Environmental changes in a Mediterranean river: implications for the fish assemblage

This study examined the impacts of climate change on hydrology and fish population dynamics in a river in central Spain. The objectives were to: (i) contextualise long-term trends in the hydrology (1943–2012) and climate (1985–2011) of the study area, and (ii) identify the environmental factors driving fish population dynamics (1998–2012). Air and water temperatures progressively increased over the study period, whereas there were substantial reductions in mean spring river discharges but increases in peak-flow discharges during the spawning and early larval period of endemic cyprinids in recent decades. In particular, the changes in spring river discharges could have fundamental implications for the future status of the endemic cyprinids because this study revealed a positive influence of stable and low flow conditions during the spawning and early larval period (in late spring) on recruitment success (young-of-the-year densities). The density of young-of-the-year Salmo trutta appeared most influenced by flow conditions during fry emergence and the early larval period (in early spring), with the highest densities associated with low peak-flow hydrological pulses. Overall, fish abundances were significantly influenced by the frequency and duration of high and low hydrological pulses, but there were interspecific and ontogenetic differences in their influence. We conclude that although it is widely accepted that global warming should favour cyprinid over salmonid species, future shifts in hydrology due to climate change could negatively affect some cyprinids, including endemic species

Taxonomy-based differences in feeding guilds of fish

It has been taken for granted that feeding guilds and behavior in animals are linked to the taxonomic relatedness of species, but empirical evidence supporting such relationship is virtually missing. To examine the importance of taxonomy on trophic ecology, I here present the first well-resolved dietary taxonomy analysis based on feeding guilds (predation, herbivory, and filtering) among families and genera within the fish order Perciformes. Taxonomic relatedness in feeding did not vary with ecosystem dimension (marine vs. freshwater). Although predation dominates among Perciformes fishes, this study shows that in most cases taxonomic units (family or genus) are composed by species with several feeding guilds. Related species are more similar in feeding compared with species that are taxonomically more distant, demonstrating that there is a greater variation of feeding guilds within families than genera. Thus, there is no consistency in feeding guilds between family- and genus-level taxonomy. This study provides empirical support for the notion that genera are more informative than families, underlining that family-level taxonomy should be avoided to infer feeding habits of fish species at finer taxonomic resolution. Thus, the choice of taxonomic resolution (family or genus level) in ecological studies is key to avoid information loss and misleading results. I conclude that high-rank taxonomic units (i.e., above the generic level) are not appropriate to test research hypotheses about the feeding of fish.J.S.-H. was supported by a postdoctoral grant from the Galician Plan for Research, Innovation, and Growth (Plan I2C, Xunta de Galicia)S

Las posturas publicadas por las Cortes de Toledo de 1207 (Nueva edición)

El texto de las posturas de 1207 es un testimonio fundamental para la historia política, cultural y lingüística de Castilla. Recoge las decisiones más antiguas conocidas de una asamblea de Cortes, refleja la variedad de productos y monedas que corrían en los mercados del reino, y lo hace en el romance hablado de toda la vida que los notarios y los poetas estaban empezando a escribir entre fines del siglo XII y principios del XIII en sustitución del latín, único medio de comunicación escrita usado hasta entonces en la España cristiana. Publiqué este texto en 1988, en el contexto de un congreso sobre las Cortes de Castilla y León y desde una perspectiva historicista y lexicográfica. Vuelvo a hacerlo ahora prestando más atención al código de escritura con que se intentaba reflejar un idioma romance que ya había cuajado como lengua, pero que estaba empezando a plasmarse como sistema de escritura

Modelling the factors influencing ontogenetic dietary shifts in stream-dwelling brown trout (Salmo trutta)

Biotic and abiotic variables shape ontogenetic trajectories of animals. This study modelled (i) the body length related timing of the ontogenetic switch from aquatic to surface prey and (ii) the impacts of habitat characteristics, prey availability, and fish densities on the relative contribution of surface prey to the overall diet of native brown trout (Salmo trutta). We used individual-based models of dietary data for 170 fish (length range 48–343 mm). There was a high degree of individual variation in the use of surface prey, but logistic regression suggested that the shift from aquatic to surface prey was established at a body length of 81 mm (range 36–127 mm). Results of linear mixed-effects models highlighted the importance of fish length, benthic invertebrates, brown trout density, and water current velocity to the switch to surface prey by riverine brown trout, with fish length being the most influential variable. Our study provides evidence of the importance of ontogeny (intrinsic features of individuals linked to fish length) and individual differences in feeding behaviour to understand water-column use for feeding by stream-dwelling salmonidsPlan I2C (Xunta de Galicia)S

