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Most studies on the geomorphological evolution of the Holocene from the Ebro depression (NE Spain) are focused on the period up to the Roman Epoch (218 BC–476 AD) while some references to medieval (476 AD–15th century) deposits are also occasionally dated. This paper focuses on the establishment of aggradation units on the valley bottoms and slopes of the Ebro depression after 1400 BP, their origin, comparison with other areas, and relationship with global paleoenvironmental changes. These units were produced after the incision phase that marked the end of the large Holocene accumulation (unit H1) around 1400 BP (at the end of the Late Roman Epoch). Morphosedimentary records enable us to establish three aggradation units during the last 1400 years: unit H2 ( ca. 1400–650 cal BP); unit H3 – with two H3A subunits ( ca. 650–500 cal BP) and H3B ( ca. 500–320 cal BP); and the H4 unit (after 320 cal BP). These units are organized following five types of aggradation/incision arrangements with differing complexities. There are also connections among these units and two slope stages in the region. Finally, the genetic relationships between these units and global paleoenvironmental changes are shown (LALIA, MCA, and LIA) and related to anthropic activity. This contribution is the first detailed and systematic approach to the study of morphosedimentary units and sedimentary arrangements during the Recent Holocene in the Mediterranean area.

The lower Gállego River has been strongly degraded since the 1960s due to human activity (gravel mining, dump accumulation, channeling works), which has produced a deep channel incision. Although these human-driven processes are usually reported in fluvial bibliography, in this case, more complex results are observable. For instance, regarding the depth and incision rates, we observed no relationship between the most anthropically impacted areas and the sections with the deepest incisions; moreover, the deepening process continues 40 years after the human interventions ceased. The reason for this maladjustment is the role played by the exhumation of the underlying Pleistocene substrate, affected by the synsedimentary processes of karstification. The appearance of paleodolines filled with fine sediments on the incision bottom and sides is the main factor conditioning the continuity and magnitude of the process. Besides, these paleodepressions direct the river dynamics and course, thus favoring its widening when they appear and causing the development of a new riverbed (Qt13) while the 1960s floodplain (Qt12) is becoming an old terrace located between 5 and 11 m above the new alluvial bottom. There are no previous records about this kind of consequences in the regional fluvial dynamics. El curso bajo del río Gállego ha sido fuertemente degradado desde los años 1960 por la actividad antrópica (extracción de áridos, acumulaciones de escombros, obras de encauzamiento) que ha conducido a una fuerte incisión. Aunque este tipo de procesos inducidos por el hombre son habituales en la bibliografía fluvial, en este caso se aprecian efectos más complejos. Son, por ejemplo, la profundidad y velocidad de la incisión, la falta de relación entre puntos de máxima intervención y los de mayor incisión o la continuidad del proceso cuarenta años después de cesar ese tipo de acciones. La respuesta a estos desajustes está en el papel que está jugando la exhumación del sustrato pleistoceno infrayacente, afectado por procesos sin sedimentarios de karstificación. La aparición de paleodolinas rellenas de sedimentos finos en el fondo y laterales de la incisión es actualmente el principal determinante de su importancia y continuidad. Además, estas paleodepresiones dirigen la dinámica y trazado del río y puntualmente fa- vorecen ensanchamientos laterales. Esto propicia la aparición de un nuevo lecho (Qt13) a medida que el lecho de los años 1960 (Qt12) va quedando como una terraza colgada entre 5 y 11 m sobre el nuevo fondo aluvial. No hay antecedentes de este tipo de consecuencias en la dinámica fluvial regional. Fil: Peña Monné, Jose Luis. Universidad de Zaragoza. Facultad de Filosofía y Letras; España Fil: Longares Aladrén, Luis Alberto. Universidad de Zaragoza. Facultad de Filosofía y Letras; España Fil: Rubio Fernández, V.. Universidad Autónoma de Madrid; España Fil: Sampietro Vattuone, Maria Marta. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Geoarqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina Fil: Sánchez-Fabre, Miguel. Universidad de Zaragoza. Facultad de Filosofía y Letras; España

