 10% KOH, 40% HF to remove the carbonates and silica; glycerol mounting; and mineral separation in heavy liquid (density 2.0). Pollen was identified under a light microscope using reference collections and standard determination keys (e.g., Moore et al., 1991) and photo atlases (e.g., Reille, 1992, 1998). Results are expressed in relative percentages, excluding spores and hydro- and hygrophytes from the pollen sum in the pollen diagram (Fig. 4). The pollen diagram was constructed using TILIA and TILIAGRAPH (Grimm, 1991) and does not show pollen types with low percentage values. CONISS (CONstrained Incremental Sum of Square cluster analysis) was used to delineate pollen zones (Grimm, 1987). 3.2.2. Sedimentary charcoals For the same core samples, at each centimetre the charcoals larger than 150 mm (Carcaillet, 2001) were estimated in order to determine fire events. Even though this dimension does not allow taxonomic determination level for each fragment, it is possible to establish the relative magnitude of these events, assuming that phases with and without fires can be detected and, in the latter case, identify the periods of particular intensity (Fig. 5) (Vannière, 2001). One cubic centimeter of each sample was soaked in 15% sodium hypochlorite (NaOCl) with potassium hydroxide (KOH) for a minimum of 3 h at 70
C, then sieved through a 150 mm mesh. The area of each charcoal fragment was estimated under a binocular (40x) using an ocular grid with 100 squares, each 0.0625 mm2 (Carcaillet et al., 2001). Fragments were classified by size, in categories that increased exponentially. The total surface area of charcoal in a sample was calculated by determining the median surface area of each size-class and multiplying it by the number of macrocharcoal particles. Charcoal counts were combined and divided by sample volume to calculate charcoal area concentration (mm2/ cm3). 4. Results 4.1. Pedoanthracology The soil charcoal analysis showed that anthracomass was present at all sampling points, but with great variation in the values

Table 1 Characteristics of soil sampling sites. Name

Altitude (m a.s.l.)

Coordinates

Orientation

Slope

Soil Classification FAOeWRB 2006

Depth profiles (cm)

Udes 1

1996

North

15e18%

Distric cambisol

55

Plaus 1

2050

West

15e18%

Haplic umbrisol

80

Plaus 4

2200

West

8%

Cambic umbrisol

75

Plaus 6

2300

West

15e18%

Umbric leptosol

73

Plaus 8

2400

South-west

1e3%

Haplic umbrisol

70

Mont 2

2463

North-west

0%

Haplic umbrisol

37

Mont 4

2550

South-west

10%

Haplic umbrisol

70

Mont 5

2593

1
160 12.091300 E, 42
370 40.552800 N 1
160 24.200500 E, 42
370 44.299300 N 1
160 33.043600 E, 42
370 46.914500 N 1
170 0.086500 E, 42
370 54.667400 N 1
170 16.777800 E, 42
370 59.430100 N 1
170 51.984400 E, 42
380 9.492200 N 1
180 22.038300 E, 42
380 17.970900 N 1
180 30.944700 E, 42
380 20.085400 N

South-west

1e3%

Haplic umbrisol

50

64

R. Cunill et al. / Quaternary International 289 (2013) 60e70

Fig. 3. Pedoanthracological diagrams (modified from Cunill et al., 2012). Taxon-specific anthracomass (TSA) by level, expressed in mg/kg. Note that the TSA scales vary by diagrams (n ¼ identified fragments).

(see Fig. 3). These numbers are much higher in the lowland points. The sampling sites were divided into three large groups. The first group includes the sites that have an anthracomass >100 mg/kg and are located below 2200 m altitude. The second group brings

together the three sampling sites located between 2300 and 2463 m, with an anthracomass close to 10 mg/kg. Lastly, the two sampling sites at highest altitude, located at 2550 and 2600 m, had a minimum anthracomass 1 mg/kg (Cunill, 2007).

R. Cunill et al. / Quaternary International 289 (2013) 60e70

65

Fig. 4. Pollen diagram of the sedimentary record in the Estanilles peat bog.

Charcoal identification showed arboreal taxa present in all of the sampling sites except those at the highest altitude, Mont 4 and Mont 5. Pinus is the most prevalent taxon and it is present in all the sampling sites. Betula sp. is the only other arboreal taxon that is found in the transect. Its presence is limited to the three sampling sites at the lowest altitude and its anthracomass never exceeds 2% of the total anthracomass of any level that was sampled. With respect to shrubs, although heath extends throughout the transect, G. balansae is found at the three sampling sites at lowest altitude (1996e2200 m). Based on the 13 samples dated from the eight soil excavation sites (see Fig. 3), the altitudinal transect that was sampled shows us episodes of burns and fires from the Late Glacial-early Holocene transition until the Middle Ages. The earliest group, based on Pinus sylvestris/uncinata charcoals, is found between 10 800 and 9500 cal BP. Another large group is found between 2500 and 1800 cal BP. Finally, the most recent datings refer to the Middle Ages (600e1200 cal BP). In these last two groups, both Pinus and G. balansae charcoals were dated. 4.2. Palynology The pollen diagram (Fig. 4) indicates that the rates of deposition varied widely over time. Different zones have been described in preliminary studies by Pérez-Obiol et al. (2011) and Rodríguez et al. (2011). From these findings, the vegetation evolution can be synthesized from the Late Glacial times until the present. In the base of the diagram, a domain of deciduous trees (Corylus, Betula) and open environments is followed by a steppe landscape dominated by Artemisia and sparse Pinus forests that indicates the

