Central Region Of Spain Research Articles

Heavy-Metal Phytostabilizing Potential of Agrostis castellana Boiss. & Reuter

The soils of many abandoned mine sites in the central region of Spain are heavily polluted with a number of different metals. Having frequently found Agrostis castellana growing at these old mine sites, this study was designed to assess its remediation capacity for this type of setting. In an initial field study, plant specimens were collected from 4 abandoned mine sites to determine pollutant concentrations in their roots and shoots. This was followed by a 4-year bioassay in a controlled environment in which soils collected from the mines were used to set up microcosms. Maximum root concentrations of the most polluting elements present in the bioassay were 3625 mg kg−1 Zn, 2793 mg kg−1 Cu, 13042 mg kg−1 Pb, 49 mg kg−1 Cd and 957 mg kg−1 As. These concentrations represent root bioaccumulation indices of over 1 and usually >2. In contrast, indices of transfer to above-ground phytomass were always < 1, indicating this species is a good candidate for use as a phytostabilizer. However, the high metal concentrations that could reach the above-ground mass of this plant determines a need for close monitoring and avoiding the use of areas under restoration for hunting or grazing.

Influence of Moisture Conditions on Residual Zn Concentrations Applied as Synthetic Chelates

The aim of this study was to compare the behavior of residual zinc (Zn) from different synthetic chelates containing the chelating agents EDTA (ethylenediaminetetraacetate acid), HEDTA (hydroxyethyl-ethylenediaminetriacetate acid), and DTPA (diethylenetriaminepentaacetate acid) applied at different rates. This incubation experiment was carried out under two different moisture conditions (60 percent field capacity and waterlogged) and in two different soils from the central region of Spain (Soilacid, Typic Haploxeralf, and Soilcalc, Typic Calcixerept). The potentially available Zn concentration and short-term available Zn were estimated using the DTPA-TEA (diethylenetriaminepentaacetic acid–triethanolamine) and LMWOAs (low-molecular-weight organic acids) methods. In both soils, the amount of water-soluble Zn was estimated under 60 percent field-capacity conditions. Immediately available Zn was estimated under waterlogged conditions. The Zn concentrations depended on the soil type, the experimental time, and the Zn chelate used. Under both moisture conditions, the soil characteristics caused the residual effects of Zn-EDTA in Soilacid and Zn-DTPA-HEDTA-EDTA applied to Soilcalc, to produce the greatest Zn concentrations.

Epidemiology and temporal trends (2000-2012) of inflammatory bowel disease in adult patients in a central region of Spain.

A growing incidence of inflammatory bowel disease (IBD) has been reported recently in southern Europe, with records of pediatric cases confirming these tendencies in Spain. Data on adult populations, however, have not been provided for over 10 years and need to be updated. A multicenter retrospective registry of all adult patients with a diagnosis of IBD, including both Crohn's disease (CD) and ulcerative colitis (UC), attending five public hospitals covering a population of 514 368 inhabitants, was assessed. In 2012, the prevalence of CD and UC in adults was 137.17/100 000 inhabitants (95% confidence interval 114-160) and 99.84/100 000 inhabitants (95% confidence interval 79-119), respectively. The mean incidence rate during the period 2000-2012 of CD and UC was 8.9 and 5.6/100 000 inhabitants per year, respectively. Most of our patients (75.55%) had been diagnosed during the last 13 years. CD affected both sexes equally; a trend toward a progressive increase in the age at diagnosis, ileal location, and inflammatory behavior was documented for CD patients. In contrast, UC affected male patients with a higher frequency (57.8%; P=0.015), specifically those older than 40 years of age. Age at UC onset tended to increase progressively from 2000 to 2012 (P<0.001), but the extension on the disease remained unchanged. IBD is a highly prevalent disorder in our region, reaching the incidence of CD similar to the figures provided for Northern Europe. Changes in IBD localization, behavior, and age at diagnosis were documented during the period 2000-2012.