The Visigothic and Paleo Islamic settlement system in the Ebro Valley (NE Spain) is yet not well known. This is due to the lack of research and low visibility of the settlements, but not to an effective demographic recession. In this paper we present the results of our research in Los Pedregales archaeological site, in Huesca Province. The site appears as a complex assemblage of archaeological artifacts from different chronologies (Roman, Early Middle Ages, Modern…) and numerous stone structures in a severely eroded terrain. Within the framework of a geoarchaeological research, we carried out an intensive surface survey and the excavation of some of the structures. Thus, we interpret the main phase of the site as an assemblage of storage pits dated between the 6th and the 9th Centuries AD. This is new data for the improvement of our understanding of past rural landscapes and the scattered peasant communities that dwelled in them. In this paper, we describe and interpret the studied structures, we study the most relevant artifacts recovered —mainly pottery— and we set the site in the context of the general settlement system and historical processes that affect this territory., El conocimiento de la ocupación visigoda y paleoislámica en el valle del Ebro resulta un tanto difuso, más por falta de investigaciones y por la escasa visibilidad de los asentamientos, que por un efectivo despoblamiento. En este artículo presentamos los resultados de nuestras investigaciones en el yacimiento de Los Pedregales, en la provincia de Huesca, un sas cronologías (romanos, altomedievales, modernos…) junto con numerosas estructuras pétreas en un área completamente alterada por procesos erosivos. Una minuciosa prospección y la excavación de algunas estructuras en el marco de un estudio geoarqueológico, nos ha permitido explicar la ocupación principal del yacimiento como un campo de silos datado entre los siglos vi y ix, que aporta una nueva referencia para la comprensión de los paisajes rurales antiguos y las comunidades campesinas dispersas que los ocupan. En el artículo se describen e interpretan las estructuras, se estudian los materiales más relevantes, especialmente los cerámicos, y se contextualiza el yacimiento con relación al poblamiento y los procesos históricos que afectan a este territorio.

On two accumulation levels, separated by an unevenness up to 2 m, two contrasted plant communities can be differentiated in subalpine stage of the Pyrenees: the dense tussock-forming grass Nardus stricta, at the upper level (L1), and the open chalk grasslands at the lower level (L2). In order to confirm the soil-relief-grasslands relationships, we analyzed and compared soil pedogenesis and properties in both accumulation levels. In addition, we classify the soils following WRB and ST systems and we discuss the finesse of both taxonomies in these high mountain environments. The work has been carried out at 1900 masl, in the Ordesa and Monte Perdido National Park (PNOMP), in the summer grasslands site of La Estiva (Fanlo, Central Pyrenees, NE Spain). Five soil pits were studied in every accumulation level (L1 and L2) for a side-by-side comparison. The study of soils in the two levels of accumulation reveals a series of differences in their genesis, properties and soil classification. The accumulation of organic matter and lixiviation are the dominant edafogenetic processes in L1, to which we must add the rejuvenation by gully erosion in L2. Soils at L1 and L2 shared many physical properties as a fine granulometry, with a homogeneous particle-size distribution with depth. In both levels, the soils lack carbonates, even though limestones are the parental material. The soils in L1 have a greater thickness and, thus, a higher water holding capacity than in L2. In relation to chemical properties, soils in L1 have a significantly lower pH, a lower base saturation, and lower available calcium content than in L2, reflecting a more intense leaching process, consistent with a longer period of slope stability. Over L1 with Nardus mat-grasslands, the main soil is classified as Orthoeutric Cambisols (Clayic, Humic), and the soil over L2, with chalk-grasslands, as Hypereutric Leptosols (Loamic, Ochric). Soil taxonomy System (USDA), giving more weight to the temperature regime, classify both soils as Haplocryept, at the level of great group, separating them at the subgroup level as Typic Haplocryept (L1) and Lithic Haplocryept (L2), according to the depth at which limestone appears (lithic contact). Definitely, the microtopograhy and geomorphologic context, is linked to the pedodiversity, which goes hand in hand with plant diversity in this subalpine environment.

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 subfunctional 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 intothe 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. Fil: Peña Monné, José Luis. Universidad de Zaragoza. Facultad de Filosofía y Letras; España Fil: Sampietro Vattuone, Maria Marta. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Geoarqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina Fil: Longares Aladrén, Luis A. Universidad de Zaragoza. Facultad de Filosofía y Letras; España Fil: Pérez Lambán, Fernando. Universidad de Zaragoza. Facultad de Filosofía y Letras; España Fil: Sánchez Fabre, Miguel. Universidad de Zaragoza. Facultad de Filosofía y Letras; España Fil: Alcolea García, M.. Universidad de Zaragoza. Facultad de Filosofía y Letras; España Fil: Vallés, L.. Universidad de Zaragoza. Facultad de Filosofía y Letras; España Fil: Echeverría Arnedo, M. T.. Universidad de Zaragoza. Facultad de Filosofía y Letras; España Fil: Baraza, C.. Universidad de Zaragoza. Facultad de Filosofía y Letras; España