Younger Dryas period. At the beginning of the Holocene, recovery of Corylus, Betula and Pinus, denoting temperate and humid conditions, precedes an increase in tree diversity (Quercus, Tilia, etc.). Thereafter, a slight clearance of the landscape is detected although mesic conditions remain since Alnus and Tilia are present. At ca 9000 cal BP, the landscape was dominated by deciduous and pine forests; however, a significant peak of Artemisia appears, affecting the Pinus percentages. Later, the forest landscape was dominated by pine and deciduous trees such as Corylus and Betula with few herbaceous plants, giving way to a pine forest domain with contributions of deciduous and evergreen Quercus besides Corylus and Betula. At ca 7400 cal BP pollen indicators of open land appeared (Artemisia, Plantago, Rumex), Pinus percentages decrease and the expansion of Poaceae became important. The beginning of the open landscapes characterizes this period. After this time, changes in forest dynamics and the appearance of Fagus could be linked to the establishment of forest clearances. The fall of arboreal pollen and the low values of the arboreal biomass denote an increase of pastures. Later, this phenomenon was accentuated, as shown by the continuous records of Plantago and frequent records of other herbaceous species. From these moments, the exploitation of natural resources increasingly reduced the forest cover and the arboreal biomass. 4.3. Macrocharcoals Fig. 5 shows the concentration of sedimentary charcoal larger than 150 mm in relation to depth. The first sign of fire appears near the base of the core (249 cm), at ca 10 000 cal BP. A maximum peak is found at 165 cm (ca 7900 cal BP). Between these two points,

66

R. Cunill et al. / Quaternary International 289 (2013) 60e70

Fig. 5. Combined diagram of the results of the three proxies used (pollen, sedimentary charcoal and soil charcoals).

diverse signs of variable magnitude but with remarkable consistency are found. After this phase there is a drastic decrease in charcoal concentration and they are found less frequently. At 97 cm (3690 cal BP) a secondary maximum is found and, later on, moderate levels appear. The last presence (at 12 cm) is represented by a minimum value at ca 70 cal BP. 5. Discussion Given the results obtained the three data sources were used in a complementary fashion to address the project objectives. First, in relation to analysis of landscape evolution in the Pyrenees Mountains above 2000 m during the Holocene, the results of the first phases of fires, where pine charcoals are found in the soil between

10,800 and 9500 cal BP at 2200 m of altitude, demonstrate the existence of arboreal mass at 2200 m altitude. This coincides with rapid colonization of the mountain space by Pinus observed in the pollen diagram curve. On the other hand, in the pollen diagram this fire event is weakly reflected in the Pinus pollen but well represented in Rumex values (related to open areas). The first peak of sedimentary charcoals appears at about 10 000 cal BP. This forest colonization above 2200 m altitude occurs rapidly and effectively at the beginning of the Holocene, just after the Younger Dryas. Environmental and edaphic conditions at the time of establishment were not very harsh. This raises the possibility that during glacial stages (Ingolfsson et al., 1997; Walker et al., 1999; Bond et al., 2001) the higher zones could have been more protected from erosion by the ice than the slopes and lower zones.

