Guadarrama Mountains Research Articles

New insights on patterns of genetic admixture and phylogeographic history in Iberian high mountain populations of midwife toads.

Multiple Quaternary glacial refugia in the Iberian Peninsula, commonly known as "refugia within refugia", allowed diverging populations to come into contact and admix, potentially boosting substantial mito-nuclear discordances. In this study, we employ a comprehensive set of mitochondrial and nuclear markers to shed light onto the drivers of geographical differentiation in Iberian high mountain populations of the midwife toads Alytes obstetricans and A. almogavarii from the Pyrenees, Picos de Europa and Guadarrama Mountains. In the three analysed mountain regions, we detected evidence of extensive mito-nuclear discordances and/or admixture between taxa. Clustering analyses identified three major divergent lineages in the Pyrenees (corresponding to the eastern, central and central-western Pyrenees), which possibly recurrently expanded and admixed during the succession of glacial-interglacial periods that characterised the Late Pleistocene, and that currently follow a ring-shaped diversification pattern. On the other hand, populations from the Picos de Europa mountains (NW Iberian Peninsula) showed a mitochondrial affinity to central-western Pyrenean populations and a nuclear affinity to populations from the central Iberian Peninsula, suggesting a likely admixed origin for Picos de Europa populations. Finally, populations from the Guadarrama Mountain Range (central Iberian Peninsula) were depleted of genetic diversity, possibly as a consequence of a recent epidemic of chytridiomycosis. This work highlights the complex evolutionary history that shaped the current genetic composition of high mountain populations, and underscores the importance of using a multilocus approach to better infer the dynamics of population divergence.

Does microhabitat use affect population differentiation? A test with southwestern Palaearctic forest birds

We tested whether microhabitat use affects dispersal and population differentiation in forest birds of the southwestern Palaearctic, a link previously suggested in Neotropical birds. To approach this, the number of subspecies within 32 species was used as a metric of population differentiation and was related to their feeding substrata and seasonal changes in abundance (a surrogate of dispersal) in a mountain range (Guadarrama Mountains, Central Spain). Multivariate analyses in which the effect of range size (a main correlate of within-species diversification) and phylogeny relatedness were considered, showed that those birds adapted to exploit the tree canopy had lower seasonal changes in abundance and more subspecies than ground-dweller birds. Our results support a cause-effect link between the use of stable resources in the canopy, seasonal movements and population differentiation of birds from temperate forests of the southwestern Palaearctic.

Comparison of the WRF and HARMONIE models ability for mountain wave warnings

Mountain lee waves usually involve aircraft icing and turbulence events. These weather phenomena, in turn, are a threat to aviation safety. For this reason, mountain lee waves are an interesting subject of study for the scientific community. This paper analyses several mountain lee waves events in the south-east of the Guadarrama mountain range, near the Adolfo Suarez Madrid-Barajas airport (Spain), using the Weather Research and Forecasting (WRF) and the HARMONIE-AROME high-resolution numerical models. For this work, simulated brightness temperature from the optimum WRF parametrization schemes and from the HARMONIE are validated using satellite observations to evaluate the performance of the models in reproducing the lenticular clouds associated to mountain lee waves. The brightness temperature probability density shows interesting differences between both models. Following, a mountain wave characterization is performed simulating some atmospheric variables (wind direction, wind speed, atmospheric stability, liquid water content and temperature) in several grid points located in the leeward, windward and over the summit of the mountains. The characterization results are compared for both numerical models and a decision tree is developed for each to forecast and warn the mountain lee waves, lenticular clouds and icing events with a 24 to 48 h lead time. These warnings are validated using several skill scores, revealing similar results for both models.