13 páginas.- 10 figuras. - 1 tabla.- referencias.- Supplementary data to this article can be found online athttps://doi.org/10.1016/j.scitotenv.2020.139121, The two most widely extended mountain grasslands in Europe (Nardus-mat grasslands and chalk grasslands) are distributed forming complex patterns. In the Ordesa and Monte Perdido National Park (Central Pyrenees, NE-Spain), they grow as secondary pastures within the treeline ecotone at the subalpine belt. This work aims to show the influence of soil properties on the spatial distribution of these pastures, under a dynamic geomorphology. Soils are sampled under both grasslands, which grow on different cumulative levels: Nardus-mat grasslands in the upper level (L1) and chalk grasslands in the lower level (L2). Soils in L1 have a significantly higher acidity, lower soluble ions and exchangeable calcium content than those in L2, reflecting a more intense leaching process, consistent with a longer period of slope stability. Qualitative differences are detected in the soil organic matter of the soil, using carbon and nitrogen isotopes, lighter in L2 soils than in L1 soils, due to a higher proportion of legumes growing in L2 (chalk grasslands). Soils in L1 and L2 shared many physical properties, such as a fine and homogeneous texture in the whole profile (silty clay or silty clay loam), and high aggregate stability and porosity in the topsoil. In contrast, the soils in L2 are shallower than in L1, which reduces their water-holding capacity. The soil is classified as Orthoeutric Cambisol (Clayic, Humic) in L1 but its rejuvenation, by gully erosion, transforms it into an Hypereutric Leptosol (Loamic, Ochric) in L2 (Typic Haplocryept and Lithic Haplocryept, respectively by Soil Taxonomy system). Definitely, the distribution of both grasslands for the studied area is linked to two cumulative levels of different ages, which in turn is strongy related to different soil properties., This study is part of the results of a microproject funded by the “Instituto de Estudios Altoaragoneses-Diputación de Huesca (Call 2018). Lucía Buendía was supported by a novel research contract, funded by the Institute for Research into Environmental Sciences (IUCA) of the University of Zaragoza. This work has been partially financed by the Regional Government of Aragón (Geoforest research group S51_17R) co-financed with FEDER 2014-2020 “Construyendo Europa desde Aragón”. The authors would also like to thank Federico Fillat for his help in the field and for their constructive comments and suggestions, which led to a substantial improvement of the paper.

The scarp of Remolinos-Juslibol is an abrupt relief formed by Miocene gypsums located on the left bank of the Ebro River, in the vicinity of the city of Zaragoza. This work provides data for the reconstruction of the channel morphology and dynamics of the Ebro River and its interaction with the gypsum scarp from the Little Ice Age (LIA) to the present day. At the same time, several scenarios are also proposed for this interaction during the MCA (Medieval Climate Anomaly). To do this, different proxies are used, such as historical maps and records, morphosedimentary records of the tributary ephemeral streams, data from paleofloods, and the evolution of Medieval castles built on the scarp. During the MCA, the river was centered on its floodplain. Large alluvial fans developed by lateral ephemeral streams coming from the north since at least the Chalcolitic-Bronze age continued with their dominant dynamics during the Medieval times. Interaction with the scarp was scarce during this period and this allowed the building of castles on this relief. Later, the Ebro River moved its meanders towards the scarp, eroding most part of the lateral alluvial fans; in addition, infilled valleys were left hanging by the rapid retreat of the scarp and the events of rockfalls and landslides were very active. The map of Dew Rodolphe (1746) and the dating of these events confirm that this erosive process developed mainly during the second part of the LIA (18–19th centuries). From the middle of the 19th century, the fluvial sinuosity of the Ebro River increased and progressively separated from the scarp, which evolved to the present relative stability, in which landslides and rockfalls are scarce.

The most important stratified screes of the Iberian Range are found in Sierra de Albarracín. These slope deposits have been traditionally considered, without absolute datings, as having been formed during various Pleistocene cold phases. The aim of this paper is to establish the sedimentological, morphological, chronological, and paleoenvironmental characteristics of these deposits through the study of four profiles recorded in the Calomarde canyon (El Rollo, El Molino, and Royuela) and Toril. The most representative profile is that of El Rollo as it is formed by basal tufa and stratified scree layers separated by paleosoils. Radiocarbon datings obtained from paleosoil samples show that the sequence ranges between the early and middle Holocene. The profiles from El Molino and Royuela, as well as the upper levels of Toril, complete the sequence showing deposits from upper Holocene (Bronze Age and ‘Little Ice Age’). These data show the oscillations during the Holocene between colder phases, represented by the stratified screes, and warmer–wetter phases with soil development and local tufa deposits. This geomorphological and pedological response to the Holocene climatic variability shows its clearest records in the canyons. However, there are almost no Pleistocene accumulations – with the exception of that of Toril (minimum age of

An interdisciplinary non-invasive research strategy combining the analysis of archival documents, detailed geomorphological mapping, Quaternary stratigraphic studies, analysis of ceramics, and radiocarbon dating was designed to reconstruct the evolution of the Mezimegeer–Juslibol Castle, northeastern Spain. This fortress had great strategic importance in the siege and conquest of the nearby Islamic city of Saraqusta by the Christians in A.D. 1118. The castle and moat complex was built in the mid-10th century. In the mid-12th century, its rapid degradation began, as it is shown by this geoarchaeological study of the sediments in the moats. Its present state of decay is due to later erosion that is promoted by the unstable bedrock of Miocene gypsum, highly deformed gravels that form a Pleistocene fluvial terrace, and the environmental aridity.

