Central Iberia Research Articles

Genetic Origin of the Grapevine Cultivar Tempranillo

Tempranillo is the most important Spanish grapevine cultivar used for red wine production and it is currently planted in many other wine regions worldwide. Genotyping analysis of single nucleotide polymorphism (SNP) and microsatellite markers in grapevine germplasm collections has identified Albillo Mayor and Benedicto as the parents of Tempranillo. The statistical support for this conclusion is very high, with a LOD value of 138 for the joint estimation. Albillo Mayor is a well-known variety still cultivated in the central Iberian Peninsula. In contrast, Benedicto is rarely cultivated today and lacks historical references in the main Spanish viticulture literature. A search for putative offspring varieties derived from Tempranillo in a database containing most of the Spanish varieties identified only one variety, Coloraíllo, as a putative progeny of Tempranillo and Moravia Dulce (prime name Marufo). Analyses of chloroplast microsatellite markers identified Tempranillo as the male parent. In addition, one putative parent-offspring relationship was detected for each of the Tempranillo parents: Albillo Mayor is related to Castellana Blanca and Benedicto to Benedicto Falso de Aragón.

Appearances can be deceptive: different diversification patterns within a group of Mediterranean earthworms (Oligochaeta, Hormogastridae)

Many recent studies on invertebrates have shown how morphology not always captures the true diversity of taxa, with cryptic speciation often being discussed in this context. Here, we show how diversification patterns can be very different in two clades of closely related earthworms in the genus Hormogaster stressing the risk of using nonspecific substitution rate values across taxa. On the one hand, the Hormogaster elisae species complex, endemic to the central Iberian Peninsula, shows morphological stasis. On the other hand, a clade of Hormogaster from the NE Iberian Peninsula shows an enormous morphological variability, with 15 described morphospecies. The H.elisae complex, however, evolves faster genetically, and this could be explained by the harsher environmental conditions to which it is confined-as detected in this study, that is, sandier and slightly poorer soils with lower pH values than those of the other species in the family. These extreme conditions could be at the same time limiting morphological evolution and thus be responsible for the observed morphological stasis in this clade. Contrarily, Hormogaster species from the NE Iberian Peninsula, although still inhabiting harsher milieu than other earthworm groups, have had the opportunity to evolve into a greater morphological disparity. An attempt to delimit species within this group following the recently proposed general mixed Yule-coalescent method showed a higher number of entities than expected under the morphospecies concept, most probably due to the low vagility of these animals, which considerably limits gene flow between distant conspecific populations, but also because of the decoupling between morphological and genetic evolution in the H.elisae complex.

Comparison of temporal features of sulphate and nitrate at urban and rural sites in Spain and the UK

A seasonal comparison of aerosol secondary inorganic component (SIC) patterns on annual, weekly and daily timescales has been performed at urban Madrid and London and at rural sites in the central Iberian Peninsula and south-eastern UK alongside data for precursor gases. A database from winter 2004 to summer 2011 has been analysed. Results show the dominant processes affecting the formation and evolution of nitrate (NO3−) and sulphate (SO42−) in both regions. In Madrid, photochemistry dominates formation of nitrate, which is mostly locally-generated. Strong thermal decomposition results in very low concentrations in summer. In contrast, in London high nocturnal values suggest the importance of heterogeneous formation processes as well as nitrate condensation at lower temperatures. The seasonal nitrate maximum in the UK is found in late winter-early spring, when the region typically receives the highest input of pollutants transported from mainland Europe. Daily evolution of nitrate in both cities is heavily influenced by meteorological factors. Seasonal sulphate patterns show no obvious trend, except at the Spanish rural site in summer where photochemical formation was apparent. In Madrid, daily SO2 and sulphate patterns exhibiting maximum concentrations at noon were found in winter. In previous studies this phenomenon was observed for SO2 in London, where it was explained by the entrainment of pollutants from aloft into the mixing layer. SIC weekend reductions were investigated at the urban background sites of Madrid and London, and in both cities statistically significant fine nitrate reductions of around 20% are found in summer. These values are consistent with the annual reductions observed by researchers in the US. Weekend sulphate reductions occurred in winter, reflecting a clear impact of anthropogenic sulphate in urban environments, in spite of the large reductions in sulphur emissions in Europe in the last decade. Ratios of nitrate and sulphate to oxidant gases and to one another have been calculated for Madrid, and are consistent with a contribution of local formation to sulphate in winter, while in summer a regional background unrelated to urban SO2 is observed. The strong differences in the behaviour seen in London and Madrid (and the rural sites) emphasises the need to study cities individually and not to extrapolate conclusions drawn in one city to others in different climate/topographic situations.