Investigation of risk factors associated with infections caused by small ruminant lentiviruses

Abstract An epidemiological study was conducted to identify risk factors related to small ruminant lentivirus (SRLV) infection in the central region of Spain. Between October 1998 and October 2000, a total of 194 sheep from 10 flocks and 163 goats from three flocks were tested for SRLV antibodies, resulting in 65.5% and 8.0% of seroprevalence, respectively. The relationship between differences in prevalence of SRLV, geographical location of the flock, and possible factors related to the flock that could enhance transmission were studied. Results of multivariable analysis showed an association between SRLV infection and geographical location of the flock and the rearing system. In addition, the differences in the productivity between infected and non-infected animals were explored. The productivity parameters were measured in 62 sheep and 28 goats. All productivity parameters studied (milk production, number of milking days, and lambing rate) appeared to be reduced in the SRLV-seropositive group in both goats and sheep. Even though, these differences were not statistically significant, it seems that animals infected are less productive than these non-infected. Statistical analyses comparing infected and non-infected sheep showed no statistical relationship between SRLV infection and milk quality.

Use of diffusive gradients in thin films (DGT) as an early detection tool of low‐intensity leakage from CO2 storage

AbstractDiffusive gradients in thin films (DGT) have been tested in CO2‐rich, metal‐bearing fluids from springs in the Campo de Calatrava region in Central Spain, to assess their applicability as a monitoring tool in onshore CO2 storage projects. These films are capable of adsorbing metals and recording changes in their concentration in water, sediments, and soils. Considering that CO2 dissolution promotes metal solubilization and transport, the use of these films could be valuable as a monitoring tool of early leakage.A number of DGT have been deployed in selected springs with constant metal concentration. The studied waters show high concentrations of Fe, as high as 1 × 104 μg·L−1, Ni, Co, Zn, Cu, and Mn. Comparing re‐calculated metal concentration in DGT with metal water concentration, two different metal behaviors are observed: (i) metals with sorption consistent with the metal concentration (i.e. plotting close to the 1:1 line in a [Me]DGT: [Me]water plot), and (ii) metals with non−linear sorption, with some data showing metal enrichment in DGT compared with the concentration in water. Metals in the first group include Fe, Mn, Co, Ni, and U, and metals in the second group are Zn, Pb, Cr, Cu, and Al. From this research, it is concluded that the metals in the first group can be used to monitor potential leakage by using DGT, providing effective leakage detection even considering low variations of concentrations, episodic metal release, and reducing costs compared with conventional, periodic water sampling.

Monitoring European wildcat Felis silvestris populations using scat surveys in central Spain: are population trends related to wild rabbit dynamics or to landscape features?

Accurate data on the European wildcat Felis silvestris population trends are scarce for most of its range, despite this information being essential in assessing the threat status of the species. Moreover, ecological correlates of these population trends have never been evaluated. The aim of this study was to describe population trends of the European wildcat in a central region of Spain during the period 1997 to 2005 on both regional and local scales. Putative associations with several landscape features and wild rabbit population trajectories were also examined. Analyses were based on temporal variations of abundance indexes calculated for both species, which were derived from the respective frequencies of occurrence of scats along linear transects. Moreover, we propose monitoring wildcat populations across their range using scat surveys. Results showed that wildcat populations remained stable between the two survey periods considered, and variations in wildcat abundances were not associated with either habitat features or changes in rabbit abundances. Moreover, results suggested that wildcat predation does not limit the growth capacity of rabbit populations. We propose standardized scat surveys as the most efficient methodology for monitoring wildcat populations across European regions. Problems with genetic analyses for correctly identifying carnivore scats are noted, which indicate that the best complementary method for monitoring wildcats is probably camera trapping (especially where hybridization is suspected). Furthermore, results showed that controlling wildcats to protect the rabbit populations is not justified.