R. Cunill et al. / Quaternary International 289 (2013) 60e70

Therefore, at the beginning of the Holocene well-preserved soils would have favored high-altitude colonization by vegetation in the flat areas, and it is possible to find well-established forests at about 2200 m at the beginning of the Holocene. After 9500 cal BP diverse macrocharcoal signs of variable magnitude but with remarkable consistency are found. The consequences of this temporal persistence in the fire sign would be, as seen in the pollen diagram, on the one hand an increase in Poaceae and on the other the decline of the percentages of Pinus. The fact that the arboreal biomass remained at relatively high levels, as shown in the diagram, means that these fires resulted in opening of the forest, in the form of small, narrow clearings. With respect to fire origins, while some authors point to the possibility that they could be the result of human activity in mountain areas (Guilaine et al., 1995; Gassiot and Jiménes, 2005; Riera and Turu, 2011), the data do not contribute enough elements to assess this aspect. There are no archeological records in the study area for this period that would provide evidence of a human presence. In addition, although the pollen curves for Plantago and Rumex show slight increases at this time, t their increase could also be a natural dynamic of the landscape itself because the forest environment at 2200 m would facilitate clearings and openings. The next episode that merits discussion is the period in which a large concentration of fire signals is recorded, between 9300 and 7600 cal BP, with a maximum peak at 7900 cal BP. In this period there is no evidence of charcoal in the soil, although clearly, with the limited number of dates of these charcoals, the lack of correlation may not be significant. However, paradoxically the pollen diagram shows the maximum forest values for the Holocene, without clearings. This divergence between the fire and pollen signs shows that the intensity or localization of the fires is not always easy to establish. It would very probably have been during this event that the treeline reached its highest levels (above 2460 m), as indicated by the presence of pine charcoals at this altitude. Another phase of fires is found between 5100 and 2200 cal BP. Here there is agreement between all three signals: soil macrocharcoals and charcoals seem to reflect a clear intervention on the high mountain landscape and the treeline, as seen in the pollen diagram. The largest Pinus decline since the beginning of the pollen diagram occurs (Fig. 4), and a clear increase in herbaceous plants, indicators of human activity, and shrubs such as Genista, which might indicate recurrent burns to maintain pastures (Cunill, 2010). This coincides with the idea that in this sector of the Pyrenees there existed a multifunctional management of the territory (Ejarque et al., 2010). It is also a time with quantities of archeological evidence for the human occupation of the high mountains (Gassiot et al., 2009). There is clear evidence of the presence of grazing herds, given the appearance of coprophilous fungi. These anthropic signals obscure recognition of climate change in the mid-Holocene described by various authors (Jalut et al., 2000; Sadori and Narcisi, 2001; Pla and Catalan, 2005; Sadori et al., 2007, 2011; Pèlachs et al., 2011; Pérez-Obiol et al., 2011). Even though during the Roman period there is great regional disparity marked by the different degrees of Romanization of the different valleys (Andorra, Cerdanya, Vall d’Aran.) (Rendu, 2003; Pèlachs et al., 2009a, b; Ejarque et al., 2010), the alpine stage presents a weak level of change, as shown by high values for forest recovery and lack of fire signs. After the 6th century (1400 cal BP), there was a generalized intensification of human activity and profound changes in the landscape, with indicators of these trends in all three proxies. The soil charcoals (Pinus and Genista) denote the creation and preservation of pasture lands in the high zones that profoundly affected the treeline. This coincides with the beginning of the Grand Transhumances organized by the feudal and church powers

67

(Marugan and Rapalino, 2005). The sedimentary macrocharcoal data show periodic burns, which undoubtedly were intended for the creation and preservation of pasturing spaces. The pollen diagram shows the greatest fall in arboreal pollen in the entire diagram. In addition, the pollen diagram shows that the common local crops were cereals. The development of their importance at high altitudes in the Medieval period is an important and new detail revealed by this study. One remarkable point is the corroboration of extensive cereal cultivation above 2200 m during the Middle Ages despite the cool weather conditions. The large tracts of fallow land undoubtedly resulted from the lack of soil efficiency and fertilizers. In addition, cereals adapted to growth in mountain areas (e.g., Secale, which has a short life cycle) have shown their resistance in cold environments (Pérez-Obiol et al., 2011). Between the 15th and 16th centuries (500400 cal BP), the phase in which minimum values of arboreal pollen, particularly Pinus, were found,close to zero, has the highest levels of Poaceae. This is a signal that the treeline is located at the lowest level of the entire pre-Holocene and the Holocene, even lower than during the Younger Dryas. Cerealia represents the maximum local intensity of human pressure. Beginning at that moment and continuing to the present, the signals of sedimentary charcoals are weak, and there are no recent charcoals. The pollen diagram shows the increase in pine populations, which coexist with the persistence of the agropastoral system, seen from the curves for coprophilous fungi and Cerealia. In the same sense, parallel studies in the same zone and based on the relationship between pollen concentration and biomass have revealed that the landscape remained open (Cunill, 2010; PérezObiol et al., 2011). This fact coincides with increased human pressure in other nearby zones and lower altitude in relation to iron metallurgy, analyzed by studying plant charcoal kiln sites (Pèlachs et al., 2009b). At the end of the 19th century, the crisis of the traditional system began to emerge, as denoted by diminishing indicators of crops (Cerealia and Secale disappear) and pastures (coprophilous fungi, Poaceae, Rumex). At the same time, certain arboreal taxa recovered significantly, colonizing these now-abandoned spaces (Betula, Corylus, Quercus and Pinus) and favoring a higher treeline. This crisis of the traditional system and the dynamics of territory and landscape that accrued continue into the present. 6. Conclusions The three proxies utilized together obtained more data than with any one approach, data that complement each other and therefore make possible a better interpretation of the vegetation dynamic during the Holocene. The lack of chronological continuity in pedoanthracology is addressed by the sedimentary analysis, and the local character of soil charcoals compensates for the lack of spatial precision in sedimentary samples (the signs are regional). Fire signs from soil charcoals and sedimentary charcoals indicates the conclusion that, despite differences in magnitude and uneven territorial extension, there has been an almost uninterrupted history of fires in this zone throughout nearly the entire Holocene, from 10 800 cal BP until the mid-20th century AD. During this period, fire peaks are recurrent above 2000 m. This confirms the presence of arboreal masses of pine at this altitude in the transition between the Late Glacial and Holocene. To discover whether the fires of this period should be attributed to human activity or were spontaneous (e.g., related to specific climate conditions), would require expansion of the proxies employed, perhaps including, for example, archeology. Fire is a key tool for the management of these high mountain areas. In the Pyrenees, forest fires have also altered this upper limit.

