Western Iberia Research Articles

New insights into the biogeography of south‐western Europe: spatial patterns from vascular plants using cluster analysis and parsimony

AbstractAimWe analysed the distributional pattern of the vascular flora of the Iberian Peninsula and Balearic archipelago using cluster and parsimony methods to delineate a biogeographical scheme for south‐western Europe and to compare the results with previous regionalizations. Additionally, we aim to identify areas of endemism.LocationSouth‐western Europe (Iberian Peninsula and the Balearic Islands).MethodsPattern analysis of a chorological dataset, consisting of the occurrences of 3041 vascular plant species in each of the 50 km × 50 km UTM cells of a grid covering Iberia and the Balearic Islands, was based on cluster analysis (unweighted pair‐group method using arithmetic averages; UPGMA) and parsimony analysis of endemicity (PAE). The Jaccard similarity index was used in the UPGMA, and the set of most parsimonious trees from the PAE were summarized in a 75% majority consensus tree.ResultsThe UPGMA dendrogram delineated two main branches in the study region: (1) an eastern area of six sectors including the Balearic Islands plus those regions of Iberia with basic substrates, and (2) a western area with three sectors comprising the regions with acidic soils. The majority rule consensus tree of 53 most parsimonious trees from PAE showed eight main clades similarly separating eastern Iberia plus the Balearic Islands with their basic substrates, from western Iberia with its acidic and basic substrates; in addition the PAE tree showed some previously undetected chorological patterns.Main conclusionsThe use of large and inclusive datasets allows for the recognition of different spatial patterns from those obtained using a limited number of endemic or indicator species. The analyses support some floristic regions previously recognized for Iberia, but not the classic Eurosiberian–Mediterranean division, and some transition territories. Our recognition of 19 areas of endemism consisting of two or more cells and 60 consisting of one cell in south‐western Europe is new.

Regional differences of column aerosol parameters in western Iberian Peninsula

This study presents a characterization of aerosols columnar properties measured at three different AERONET sites in the western part of the Iberian Peninsula, namely Évora and Cabo da Roca, in Portugal, and Cáceres, in Spain, during the period from 2005 to 2010. AERONET level 2.0 products have been analyzed. The comparison of these three stations has great interest because it has not been conducted yet and it allows to characterize the aerosols of a wide region in western Iberian Peninsula by a long-term analysis of their aerosol properties. In addition, it allows analyzing the possible differences in these properties between the three sites located at different distances from the coast. The results show differences between the aerosol optical depth at 440 and 1020 nm at the three stations, being the mean values in Cabo da Roca at 1020 and 440 nm (0.08 and 0.16) slightly higher than in the other two stations (Évora: 0.06 and 0.15; Cáceres: 0.05 and 0.14). Greater differences among the three stations are found for the Ångström exponent values. Thus, Cáceres shows the highest mean value (1.33), followed by Évora (1.14) and, finally, by Cabo da Roca (1.00) which exhibits the smallest median α values due to the presence of coarse sea salt particles and high atmospheric humidity. These values are consistent with the values of volume size distribution, exhibiting a greater value of large particles at Cabo da Roca. The mean values of the single scattering albedo (ω) have been also analyzed, obtaining higher results as the coast is approached: Cabo da Roca: ω (440) = 0.95; ω (1020) = 0.96, Évora: ω (440) = 0.93; ω (1020) = 0.95 and Cáceres: ω (440) = 0.88; ω (1020) = 0.83. The differences between the three stations are explained in terms of the distance to the coast and to the occasional arrival of diverse air masses transporting different aerosol types to each station. One classification method proposed for the study region has been applied to multi-year measurements performed at the three sites and verified by means of daily 120-h back-trajectory analyses of air masses. The most frequent situations observed at all sites include the clean, maritime and continental situations, which account for about 80% or more. The remaining percentage is accounted by the more episodic situations of desert dust (10–14%) and forest fires emissions (3–5%). The probability density plots calculated for the different classified aerosol situations show significant differences consistent with the different paths of the air masses corresponding to each aerosol situation.

