Holocene alluvial sequence in the val de zaragoza (Los Monegros) in the palaeoenvironmental context of the ebro basin (Ne Spain)

Flat-bottomed valleys formed by Holocene fills are the most characteristic landforms in the center of the Ebro basin. This paper analyzes, within a regional framework, a small fluvial basin located in the north of the Alcubierre Range. Three Holocene morphosedimentary units (H1-H3) and a sub-functional level (H4) are identified. These units are representative of the regional geomorphological evolutionary process in the Ebro basin. New chronological insights on climate and landscape management are provided by a study of the Bastarás weir, a construction made for water flow management during the Little Ice Age (LIA). The integration of Val de Zaragoza radiocarbon datings into the regional framework enables the authors to identify the main formation stages, as well as the influence of climatic and human factors on its evolution. The intensification of human pressure in the territory is reflected in a progressive increase in sediment accumulation rates in the valleys, peaking during Roman times and the Little Ice Age. Los valles de fondo plano formados por rellenos holocenos constituyen los paisajes más característicos del sector central de la cuenca del Ebro. En este trabajo se analiza una pequeña cuenca fluvial localizada en el norte de la Sierra de Alcubierre, en la que se han identificado tres unidades morfosedimentarias holocenas (H1-H3) y un nivel subfuncional (H4), que son representativos de la evolución geomorfológica regional de la Cuenca del Ebro. Uno de los aspectos más relevantes del valle lo constituye el azud de Bastarás, construcción realizada durante la Pequeña Edad del Hielo para el aprovechamiento del agua, que aporta nuevos datos cronológicos sobre dicha época y acerca de la gestión del territorio. La integración de las dataciones radiocarbónicas obtenidas en la Val de Zaragoza en un marco regional ha permitido precisar las principales etapas de formación de los valles de fondo plano, así como la importancia de los factores climáticos y humanos en su evolución. La intensificación de la presión humana sobre el territorio queda reflejada en un progresivo aumento en las tasas de acumulación de sedimentos en los valles, alcanzando sus picos máximos en Época Romana y en la Pequeña Edad del Hielo

Comparison of different methods to measure soil erosion in the central Ebro valley

Fire is a natural factor of landscape evolution in Mediterranean ecosystems. Due to social and economical changes, wildfires have caused hydrological and geomorphological changes to be more pronounced, resulting in enhanced soil erosion. The study area is located in the Zuera Mountains, near the city of Zaragoza (Spain) in the Middle Ebro Valley. These mountains were affected by two wildfires in 2008 and 2009, burned around 2000 ha and 6000 ha, respectively. Middle Ebro Valley has extreme aridity, which results in a low plant cover and high soil erodibility enhanced by the fire effects. Soil infiltration is one of the properties affected by fire as a consequence of litter and vegetation removal, heating of and changes to the biological, chemical and physical soil properties. The objective was to compare two different methods –rainfall simulations and erosion plots–, to assess soil erosion after forest fires. We compared different measurements with rainfall simulators and erosion plots, applying a woodchip cover –in order to reduce the rain splash effect–, and to measure the erosion reduction. The work showed low sediment rates in both experiments covered with woodchips

Wildfire effects on nutrients and organic carbon of a Rendzic Phaeozem in NE Spain: Changes at cm-scale topsoil