68

R. Cunill et al. / Quaternary International 289 (2013) 60e70

Using pedoanthracology, a precise estimate of the treeline has been calculated, and it is evident that there was a Pinus population up to 2463 m. Palynology indicates that this situation probably developed between 9300 and 7600 cal BP. This presents a large contrast with the current situation, when the forest only reaches 2000 m in the study area. The first openings in the forest occurred at about 7500 cal BP: throughout this period are the first indicators of forest openings made by Neolithic societies. Later, between 5100 and 2200 cal BP, an anthropic signal is detected by all three proxies. These results indicate the difficulties in this type of area of studying treeline behavior as an indicator of climate change. It is possible that this study can only be separated from human history in the pre-Holocene. The period of maximum deforestation occurred between the 15th and 16th centuries, coinciding with the highest cereal values in the pollen diagram. One remarkable point is the corroboration of extensive cereal cultivation above 2200 m during the Middle Ages, despite the weather in places that traditionally have been considered inaccessible (pastures above 2000 m altitude). Specialized processes related to agropastoral activities have occurred during the past millennium. The fact that human management was not strictly linked to altitudinal and slope orientation parameters brings into question the suitability of a climatic/temperature gradient as the main factor triggering human land-use at a highaltitude. The three signals coincide in showing that the current trend in this zone’s vegetation dynamic is the recovery of space by the forest because of the progressive abandonment of anthropic management since the end of the 19th century: no fire signs in the soil or in the sedimentary record, a slow but uninterrupted increase in arboreal pollen, drastic decrease in signals linked to grazing and the disappearance of cereal pollen. Acknowledgements This research was developed within the framework of three projects, all of which were funded by Spain’s Ministry of Education Science (MEC): Sustainable local development in mountain zones at the threshold between territorial abandonment and naturbanization (SEJ2006-04009/GEOG: El desarrollo local sostenible de las zonas de montaña en el umbral entre el abandono del territorio y naturbanización). Mountain landscapes: Patterns of management and occupation of the territory (CSO2009-08271: Los paisajes de las áreas de montaña. Patrones de gestión y de ocupación del territorio) and Technocultural and landscape changes in the PleistoceneeHolocene transition in the Mediterranean catchment areas of the Iberian Peninsula (II). (HAR2008-01984/HIST: Cambios tecno-culturales y de paisaje en la transición Pleistoceno-Holoceno en las zonas de influencia mediterránea de la Peninsula Iberica [II]). This work was made possible by support from the Generalitat de Catalunya’s Program of Fellowships and Grants for the training and support of new investigators and from European Social Funds (BE) (2009FIC 00046), as well as the Generalitat’s funding for the Applied Geography Research Group (SGR2001-00153) and Palynological Research Group (2009 SGR 1102). Finally, the authors thank Elaine Lilly, Ph.D., of Writer’s First Aid for English translation and review. References Aldomà, I., Mendizàbal, E., Pèlachs, A., Soriano, J.M., 2004. La Transformació del territori i del Paisatge de l’Alt Pirineu. In: Vicedo Rius, E. (Ed.), Medi, territori i història. Les transformacions territorials en el món rural català occidental. Pagès, Lleida, pp. 139e164. Améztegui, A., Brotons, L., Coll, L., 2010. Land-use changes as major drivers of mountain pine (Pinus uncinata Ram.) expansion in the Pyrenees. Global Ecology and Biogeography 19 (5), 632e641.