Ontogenetic Shifts in Terrestrial Reliance of Stream-Dwelling Brown Trout

This study focuses on terrestrial reliance of brown trout (Salmo trutta) and compared it to the potential prey available (macrozoobenthos and drifting invertebrates) in three temperate rivers (Galicia, NW Spain), with special emphasis on variations in terrestrial energy intake through the ontogeny of brown trout. Additionally, we paid particular attention to individual variation of terrestrial resource use within and between age classes. Prey items were grouped in four categories: i) aquatic invertebrates; ii) imagoes of aquatic invertebrates; iii) terrestrial invertebrates; and iv) fish prey. Next, energy composition was measured according to dry weight-energy equations for each individual in line with above-mentioned prey categories. Our findings illustrate that terrestrial invertebrates appeared to be scarce in the environment, whereas aquatic food resources were rather abundant and accessible. The use of terrestrial invertebrates tended to increase with age, but with a high degree of inter-individual variation in resource use. In fact, the individual reliance of brown trout on terrestrial invertebrates may vary considerably (between 0% and 76.9%). Besides, the frequency of terrestrial foragers, i.e., individuals with terrestrial invertebrates in their stomachs, increased with age, except in one population which had the maximum value in the age-2 class. The acquisition of terrestrial invertebrates thus appears to be a process strongly dependent upon the actual food availability in the environment, but with a high degree of individual variance in resource use within the same age class. Finally, we discuss that terrestrial invertebrates may largely contribute to cover the energy intake of the species, highlighting the interface between terrestrial and aquatic ecosystems, and thereby the importance of riparian canopy cover as a key factor for food supply of stream-dwelling salmonids speciesThe authors would like to thank the staff of the Station of Hydrobiology of the USC ‘Encoro do Con’ for their participation in the field work. We also appreciate the constructive comments on the manuscript given by one anonymous referee. J. Sánchez-Hernández was supported by a postdoctoral grant from the Galician Plan for Research, Innovation, and Growth 2011-2015 (Plan I2C, Xunta de Galicia)S

Ontogenetic dietary shifts and food selection of endemic Squalius carolitertii (Actinopterygii: Cypriniformes: Cyprinidae) in River Tormes, Central Spain, in summer

Background. The northern Iberian chub Squalius carolitertii (Doadrio, 1988) is a small endemic cyprinid inhabiting the rivers of the Iberian Peninsula. The knowledge of feeding patterns is essential to understand the ecological role of fish populations, helping to the development of conservation and management plans. The aim of the present study was to analyze the ontogenetic dietary shifts and food selection of S. carolitertii, contributing to knowledge of the feeding behaviour of this fish species. Materials and methods. Diet composition of S. carolitertii was compared to benthos and drift composition in a river of Central Spain (Ávila, River Tormes) using selectivity indices of Ivlev and Savage. The age of 57 S. carolitertii collected in August 2010 was determined by scale reading and by length frequency analyses (LFA) with the Petersen method. Maximum length of benthos, drift and prey invertebrates was measured for each item to establish whether prey-size selection depends upon the size-frequency distribution of available prey. Results. Detritus were found in 33 fish (57.9% of occurrence). Nymphs of Baetis spp. were the most abundant prey (46.6%) and were identified in the 49.1% of the stomachs. Moreover, Baetis spp. was selected positively from the benthos and drift by all age classes. Abundant potential prey items such as Epeorus spp. in the benthos and Simuliidae in the drift were negatively selected. Individuals without detritus in the gut contained more animal prey items than individuals with a dominance of detritus, and the frequency of occurrence of detritus decreased with the age. Mean prey size increased with fish size (r = 0.646, P < 0.001). Conclusion. Age-related diet shifts occur at three different levels: (1) frequency of occurrence of detritus decreases with fish age; (2) prey selection varied with fish age; and (3) mean prey size increased as fish size increased. The rejection of Epeorus spp. and Simuliidae suggests that other factors, apart of prey abundance, including sitespecific prey accessibility, prey size, energetic selection criteria and prey preference of fishes play an important role in feeding behaviour of S. carolitertii. Prey-size selection is probably dependent on the size-frequency distribution of the available prey.This work has been partially supported by the project 10PXIB2111059PR of the Xunta de Galicia and the project MIGRANET of the Interreg IV B SUDOE (SouthWest Europe) Territorial Cooperation Programme (SOE2/P2/E288)S

