Fire has been one of the main causes of disturbance of vegetation over time, and since the Neolithic has become an irreplaceable tool for the opening of forest spaces and maintenance of pastures. Previous studies showed that the intensity and effects of wildfires are related to the biomass and controlled by climate factors. However, in regions such as Cantabria, where agriculture and livestock have spread throughout the territory since prehistory, fires should also be closely related to human land uses. The aim of this paper was to investigate the history of fires and vegetation since the Neolithic in the Cantabrian Mountains, using sedimentary charcoal and pollen data to study the role of human activities in the processes that have shaped ecosystems throughout the Holocene. The asynchrony and quantitative differences in the results obtained at different sites indicate significant variations in fire patterns at regional scale since the Neolithic, although the type and size of each basin also had a strong influence on charcoal accumulation. Maximum values for charcoal accumulation rate at La Molina were observed between the Neolithic and the Bronze Age but occurred after about 3500 cal years BP at El Cueto de la Avellanosa. At El Sertal, low charcoal accumulation rate values were observed, probably because the sequence begins in a space that already had been cleared; the maximum values occurred during the most recent millennium. These data provide evidence that fire has been a key factor in forest retreat and in maintaining open landscapes since the Neolithic.
Proper management of the perceived value of any geographic space requires the capacity to interpret research results from spatial, temporal, and environmental points of view, applying the principles of environmental geohistory. Basic concepts such as baseline, threshold, or resilience are discussed from a long-term ecological perspective, with examples that explain the dynamics of fir forests as well as the changes in agricultural cover. Studying the changes in the altitudinal limit of the forest and surveying the wetlands dynamics on the southern slopes of the central Catalan Pyrenees have been shown to be effective tools to develop appropriate management tasks. The arguments presented are useful to enrich the public debate over management policies for natural protected spaces in high-mountain areas.
In recent years, environmental history geographers have shown the importance of a joint consideration of natural dynamics and human influence when interpreting landscape changes during the Holocene (Battarbe et al., 2004). As a result, paleoecology studies have given way to multiproxy studies as we attempt to clearly discern the human and natural signs that remain from those changes. Researchers have synthesized the changing plant landscape of the Iberian peninsula during the Holocene based on pollen (
This paper examines the characteristics and long-term variability of storminess for the Spanish coast of the Bay of Biscay for the period 1948 to 2015, by coupling wave (observed and modelled) and atmospheric datasets. The diversity of atmospheric mechanisms that are responsible for wave storms are highlighted at different spatial and temporal scales: synoptic (cyclone) and low frequency (teleconnection patterns) time scales. Two types of storms, defined mostly by wave period and storm energy, are distinguished, resulting from the distance to the forcing cyclones, and the length of the fetch area. No statistically significant trends were found for storminess and the associated atmospheric indices over the period of interest. Storminess reached a maximum around the decade of the 1980s, while less activity occurred at the beginning and end of the period of study. In addition, the results reveal that only the WEPI (West Europe Pressure Anomaly Index), EA (Eastern Atlantic), and EA/WR (Eastern Atlantic/Western Russia) teleconnection patterns are able to explain a substantial percentage of the variability in storm climate, suggesting the importance of local factors (W-E exposition of the coast) in controlling storminess in this region.
Sea level height variability along the coast of southwestern Europe is analyzed in relation with local and regional scale atmospheric forcing mechanisms. A circulation type (CP) catalogue, derived from a combination of principal component analysis and cluster analysis was used to characterize the regional scale atmospheric circulation, whereas the local scale was highlighted through the analysis of hourly wind records during extreme events. A large portion of common anomalous sea level variability at 6‐hourly time frame can be explained by the effect of one CP, depicting a deep extra‐tropical disturbance, close to the Iberian Peninsula, which represents the dominance of the inverse barometer mechanism. Other CPs can induce occasionally similar effects, but showing a spatially restricted scope, in relationship with the location of the main centres of action. Embedded into this synoptic framework, a local forcing, related to both meteorological processes (wind set up) and coastal oceanographic features (depth of the continental shelf) usually control the timing and less frequently, the magnitude of the surges. The decreasing trend observed in the magnitude of the sea level residuals derived from a hindcast model as well as some spatial differences (more intense trend in the upper percentiles along the northern Spain and Mediterranean coasts) can also be explained by long‐term changes in the frequency, and specially, in the internal variability of the CPs, which might be linked to the recent positive phase and eastward displacement of the southern node of the North Atlantic Oscillation. An overall increase in sea level pressure, detected in all CPs, has been accompanied by significant increases in types characterized by anticyclones over the Iberian Peninsula and decreases of northerly flows, related to a reduction of the number of cyclones passing through the Gulf of Biscay and the Western Mediterranean Basin.
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