Bal, M.C., Rendu, C., Ruas, M., Campmajo, P., 2010. Paleosol charcoal: reconstructing vegetation history in relation to agro-pastoral activities since the Neolithic. A case study in the Eastern French Pyrenees. Journal of Archaeological Science 37 (8), 1785e1797. Bal, M.C., Pèlachs, A., Pérez-Obiol, R., Julià, R., Cunill, R., 2011. Fire history and human activities during the last 3300 cal yr BP in Spain’s Central Pyrenees: the case of the Estany de Burg. Palaeogeography, Palaeoclimatology, Palaeoecology 300, 179e190. Batllori, E., Gutiérrez, E., 2008. Regional tree line dynamics in response to global change in the Pyrenees. Journal of Applied Ecology 96 (6), 1275e1288. Batllori, E., Camarero, J., Ninot, J.M., Gutiérrez, E., 2009. Seedling recruitment, survival and facilitation in alpine Pinus uncinata tree line ecotones. Implications and potential responses to climate warming. Global Ecology and Biogeography 18 (4), 460e472. Bond, G., Kromer, B., Beer, J., Muscheler, R., Evans, M.N., Showers, W., Hoffmann, S., Lotti-Bond, R., Hajdas, I., Bonani, G., 2001. Persistent solar influence on north Atlantic climate during the Holocene. Science 294, 2130e2136. Carcaillet, C., 1998. A spatially precise study of Holocene fire history, climate and human impact within the Maurienne valley, North French Alps. Journal of Ecology 86, 384e396. Carcaillet, C., 2001. Are Holocene wood-charcoal fragments stratified in alpine and subalpine soils? Evidence from the Alps based on AMS 14C dates. The Holocene 11 (2), 231e242. Carcaillet, C., Thinon, M., 1996. Pedoanthracological contribution to the study of the evolution of the upper treeline in the Maurienne valley (North French Alps): methodology and preliminary data. Review of Palaeobotany and Palynology 91 (1e4), 399e416. Carcaillet, C., Bouvier, M., Fréchette, B., Larouche, A.C., Richard, P.J.H., 2001. Comparison of pollen-slide and sieving methods in lacustrine charcoal analyses for local and regional fire history. The Holocene 11, 467e476. Carnelli, A.L., Theurillat, J.P., Thinon, M., Vadi, G., Talon, B., 2004. Past uppermost tree limit in the Central European Alps (Switzerland) based on soil and soil charcoal. The Holocene 14 (3), 393e405. Cunill, R., 2007. Estudi de l’evolució del límit superior del bosc mitjançant la pedoantracologia a la zona de Plaus de Boldís-Montarenyo (Pallars Sobirà) [Study of the upper tree line evolution by pedoanthracology proxy in the Plaus de Boldís-Montarenyo àrea (Pallars Sobirà)]. Master thesis, Universitat Autònoma de Barcelona. Cunill, R., 2010. Estudi interdisciplinari de l’evolució del límit superior del bosc durant el període holocènic a la zona de Plaus de Boldís-Montarenyo, Pirineu central català. Pedoantracologia, palinologia, carbons sedimentaris i fonts documentals. [Interdisciplinary study of the upper tree line evolution during the Holocene in the Plaus de Boldís-Montarenyo, Central Catalan Pyrenees: pedroanthracology, palynology, sedimentary charcoals and documentary sources], PhD Dissertation, Universitat Autònoma de Barcelona. http://www. tdx.cat/handle/10803/4995 (accessed on 22.06.11). Cunill, R., Soriano, J.M., Bal, M.C., Pèlachs, A., Pérez-Obiols, R., 2012. Holocene treeline changes on the south slope of the Pyrenees: a pedoanthracological analysis. Vegetation History and Archaeobotany. doi:10.1007/s00334-011-0342-y. Danzeglocke, U., Jöris, O., Weninger, B., 2012. CalPal-2012. online (accessed on 01.03.12). http://www.calpalonline.de/. Di Pasquale, G., Marziano, M., Impagliazzo, S., Lubritto, C., De Natale, A., Bader, M.Y., 2008. The Holocene treeline in the northern Andes (Ecuador): first evidence from soil charcoal. Palaeogeography, Palaeoclimatology, Palaeoecology 259 (1), 17e34. Dutoit, T., Thinon, M., Talon, B., Buisson, E., Alard, D., 2009. Sampling soil wood charcoals at a high spatial resolution: a new methodology to investigate the origin of grassland plant communities. Journal of Vegetation Science 20 (2), 349e358. Ejarque, A., Julià, R., Riera, S., Palet, J.M., Orengo, H.A., Miras, Y., Gascón, C., 2009. Tracing the history of highland human management in the eastern PrePyrenees: an interdisciplinary palaeoenvironmental study at the Pradell fen, Spain. The Holocene 19, 1241e1255. Ejarque, A., Miras, Y., Riera, S., Palet, J.M., Orengo, H.A., 2010. Testing micro-regional variability in the Holocene shaping of high mountain cultural landscapes: a palaeoenvironmental case-study in the eastern Pyrenees. Journal of Archaeological Science 37, 1468e1479. Esteban, A., Oliver, J., Còts, P., Pèlachs, A., Mendizàbal, E., Soriano, J.M., Nasarre, E., Matamala, N., 2003. La humanización de las altas cuencas de la Garona y las Nogueras (4500 aCe1955 dC). Servicio Nacional de Parques Nacionales, Madrid. Galop, D., 1998. La forêt, l’homme et le troupeau dans les Pyrénées. 6000 ans d’histoire de l’environnemententre Garonne et Méditerranée. Laboratoire d’écologie terrestre: FRAMESPA, Toulouse. García-Ruiz, J.M., Lasanta, T., Ruiz-Flaño, P., Ortigosa, L., White, S., González, C., Marti, C., 1996. Land-use changes and sustainable development in mountain areas: a case study in the Spanish Pyrenees. Landscape Ecology 11, 267e277. Gassiot, E., Jiménes, J., 2005. Informe de l’ « Excavació Arqueològica a l’Abric de l’Estany de la Coveta I (JunySetembre 2005). Servei d’Arqueologia de la Generalitat de Catalunya, Barcelona. Gassiot, E., García, V., Celma, M., 2008. Tres anys de recerca arqueològica al Parc Nacional d’Aigüestortes i Estany de Sant Maurici. In: Aniz, M. (Ed.), VII Jornades sobre recerca al Parc Nacional d’Aigüestortes i Estany de Sant Maurici. Generalitat de Catalunya, pp. 365e385. Gassiot, E., Rodríguez, D., Garcia, V., 2009. El poblament del Parc Nacional d’Aigüestortes i estanys de Sant Maurici durant el neolític. Novesa dades