Diverging facets of grassland ant diversity along a Mediterranean elevational gradient

1. We address associations of taxonomic diversity (TD), functional diversity (FD), and phylogenetic diversity (PD) of ant assemblages with gradients of elevation to assess whether energetic limitations or deterministic or stochastic niche‐building processes are more relevant to the assembly of communities.2. We sampled ant assemblages using pitfall traps in grassland habitats along an elevational gradient of 1712 m in the Guadarrama Mountains of Central Spain. The relationships of alpha and beta diversity metrics with soil temperature, productivity, elevation, and geographical distances were examined with generalised additive (mixed) models.3. The facets of diversity showed strong and partially coincident responses to the gradients, but the responses and the similarities among them weakened or disappeared when the effects of species richness were factored out. TD and FD changed roughly in a similar manner with elevation and productivity, but PD did not show clear responses to those factors. Taxonomic and functional richness increased with productivity and decreased with elevation. Mean pairwise functional and phylogenetic dissimilarities did not change along the gradients. Elevation and productivity gradients accounted for much of the beta TD among assemblages but only explained a moderate variation of functional traits and phylogenetic relationships, while geographical distances were more explanatory of beta PD.4. The partial redundancies among facets of diversity suggest that the spatial variation of diversity is mainly related to the sheer number of species. However, both environmental filtering and limiting similarity could be acting in concordance to reduce the number of species present in communities.

Modelling the distribution of bat activity areas for conservation in a Mediterranean mountain range

AbstractThere is a lack of studies designed to detect the most important areas for bat conservation. In this context, areas of high bat activity have been rarely considered in the delimitation of protected areas for bats, which are generally focused on the protection of roosting sites. This has been due to the difficulties of sampling the distribution of these nocturnal animals when moving at night. This methodological constraint has been overcome by the development of bioacoustic sampling, which allows mapping the occurrence of active bats over large areas. In this study, we use bat detectors to sample the distribution of bat activity in central Spain. This region is under the environmental effects of a mountain range (Guadarrama Mountains) and the urban encroachment of the city of Madrid. The occurrences provided by the detectors were used to produce species distribution models of which the resulting layers were arranged to detect the most suitable areas for bat richness and rarity indices. We performed a gap analysis to explore whether the areas most commonly used by active bats are covered by the current network of protected areas. The results showed that the best areas of high bat activity are located at the piedmont of the mountains and that most of these areas overlap with the existing network of protected areas. The best areas for bats excluded the most urbanized areas and within a similar urban gradient, protected areas tended to be located within the best sites for conservation. These results suggest that bats currently benefit from a network of protected areas initially aimed to protect birds and habitats (Natura 2000). In addition, monitoring areas of high bat activity could complement roosting site protection in the conservation of bat assemblages.

DNA integrity and ecophysiological responses of Spanish populations of Ulmus glabra to increasing ozone levels.

Ulmus glabra is a deciduous tree with a wide distribution in the Eurosiberian region. The southernmost populations, in the Mediterranean area, are fragmented in mountain areas which act as a refugium. These small relict populations can act as sentinel of global change, including climate change and impacts of human activities such as air pollution. Besides, tropospheric ozone (O3) is an additional stress factor in the Mediterranean region affecting plant physiology and health. Moreover, oxidative stress caused by O3 could increase DNA damage in plants cells. U. glabra 4-year-old seedlings originated from a natural population growing in the Guadarrama mountain range (central Spain), were exposed in Open Top Chambers to four O3 treatments: charcoal filtered air, non-filtered air reproducing ambient levels, non-filtered air supplemented with 15 nl l-1 O3 and non- filtered air supplemented with 30 nl l-1 O3. Ozone effects on the DNA integrity through Comet assay were evaluated and eco-physiological responses were explored as well as. Comet assay showed a significant increase of DNA damage with increasing levels of O3 after only one-month exposure, when no eco-physiological symptoms of damage could be detected. Comet assay could thus be suggested as a predictive test to detect DNA damage induced in plants by other abiotic stresses as well as to identify tolerant and sensitive species or in preservation strategies of small relict populations. The discovery of a test for an early identification of stressed plants could be important to speed the selection of tolerant individuals for breeding programmes.

Watercore in Apple Landraces (Malus domestica Borkh.) as a quality indicator

Watercore is the presence of a vitrified texture intruded in the pulp of the fruit. It is found in fruits from different genus and families; and it has been studied in apples. Watercore was described, in apples, as a texture with differential sensorial characteristics in relationship with the ordinary pulp, and its presence is currently considered a defect in apple production, causing economic losses. In this study, it is described as a dichotomous descriptor. We analysed 641 apples from a region belonging to Central Spain (Guadarrama mountain range and the close Tagus Basin River); it was found that around 30% of those apples shown this characteristic, being practically all of them from landraces. Studies related to traditional cultivars do not analyze such characteristic, considered up today as a defect. Nevertheless, we discuss that watercore can have some potential as it gives to apple a distinct appearance and aroma, all of them of value in differential quality and international seal protection. As a result, we conclude our preliminary analysis that it is highly recommended to take into consideration watercore as a descriptor in apple characterizations.