Badía, David et al.-- 9 páginas, 4 figuras, 4 tablas, 54 referencias.Soil organic carbon and nutrient content are analysed at topsoil cm-scale in a Rendzic Phaeozem from an Aleppo pine forest in semiarid Central Ebro Basin (NE-Spain). Soil depth affected by a severe wildfire is studied immediately after burning and a year later, trying to differentiate the heat shock and the ash/charcoal deposition effects. One week after the wildfire, soil organic carbon content (SOC) on burned topsoil decreases significantly at 0-1. cm soil depth. Wildfire degrades polysaccharides and proteins and eliminates, or at least reduces, biogenic compound markers, derived from lignin and lipids, but only above 2. cm soil depth. A characteristic cracking in the alkane series, as well as the presence of pyrogenic polycyclic aromatic hydrocarbons are also observed in the burned 1st cm topsoil. Below 2. cm the fire has little or no effect in soil organic matter molecular assemblage. Calcium, magnesium, potassium, ammonium, nitrate and phosphorous increased significantly a week after the fire, in the first cm soil depth. These modifications detected immediately after the fire (SOC decrease and nutrient increase) are related to the heat released during the severe wildfire. One year after the wildfire, SOC in the 1st cm of burned topsoil regain the same level to that observed in unburned sites, which could be a consequence of burned residues and black ash incorporation and even new inputs on soil surface derived from the reblooming processes, which starts after the fire. With the exception of nitrates whose concentration is higher in burned plots than the control ones within 0-3. cm of soil depth studied, nutrient concentration relatively decreased one year after the wildfire. Despite this decrease, fire effect (memory) still remains at the 1st cm topsoil, with many nutrients having comparatively high concentration in the burned soils under semiarid climate.The Aragon Government—La Caixa (FUEGOSOL Project: GA-LC-055/2011), the Spanish Government (CETSUS Project: CGL2007-66644-C04-04/HIDCLI and GEOFIRE Project: CGL2012-38655), and the University of Zaragoza provided financial support for this research.Peer Reviewe

Analysing the effect of land use and vegetation cover on soil infiltration in three contrasting environments in notheast Spain

This study presents a joint analysis of the information from 195 field infiltration experiments, using double ring devices. The experiments were carried out in 20 contrasting types of land use, distributed across three geographic contexts (coast of NE Catalonia, low mountains in the central Ebro Valley and mid-height mountains from the southern range of the Central Pyrenees). The objective of this research was to determine the most important factors explaining infiltration variability: land use, type of vegetation cover, soil and bedrock characteristics, soil moisture and altitude. Data analysis was performed by comparing variables using statistical methods: bivariate lineal correlation, ANOVA and Bonferroni multiple comparison tests. Results show that infiltration variability is the most important factor and mainly linked to land use, followed by vegetation type. In contrast, soil moisture did not show any relation with infiltration. The interpretation of these results suggests that the characteristics of the study areas are more decisive than temporal variations of soil water content, although humidity can influence land use to a greater or lesser degree. The validity of the results obtained in this study is supported by the wide range of land use and land cover analysed, located in areas with different geographical and geological characteristic

European small portable rainfall simulators : a comparison of rainfall characteristics

Small-scale portable rainfall simulators are an essential research tool for investigating the process dynamics of soil erosion and surface hydrology. There is no standardisation of rainfall simulation and such rainfall simulators differ in design, rainfall intensities, rain spectra and research questions,which impede drawing a meaningful comparison between results. Nevertheless, these data become progressively important for soil erosion assessment and therefore, the basis for decision-makers in application-oriented erosion protection. The artificially generated rainfall of the simulators used at the Universities Basel, La Rioja, Malaga, Trier, Tübingen, Valencia, Wageningen, Zaragoza, and at different CSIC (Spanish Scientific Research Council) institutes (Almeria, Cordoba, Granada, Murcia and Zaragoza) was measured with the same methods (Laser Precipitation Monitor for drop spectra and rain collectors for spatial distribution). Data are very beneficial for improvements of simulators and comparison of simulators and results. Furthermore, they can be used for comparative studies, e.g. with measured natural rainfall spectra. A broad range of rainfall data was measured (e.g. intensity: 37–360 mm h−1; Christiansen Coefficient for spatial rainfall distribution: 61–98%; median volumetric drop diameter: 0.375–6.5 mm; mean kinetic energy expenditure: 25–1322 J m−2 h−1;meankinetic energy per unit area and unit depth of rainfall: 0.77–50 J m−2 mm−1). Similarities among the simulators could be found e.g. concerning drop size distributions (maximum drop numbers are reached within the smallest drop classes b1 mm) and low fall velocities of bigger drops due to a general physical restriction. The comparison represents a good data-base for improvements and provides a consistent picture of the different parameters of the simulators that were tested