Giant sex chromosomes retained within the Portuguese lineage of the field vole (Microtus agrestis)

The field vole (Microtus agrestis) is characterised by extremely large blocks of heterochromatin on both the X and Y chromosome. Some other Microtus also have blocks of heterochromatin on their sex chromosomes but not as extensive and always of independent origin from the heterochromatic expansion found in M. agrestis. Coupled with evidence of geographic variation in large heterochromatic blocks within other species (e.g. in the western hedgehog Erinaceus europaeus), it might be expected that field voles would show substantial variation in size and disposition of the sex chromosome heterochromatin. In fact, only minor variation has been described up to now. Those studies conducted previously were largely on field voles from central and northern Europe. Here, we describe the karyotype of field voles from Portugal, of interest because recent molecular studies have shown field voles from western Iberia to be a separate evolutionary unit that might be considered a cryptic species, distinct from populations further to the east. The two Portuguese field voles (one female, one male) that we examined also had essentially the same karyotype as seen in other field voles, including the giant sex chromosomes, but with small differences in the structure of the Y chromosome from that described previously. The finding that field voles throughout Europe show relatively little variation in their giant sex chromosomes is consistent with molecular data which suggest a recent origin for this complex of species/near-species.

A major Late Jurassic fluid event at the basin/basement unconformity in western France: 40Ar/39Ar and K–Ar dating, fluid chemistry, and related geodynamic context

The Malm–Lower Cretaceous period is often considered to represent a period of time markedly devoid of crustal deformations, and of heat and mass transfers in western France, although numerous evidences of such transfers are reported in varied basins from western Iberia to western Africa. Migrating evaporitic-derived brines and seawater interacted with both the sedimentary cover and the basement in the Poitou High located at the boundary between Aquitaine and Paris Basins. Occurring after sedimentation, this activity induced significant alterations of the sediments by dolomitization and silicification, and the basement by adularization and locally by concentration of F–Ba (Pb–Zn) assemblages that are typical of carbonate-hosted metal deposits. Thus, metals were leached from metamorphic/granitic basement already weathered and peneplaned during Triassic time, and were redeposited by brines during this main fluid event. The main objective of this study was to decipher the timing of this major fluid/heat/mass transfer on the basis of 40Ar/39Ar and K–Ar dating of epigenetic minerals having similar paragenetic and geochemical signatures over an extended area from the Atlantic Ocean coast to the French Massif Central. A Late Jurassic fluid stage (146–156Ma) significantly younger than what is generally reported in Western Europe was obtained. This fluid event occurred within a segment of a continental margin that was located away from main rift zones and far (more than 500km) from major deformation areas such as the main rift or orogenic zones all over Western Europe. These results yield a new concept based on wide wavelength relationships between fluid movements and geodynamic events affecting both the sedimentary basins and their basements.

Circulation weather types and wildland forest fires in the western Iberian Peninsula

The use of six indices associated with geostrophic wind and vorticity has allowed a classification of circulation weather types to be determined. This classification was employed to study the impact of low-level circulations at low levels on the daily number of forest fires over the western Iberian Peninsula (Portugal and the Spanish region of Galicia). It was found that easterly circulations [east (E), northeast (NE), and hybrid anticyclonic northeast (HANE)] were associated with an increase in the number of forest fires in the domain studied. The number of forest fires per day was 549, 357, and 309 for the E, NE, and HANE, respectively, whereas the average value was 299 fires per day. It was seen that this effect is the result of the low-level heating and drying caused by easterly circulations. The possible impact of easterly circulations on the low-level wind was also analysed, although in this case the results were not clear. The indices used to classify the circulation weather types were also employed to develop a statistical model for the daily number of forest fires. Stepwise multiple regression showed that only two indices are necessary (correlation coefficient 0.5, significant at the 0.01% level): the western component of geostrophic wind and geostrophic wind intensity. Copyright © 2012 Royal Meteorological Society

Middle Paleolithic human remains from the Gruta Da Oliveira (Torres Novas), Portugal

Additional Middle Paleolithic human remains from layers 17, 18, and 22 of the Gruta da Oliveira, Portugal consist of a proximal manual phalanx 2 (Oliveira 5), a partial postcanine tooth (Oliveira 6), a humeral diaphysis (Oliveira 7), a distal mandibular molar (Oliveira 8), and a mandibular premolar (P(3) ) (Oliveira 9). Oliveira 5, 6, and 8 are unremarkable for Late Pleistocene humans. The Oliveira 7 right humerus is moderately robust or the individual had the stocky body proportions of other European (including Iberian) Neandertals. The Oliveira 9 P(3) has a large and symmetrical crown and lacks a distal accessory ridge and accessory lingual cusps, overlapping both Neandertal and recent human ranges of variation. It contrasts with at least recent human P(3) s in having relatively thin enamel. These join the Oliveira 1 to 4 remains in further documenting early MIS 3 Neandertal morphology in western Iberia.