For Whom the Bell Tolls: A Story of War for the Cause of Humanity and Democracy

Set against the backdrop of Spanish Civil War (1936-1939), For Whom the Bell Tolls provides the firsthand account of that war which Hemingway experienced by serving as a war correspondent. In the novel he takes the side of the Republic for the cause of humanity and democracy. The protagonist Robert Jordan, an American professor from Montana, volunteers his services in the war for anti-fascist cause. He himself thinks that he is inherently antifascist republican, who believes in life, liberty and pursuit of happiness. The novel asserts that the activities shown by the fascists or nationalists were full of selfish and misdirected aggressive impulses. This paper claims that the protagonist and other characters voluntarily involve in the war for the cause of humanity and democracy. The protagonist voluntarily takes part in blowing up the bridge at Guadarrama Mountains near Segovia to stop the Fascists away from the mountains to make the Republican attack successful. He was convinced that the Republicans meant for democratic, civilian, secular order. So he takes part in the war in foreign land for the cause of humanity. This war is related to politics, and the novel is in favour of republican alliance. The novel shows that war is inevitable part for the Republicans for their humanitarian cause. The novel tries to justify the war for the sake of preservation of republican norms like humanity, democracy, freedom, equality, rights of people and brotherhood.

Mountain Waves Analysis in the Vicinity of the Madrid-Barajas Airport Using the WRF Model

Turbulence and aircraft icing associated with mountain waves are weather phenomena potentially affecting aviation safety. In this paper, these weather phenomena are analysed in the vicinity of the Adolfo Suárez Madrid-Barajas Airport (Spain). Mountain waves are formed in this area due to the proximity of the Guadarrama mountain range. Twenty different weather research and forecasting (WRF) model configurations are evaluated in an initial analysis. This shows the incompetence of some experiments to capture the phenomenon. The two experiments showing the best results are used to simulate thirteen episodes with observed mountain waves. Simulated pseudosatellite images are validated using satellite observations, and an analysis is performed through several skill scores applied to brightness temperature. Few differences are found among the different skill scores. Nevertheless, the Thompson microphysics scheme combined with the Yonsei university PBL scheme shows the best results. The simulations produced by this scheme are used to evaluate the characteristic variables of the mountain wave episodes at windward and leeward and over the mountain. The results show that north-northwest wind directions, moderate wind velocities, and neutral or slightly stable conditions are the main features for the episodes evaluated. In addition, a case study is analysed to evidence the WRF ability to properly detect turbulence and icing associated with mountain waves, even when there is no visual evidence available.

The Production and Marketing of Mineral Water in 21st Century Spain

Since the end of the last century, Spain has become a country of reference in the European Union due to its volume of bottled mineral water. This study aims to analyze the evolution of the key aspects of this sector over the last two decades. Through this research, it has been verified that (i) Spanish mineral water has been analyzed for a long time from a medicinal and geochemical point of view, and not so much in commercial analysis; (ii) water has great diversity due to the abundance of hydrogeological domains that this country offers; (iii) a very strict legal framework must be complied for its commercialization; (iv) its consumption has been growing; and (v) the business structure is characterized by the predominance of a small group of companies, with a very important role in multinational corporations. Three nature reserves: Montseny, Sierra Nevada, and Guadarrama Mountains, stand out from the rest of the Spanish territory in terms of catchment and packaging of natural mineral water, which is an increasingly strategic resource.