Genetic Differences Among Iberian White-Throated DipperCinclus cinclusPopulations Based on the CytochromebSequence

Although widespread in Europe, the white-throated dipper Cinclus cinclus has a fragmented distribution in the Iberian Peninsula. We investigated whether Iberian dipper populations are genetically differentiable by assessing a fragment of the cytochrome b gene in birds from 11 geographical areas encompassing 48 Iberian rivers. Four population groups North, Centre, East and South were differentiated a priori on the basis of geographical criteria. Genetic differences between these groups explained 35.9% of the total variation. Eight new haplotypes have been recorded for this species. The most abundant haplotype (H3) was shared by 75.8% of the birds and was found in all areas. The second most abundant haplotype (H10, 17.6% of individuals) was present in three areas: two in the southern mountains and one in central Iberia. The third most abundant (H5, 4.8% of birds) occurred only in central Iberia. Southern populations are genetically distinct from the others.

Violence in the Central Iberian Peninsula during the Bronze Age: A Possible Prehistoric Homicide

ABSTRACTOne of the most interesting sites of the Bronze Age in the central area of the Iberian Peninsula is La Motilla del Azuer (Daimiel, Ciudad Real), dated between 2200 and 1350 bc. The main objective of this study was to investigate interpersonal violence in this site and to report an uncommon case of violent death. No traumatic injury was detected in any child, and men and women significantly differed in the frequency of traumas. More traumatisms were found in men from the earlier stages of occupation, including a young man with at least three blunt force traumas and 26 sharp force traumas. The archaeological findings and trauma patterns in the skeletons of the 65 individuals studied suggest a relatively intense level of exposure to violence for adult men in the earlier stages of occupation of this settlement. Copyright © 2012 John Wiley & Sons, Ltd.

Isotopic paleoecology of mammals and the Middle Miocene Cooling event in the Madrid Basin (Spain)

The Middle Miocene underwent profound climatic perturbations detected in worldwide marine and continental records. The Miocene Climatic Optimum (~17 to 14Ma), a warm and humid period, was followed by the Middle Miocene Cooling (~14–13.8Ma) characterized by a sharp drop in temperatures and an increase in aridity triggered by the reestablishment of the Eastern Antarctica ice sheet. The Madrid Basin, located in the central Iberian Peninsula, has furnished a considerable number of Miocene fossil sites with a very complete succession of localities from the Lower Middle Miocene to the Upper Middle Miocene (Middle and Upper Aragonian, MN5 and MN6, local zones Db to G). Mammalian fossil tooth enamel of different taxa including rhinoceros, equids, gomphothere, suids and ruminants from 16 fossil sites spanning from ~15.9Ma to ~13.2Ma were analyzed for δ13C, δ18OCO3 and δ18OPO4 values with the aim of determining regional paleoecological, paleoenvironmental and paleoclimatic changes across this important climate transition. The δ13C values vary between −11.9‰ and −6.4‰ (VPDB), indicating a C3 environment ranging from woodlands to more open conditions. The rhinoceros Alicornops simorrense and Hoploaceratherium tetradactylum, the gomphothere Gomphotherium angustidens, the cervid Heteroprox moralesi and the paleomerycid Triceromeryx pachecoi may be regarded as browsers inhabiting more closed environments, whereas the equid Anchitherium, the rhinoceros Hispanotherium matritense and the bovid Tethytragus langai show a mixed feeding diet related to more open conditions. Furthermore, the variation in δ13C values across the fossil sites and local zones indicates drier conditions in local zones Db and Dc (~15.9–14.8Ma), a more humid period in local zone Dd (~14.8–14.1Ma), before a return to a drier environment in local zones E, F and G (~14.1–13.2Ma). The δ18OCO3 and δ18OPO4 values and calculated δ18Ow values all track a declining trend from local zones Db to Dd (~15.9–14.1Ma), with minimum values in local zone E (δ18OCO3=26.5±2.1‰, δ18OPO4=18.4±2.4‰, and δ18Ow=−5.3±2.9‰). The minimum in δ18O values in local zone E (~14.1–13.7Ma) appears to coincide with a drop in temperature at the time of the Middle Miocene Cooling (~14–13.8Ma). After this minimum, δ18OCO3, δ18OPO4 and δ18Ow values recover in local zones F and G (13.7–13.2Ma). The calculation of Δ13Cleaf values allowed us to determine plausible biomes that might have existed in the Madrid Basin during the Middle Miocene (i.e., a tropical rain forest, a tropical deciduous forest, a temperate evergreen forest and a xeric woodland–scrubland), although this method was not able to detect more savanna-like environments. Finally, δ13Cdiet, meq values were used to infer mean annual precipitation, with values ranging from ~250mm/yr (local zone Dc) to ~670mm/yr (local zone Dd) which are in accordance with the proposed biomes suggested by the Δ13Cleaf values and fossil mammal assemblages.