R. Cunill et al. / Quaternary International 289 (2013) 60e70 arqueològiques i les seves implicacions per a l’estudi de les zones d’alta muntanya. In: Aniz, M. (Ed.), VIII Jornades sobre recerca al Parc Nacional d’Aigüestortes i Estany de Sant Maurici. Generalitat de Catalunya, Lleida, pp. 153e164. Goepp, S., 2007. Origine, histoire et dynamique des Hautes-Chaumes du massif vosgien. Déterminismes environnementaux et actions de l’Home. Phd dissertation. Université Louis Pasteur Strasbourg I, Strasbourg. Grimm, E.C., 1987. CONISS: a FORTRAN 77 program for stratigraphically constrained cluster analysis by the method of incremental sum of squares. Computers & Geosciences 13 (1), 13e35. Grimm, E.C., 1991. Tilia Version 2.0.B.4, Tiliagraph Version 2.0 and Tiliagraph View Version 1.0.5.2. Research and Collection Section, Illinois State Museum, Illinois. Guilaine, J., Martzluff, M., Barbaza, M., 1995. Les excavacions a la Balma de la Margineda (1979-1991). Ministeri d’Afers Socials i Cultura, Andorra. Hansen, A.J., di Castri, F., 1992. Lanscape Boundaries: Consequences for Biotic Diversity and Ecological Flows. Springer-Verlag, New York. Henry, F., Talon, B., Dutoit, T., 2010. The age and history of the French Mediterranean steppe revisited by soil wood charcoal analysis. The Holocene 20 (1), 25e34. Holtmeier, F.-K., 2003. Mountain Timberlines. Ecology, Patchiness, and Dynamics. In: Advances in Global Change Research, 14. Kluwer Academic, Dordrecht. Ingolfsson, O., Björck, S., Haflidason, H., Rundgren, M., 1997. Glacial and climatic events in Iceland reflecting regional north Atlantic climatic shifts during the PleistoceneHolocene transition. Quaternary Science Reviews 16, 1135e1144. Jalut, G., Esteban, A., Bonnet, L., Gauquelin, T., Fontugne, M., 2000. Holocene climatic changes in the Western Mediterranean, from south-east France to south-east Spain. Palaeogeography, Palaeoclimatology, Palaeoecology 160 (3), 255e290. Jouffroy-Bapicot, I., Pulido, M., Baron, S., Galop, D., Monna, F., Lavoie, M., Ploquin, A., Christophe, P., de Beaulieu, J.-L., Richard, H., 2007. Environmental impact of early paleometallurgy: pollen and geochemical analysis. Vegetation History and Archaeobotany 16, 251e258. Kullman, L., 1998. Tree-limits and montane forests in the Swedish Scandes: sensitive biomonitors of climate change and variability. Ambio 27 (4), 312e321. Lasanta-Martínez, T., Vicente-Serrano, S.M., Cuadrat-Prats, J.M., 2005. Mountain Mediterranean landscape evolution caused by the abandonment of traditional primary activities: a study of the Spanish Central Pyrenees. Applied Geography 25, 47e65. Marugan, C., Rapalino, V., 2005. Història del Pallars del orígens als nostres dies. Pagès editors, Lleida. Mazier, F., Galop, D., Gaillard, M.J., Rendu, C., Cugny, C., Legaz, A., Peyron, O., Buttler, A., 2009. Multidisciplinary approach to reconstructing local pastoral activities: an example from the Pyrenean Mountains (Pays Basque). The Holocene 19, 171e188. Mercuri, A.M., Sadori, L., Blasi, C., 2010. Editorial: archaeobotany for cultural landscape and human impact reconstructions. Plant Biosystems 144 (4), 860e864. Métailié, J.P., Faerber, J., 2003. Quinze années de gestion des feux pastoraux dans les pyrénées: Du blocage à la concertation (Fifteen years of pastoral fires management: from mental block to consultation). Sud-Ouest européen 16, 37e51. Miras, Y., Laggoun-Defarge, F., Guenet, P., Richard, H., 2004. Multi-disciplinary approach to changes in agro-patoral activities since the Subboreal in the surroundings of the narse d’Espinasse (Puy de Dôme, French Massif Central). Vegetation History and Archaeobotany 13, 91e103. Miras, Y., Ejarque, A., Riera, S., Palet, J.M., Orengo, H., Euba, I., 2007. Dynamique holocène de la végétation et occupation des Pyrénées andorranes depuis le Néolithique ancien, d’après l’analyse pollinique de la tourbière de Bosc dels Estanyons (2180 m, Vall del Madriu, Andorre). Comptes Rendus Palevol 6 (4), 291e300. Miras, Y., Ejarque, A., Orengo, H., Morad, S.R., Palet, J.M., Poiraud, A., 2010. Prehistoric impact on landscape and vegetation at high altitudes: an integrated palaeoecological and archaeological approach in the eastern Pyrenees (Perafita valley, Andorra). Plant Biosystems 144 (4), 924e939. Moore, P.D., Webb, J.A., Collinson, M.E., 1991. Pollen Analysis. Blackwell Scientific Publication, Oxford. Morales-Molino, C., Postigo-Mijarra, J., Morla, C., García-Antón, M., 2011. Long-term persistence of Mediterranean pine forests in the Duero Basin (central Spain) during the Holocene: the case of Pinus pinaster Aiton. The Holocene. doi:0959683611427339. Ninyerola, M., Sáez, L., Pérez-Obiol, R., 2007. Relating postglacial relict plants and Holocene vegetation dynamics in the Balearic Islands through field surveys, pollen analysis and GIS modelling. Plant Biosystems 141 (3), 292e304. Novák, J., Petr, L., Treml, V., 2010. Late-Holocene human-induced changes to the extent of alpine areas in the East Sudetes, Central Europe. The Holocene 20, 895. Palet, J.M., Ejarque, A., Miras, Y., Euba, I., Orengo, H.A., Riera, S., 2007a. Formes d’ocupació d’alta muntanya a la serra del Cadí (Alt Urgell) i la vall de MadriuPerafita Claror (Andorra): estudi diacrònic de paisatges culturals pirinencs. Tribuna d’Arqueologia 2006, 229e254. Palet, J.M., Riera, S., Miras, Y., Ejarque, A., Euba, I., 2007b. Estudi i revalorització dels paisatges culturals d’alta muntanya: els projectes vall del Madrid (Andorra) i La Vansa e Serra del Cadí (Alt Urgell). IBIX 4, Annals 2004-2005, 89e107. Pèlachs, A., Pérez-Obiol, R., Ninyerola, M., Nadal, J., 2009a. Landscape dynamics of Abies and Fagus in the southern Pyrenees during the last 2200 years as a result of anthropogenic impacts. Review of Palaeobotany and Palynology 156 (3e4), 337e349. Pèlachs, A., Nadal, J., Soriano, J.M., Molina, D., Cunill, R., 2009b. Changes in Pyrenean woodlands as a result of the intensity of human exploitation: 2,000 years of