Resumen: En este trabajo, se plantea el estudio zoogeografico del hayedo del Moncayo (Aragon, Espana), en relacion con la situacion limite de distribucion de dicha formacion vegetal. Su comparacion con la fauna detectada en diferentes hayedos, permite detectar presencias y ausencias faunisticas significativas, las cuales, indican la situacion ecologica y el verdadero caracter corologico de esta masa boscosa sometida a estudio. Palabras clave: Zoogeografia, corologia, fauna, hayedo.

En todas las poblaciones naturales de aves rapaces existen unidades reproductoras (UR) cuya productividad, entendida como pollos volados/año, es baja o nula. Las molestias humanas en las zonas de nidificación han sido una de las causas más relacionadas con el descenso de la productividad de muchas aves rapaces (Richardson y Miller, 1997). Según Arroyo y Razin (2006) las actividades humanas cercanas a los nidos del Quebrantahuesos (Gypaetus barbatus L.) pueden causar molestias en la reproducción. Los vigentes planes de recuperación de la especie en la Cordillera pirenaica contemplan acciones específicas para evitar el fracaso reproductivo, mediante la aplicación de medidas preventivas de factores de perturbación: molestias por batidas de caza, escalada deportiva, etc. Durante los últimos 10 años el deporte de escalada en Aragón (en todas sus modalidades) ha experimentado un aumento en cuanto al número de escaladores y sectores donde se practica. Con el fin de conocer las posibles repercusiones de la escalada en roca en la conservación del Quebrantahuesos se ha recopilado información sobre sectores de escalada en la provincia de Huesca. Posteriormente dicha información ha sido georreferenciada espacialmente y se le han aplicado diversos métodos de análisis geoespacial con técnicas SIG en el entorno ArcGis. El objetivo ha sido realizar una aproximación al análisis de la posible relación entre el deporte de escalada y la nidificación de la especie. De un total de 315 nidos conocidos de Quebrantahuesos en Aragón (2011), se ha comprobado que el 11,75% de estos (n= 37) podrían estar afectados por la escalada en roca.

Resumen: La dinamica del curso bajo del rio Gallego ha cambiado de forma significativa tras las transformaciones generadas en las ultimas decadas por la accion humana. Como testimonio de su funcionamiento actual, se analiza uno de los meandros de este tramo fluvialdurante las crecidas de 2003-2004, en el que se pone de manifiesto su comportamiento mixto. Por una parte, en momentos de crecida es capaz de generar barras lobuladas y transversas con una trayectoria y funcionamiento mas cercano al sistema braided, mientras que al descender su caudal genera rupturas de barras, que alimentan la formacion de point-barsy la recuperacion de sutrazado meandriforme habitual. Esta dinamica alternante genera rupturas de pendiente, con rapidos que,en ocasiones, se venincrementados localmente por cambios en la resistenciadel sustrato, al que consigue accederel rio como consecuencia de los procesos de incision activados en epoca reciente. Palabras clave:Rio Gallego, dinamica fluvial, barras fluviales, incision.

Se presenta un estudio que valora las comunidades faunísticaspresentes en el Aiguabarreig del Segre, Cinca y Ebro desde un punto devista geográfico, considerando su distribución espacial y las relacionesque se establecen entre los distintos ambientes naturales que configuraneste territorio húmedo. A través de la creación de áreas faunísticas apoyadasen el manejo de SIG y la interpretación de los datos recogidos encampo, se ha obtenido una división de la zona de estudio en función delos hábitats potenciales para proceder a su valoración en base a criteriosde naturaleza ecológica.

Se estudia la comunidad aviar presente en el sector de piedemonte del Sistema Ibérico zaragozano que forma parte de la Comarca del Campo de Borja (Zaragoza, España), durante la época invernal y reproductora. Se analizan los parámetros de Diversidad, Riqueza específica y Constancia para el conjunto del área de estudio, así como para el humedal artificial conocido como “La Estanca de Borja”. Además se procede al análisis de los cambios observados en la composición de esta comunidad aviar entre 1970 y 2009, comparándolos con los cambios que se han producido durante dicho periodo en cuanto al uso del territorio y los hábitats establecidos para el estudio de la dinámica temporal de los mismos.