Seasonal trends of the reproductive cycle of Octopus vulgaris in two environmentally distinct coastal areas

Octopus vulgaris is an important fisheries resource, particularly in Iberian waters. Species life cycle is short with capacity to adapt to different environmental conditions and, considered a simultaneous terminal spawner. Data on maturation and other biological parameters collected from January 2007 to November 2010 are used to define spawning seasons for octopus landed by the small-scale trap fisheries in two oceanographically distinct Portuguese coastal areas: the northwest coast (western Iberia upwelling system) and the south coast (Gulf of Cadiz system). On a monthly basis, we followed the proportion of mature individuals, and the Gonad-Somatic and Hayashi Indices. Length–weight relationship, weight-at-maturity, body condition and energy allocation were other biological parameters studied. Spawning season was markedly different in both areas. The northwest population spawns from March to July, in synchrony with the northwest coast upwelling season, and the south coast population spawns mainly in summer, between August and September. A less intense spawning peak in early spring is present occasionally in the south coast. Weight-at-maturity is geographically indistinct, but in both areas males mature at smaller sizes than females. Body condition increases significantly during maturation and mass allocation for reproduction results indicate that males and females channel energy to reproduction from several sources.

Genetic diversity of mountain plants: Two migration episodes of Mediterranean Erodium (Geraniaceae)

This paper examines the phylogeny of Erodium subsect. Petraea, a group of six morphologically and genetically very similar species from the mountains of the western Mediterranean. Combined trnL–F-ITS analysis was unable to determine the phylogenetic relationships of these species owing to sequence similarity. AFLP fragment analysis showed different populations to cluster in six closely related phylogroups that partially coincided with morphological species. In the Iberian Peninsula, high temperatures during interstadial periods probably impeded the survival of these species at low altitudes, and their populations may have been forced to migrate northward within Iberia or remain isolated on high mountains. AFLP variation suggests that this might have led to their differentiation into groups and speciation during interglacials, but it probably also provided the basis for recurrent recolonisations and the mixing of neighbouring populations at the last glacial maxima. The genetic diversity of the two Erodium lineages suggests two migration episodes took place from southern Iberia towards the north, with one lineage migrating via western Iberia and the other via eastern Iberia. The patterns of genetic diversity observed in populations of 56 European species (27 genera) leads to the hypothesis that disparate proportions of unique polymorphic fragments are the result of the evolutionary histories of their mountain populations irrespective of the currently recognised species.

Pathways for resilience in Mediterranean cork oak land use systems

Abstract Context Loss of woodlands and degradation of vegetation and soil have been described for all Mediterranean-type ecosystems worldwide. In the Western Iberian Peninsula, overexploitation of evergreen cork oak land use systems has led to soil erosion, failures in oak recruitment, and loss of forests. Degraded and dry sites are quickly colonised by pioneer heathland rockrose (Cistus spp.) shrubs forming highly persistent patches. Aims Although traditionally shrublands have been considered as a transient successional state, we present evidence that they can represent persistent alternative states to former cork oak forests. Review trends and conclusions We first describe how Mediterranean vegetation evolved in the Iberian Peninsula and the role of fire and long-term human management as main disturbances. We then discuss alternative pathways through state-and-transition models indicating the ecological and land use variables that halt cork oak regeneration and recruitment and drive vegetation transitions towards persistent shrublands. Unless concerted management actions and restoration programmes are undertaken, the cork oak land use systems will not be sustainable.