Azole and amphotericin B MIC values against aspergillus fumigatus: High agreement between spectrophotometric and visual readings using the EUCAST EDef 9.3.2 procedure

The EUCAST EDef 9.3.2 procedure recommends visual readings of azole and amphotericin B MICs against Aspergillus spp. Visual determination of MICs may be challenging. In this work, we aim to obtain and compare visual and spectrophotometric MIC readings of azoles and amphotericin B against Aspergillus fumigatus sensu lato isolates. A total of 847 A. fumigatus sensu lato isolates (A. fumigatus sensu stricto [n = 828] and cryptic species [n = 19]) were tested against amphotericin B, itraconazole, voriconazole, posaconazole, and isavuconazole using the EUCAST EDef 9.3.2 procedure. Isolates were classified as susceptible or resistant/non-wild type according to the 2020 updated breakpoints. The area of technical uncertainty for the azoles was defined in the updated breakpoints. Visual and spectrophotometric (fungal growth reduction of >95% compared to the control, read at 540 nm) MICs were compared. Essential (+1 2-fold dilution) and categorical agreements were calculated. Overall, high essential (97.1%) and categorical (99.6%) agreements were found. We obtained 100% categorical agreements for amphotericin B, itraconazole, and posaconazole, and consequently, no errors were found. Categorical agreements were 98.7 and 99.3% for voriconazole and isavuconazole, respectively. Most of the misclassifications for voriconazole and isavuconazole were found to be associated with MIC results falling either in the area of technical uncertainty or within one 2-fold dilution above the breakpoint. The resistance rate was slightly lower when the MICs were obtained by spectrophotometric readings. However, all relevant cyp51A mutants were correctly classified as resistant. Spectrophotometric determination of azole and amphotericin B MICs against A. fumigatus sensu lato isolates may be a convenient alternative to visual endpoint readings

Control of paratuberculosis: Who, why and how. A review of 48 countries

Paratuberculosis, a chronic disease affecting ruminant livestock, is caused by Mycobacterium avium subsp paratuberculosis (MAP). It has direct and indirect economic costs, impacts animal welfare and arouses public health concerns. In a survey of 48 countries we found paratuberculosis to be very common in livestock. In about half the countries more than 20% of herds and flocks were infected with MAP. Most countries had large ruminant populations (millions), several types of farmed ruminants, multiple husbandry systems and tens of thousands of individual farms, creating challenges for disease control. In addition, numerous species of free-living wildlife were infected. Paratuberculosis was notifiable in most countries, but formal control programs were present in only 22 countries. Generally, these were the more highly developed countries with advanced veterinary services. Of the countries without a formal control program for paratuberculosis, 76% were in South and Central America, Asia and Africa while 20% were in Europe. Control programs were justified most commonly on animal health grounds, but protecting market access and public health were other factors. Prevalence reduction was the major objective in most countries, but Norway and Sweden aimed to eradicate the disease, so surveillance and response were their major objectives. Government funding was involved in about two thirds of countries, but operations tended to be funded by farmers and their organizations and not by government alone. The majority of countries (60%) had voluntary control programs. Generally, programs were supported by incentives for joining, financial compensation and/or penalties for non-participation. Performance indicators, structure, leadership, practices and tools used in control programs are also presented. Securing funding for long-term control activities was a widespread problem. Control programs were reported to be successful in 16 (73%) of the 22 countries. Recommendations are made for future control programs, including a primary goal of establishing an international code for paratuberculosis, leading to universal acknowledgment of the principles and methods of control in relation to endemic and transboundary disease. An holistic approach across all ruminant livestock industries and long-term commitment is required for control of paratuberculosis. © 2019 The Author(s)