Understanding the ancient habitats of the last-interglacial (late MIS 5) Neanderthals of central Iberia: Paleoenvironmental and taphonomic evidence from the Cueva del Camino (Spain) site

The Cueva del Camino site (Pinilla del Valle, Madrid) represents the most complete MIS 5 record from the Iberian Peninsula (away from the Mediterranean margin), including a large accumulation of fossilized remains of small and large vertebrates and two human teeth. The presence of carnivores (mainly hyenas) and humans suggests that the site should be interpreted as a spotted hyena den, a human occupation, or both. During an earlier phase of excavation undertaken during the 1980s, an anthropic origin was suggested for the accumulation at the site. However, research was resumed in 2002, leading to an increase in the number of vertebrate remains recovered, as well as the recognition of new vertebrate species. These have now been incorporated into the site’s list of fauna. In addition, new palaeobotanical, geochronological and stratigraphic data have been recorded and analysed, and the human teeth identified as being of Neanderthal origin. Floristic data (pollen and charcoal remains) obtained for the north sector of this site indicate an open landscape with Pinus sylvestris-nigra as the main arboreal taxon. The available evidence suggests this accumulation to be the result of spotted hyena activity during a warm phase of Marine Isotope Stage 5 (MIS 5) in an environment in which fallow deer was the most abundant herbivore.

Extreme pointer years in tree-ring records of Central Spain as evidence of climatic events and the eruption of the Huaynaputina Volcano (Peru, 1600 AD)

Abstract. The study of pointer years of numerous tree-ring chronologies of the central Iberian Peninsula (Sierra de Guadarrama) could provide complementary information about climate variability over the last 405 yr. In total, 64 pointer years have been identified: 30 negative (representing minimum growths) and 34 positive (representing maximum growths), the most significant of these being 1601, 1963 and 1996 for the negative ones, and 1734 and 1737 for the positive ones. Given that summer precipitation was found to be the most limiting factor for the growth of Pinus in the Sierra de Guadarrama in the second half of the 20th century, it is also an explanatory factor in almost 50% of the extreme growths. Furthermore, these pointer years and intervals are not evenly distributed throughout time. Both in the first half of the 17th and in the second half of 20th, they were more frequent and more extreme and these periods are the most notable for the frequency of negative pointer years in Central Spain. The interval 1600–1602 is of special significance, being one of the most unfavourable for tree growth in the centre of Spain, with 1601 representing the minimum index in the regional chronology. We infer that this special minimum annual increase was the effect of the eruption of Huaynaputina, which occurred in Peru at the beginning of 1600 AD. This is the first time that the effects of this eruption in the tree-ring records of Southern Europe have been demonstrated.

Anomalous xenocryst dispersion during tonalite–granodiorite crystal mush hybridization in the mid crust: Mineralogical and geochemical evidence from Variscan appinites (Avila Batholith, Central Iberia)