Records of human occupation from Pleistocene river terrace and aeolian sediments in the Arneiro depression (Lower Tejo River, central eastern Portugal)

In the uppermost reach of the Lower Tejo River (eastern central Portugal), where the river crosses two quartzite ridges that separate the Ródão (upstream) and Arneiro (downstream) depressions, Palaeolithic artefacts have been recovered from three lower river terrace levels and a cover unit of aeolian sands. This paper presents data on the discovery of archaeological artefacts from the terrace levels and the aeolian sands that can be linked to Middle and Upper Palaeolithic industries from new field sites at Tapada do Montinho and Castelejo. The archaeological data when placed in a geomorphological, sedimentary and chronological framework, contribute new information on the understanding of human occupation in western Iberia during cold-climate episodes of the last 62 to 12ka; and especially during the cooler and driest conditions that occurred between 32 and 12ka, when the climate favoured aeolian sediment transport. In the Lower Tejo River, the integration of absolute age datasets with archaeological, geomorphological and sedimentary data indicate that in westernmost Iberia the first appearance of artefacts in river terrace sediments suggests that the earliest marker for human occupation dates from the lower Acheulian (Lower Palaeolithic), probably corresponding to an age of ~340ka. Data also suggest, for the first time, that Acheulian lithic industries were replaced by Middle Palaeolithic ones (namely the Levallois stone knapping technique) by ~160ka (~MIS6). Middle Palaeolithic industries were later replaced by Upper Palaeolithic industries at 32ka. The post 32ka period, dominated by aeolian sediment transport, is related to the onset of cold-dry climate conditions which resulted in low river flow discharges, floodplain exposure and reworking by NW winds. This cold-dry period is coeval with the disappearance of Megafauna and associated Neanderthal communities, and the replacement of the Middle Palaeolithic industries by Upper Palaeolithic ones in this westernmost part of Europe.

A new species of sand racer, Psammodromus (Squamata: Lacertidae), from the Western Iberian Peninsula

A new species of lacertid lizard of the genus Psammodromus is described from the Iberian Peninsula. Genetic and recentlypublished phenotypic data support the differentiation of Psammodromus hispanicus into three, and not as previously sug-gested two, distinct lineages. Age estimates, lineage allopatry, the lack of mitochondrial and nuclear haplotype sharingbetween lineages, ecological niche divergence, and the current biogeographic distribution, indicated that the three lineagescorrespond to three independent species. Here, we describe a new species, Psammodromus occidentalis sp. n., which isgenetically different from the other sand racers and differentiated by the number of femoral pores, number of throat scales,snout shape, head ratio, green nuptial coloration, and number of supralabial scales below the subocular scale. We also pro-pose to upgrade the two previously recognized subspecies, Psammodromus hispanicus hispanicus Fitzinger, 1826 fromcentral Spain and Psammodromus hispanicus edwardsianus (Duges, 1829) from eastern Spain, to the species level: Psam- modromus hispanicus stat. nov. and Psammodromus edwardsianus stat. nov. Given that the holotype of Psammodromus hispanicus was lost, we designate a neotype. We also analysed museum specimens of P. blanci, P. microdactylus and P. algirus to describe differentiation of the Psammodromus hispanicus lineages/species from their closest relatives.

A new species of sand racer, Psammodromus (Squamata: Lacertidae), from the Western Iberian Peninsula

A new species of lacertid lizard of the genus Psammodromus is described from the Iberian Peninsula. Genetic and recentlypublished phenotypic data support the differentiation of Psammodromus hispanicus into three, and not as previously sug-gested two, distinct lineages. Age estimates, lineage allopatry, the lack of mitochondrial and nuclear haplotype sharingbetween lineages, ecological niche divergence, and the current biogeographic distribution, indicated that the three lineagescorrespond to three independent species. Here, we describe a new species, Psammodromus occidentalis sp. n., which isgenetically different from the other sand racers and differentiated by the number of femoral pores, number of throat scales,snout shape, head ratio, green nuptial coloration, and number of supralabial scales below the subocular scale. We also pro-pose to upgrade the two previously recognized subspecies, Psammodromus hispanicus hispanicus Fitzinger, 1826 fromcentral Spain and Psammodromus hispanicus edwardsianus (Dugès, 1829) from eastern Spain, to the species level: Psam-modromus hispanicus stat. nov. and Psammodromus edwardsianus stat. nov. Given that the holotype of Psammodromushispanicus was lost, we designate a neotype. We also analysed museum specimens of P. blanci, P. microdactylus and P. algirus to describe differentiation of the Psammodromus hispanicus lineages/species from their closest relatives.