Prevalence of eosinophilic oesophagitis in adult patients in a central region of Spain

Eosinophilic oesophagitis (EoE) is a common cause of oesophageal disease. Limited data have been reported on its epidemiology in Europe as the only available information has been estimated for Swiss adult patients, among whom a prevalence of 42.9 per 100,000 was calculated. We estimate for the first time the prevalence of EoE in adult patients in two healthcare areas located in a central region of Spain. All patients older than 16 years of age and living in the study areas appointed to two hospitals located in a central region of Spain who were consecutively diagnosed with EoE between 2005 and 2011 were analyzed retrospectively. Annual incidence and period prevalence were estimated along with a confidence interval (CI) of 95%. Between January 2005 and December 2011, 40 adult patients were diagnosed with EoE in our areas, with an average overall adult reference population of 89 642. No significant differences in clinical data or prevalence figures were found between both hospitals. The average age was 29.4 years (rank 16-53), 80% of patients being younger than 40 years of age. The estimated mean annual incidence of adult EoE for the study period was 6.37 per 100 000 (95% CI: 6.31-6.44) and remained relatively stable during the study period. The period prevalence was 44.6 cases per 100 000 inhabitants (95% CI: 30-59), with a male/female ratio of 19 : 1. EoE was highly prevalent in adults from central Spain, being diagnosed in one out of 2250 inhabitants older than 16 years of age.

Landscape species pools and connectivity patterns influence tree species richness in both managed and unmanaged stands

Disturbance intensity and metapopulation dynamics are among the theoretical mechanisms explaining species coexistence at the local and landscape scale. Both mechanisms might interact, so that the consequences of local disturbances might depend on long distance dispersal events. In this study we examined whether the richness of tree species potentially able to colonize a locality from the surroundings was associated with the tree species richness observed in that locality, and/or with the response of that richness to partial harvesting. The study was located in a Mediterranean region in central Spain where partially harvested forests had been found to have more tree species than unmanaged forests. We used a top-down hierarchical modeling structure to account for the effect of other factors such as climate, lithology and amount of forest cover at the landscape scale. Species richness of trees was strongly associated to annual precipitation, and was maximized at intermediate rainfall levels. Under homogeneous climate and lithological conditions, the composition and connectivity of seed sources in the landscape seemed to play a more relevant role explaining tree species richness than the amount of forest habitat in the surroundings. Particularly, higher species richness was observed in forest stands susceptible of receiving a higher diversity of seed fluxes. Patterns in the response of species richness to partial harvesting were less clearly explained by differences in the diversity of potential seed fluxes, but time lags in the responses, or differences in the proportion of shade-tolerant species in the landscape could mediate this interaction. Stronger importance of the amount of forest habitat and diversity of potential seed fluxes may be masked by their correlations with precipitation gradients in the study area. Our results emphasize the need of a wide scale approach to forest planning in order to be able to account for and to influence determinant processes of diversity patterns from the stand to the landscape levels.

Breastfeeding Promotion Plan in Madrid, Spain

Promotion and protection of breastfeeding is a public health objective. In April 2009, health authorities in the Madrid region in central Spain signed a collaboration agreement with The United Nations Children's Fund and created a breastfeeding committee. To report the creation and implementation of a plan to promote and improve the quality of breastfeeding care in public hospitals in the region of Madrid, according to the Baby-Friendly Hospital Initiative (BFHI) standards. The action plan included institutional commitment; creation of a breastfeeding committee in each hospital; outcome analyses, staff training, creation of educational materials; and dissemination of activities. The plan was adopted by the 19 non-BFHI-designated public maternity units in the Madrid region. Each hospital completed a modified version of the World Health Organization self-assessment questionnaire in 2009 (pre-intervention) and again in 2011. Thirteen maternity units (68.4%) established a breastfeeding committee, and 32 months after implementation of the plan, the other 6 hospitals have created one. Nine training courses have been carried out to train professional experts on breastfeeding as trainers. The 271 trainers provided 18-hour breastfeeding courses for 1423 professionals. In 2009, there was only 1 BFHI-accredited hospital. Currently, 52.6% of the other 19 hospitals have some level of accreditation, and 2 are fully accredited. An intervention to improve the quality of breastfeeding care based on an organized regional approach to the BFHI was useful for BFHI implementation.