Long-term altitudinal change in bird richness in a Mediterranean mountain range: habitat shifts explain the trends

The altitudinal distribution of species richness is affected by climate and habitat changes, and the balance between these drivers will produce an idiosyncratic pattern in each mountain range. However, the potential effect of habitat change has rarely been included in studies designed to detect the effect of climate change on mountain biodiversity. This paper explores the changes in the altitudinal distribution of forest bird richness in the Guadarrama Mountains (600–2400 m a.s.l., Central Spain) over the last several decades. These mountains are affected by global warming and increased tree density resulting from rural abandonment. Nothing is known, however, about the way these changes have affected the altitudinal distribution of bird richness. Bird counts carried out in 1976–1980 were repeated in 2014–2015 along an altitudinal succession of forest belts. The results show that the relationship of bird richness to elevation shifted from a hump-shaped model typical of dry mountains to a monotonic negative model characteristic of humid mountains. These trends diverged from predictions on the effects of climate warming and were related to a loss of bird richness in endemic Scots pinewoods in the upper parts of the mountains. Variations in the composition of bird assemblages suggested that these pinewoods have experienced a process of tree densification and understory loss. As a result, the reshuffling of the altitudinal distribution of bird richness produced by habitat changes has eclipsed any effects of climate warming. These results emphasize the importance of considering habitat and climate interactions when exploring the altitudinal shift of species richness in the context of global change.

Modern pollen representation of the vegetation of the Tagus Basin (central Iberian Peninsula)

The study of modern vegetation–pollen relationships has long been recognized as crucial for the proper interpretation of fossil pollen records. Despite the quickly growing number of palynological studies from central Iberia and its adjacent Atlantic margin, comprehensive studies about modern pollen representation at broad spatial scales were still lacking. In this paper, we have studied the vegetation–pollen relationships in the Tagus Basin in 62 sites located along a wide environmental gradient from Thermomediterranean evergreen mixed thermophilous woodlands by the Atlantic coast to Oromediterranean shrublands above the treeline in the Guadarrama Mountains (central Spain). At each site, we analyzed pollen from moss polsters and conducted vegetation surveys. Most forested vegetation types (pinewoods, oak woods, evergreen mixed thermophilous woodlands) presented rather distinct pollen assemblages dominated by the pollen equivalents of the major tree species. Nevertheless, enhanced taxonomic resolution within Pinus and Quercus ilex-type would represent significant progress, e.g., enabling to separate Mediterranean and mountain pinewoods. Pollen spectra from shrubland and steppic communities are in general less differentiated, due to high regional pollen input associated with low local pollen production and/or the dominance of insect-pollinated species (e.g., Cytisus oromediterraneus in mountain shrublands). The results presented here will readily assist the interpretation of regional fossil pollen records from small mires/bogs/lakes and forest hollows, given their comparable pollen catchments. Comparison of modern pollen assemblages with pollen records from larger lakes and marine settings is not so straightforward, but our results suggest that marine pollen assemblages might average the pollen signature of the entire basin.

Uneven-aged silviculture of Scots pine in Bohemia and Central Spain: comparison study of stand reaction to transition and long-term selection management

The achievement of sustainable forest management requires the incorporation of ongoing environmental changes into long-term planning. Moreover, in time of climatic change and changing company demands, importance of Scots pine (Pinus sylvestris L.) is still increasing at the expense of other tree species due to its low ecological requirements. The aim of the study was to compare the structure and production of Scots pine stands managed under different silvicultural systems on four research plots, assess the structural and diversity indices, and analyse the increment structure using tree-ring dating in the Czech Republic and Spain. Area of study was Western Bohemian and Guadarrama Mountain range in Central Spain. The results indicate that stand volume on the investigated plots ranged from 231 to 441 m<sup>3</sup>∙ha<sup>–1</sup> with tree density 276–996 trees∙ha<sup>–1</sup>. Intensively managed (uneven-aged) permanent research plots showed increased growth on basal area. The difference was evident also for older trees. The transition to uneven-aged forest does not negatively influence stocking and wood production and provide higher benefits for diversity and structural complexity in comparison to regular stands.

The Hidden Life of the Historical System of Rural Roads in a Sector of the Guadarrama Mountains, Central Spain

Historical geography has had as a preferred area of study of rural landscapes and societies in the past. In the context of the new rural geography, a road system is analyzed and its historical evolution is used as the source to make a narrative interpretation of the landscape. This narrative interpretation is understood as the evolutionary expression of different values, traditions, actions and hopes of the inhabitants of the area in the course of history. From this perspective, the paths can be used to establish an adequate continuity between the past and the present. The methodology combines the use of cartography, territorial recognition and in-depth surveys. The case study is a sector of the Sierra de Guadarrama located in central Spain.