The Llamas de Cabrera gold district, a new discovery in the Variscan basement of northwest Spain: A fluid inclusion and stable isotope study

The northwest of the Iberian Massif is well known to host numerous gold mineralizations which were exploited during Roman times. This study presents a multidisciplinary approach leading to the mineralogical, fluid inclusions, and geochemical characterization of the recently rediscovered Roman gold district of Llamas de Cabrera. Gold occurs in extensional quartz veins hosted in the upper layers of the Lower to Middle Ordovician Armorican quartzite and occasionally in the overlaying Middle Ordovician slates from Luarca Formation. The veins are characterized by multistage ore deposition developed along three hydrothermal stages: As–Fe (I), As–Fe (II), and Au–Zn–Cu–Pb, followed by late supergene alteration processes. The fluid inclusion study undertaken on mineralized quartz revealed the presence of three types of fluids: (1) CO2–(CH4) fluid inclusions, (2) aqueous-carbonic fluid inclusions dominated by CO2 and subordinate CH4 related to quartz–arsenopyrite–pyrite deposition, and (3) aqueous fluid inclusions related to the Au-sulfide deposition. In conjunction with arsenopyrite geothermometry and fluid-inclusion data an attempt was made to determine the P–T conditions of ore formation. Changes occurred in the P–T conditions from arsenopyrite and pyrite deposition in quartz veins from aqueous-carbonic fluids at 300–390°C and 200–220MPa towards 180–310°C and <200MPa at the stage of gold from aqueous fluids. Mixing of two aqueous fluids of relatively contrasted salinity were favorable factors for decreasing gold solubility and could allow gold deposition. The δ34S values are similar for the two As–Fe stages, +8.0‰ to +16.3‰ and +9.0‰ to +19.5‰ respectively, and for the post-S1 pyrites from siliciclastic Luarca Formation suggesting a comparable sulfur source. Combining calculated δ18O values of fluids of +6.7 to +9.4‰ with fluid inclusion data indicates that fluids of unknown origin are largely equilibrated with metamorphic lithologies at medium–high temperatures. The ascent of some late Variscan magmatic bodies, not exposed at the present day erosion level, provides the heat source for convective water circulation. Gold quartz veins from Llamas de Cabrera display similar features and processes to related deposits of similar type elsewhere in the Variscan belt of western Europe (northwest and central/western Iberia, French Massif Central, Bohemian Massif). However Llamas de Cabrera shows certain differences, such as the non-appearance of igneous rocks in the area and the absence of Sb-rich minerals compared to some Variscan Sb–Au deposits, including northern, central, and western Iberia. This last could probably be due to a greater depth of formation for the As–Au veins in comparison to Sb–Au veins.

Ground-Motion Models for Seismic-Hazard Assessment in Western Iberia: Constraints from Instrumental Data and Intensity Observations

Abstract The lack of constraints regarding ground‐motion propagation characteristics in western Iberia remains one of the major hindrances to accurate seismic‐hazard and seismic‐risk assessment in the region. The fact that western Iberia is geographically located near the confluence of oceanic crust, active continental crust, and stable continental crust further complicates the selection of appropriate ground‐motion models. To address this question we compare, through visual inspection and residual analysis, the regional ground‐motion data for moderate magnitude earthquakes with a set of six ground‐motion prediction equations, some of which were developed for active tectonic regions and the others for stable continental regions. Although the available data pertain mostly to offshore moderate magnitude earthquakes ( M 4.8–6.0) at large distances (100–400 km), the few records from an onshore M 4.0 earthquake and from the 1969 M 7.8 earthquake display similar trends. The results show that the performance of the models is period‐dependent, with shorter spectral periods (0.01 s, 0.1 s, 0.2 s, and 0.5 s) being strongly underpredicted by models developed for shallow active tectonic regions. More interestingly, the performance of the models for stable continental regions seems to be magnitude‐dependent, with response spectra amplitudes for magnitudes of engineering interest being accurately estimated by the models. The inspection of the residual distributions of intensity observations leads to similar conclusions for the offshore data, while highlighting the extent of epistemic uncertainty in predicting the ground motions for moderate magnitude earthquakes at short to moderate distances.

Discrete vs. continuum approaches to the assessment of the ecological status in Iberian rivers, does the method matter?