Prevalence and incidence of microscopic colitis in patients with diarrhoea of unknown aetiology in a region in central Spain

BackgroundOften previously overlooked, microscopic colitis, including collagenous colitis and lymphocytic colitis, has now emerged as a common cause of chronic diarrhoea. AimsTo evaluate the prevalence and incidence of microscopic colitis in patients with diarrhoea of unknown aetiology. Methods271 consecutive patients who were referred to the General Hospital of Tomelloso from April 2008 to December 2010 for diarrhoea of unknown aetiology underwent a full colonoscopy to obtain biopsy samples to diagnose microscopic colitis on the basis of commonly accepted histological criteria. All patients were classified according to the Roma III criteria for diarrhoea-dominant irritable bowel syndrome. ResultsIn 234/271 consecutive patients with normal endoscopic appearance we observed 32/234 patients with microscopic colitis (30 lymphocytic colitis and 2 collagenous colitis) with a prevalence of microscopic colitis of 48 cases/100,000 inhabitants (95%CI: 30–65) and mean annual standardised incidence of 18 cases/100,000 inhabitants (95%CI: 16.0–20.0). Analysing only the patients that met the Roma III criteria (84/271), we observed 10.7% microscopic colitis diagnosis, with higher risk in the presence of autoimmune disease, seronegative celiac disease and intake of non-steroidal anti-inflammatory drugs. ConclusionsMicroscopic colitis was found in 13.7% of patients with chronic diarrhoea. Microscopic colitis is present in a relevant proportion of symptomatic patients meeting diagnostic criteria for irritable bowel syndrome (10.7%).

Estimated soil organic carbon change due to agricultural land management modifications in a semiarid cereal-growing region in Central Spain

Maintaining or increasing soil organic carbon (SOC) in agricultural lands is important for soil productivity, restoration and could potentially be a factor in reducing carbon emissions. In order to implement best practices for maintaining productivity and increasing SOC, there is a need for understanding how management changes may alter SOC levels. This applied study presents a methodology to assess and predict SOC levels to better understand effects modification to land management can have in semiarid central Spain. Results show extensification using longer-term pasture rotations (e.g. 5-year) could increase SOC levels and have an impact on soil restoration important in maintaining productivity. SOC increases brought about by new management may also have a role in contribution to national carbon emission reduction plans.

Temporal and spatial spread of Lettuce mosaic virus in lettuce crops in central Spain: factors involved in Lettuce mosaic virus epidemics

Abstract Lettuce mosaic virus (LMV) is transmitted by aphid vectors in a nonpersistent manner as well as by seeds. The virus causes severe disease outbreaks in commercial lettuce crops in several regions of Spain. The temporal and spatial patterns of spread of LMV were studied in autumn 2002 in the central region of Spain. Symptomatic lettuce (var. Cazorla) plant samples were collected weekly, first at the seedling stage from the greenhouse nursery and later outdoors after transplantation. The exact position of symptomatic plants sampled in the field was recorded and then material was tested by enzyme‐linked immunosorbent assay to assess virus infection. Cumulative spatial data for infected plants at different growth stages were analysed using spatial analysis by distance indices. For temporal analysis, the monomolecular, Gompertz, logistic and exponential models were evaluated for goodness of fit to the entire set of disease progress data obtained. The results indicated that the disease progress curve of LMV epidemics in the selected area is best described by a Gompertz model and that the epidemic follows a polycyclic disease progression. Our data suggest that secondary cycle of spread occurs when noncolonising aphid species land on the primary infected plants (probably coming from infected seed) and move to adjacent plants before leaving the crop. The role of weeds growing close to lettuce fields as potential inoculum sources of virus and the aphid species most likely involved in the transmission of LMV were also identified.