69

metallurgy in Vallferrera, northeast Iberian Peninsula. Vegetation History and Archeobotany 18 (5), 403e416. Pèlachs, A., Julià, R., Pérez-Obiol, R., Soriano, J.M., Bal, M.C., Cunill, R., Catalan, J., 2011. Potential influence of Bond events on mid-Holocene climate and vegetation in southern Pyrenees as assessed from Burg lake LOI and pollen records. The Holocene 21 (1), 95e104. Pérez-Obiol, R., Bal, M.C., Pèlachs, A., Cunill, R., Soriano, J.M., 2012. Vegetation dynamics and anthropogenically forced changes in the Estanilles peat bog (southern Pyrenees) during the last seven millennia. Vegetation History and Archaeobotany. doi:10.1007/s00334-012-0351-5. Pérez-Obiol, R., Jalut, G., Julià, R., Pèlachs, A., Iriarte, M.J., Otto, T., HernándezBeloqui, B., 2011. Mid-Holocene vegetation and climatic history of the Iberian Peninsula. The Holocene 21 (1), 75e93. Pla, S., Catalan, J., 2005. Chrysophyte cysts from lake sediments reveal the submillennial winter/spring climate variability in the northwestern Mediterranean region throughout the Holocene. Climate Dynamics 24 (2), 263e278. Poschlod, P., Baumann, A., 2010. The historical dynamics of calcareous grasslands in the central and southern Franconian Jurassic Mountains: a comparative pedoanthracological and pollen analytical study. The Holocene 20 (1), 13. Quilès, D., Rohr, V., Joly, K., Lhuillier, S., Ogereau, P., Martin, A., Bazile, F., Vernet, J., 2002. Les feux préhistoriques holocènes en montagne sub-méditerranéenne: premiers résultats sur le Causse Méjean (Lozère, France)Prehistoric Holocene Fires in sub Mediterranean low mountains: first results from the Causse Méjean (Lozère, France). Comptes Rendus de l’Académie des Sciences. Serie Palevol 1 (1), 59e65. Reille, M., 1992. Pollen et spores d’Europe et d’Afrique du nord. Laboratoire de botanique historique et palynologie. URA, CNRS, Marseille, France. Reille, M., 1998. Pollen et spores d’Europe et d’Afrique du nord, Supplement 2. Laboratoire de botanique historique et palynologie. URA CNRS, Marseille, France. Reimer, P.J., Baillie, M.G.L., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Bronk Ramsey, C., Buck, C.E., Burr, G.S., Edwards, R.L., Friedrich, M., Grootes, P.M., Guilderson, T.P., Hajdas, I., Heaton, T.J., Hogg, A.G., Hughen, K.A., Kaiser, K.F., Kromer, B., McCormac, F.G., Manning, S.W., Reimer, R.W., Richards, D.A., Southon, J.R., Talamo, S., Turney, C.S.M., van der Plicht, J., Weyhenmeyer, C.E., 2009. IntCal09 and Marine09 radiocarbon age calibration curves, 0e50,000 years cal BP. Radiocarbon 51 (4), 1111e1150. Rendu, C., 2003. La montagne d’Enveig: un estive pyreneen dans la longue durée. Trabucaire, Perpinyà. Riera, S., Turu, V., 2011. Cambios en el paisaje del Valle de Ordino al inicio del Holoceno: evolución geomorfológica, paleovegetal e incendios de época mesolítica (NW del Principado de Andorra, Pirineos orientales). In: Turu, V., Constante, A. (Eds.), El Cuaternario en España y Áreas Afines. Avances en 2011. Imprenta Envalira, Andorra la Vella, pp. 201e204. Rodríguez, J.M., Pérez-Obiol, R., Pèlachs, A., Cunill, R., Soriano, J.M., 2011. Dinàmica del clima y del paisaje del Pirineo de Lleida durante la transición TardiglaciarHoloceno. La secuencia de Estanilles. In: Turu, V., Constante, A. (Eds.), El Cuaternario en España y Áreas Afines. Avances en 2011. Imprenta Envalira, Andorra la Vella, pp. 287e290. Rull, V., González-Sampériz, P., Corella, J.P., Morellón, M., Giralt, S., 2011. Vegetation changes in the southern Pyrenean flank during the last millennium in relation to climate and human activities: the Montcortès lacustrine record. Journal of Paleolimnology 46 (3), 387e404. Sadori, L., Narcisi, B., 2001. The postglacial record of environmental history from Lagodi Pergusa, Sicily. The Holocene 11 (6), 655e671. Sadori, L., Zanchetta, G., Giardinia, M., 2007. Last Glacial to Holocene palaeoenvironmental evolution at Lago di Pergusa (Sicily, Southern Italy) as inferred by pollen, microcharcoal, and stable isotopes. Quaternary International 181 (1), 4e14. Sadori, L., Mercuri, A.M., Mariotti Lippi, M., 2010. Reconstructing past cultural landscape and human impact using pollen and plant macroremains. Plant Biosystems 144 (4), 940e951. Sadori, L., Jahns, S., Peyron, O., 2011. Mid-Holocene vegetation history of the central Mediterranean. The Holocene 21 (1), 117e129. Schweingruber, F.H., 1990a. Mikroskopische Holzanatomie: formenspektren mitteleuropäischer Stamm- und Zweighölzer zur Bestimmung von rezentem und subfossilem Material ¼ anatomie microscopique du bois (Microscopic wood anatomy). Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft, Birmensdorf. Schweingruber, F.H., 1990b. Anatomie europäischer Hölzer: ein Atlas zur Bestimmung europäischer Baum-, Strauch- und Zwergstrauchhölzer (Anatomy of European woods: an atlas for the identification of European trees, shrubs and dwarf shrubs). Paul Haupt AG Verlag, Bern. Talon, B., Carcaillet, C., Thinon, M., 1998. Études pédoanthracologiques des variations de la limite supérieure des arbres au cours de l’Holocene dans les alpes françaises. Géographie Physique et Quaternaire 52, 195e208. Talon, B., 2010. Reconstruction of Holocene high-altitude vegetation cover in the French southern Alps: evidence from soil charcoal. The Holocene 20 (1), 35e44. Tessier, L., Beaulieu, J.-L.D., Couteaux, M., Edouard, J.-L., Ponel, P., Rolando, C., Thinon, M., Thomas, A., Tobolski, K., 1993. Holocene palaeoenvironments at the timberline in the French Alpsda multidisciplinary approach. Boreas 22 (3), 244e254. Thinon, M., 1992. L’analyse pédoanthracologique, aspects méthodologiques et applications. PHD dissertation, Univ. Aix-Marseille III.