Altitudinal shifts in forest birds in a Mediterranean mountain range: causes and conservation prospects

SummaryMediterranean mountains are biodiversity hotspots where northern species occur surrounded by drier and warmer lowlands. In this context, global warming is pushing these species to higher elevations. This paper assesses whether forest birds have experienced a shift upwards over the elevation gradient in the last 35 years in the Guadarrama Mountains (600–2,400 m asl; central Spain). Alternatively, the paper tests whether the reported shifts are related to changes in forest structure resulting from rural abandonment and/or forest management. To do this, sampling carried out from 1976 to 1980 along the elevation gradient was repeated in 2014–2015. In addition, the habitat preferences of birds were used to test if the elevation shifts were related to changes in forest structure. Results show that the mean range position of birds associated with tree cover shifted downwards, a trend supported by an increase in tree-dependent birds at mid-elevations. These trends suggest that an increase in tree cover has buffered the altitudinal shifts of forest birds predicted by climate warming. Results also suggest that proper forest management may improve the resilience of forest bird communities to the pervasive effects of climate warming.

The study of hidden habitats sheds light on poorly known taxa: spiders of the Mesovoid Shallow Substratum.

The scarce and biased knowledge about the diversity and distribution of Araneae species in the Iberian Peninsula is accentuated in poorly known habitats such as the Mesovoid Shallow Substratum (MSS). The aim of this study was to characterize the spiders inventory of the colluvial MSS of the Sierra de Guadarrama National Park, and to assess the importance of this habitat for the conservation of the taxon.Thirty-three localities were selected across the high peaks of the Guadarrama mountain range and they were sampled for a year using subterranean traps specially designed to capture arthropods in the MSS. Species accumulation curves were built both for the observed species richness and for the non-parametric richness estimators. The literature was reviewed in order to update the distributional maps of the rarest species.Forty-two species were collected, of which four were species new to science. More than half were represented by one or two individuals which caused the accumulation curves to rise slowly and to end without reaching an asymptote. Almost half of the species showed significant increases in their Iberian distribution ranges. Two species were recorded for the first time in the Iberian Peninsula and 32 species were new additions to the spider checklist of the Sierra de Guadarrama National Park.

Comparing mountain breezes and their impacts on CO2 mixing ratios at three contrasting areas

This work presents the characterisation and comparison of daytime and nighttime mountain breezes observed at three sites through the analysis of tower data. The sites are located: (i) in the foothills of the Guadarrama Mountains in Spain, (ii) on a plateau adjacent to the Pyrenees in France, and (iii) in the Salt Lake Valley (SLV) in the southwest of the United States. The thermally-driven winds are detected through a systematic algorithm which considers both synoptic and local meteorological conditions. The characteristics of the mountain breezes depend on the scale of the breeze at each site. Nighttime events are associated with stronger wind speeds at the two sites located farther away from the mountains due to larger-scale phenomena (valley winds and mountain-plain winds). The arrival of both nighttime and daytime flows to the sites are observed approximately when the buoyancy heat flux changes sign, being a few hours delayed at the sites farther from the mountains.In addition, the impacts of these breezes on CO2 mixing ratios are analysed. The characteristic increase of CO2 mixing ratio observed during the evening transition takes place approximately when the nocturnal breeze arrives at the site. Nonetheless, both processes are not always simultaneous, indicating that CO2 advection is not the main mechanism controlling the drastic CO2 increase. An analogous result is obtained for the CO2 decrease at the morning transition. However, we have found that the CO2 mixing ratio is sensitive to wind direction (horizontal advection) in highly heterogeneous areas like the SLV, where CO2 emissions from the nearby city centre play an important role.Finally, a clear relationship is found between the CO2 mixing ratio and near-surface turbulence at night. Maximum CO2 mixing ratios are found for specific turbulence thresholds, which depend on the height of the CO2 sensor. Conditions associated with both stronger and weaker turbulence levels lead to reduced CO2 mixing ratios at the local measurement height due to excessive and ineffective mixing, respectively.