Issues in Simulating the Annual Precipitation of a Semiarid Region in Central Spain

Abstract Running regional climate models at a high resolution may improve their ability to simulate regional precipitation patterns, making them suitable for studying the impact of human-induced land-cover changes on hydrometeorology. The performance of the Regional Atmospheric Modeling System (RAMS) run in the high-resolution climate mode (4-km grid mesh) has been tested over a small domain in a semiarid region in central Spain. Three 1-yr simulations representing dry, intermediate, and wet conditions were compared to observations collected in 35 rain gauges. The model captured general spatiotemporal features of precipitation, such as the timing of precipitation events and approximate location of storms. A high correlation (0.82) between monthly domain-averaged observed and modeled precipitation was obtained. However, the model had a systematic dry bias, averaging −0.29 mm day−1, equivalent to 26% of annual rainfall. The small domain size, chosen because of computational limits, induced strong lateral boundary forcing, which, combined with uncertainty in NCEP relative humidity fields, was a likely cause for this dry bias.

Epidemiology of Oestrus ovis (Linneo, 1761) infestation in goats in Spain

This survey was conducted to determine the chronobiology and seroprevalence of nasal bot infestation ( Oestrus ovis) in Spain and to identify the risk factors associated with this disease in caprine herds. A total of 1590 sera from adult goats were collected at random on 175 farms in southwestern Spain. Sera were tested by ELISA, using crude protein from second stage larvae as antigen. The mean seroprevalence was 46.04% and mean percentage of optical densities was 41.83. These data indicate a high prevalence of this parasite in the investigated areas. The serological survey revealed that goats managed at higher altitudes, at meridians latitudes and on farms with small herds had a smaller probability of infestation. Eighty goat heads, obtained from abattoirs in the central region of Spain, were collected and examined for nasal botflies from February to October 2002. O. ovis larval stages were recovered from the nasal-sinus cavities of 23 goats, reaching a prevalence of 34.94%. The mean larval burden was 3.9 larvae per infested head. No first instars were found during February and March, when the second instar reached its larger count. The third instar was observed in very small number during the whole period of study, with one peak occurring in July–August. These data show the existence of a favourable period for the development of larval instars of O. ovis in goats that starts in February and finishes in September.

Genetic analysis of Spanish melon (Cucumis melo L.) germplasm using a standardized molecular-marker array and geographically diverse reference accessions

Genetic relationships among 125 Spanish melon ( Cucumis melo L.) accessions from a Spanish germplasm collection were assessed using a standard molecular-marker array consisting of 34 random amplified polymorphic DNA (RAPD) markers bands (19 primers) and 72 reference accessions drawn from previous studies. The reference accession array consisted of a broad range [Japanese (19) Crete (17), African (15), and USA and Europe (US/EU, 21)] of horticultural groupings (Group Cantalupensis, Group Conomon, Group Inodorus, Group Flexuosus, and Group Chito), and of melon market classes (e.g., Charentais, U.S. Western and European Shipper types, Ogen, and Galia, Honeydew, and Casaba). Spanish melon accessions (largely Casaba, Group Inodorus) were genetically distinct from the reference accessions and other Group Inodorus melons of different origins. Most African accessions showed common genetic affinities, and grouped with the Group Chito and the Group Conomon accessions examined. Those accession groupings were distinct from all other accessions belonging to Group Cantalupensis, Flexuosus, and Inodorus accessions originating from Crete, Japan, Europe, and the U.S. Genetic diversity was highest in accessions of African origin and lowest in accessions of Spanish origin. Additional RAPD markers (49 primers, 141 bands) and 22 selected agronomic traits (quantitative and qualitative) were then used to assess the genetic diversity among Spanish accessions. While cluster analysis using fruit characteristics grouped accessions into cultivars, RAPD-based genetic-distance estimate did not provide consistent accession groupings either by cultivar or geographic origin. While the highest level of polymorphism was detected among melons originating from the central region of Spain, and in the Rochet cultivar, accessions from the Andalucía region and Green cultivars were comparatively less diverse. These results indicate that the Spanish melon accessions could be used to broaden the genetic base of local and foreign Casaba germplasm, to enhance the genetic diversity of U.S and European commercial melon germplasm, and to delineate collection strategies for acquisition of additional Spanish landraces.

