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

Abstract

We reconstructed vegetation responses to climate oscillations, fire and human activities since the last glacial maximum in inland NW Iberia, where previous paleoecological research is scarce. Extremely sparse and open vegetation composed of steppic grasslands and heathlands with scattered pioneer trees suggests very cold and dry conditions during the Oldest Dryas, unsuitable for tree survival in the surroundings of the study site. Slight woodland expansion during the Bolling/Allerod was interrupted by the Younger Dryas cooling. Pinewoods dominated for most of the early Holocene, when a marked increase in fire activity occurred. Deciduous trees expanded later reaching their maximum representation during the mid-Holocene. Enhanced fire activity and the presence of coprophilous fungi around 6400-6000 cal yr BP suggest an early human occupation around the site. However, extensive deforestation only started at 4500 calyr BP, when fire was used to clear the tree canopy. Final replacement of woodlands with heathlands, grasslands and cereal crops occurred from 2700 cal yr BP onwards due to land-use intensification. Our paleoecological record can help efforts aimed at restoring the natural vegetation by indicating which communities were dominant at the onset of heavy human impact, thus promoting the recovery of currently rare oak and alder stands.

Mid-Holocene vegetation history and Neolithic land-use in the Lake Banyoles area (Girona, Spain)

“…5.5 cal ka BP, reaching high values from ca. 5.25 cal ka BP, is consistent with previous studies in Atlantic-influenced sequences (Rius et al, 2012;Morales-Molino and García-Antón, 2014).…”

“…In fact, forest clearance maintenance could be the cause for the frequency of fire episodes at ca. 6.0 cal ka BP, in the context of a trend towards the spread of fire caused by increased aridity in the Mediterranean area of Iberian Peninsula after 6.0-5.0 cal ka BP (Reed et al, 2001;Carrión, 2002;Mayewski et al, 2004;Wanner et al, 2011;Pérez-Sanz et al, 2013;Morales-Molino and García-Antón, 2014). The occurrence of Salix sp.…”

Variación de los dominios forestal y herbáceo en el paisaje vegetal de la península Ibérica en los últimos 20.000 años. Importancia del efecto de los grandes herbívoros sobre la vegetación

“…El Neolítico en Europa se inició con la adopción de la agricultura y la ganadería y supuso un incremento importante de los incendios desbrozadores de origen antrópico (Vannière et al, 2011;Rius et al, 2011;Marlon et al, 2013; Morales-Molino y García-Antón, 2014). Ahora ya no se trataba de frenar el avance del bosque y crear algunos claros forestales sino de modificar el paisaje para expandir campos de cultivo y pastos (Kaal et al, 2011;Innes et al, 2013).…”

“…El uso del fuego como agente desbrozador sin duda tuvo importantes y crecientes consecuencias en el paisaje por reducción drástica del bosque y expansión de los pastos y campos de cultivo (Kaal et al, 2011; Morales-Molino y García-Antón, 2014; García- Ruiz et al, 2016). La reiteración en el uso del fuego para someter árboles y arbustos ocasionó la degradación del territorio por la pérdida de fertilidad y suelo y la expansión de matorral muy poco productivo (Kaal et al, 2011; Morales-Molino y García-Antón, 2014). Esta actividad ha dejado numerosas huellas geomorfológicas en el paisaje que se reconocen en la actualidad (García-Ruiz et al, 2016).…”

Deglaciación en la Cordillera Cantábrica: modelo y evolución

“…Since 13.5 ka BP the Enol Lake shows a low lacustrine productivity and low carbonate content, which is interpreted as a response to colder temperatures and decrease in rainfall (Moreno et al, 2011). Younger Dryas (YD) in the NW of the Iberian Peninsula has been defined as a cold and dry period from sea cores (Martrat et al, 2007;Vegas et al, 2013;Salgueiro et al, 2014), analysis of speleothems (Stoll et al, 2014;Morales-Molino and García-Antón, 2014) and palynological records (Naughton et al, 2007;Jalut et al, 2010). Also, the organic content decreased in proglacial sediments of Picos de Europa Serrano et al, 2013).…”