The Variscan appinites from the San Martin del Pimpollar intrusion (Avila Batholith, Central Iberia) display geochemical and mineralogical evidence for hybridization with crustal-derived, partially molten, granodiorites and for rapid crystallization of residual melts.Quenching, apparently induced by the thermal contrast between mixing magmas, caused crystallization of hollow microphenocrysts of labradorite–bytownite, and of aggregates of fine-grained plagioclase+quartz+biotite±hornblende which trapped abundant acicular grains of apatite. Both inner cores and outer rims of anorthite-rich microphenocrysts were subsequently infilled and overgrown, respectively, by andesine. The sharp change in the anorthite content of plagioclase microcphenocrysts could be due to disequilibrium partitioning during supercooling, although decrease in H2O activity or Al/(Al+Si) ratio of the melt after An-rich plagioclase crystallization cannot be disregarded. Coarse-grained xenoliths and xenocrysts (quartz with reaction rims and embayment, rapakivi K-feldspar with irregular distribution of Ba-rich zones, oscillatory zoned oligoclase–andesine and biotite with inclusions of stubby apatite) were entrained into the appintic magma during hybridization. The xenocrysts were most probably derived from the country-rock granodiorites. The composition of coarse-grained biotite, however, is similar to that of matrix grains, implying total compositional resetting by exchange reaction with the appinitic magma if it was originally xenocrystic. Otherwise, biotite+apatite saturation would have to have been achieved before quenching.The most evolved rock terms of the appinite suite, hybrid granodiorites and hybrid biotite tonalites, have Nd and Sr isotope compositions matching those of the country-rock granodiorites. However, hybrid biotite tonalites are significantly more depleted in K2O, Ba, Zr, Th and REE than would be expected from appinite/country-rock granodiorite hybridization. This anomalous geochemical pattern could be caused by an inefficient dispersion of xenocrysts into the hybrid magma due to the quenching of the residual appinitic melts. Therefore, the ratios of mineral abundances in the country rocks may not have been conserved during xenocryst entrainment into the appinitic magma.

Oroclines of the Variscan orogen of Iberia: Paleocurrent analysis and paleogeographic implications

Coupled structural and paleomagnetic analyses have shown that the northern Iberian bend of the Variscan orogen, referred to as the Cantabrian Orocline, developed by vertical axis rotation of an originally linear orogen. However, palinspastic restoration of the orocline has proven difficult owing to (1) an unusually great orogenic width of over 700km and (2) exposure of shallow water strata of the Gondwanan margin in the northern and southern portions of the orogen. We present paleocurrent data from Lower Ordovician shallow marine clastic sedimentary rocks across the Variscan of northern and central Iberia collected to constrain palinspastic restoration of the orogen. Paleocurrent data were collected from over 50 sites, and include cross bed foresets, ripple crests and casts, as well as rare ball and pillow structures, syn-sedimentary slump folds, and incised channels. Paleocurrent directions fan around the Cantabrian Orocline, are consistently oriented at a high angle to structural strike, and yield a consistent offshore direction outward from the oroclinal core. Similarly, changes in structural strike and paleocurrent direction across central Iberia imply the presence of a second more southerly orocline, the Central Iberian Orocline, that is continuous with, but convex in the opposite direction of the Cantabrian Orocline. Together, the Cantabrian and Central Iberian oroclines define an S-shaped pair of continental-scale buckle folds. Palinspastic restoration of the oroclines yields a linear continental margin >1500km long characterized by consistent offshore paleoflow to the west, defining a westerly oceanic domain (presumably the Rheic Ocean) and an easterly landward direction (presumably Gondwana). Recognition of the southern orocline explains the unusual width of the orogen, the geometry of aeromagnetic anomalies attributable to Variscan rocks, and is consistent with available structural data, paleomagnetic declination data, and the distribution of correlative Paleozoic and older rock sequences including shallow water strata of the Gondwanan margin. The S-geometry of the oroclines is similar to the Z-geometry of the Alaskan oroclines of the North America Cordillera, suggesting that as in the Cordillera, the Iberian oroclines may record a significant, margin-parallel translation event.