Detection and identification of Toscana and other phleboviruses by RT-nested-PCR assays with degenerated primers.

Phleboviruses are a large and widespread group of viruses that are transmitted by arthropods. Toscana virus is one of the principal agents that causes meningitis in humans during the summer in Italy and, possibly, in other Mediterranean countries. Rift Valley Fever virus can cause serious illness in both animals and humans, leading to high morbidity and mortality, and is considered to be a potential agent for epizootics and human epidemics. Since information on this group of viruses is still scant, reliable laboratory tools for diagnosis and epidemiological surveillance must be developed, in order to ascertain their real impact on Public Health. Sequence data obtained from Spanish isolates of Toscana virus and other phleboviruses confirmed that natural genome variability may hamper the diagnosis of these agents by molecular methods, so this must be borne in mind when developing reliable assays. In view of the above, a novel and useful protocol has been developed for the detection and specific identification of every member of the phlebovirus genus present in a sample, including Toscana virus, based on a generic RT-nested-PCR, followed by sequencing of the amplified fragment. A change in this method also allowed specific direct detection and identification of wild isolates of Toscana virus of different geographical origin, using newly designed primers. Testing clinical samples with these assays confirmed the role of Toscana virus as an agent that causes acute aseptic meningitis in the central region of Spain.

Further molecular discrimination of Spanish strains of Echinococcus granulosus

We have designed two polymerase chain reaction (PCR) primer sets (PEg9F1-PEg9R1 and PEg16F1-PEg16R1) and two PCR protocols (Eg9-PCR and Eg16-PCR) for discrimination of Echinococcus granulosus genotypes. The oligonucleotide sequences originate from two E. granulosus DNA multiplex-PCR amplification fragments, previously reported, that allows species-specific discrimination between Taenia saginata, Taenia solium, and E. granulosus. The Eg9-PCR, Eg16-PCR, and Eg9-PCR linked restriction fragment length polymorphism (RFLP) analysis was used to characterize 53 E. granulosus isolates from the central region of Spain, highly endemic for echinococcosis. The analysis resulted in: (i) the discrimination of E. granulosus from Echinococcus multilocularis; (ii) the characterisation and discrimination of discrete E. granulosus strains from Spain; and (iii) the identification of two distinct genotypes within E. granulosus Spanish pig isolates. To further characterize the genetic variants in pigs, fragments of the NADH dehydrogenase I (ND1) and the cytochrome c oxidase subunit I (CO1) genes were amplified from parasite DNA and sequenced. The results again revealed the presence of two distinct genotypes: the G1 (sheep–dog strain) and G7 (pig–dog strain) genotypes. This observation could have important consequences for human health in Spain. Furthermore, the Eg9-PCR, Eg16-PCR, and Eg9-PCR-RFLP protocols can be used as additional methods to discriminate various E. granulosus genotypes.