Assessing the ecological status of freshwater ecosystems has become an important topic as a first step towards improving their poor condition. Ecological status is usually measured as the deviation of observed conditions from expected reference conditions in the absence of human disturbances. The ability to produce objective evaluations depends largely on the capacity to correctly define reference conditions. Defining reference conditions is typically done by using either a type-specific (classification-based) or site-specific approach. Despite the often weak correspondence of classifications used in the type-specific approach there have been few assessments of the consequences associated with using this approach to define reference condition.To address this gap in knowledge, we tested the capacity of an environmental classification derived from the implementation of the European Water Framework Directive (WFD) to represent freshwater fish assemblages in a Mediterranean basin in South Western Iberian Peninsula. We determined the effect of using type-specific vs. site-specific approaches on the performance of different predictive models, as they are common tool for defining reference conditions. We compare predictive model performance using two different classification approaches (top-down vs. bottom-up) with the same predictive model (RIVPACS) and a continuum-like predictive model (ANNA).Our results indicated that the top-down environmental classification did not group reference sites better than random, with high within-class heterogeneity and high between-class homogeneity. Although slightly better, the bottom-up approach did not show high classification performance. This result was not related to a weak biological response to environmental gradients; since biotic gradient was shown (i.e., there were gradual changes in fish assemblage along a longitudinal gradient). Consequently, the classification-based predictive methods failed to fit the biological data, and failed to predict the expected fish assemblages. Only the continuous predictive method succeeded and was accurate enough to be used to define reference condition.Our results demonstrate that classifications that lack biological significance may have severe consequences for bioassessment programs. We recommend verifying the accuracy of classifications before using them as the basis for bioassessment under type-specific approaches. Alternatively, a continuous approach without pre-defined classes should be considered.

Foraging ecology of five toothed whale species in the Northwest Iberian Peninsula, inferred using carbon and nitrogen isotope ratios

The feeding ecology and habitat use of the most frequently sighted and/or regularly reported stranded or by-caught toothed whale species of the North Western Iberian Peninsula (NWIP) were examined, with a special focus on their trophic position (TP) and relationships with their prey. With this aim, the stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) of common dolphin (Delphinus delphis), bottlenose dolphin (Tursiops truncatus), harbour porpoise (Phocoena phocoena), striped dolphin (Stenella coeruleolba) and long-finned pilot whale (Globicepahala melas) were analyzed in muscle samples taken from stranded and by-caught animals between 2004 and 2008. Stable isotopes were also measured in 17 species of fish and cephalopods previously identified as prey species, based on stomach content analyses, and in plankton. The trophic enrichment factors (TEF) were calculated for all five species and in addition, isotopic mixing models were applied to estimate the proportional contribution of each prey source to the diet of the common dolphin, which was the toothed whale species best sampled in our study. Plankton, fish and cephalopods exhibited an increasing trend in their δ13C values (from −19.6‰ to −15.3‰) along the offshore-inshore axis, with a less clear spatial pattern observed for δ15N values. Striped dolphins exhibited the lowest mean δ13C, δ15N and TP values (−17.6‰, 10.8‰ and 4.3, respectively), which confirms the oceanic character of this species and its lower trophic position when compared to the other toothed whales analyzed. The common dolphin exhibited mean δ13C, δ15N and TP values that were at an intermediate level (−17.0‰, 11.7‰ and 4.7, respectively) and results of the mixing model indicated that blue whiting (Micromesistius poutassou) was the main component of the diet. The harbour porpoise, bottlenose dolphin and pilot whale exhibited higher and very similar isotopic compositions and TPs. The mean TEF obtained between predators and their main prey were 1.4‰ for δ15N and 0.8‰ for δ13C. These results provide information on stable isotope incorporation data for toothed whales, which are essential if conclusions are to be drawn in issues concerning trophic structures and habitat use in the NWIP.

Comparison of five modelling techniques to predict the spatial distribution and abundance of seabirds

Knowledge about the spatial distribution of seabirds at sea is important for conservation. During marine conservation planning, logistical constraints preclude seabird surveys covering the complete area of interest and spatial distribution of seabirds is frequently inferred from predictive statistical models. Increasingly complex models are available to relate the distribution and abundance of pelagic seabirds to environmental variables, but a comparison of their usefulness for delineating protected areas for seabirds is lacking. Here we compare the performance of five modelling techniques (generalised linear models, generalised additive models, Random Forest, boosted regression trees, and maximum entropy) to predict the distribution of Balearic Shearwaters (Puffinus mauretanicus) along the coast of the western Iberian Peninsula. We used ship transect data from 2004 to 2009 and 13 environmental variables to predict occurrence and density, and evaluated predictive performance of all models using spatially segregated test data. Predicted distribution varied among the different models, although predictive performance varied little. An ensemble prediction that combined results from all five techniques was robust and confirmed the existence of marine important bird areas for Balearic Shearwaters in Portugal and Spain. Our predictions suggested additional areas that would be of high priority for conservation and could be proposed as protected areas. Abundance data were extremely difficult to predict, and none of five modelling techniques provided a reliable prediction of spatial patterns. We advocate the use of ensemble modelling that combines the output of several methods to predict the spatial distribution of seabirds, and use these predictions to target separate surveys assessing the abundance of seabirds in areas of regular use.