A seismological evidence for the northwestward movement of Africa with respect to Iberia from shear-wave splitting

Seismic anisotropy and its main features along the convergent boundary between Africa and Iberia are detected through the analysis of teleseismic shear-wave splitting. Waveform data generated by 95 teleseismic events recorded at 17 broadband stations deployed in the western Mediterranean region are used in the present study. Although the station coverage is not uniform in the Iberian Peninsula and northwest Africa, significant variations in the fast polarization directions and delay times are observed at stations located at different tectonic domains. Fast polarization directions are oriented predominantly NW-SE at most stations which are close to the plate boundary and in central Iberia; being consistent with the absolute plate motion in the region. In the northern part of the Iberian Peninsula, fast velocity directions are oriented nearly E–W; coincident with previous results. Few stations located slightly north of the plate boundary and to the southeast of Iberia show E–W to NE-SW fast velocity directions, which may be related to the Alpine Orogeny and the extension direction in Iberia. Delay times vary significantly between 0.2 and 1.9 s for individual measurements, reflecting a highly anisotropic structure beneath the recording stations. The relative motion between Africa and Iberia represents the main reason for the observed NW-SE orientations of the fast velocity directions. However, different causes of anisotropy have also to be considered to explain the wide range of the splitting pattern observed in the western Mediterranean region. Many geophysical observations such as the low Pn velocity, lower lithospheric Q values, higher heat flow and the presence of high conductive features support the mantle flow in the western Mediterranean, which may contribute and even modify the splitting pattern beneath the studied region.

The role of lithospheric heterogeneities in the location of the Cenozoic intraplate deformation of Iberia from finite element modeling

The Cenozoic evolution of the Central System basement uplift and of the continental Duero and Madrid basins on the Iberian Peninsula occurred in a compressive context triggered by the Alpine orogeny. Although several models of deformation have been suggested, the factors that led to the development of these have not been analyzed to date. We present here finite element modeling of the intraplate deformation of the Iberian lithosphere during the Cenozoic. This modeling has taken into account the role played by (1) the tectonic shortening originating from the Pyrenean and Betic collisions, (2) the weight of Tertiary continental sediments, and (3) thermomechanical heterogeneities present in the lithosphere. The numerical model represents a lithospheric section, with a creep‐type mechanical behavior, perpendicular to the Central System, and the two sedimentary basins. Both initial conditions and the results obtained have been specified based on the available geophysical and geological data. This study has enabled us to simulate the present lithospheric structure of the central Iberian peninsula: (a) the formation of the Central System relief and its horizontal shortening, (b) the basement folding in the Duero and Madrid basins, (c) the development of the root of the mountain range, and (d) the depth of the lithosphere‐asthenosphere border in the interior of Iberia. The deformations occurred through a large‐scale folding and thickening mechanism, by the shortening of a lithosphere that was initially thinner, and with lateral contrasts in temperatures and composition.

Revisión sintaxonómica de las comunidades de Cytisetea scopario-striati communities en el centro de España.

A syntaxonomical study was carried out using techniques of multivariate analysis on the nanophanerophytic vegetation of Genistées included in the class Cytisetea scopario-striati, in the central Iberian Peninsula. 700 relevés -both published and unpublished- have been analysed using various types of classifications and ordinations in different stages. For this vast territory a total of 15 associations have been recognised, distributed into the four alliances traditionally recognised for the area: Retamion sphaerocarpae, Genistion floridae, Genistion polygaliiphyllae and Ulici europaei-Genistion polygaliiphyllae. The concepts of subassociation and variant recently developed have been applied in the syntaxonomical nomenclature. Of these three subassociations are proposed as new.

Adaptive diversity in Castanea sativa Mill. half-sib progenies in response to drought stress

Variation patterns in phenotypic expression after cultivation in two water regimes: 50% and 90% substrate saturation were studied in progenies of chestnut (Castanea sativa Mill.) cultivars originating from two main origins in the Iberian Peninsula: North (specifically from Asturias and Galicia) and Central Iberian Peninsula (specifically from the Canary Islands and Andalusia in Southern Spain related to this gene pool). The restricted water supply reduced the water potential of all the families as well as their growth, both in terms of height and weight. Root development increased whilst leaf area decreased as a result of reduction in number and surface area of individual leaves as well as sprouting rather than through defoliation. Drought stress also modified the morphology of the leaves and the relationships indicating the rate of relative development of the leaves compared to the rest of the plant. A correlation with the minimum summer rainfall in the regions of provenance was observed for several traits. The phenotypic variation observed was greater than expected from progenies of selected fruit cultivars. The results of this study show that (i) phenotypic variation exists between the two origins of variability corresponding to the two identified gene pools; (ii) the Northern group might be considered more tolerant to drought stress when considering plantlets’ ability to recover water potential, though important phenotypic plasticity was found in both origins of variability; and (iii) the pattern of variation found in some physiological and morphological traits suggests that Spanish chestnut stands have great potential to respond to the expected increase in drought in the Iberian Peninsula over the present century.