Analysis and numerical simulation of an aircraft icing episode near Adolfo Suárez Madrid-Barajas International Airport

Aircraft icing is one of the most dangerous weather phenomena in aviation security. Therefore, avoiding areas with high probability of icing episodes along arrival and departure routes to airports is strongly recommended. Although such icing is common, forecasting and observation are far from perfect. This paper presents an analysis of an aircraft icing and turbulence event including a commercial flight near the Guadarrama Mountains, during the aircraft approach to the airport. No reference to icing or turbulence was made in the pre-flight meteorological information provided to the pilot, highlighting the need for additional tools to predict such risks. For this reason, the icing episode is simulated by means of the Weather Research and Forecasting (WRF) model and analyzed using images from the Meteosat Second Generation (MSG) satellite, with the aim of providing tools for the detection of icing and turbulence in the airport vicinity.The WRF simulation shows alternating updrafts and downdrafts (>2ms−1) on the lee side of the mountain barrier. This is consonant with moderate to strong turbulence experienced by the aircraft on its approach path to the airport and suggests clear air turbulence above the mountain wave cloud top. At the aircraft icing altitude, supercooled liquid water associated with orographic clouds and mountain waves is simulated. Daytime and nighttime MSG images corroborated the simulated mountain waves and associated supercooled liquid water. The results encourage the use of mesoscale models and MSG nowcasting information to minimize aviation risks associated with such meteorological phenomena.

Land-use history as a major driver for long-term forest dynamics in the Sierra de Guadarrama National Park (central Spain) during the last millennia: implications for forest conservation and management

In the Mediterranean Basin, long-lasting human activities have largely resulted in forest degradation or destruction. Consequently, conservation efforts aimed at preserving and restoring Mediterranean forests often lack well-defined targets when using current forest composition and structure as a reference. In the Iberian mountains, the still widespread Pinus sylvestris and Quercus pyrenaica woodlands have been heavily impacted by land-use. To assess future developments and as a baseline for planning, forest managers are interested in understanding the origins of present ecosystems to disclose effects on forest composition that may influence future vegetation trajectories. Quantification of land-use change is particularly interesting to understand vegetation responses. Here we use three well-dated multi-proxy palaeoecological sequences from the Guadarrama Mountains (central Spain) to quantitatively reconstruct changes occurred in P. sylvestris forests and the P. sylvestris-Q. pyrenaica ecotone at multi-decadal to millennial timescales, and assess the driving factors. Our results show millennial stability of P. sylvestris forests under varying fire and climate conditions, with few transient declines caused by the combined effects of fire and grazing. The high value of pine timber in the past would account for long-lasting pine forest preservation and partly for the degradation of native riparian vegetation (mostly composed of Betula and Corylus). Pine forests further spread after planned forest management started at 1890CE. In contrast, intensive coppicing and grazing caused Q. pyrenaica decline some centuries ago (ca. 1500–1650CE), with unprecedented grazing during the last decades seriously compromising today's oak regeneration. Thus, land-use history played a major role in determining vegetation changes. Finally, we must highlight that the involvement of forest managers in this work has guaranteed a practical use of palaeoecological data in conservation and management practice.

Historical water supply to The Monastery of El Paular: a “qanat” in the Guadarrama mountain range (Madrid, Spain)

The "qanat" is an ingenious system of collecting and conducting groundwater to a supply point. Its origin dates back to 3,000 years ago in the area known today as Armenia, and it had spread widely throughout Persia by 600 BC. The expansion of Islam spread this technique from China to the Iberian Peninsula, where it has received various local names. In Madrid, the technique was widely used for water supply from the ninth century until the mid-twentieth century, and in recent centuries received the name "Viajes de agua". However, the geological and socio-economic environment of the Sierra de Guadarrama in Madrid is not, and has never been, appropriate for the implementation of this type of water catchment. This is why the qanat supply of the former Charterhouse of Santa María de El Paular (Rascafría), which shows a very similar typology to the "Viajes de agua" modified or constructed in Madrid between the 17th and 19th centuries, is so original. Three "capirotes" (hoods) and a "distribution ark" have been located "in situ" in the vicinity of the Monastery and another "capirote" is used as an ornamental element in the courtyard of the old Hotel El Paular. In this paper, we present the results obtained in the field study and files on this "Viaje de agua", its context within the old Monastery supply, its water quality, and various hydrological and hydraulic considerations. Its builders must have been "plumbers" from Madrid in the seventeenth century, and it underwent several modifications during the eighteenth century.