Thermal and mechanical structure of the central Iberian Peninsula lithosphere

The central Iberian Peninsula (Spain) is made up of three main tectonic units: a mountain range, the Spanish Central System and two Tertiary basins (those of the rivers Duero and Tajo). These units are the result of widespread foreland deformation of the Iberian plate interior in response to Alpine convergence of European and African plates. The present study was designed to investigate thermal structure and rheological stratification in this region of central Spain. Surface heat flow has been described to range from ∼80 to ∼60 mW m −2. Highest surface heat flow values correspond to the Central System and northern part of the Tajo Basin. The relationship between elevation and thermal state was used to construct a one-dimensional thermal model. Mantle heat flow drops from 34 mW m −2 (Duero Basin) to 27 mW m −2 (Tajo Basin), and increases with diminishing surface heat flow. Strength predictions made by extrapolating experimental data indicate varying rheological stratification throughout the area. In general, in compression, ductile fields predominate in the middle and lower crusts and lithospheric mantle. Brittle behaviour is restricted to the first ∼8 km of the upper crust and to a thin layer at the top of the middle crust. In tension, brittle layers are slightly more extended, while the lower crust and lithospheric mantle remain ductile in the case of a wet peridotite composition. Discontinuities in brittle and ductile layer thickness determine lateral rheological anisotropy. Tectonic units roughly correspond to rheological domains. Brittle layers reach their maximum thickness beneath the Duero Basin and are of least thickness under the Tajo Basin, especially its northern area. Estimated total lithospheric strength shows a range from 2.5×10 12 to 8×10 12 N m −1 in compression, and from 1.3×10 12 to 1.6×10 12 N m −1 in tension. Highest values were estimated for the Duero Basin. Depth versus frequency of earthquakes correlates well with strength predictions. Earthquake foci concentrate mainly in the upper crust, showing a peak close to maximum strength depth. Most earthquakes occur in the southern margin of the Central System and southeast Tajo Basin. Seismicity is related to major faults, some bounding rheological domains. The Duero Basin is a relative quiescence zone characterised by higher total lithospheric strength than the remaining units.

Habitat preferences of great bustard Otistarda flocks in the arable steppes of central Spain: are potentially suitable areas unoccupied?

Summary Great bustards Otistarda are globally endangered and 50% of the world population now occurs in agro‐steppe habitats in Spain. An understanding of the relationship between land use and the species’ habitat requirements is necessary to predict the consequences of land‐use change on this declining species. A 2‐year study of great bustard substrate preferences was conducted in a large region in central Spain where most cereals are still cultivated in a traditional 2‐year rotation. Great bustards showed year‐round selection of stubble fields, but avoided ploughed and uncultivated areas. Other substrate types were variously selected, avoided or used in proportion to availability depending on season. Patterns were consistent over 2 years. Human artefacts such as roads, tracks and powerlines were avoided. Variables correlating with flock locations could not discriminate between occupied and unoccupied but apparently suitable areas of traditionally managed cereal steppe. This suggests that great bustard distribution in central Spain is not limited by inappropriate land use in steppe areas. The evidence suggests that great bustards show fidelity to sites regardless of the availability of suitable habitat elsewhere. Settlement patterns are probably determined by the presence of conspecifics rather than habitat cues. This result demonstrates the value of integrating observations of habitat use with knowledge of species’ behaviour in order to understand distribution more fully. We propose that conservation efforts should be directed towards securing traditional lek sites and we make three recommendations: first all great bustard lek sites should be identified; secondly, existing European Union legislation should be used to protect these and to ensure that compatible land management practices are applied or maintained; and finally, research programmes should be conducted that aim to enhance the conservation value of stubble fields rather than simply demonstrate their selection.

Estimation of Vector Propensity of Potato Virus Y in Open-Field Pepper Crops of Central Spain

During 3 successive years (1991, 1992, and 1993), 49 different species of alatae aphids were captured alive using net traps located in pepper fields in central Spain (Madrid). Aphids were trapped and transferred individually to pepper test seedlings to assess transmission of potato virus Y (PVY). In 1991, only 1 individual aphid transmitted PVY of 582 aphids captured. None of the 757 aphids captured in 1993 transmitted PVY to test plants. However, the percentage of transmitters was higher during 1992 (55/780,7%). Most aphids transmitting PVY were identified either as Diuraphis noxia (Mordvilko) or Aphis spp. A series of transmission assays were conducted under controlled conditions to confirm the transmission ability of D. noxia. Results showed that D. noxia transmits PVY with low efficiency under laboratory conditions. The role of D. noxia as a vector of PVY in the central region of Spain is discussed.