Ancient pine forest on inland dunes in the Spanish northern meseta

Abstract

We present a new stratigraphic (pollen and nonpollen microfossils and charcoal particle) sequence with five AMS dates, covering about the last 9000 yr, of a core collected from the Spanish northern meseta, one of the territories of the Iberian Peninsula for which little paleobotanical information is available. The results support the hypothesis of the permanence of the pine forests, in more or less pure masses or large timber stands, during the Holocene in some Iberian continental zones. The typical substitution in postglacial dynamics of heliophyllous species, such as pines or Cupressaceae, by broadleaf trees did not occur in this inland region. Presumably, factors linked to the substrate, in this case very deep sand dunes covering vast areas, may have contributed to the scarce local competitiveness of the broadleaf trees, which would account for the hegemony of pines in this region. Based on the dynamics of aquatic plants and nonpollen microfossils, an initial phase previous to 7500 14C yr B.P. of high levels in the lake can be identified by high percentages of hydrophytes. A progressive increase in helophytes and the gradual infilling of the lake over the last 5000 yr appear to indicate a phase of aridification similar to those established for the western Mediterranean. Study of charcoal particles, more abundant in the last 2500 yr, has given rise to certain hypotheses regarding the incidence of recurring fires of a local or regional nature.

Expected trends and surprises in the Lateglacial and Holocene vegetation history of the Iberian Peninsula and Balearic Islands

“…yr BP (López-García, 1977). In El Carrizal, Pinus forests prevailed throughout the Holocene with a minor, subsidiary component of broadleaved forests (Franco-Múgica et al, 2005). In Espinosa de Cerrato, the dominance of Pinus is still more prolonged (Franco-Múgica et al, 2001) (Fig.…”

Vegetation and fire history since the last glacial maximum in an inland area of the western Mediterranean Basin (Northern Iberian Plateau, NW Spain)

“…The period with low fire activity could be due to better control of fire by humans but more probably to cooler and more humid climate during the Little Ice Age in Spain (MartinPuertas et al, 2008;Morellon et al, 2011). Other relatively close sites show maximum fire activity for the last 2500-3000 years (Allen et al, 1996;Franco-Mugica et al, 2005;Lopez-Merino et al, 2012), in marked contrast with Ayoo record.…”

“…Focusing on the Northern Iberian Plateau, most of the existing sequences spanning the Holocene are located in its eastern half (Garcia-Anton et al, 1995;Munoz Sobrino et al, 1996;FrancoMugica et al, 2001;Iriarte et al, 2001;Iriarte-Chiapusso et al, 2003;Franco-Mugica et al, 2005;Garcia-Anton et al, 2011), while almost no paleoecological information is available from the western sector Morales-Molino et al, 2013). Furthermore, some of these sites record only part of the Holocene or lack an accurate chronology, reinforcing the importance of obtaining new paleoecological data with a well-established chronological framework.…”

Using local autocorrelation analysis to identify conservation areas: an example considering threatened invertebrate species in Spain

“…The poor ''island'' cells detected, which represent approximately half the number of hot spot cells, are environmentally indistinguishable from hot spots but characterised by a significantly higher degree of human alteration. Furthermore, the detected cold spots correspond to the two Iberian plateaus that have been subjected to the most intense and secular human disturbance since Mid-to Late Holocene times (Carrión et al 2010), especially during the last 2500 years (Franco-Múgica et al 2005). Thus, if Iberian hot spots were partially located in areas subjected to less intense anthropogenic action, the rich ''island'' cells would correspond to relatively unaltered but isolated localities included within a severely transformed regional matrix that reflects a severe fragmentation process during the last centuries.…”