70

R. Cunill et al. / Quaternary International 289 (2013) 60e70

Tinner, W., Conedera, M., Ammann, B., Lotter, A.F., 2005. Fire ecology north and south of the Alps since the last Ice Age. The Holocene 15, 1214e1226. Touflan, P., Talon, B., 2008. Étude pédoanthracologique à haute résolution spatiale de l’histoire holòcene d’une forêt subalpine (Alpes du Sud, France). Ecologia Mediterranea. Revue d’écologie terrestre et limnique 34, 13e23. Touflan, P., Talon, B., 2009. Spatial reliability of soil charcoal analysis: the case of subalpine forest soils. Ecoscience 16 (1), 23e27. Touflan, P., Talon, B., Walsh, K., 2010. Soil charcoal analysis: a reliable tool for spatially precise studies of past forest dynamics: a case study in the French southern Alps. The Holocene 20 (1), 45e52. Vannière, B., 2001. Feu, agro-pastoralisme et dynamiques environnementales en France durant l’Holocène, analyse du signal incendie, approches

sédimentologiques et études de cas en Berry, Pyrénées et Franche-Comté, PhD dissertation. Institut National Agronomique, Paris-Grignon. Walker, M.J.C., Björck, S., Lowe, J.J., Cwynar, L., Johnsen, S., Knudsen, K.-L., Wohlfarth, B., INTIMATE group, 1999. Isotopic ‘events’ in the GRIP ice core: a stratotype for the Late Pleistocene. Quaternary Science Reviews 18, 1143e1150. Walsh, K., Richer, S., de Beaulieu, J.I.L., 2006. Attitudes to altitude: changing meanings and perceptions within a ‘marginal’ Alpine landscape  the integration of palaeoecological and archaeological data in a high altitude landscape in the French Alps. World Archaeology 38 (2), 436e454. Walsh, M.K., Whitlock, C., Bartlein, P.J., 2008. A 14,300-year-long record of fireevegetationeclimate linkages at Battle Ground Lake, southwestern Washington. Quaternary Research 70, 251e264.