Morphological and Biometric Features of Male BluethroatsLuscinia svecicain Central Iberia

In order to test biometrics and plumage variability in bluethroats Luscinia svecica in central Iberia, 185 birds were captured in four areas (Sierra-Béjar, Sierra-Piedrahita, Sierra-Gredos and Sierra-Paramera). Older bluethroats were significantly larger than second calendar year birds in wing, tail, and total body lengths, but not in tarsus and bill lengths. A multivariate analysis of variance (MANOVA) and a principal component analysis (PCA) were used. Total body length only varied significantly between sampling areas: the birds from Sierra-Béjar were larger than those from Sierra-Gredos and Sierra-Paramera, but were similar to those of Sierra-Piedrahita. Birds with a white spot, a chestnut spot or no spot were found. Therefore, the question arises whether there are three subspecies (L. s. cyanecula, L. s. svecica and L. s. azuricollis), or three forms of a single subspecies (L. s. azuricollis). The percentage of birds with and without a throat spot was similar in the four sampled areas, and the percentage of birds with a spot significantly increased with age. These observations suggest that some plumage characters, such as the throat spot, should not be used as taxonomic characters, at least in the area where this study was conducted.

The importance of traditional farmland areas for steppe birds: a case study of migrant female Great Bustards Otis tarda in Spain

A detailed knowledge of the habitat requirements of steppe birds living in farmland habitats is necessary to identify agricultural practices compatible with their conservation. The globally threatened Great Bustard Otis tarda is a partial migrant in central Iberia, but factors affecting its winter habitat use have not been identified. We assessed habitat differences between breeding and wintering areas and winter habitat selection of radiotagged migrant female Great Bustards in central Spain. Of 68 tagged females, 35% moved to wintering areas located 64.3 ± 24.0 km south of their breeding areas, and 80% wintered in a single area of c. 236 km2. A census of the population in this area identified it as one of the most important wintering areas of this species in the world, holding c. 1500 individuals. There were significant differences between breeding and wintering habitats of individually marked migrant females. Compared with breeding areas, wintering areas of migrant females were located further from roads and urban nuclei, had lower human population densities and area of urban developments, and a higher diversity of land‐use types, with less cover of cereals and more vineyards and olive groves. Within this area, radiotracked migrant females preferred sites with more vineyards and a lower land‐use diversity. Our results highlight the importance of traditional Mediterranean dry farmland mosaics, and suggest that different conservation strategies are needed for migrant and resident populations in winter to secure the conservation of suitable wintering habitat for Great Bustards in the Iberian Peninsula.

Glacial landforms and their paleoclimatic significance in Sierra de Guadarrama, Central Iberian Peninsula

This paper investigates the glacial evolution on the east face of Pico de Peñalara (40°51′N, 3°57′W; 2428 m), the highest elevation of Sierra de Guadarrama in the center of the Iberian Peninsula. The geomorphologic stability of glacial landforms and permanence of snow cover were examined, and 18 samples were selected for dating with cosmogenic isotope 36Cl from moraine formations in four well-differentiated phases, as well as from a pre-glacial periglacial blockfield and a glacial threshold near the headwall. The results show the synchrony between the Last Glacial Maximum (LGM) advance and most results obtained recently by cosmogenic dating in southern Europe, within the MIS (Marine Isotope Stage) 2 stadial but earlier than the global LGM, i.e. between 25 and 19 ka BP. There was slow glacial retreat with minor re-advances between 19 and 16 ka and rapid deglaciation from 16 ka. This paper presents initial results, still pending confirmation, for the minimum age of the periglacial summit block formation around 80 ka for the existence of moraine formations older than the last advance and for the existence of glaciers during the Younger Dryas stadial. To explain the synchrony between two moraine formations at different altitudes, this paper formulates the hypothesis of the ‘secondary moraine’ evidenced in currently existing glaciers similar to those which existed on Peñalara.