Long term precipitation trends and variability within the Mediterranean region

Abstract. In this study, the trends and variability of annual precipitation totals and annual rain days over land within the Mediterranean region are analyzed. Long term ground-based observations concerning, on one hand, monthly precipitation totals (1900–2010) and rain days (1965–2010) from 40 meteorological stations within the Mediterranean region were obtained from the Hellenic National Meteorological Service and the World Climate Data and Monitoring Programme (WCDMP) of the World Meteorological Organization. On the other hand, high spatial resolution (0.5° × 0.5°) gridded monthly data CRU TS 3.1 were acquired from the Climatic Research Unit, University of East Anglia, for the period 1901–2009. The two datasets were compared by means of trends and variability, while the influence of the North Atlantic Oscillation (NAO) in the Mediterranean precipitation was examined. In the process, the climatic changes in the precipitation regime between the period 1961–1990 (reference period) and the period 2071–2100 (future climate) were presented using climate model simulations (RACMO2.1/KNMI). The future climate projections were based on SRES A1B. The findings of the analysis showed that statistically significant (95% confidence level) negative trends of the annual precipitation totals exist in the majority of Mediterranean regions during the period 1901–2009, with an exception of northern Africa, southern Italy and western Iberian peninsula, where slight positive trends (not statistically significant at 95% CL) appear. Concerning the annual number of rain days, a pronounced decrease of 20 %, statistically significant (95% confidence level), appears in representative meteorological stations of east Mediterranean, while the trends are insignificant for west and central Mediterranean. Additionally, NAO index was found to be anticorrelated with the precipitation totals and the number of rain days mainly in Spain, southern France, Italy and Greece. These correlations are higher within the rain season (October–March) than the entire year. Based on the results of regional climate model RACMO2.1/KNMI, precipitation is very likely to decrease almost 20% in the period 2071–2100 compared to 1961–1990, under SRES A1B.

Negative responses of highland pines to anthropogenic activities in inland Spain: a palaeoecological perspective

Palaeoecological evidence indicates that highland pines were dominant in extensive areas of the mountains of Central and Northern Iberia during the first half of the Holocene. However, following several millennia of anthropogenic pressure, their natural ranges are now severely reduced. Although pines have been frequently viewed as first-stage successional species responding positively to human disturbance, some recent palaeobotanical work has proposed fire disturbance and human deforestation as the main drivers of this vegetation turnover. To assess the strength of the evidence for this hypothesis and to identify other possible explanations for this scenario, we review the available information on past vegetation change in the mountains of northern inland Iberia. We have chosen data from several sites that offer good chronological control, including palynological records with microscopic charcoal data and sites with plant macro- and megafossil occurrence. We conclude that although the available long-term data are still fragmentary and that new methods are needed for a better understanding of the ecological history of Iberia, fire events and human activities (probably modulated by climate) have triggered the pine demise at different locations and different temporal scales. In addition, all palaeoxylological, palynological and charcoal results obtained so far are fully compatible with a rapid human-induced ecological change that could have caused a range contraction of highland pines in western Iberia.

Coastal and oceanic SST variability along the western Iberian Peninsula

The inter-annual variability of the sea surface temperature (SST) was analyzed along the western Iberian Peninsula in the region ranging from 9.5 °W to 21.5 °W and from 37.5 °N to 42.5 °N with a spatial resolution of 1°×1° from 1900 to 2008. Both coastal and oceanic SST showed an overall increase with warming and cooling cycles similar to those observed in the North Atlantic region and in previous regional studies. In addition, the evolution of coastal and ocean water has been observed to be different. In general, ocean water is more affected by the different warming–cooling cycles than coastal water. In spite of coast and ocean are highly influenced by global changes affecting the whole North Atlantic region, near shore SST has been observed to be correlated with local wind regime, which is itself a manifestation of the Eastern Atlantic (EA) teleconnection pattern.