Measuring medium-term sheet erosion in gullies from trees: A case study using dendrogeomorphological analysis of exposed pine roots in central Iberia

The assessment of gully erosion poses a great challenge because of the complexity and connectivity of the geomorphic processes involved. This study focuses on the quantification of sheet erosion rates in a set of slope gullies located on the northern piedmont of the Guadarrama Mountains (Spanish Central System). In order to delineate accurately the gully areas in which sheet erosion was predominant, the Hydrologic/Erosion Response Unit (HRU/ERU) approach was used and a dendrogeomorphological analysis of exposed tree roots was carried out to quantify sheet erosion rates in one selected HRU/ERU. Identification of the first year of exposure by erosion from anatomical criteria was therefore critical. The 29 samples taken were prepared for anatomical analysis and cross-dated. Anatomical analysis of the samples showed a reduction in the lumen area of earlywood tracheids following root exposure and also, in most cases, a slight increase in growth rings. Moreover, at the end of the ring, latewood tissue and visible annual borders were very clearly defined by several rows of thick-walled tracheids. A non-parametric test was used on the findings derived from this qualitative analysis to objectify determination of the first year of exposure. Estimates of sheet erosion were obtained by dividing the height of eroded soil by the number of years that each root was exposed. The mean value of soil erosion for the entire study site was then determined from statistical inference. Using this procedure, a range of sheet erosion rates between 6.2 and 8.8 mm y −1 (125.2 and 177.8 t ha −1 year −1) was obtained for the dominant HRU/ERU of these gullies in central Iberia. These estimates of eroded soil thickness were adjusted based on the recent finding that root anatomical changes occur prior to their exposure by erosion.

Selective logging in public pine forests of the central Iberian Peninsula: Effects of the recovery process on ant assemblages

Pine forests on the northern plateau of the Iberian Peninsula have a long history of use, exploitation, and management. Current management practices consist of selective logging with relatively short periods of time between logging events. The main objective of this study is to detect changes in ant assemblages in the short time periods between selective logging activities. Ants were sampled at 44 sites considering three grouping categories of time periods after the last timber extraction: short (<4 years), medium (4–8 years) and long (>8 years). After selective logging the number of ant species increases as the forest recovers. A look at the differences between the assemblages when the analysis shifts from the species-specific level to functional groups showed differences between the short and long categories. This indicates that in certain circumstances the functional groups may be more informative of the functional restructuring of the ant assemblages in a disturbed habitat. Ant species from three functional groups display significant indicative values (Opportunist, Hot Climate Specialists and Subordinate Camponotini) in the medium- and long-time-after-logging categories: Messor capitatus (HCS) for medium-time category sites; and Aphaenogaster iberica (Op), Camponotus cruentatus (SC) and, Cataglyphis velox (HCS) for long-time category sites. No indicator species were found for the early stages of recovery. This information may also be of interest to managers because it reduces the number of data elements of the recovery status of these forests, and can be translated into monitoring protocols. The continued exploitation of these forests leads to an ant fauna that reflects this change. The results show that ant assemblages need at least 8 years to recover since only after that much time there is an emergence of Subordinate Camponotinae, a behaviorally dominant and low stress-tolerant functional group. This selective logging maintains the relative diversity and structure of ant assemblages.

Description of Distolabrellus magnivulvatus sp. n. (Nematoda, Rhabditida, Mesorhabditidae) from Iberian peninsula, the second species of a rare genus

Distolabrellus magnivulvatus sp. n., collected from green-house soil in central Iberian peninsula, is described and illustrated. It is characterized by having 0.89–1.07 mm long body in females and 0.65–0.99 mm in males, cuticle tesselated, lateral fields with three longitudinal incisures, lip region almost continuous and 10–13 µm wide, lips dimorphic (alternately extremely reduced and ovoid), stoma 22–30 μm long or 2.0–2.8 times lip region diameter, pharyngeal collar shorter than half of total stoma length, distance to pharyngo-intestinal junction 148–190 µm, V = 82–86, vulva a transverse slit located in a vulval cone and with its anterior lip bearing a flap-like structure, body cuticle surrounding the vulva especially differentiated, female tail conical with acute tip (68–90 μm, c = 10.9–14.6, c’ = 2.1–4.5), male tail conical (23–32 μm, c = 24.8–34.0; c’ = 1.0–1.4), bursa peloderan and open anteriorly, genital papillae ten pairs (2+1/4+3), spicules 54–64 μ m long and fused two-thirds, and gubernaculum 32–41 μm long. The new taxon is the second species of the genus Distolabrellus and is compared to type species D. veechi.