A Multi-Temporal Object-Based Image Analysis to Detect Long-Lived Shrub Cover Changes in Drylands

Climate change and human actions condition the spatial distribution and structure of vegetation, especially in drylands. In this context, object-based image analysis (OBIA) has been used to monitor changes in vegetation, but only a few studies have related them to anthropic pressure. In this study, we assessed changes in cover, number, and shape of Ziziphus lotus shrub individuals in a coastal groundwater-dependent ecosystem in SE Spain over a period of 60 years and related them to human actions in the area. In particular, we evaluated how sand mining, groundwater extraction, and the protection of the area affect shrubs. To do this, we developed an object-based methodology that allowed us to create accurate maps (overall accuracy up to 98%) of the vegetation patches and compare the cover changes in the individuals identified in them. These changes in shrub size and shape were related to soil loss, seawater intrusion, and legal protection of the area measured by average minimum distance (AMD) and average random distance (ARD) analysis. It was found that both sand mining and seawater intrusion had a negative effect on individuals; on the contrary, the protection of the area had a positive effect on the size of the individuals’ coverage. Our findings support the use of OBIA as a successful methodology for monitoring scattered vegetation patches in drylands, key to any monitoring program aimed at vegetation preservation

Study of Approaches to Teaching in Primary School Teachers

Research into teaching in education has increased considerably during the last three decades. Research on teachers’ approaches to teaching has identified two different categories of approaches: the learning-focused approach and the teaching-focused approach. The former views teaching as facilitating students’ learning, while the content-focused approach regards teaching as transmission of knowledge. The aim of the present study is to explore approaches to teaching in 32 primary school teachers. The results showed that teachers were either learning- (46.9 %) or content-focused (53.1%).  We also analyse the correlation between questionnaire subscales, intention and strategies. The results of the present study show that approaches to teaching are no conclusive, as some teachers display a combination of learning-based and teaching-based subscales, resulting in a dissonant coherence of profiles

Los espacios de participación política y los partidos políticos en el Estado de México

Estudiar la participación política conlleva necesariamente a referirse a las aristas y corazón de la democracia moderna, a las arterias en donde circulan los derechos de los ciudadanos que son los que dan el flujo indispensable para darle vida y direccionalidad a la organización del Estado. Sin embargo, son esos mismos ciudadanos los que en la vida cotidiana han quedado subordinados a las políticas de direccionalidad que se imponen desde el Estado a través de la formación de regímenes autoritarios, y, en lo particular, gobiernos que excluyen el interés ciudadano respecto del quehacer político de la organización y funcionamiento estatal. En este ensayo se estudia al Estado como un conjunto organizado de instituciones, pero también como un proceso que se construye en las relaciones sociales en continua formación y transformación, determinado espacial y temporalmente en donde sus estructuras de gobierno y las instituciones que configuran al régimen político le dan un perfil autoritario que excluye, limita y controla todo tipo de participación ciudadana. Las relaciones políticas que caracterizan a los regímenes contemporáneos se han construido a través de entramados institucionales y pragmáticos que tienen la finalidad principal de hacer de la política espacios exclusivos de interacción de grupos y de coaliciones de poder que toman para sí las tareas legislativas, judiciales y de administración de gobierno, pero, siempre aisladas del escrutinio e interés social. Así, por ejemplo, en la actualidad los partidos políticos se constituyen como instituciones profesionales de burocracias organizacionales, como intermediarios entre sociedad y gobierno, como los 5 únicos representantes del ejercicio soberano de los ciudadanos, es decir, construyen la legalidad necesaria que les garantice permanencia, recursos y espacio político de acción unilateral en donde forman alianzas, coaliciones y construyen la legalidad de los triunfos electorales y con ello legitimar la formación de gobiernos autoritarios y la consolidación de grupos de poder (Alarcón, 2003)

Sistemas de comunicación por satélite: utilización en los sistemas de navegación aeronáuticos

Este Proyecto Fin de Carrera tiene como principal objetivo analizar la evolución de los Sistemas de Comunicación por Satélite, así como dar a conocer al lector la tecnología EGNOS y su aplicabilidad como ayuda a la navegación Aeronáutica. Este trabajo comenzará con una primera parte, la cual está dedicada a conocer qué es un satélite y como ha sido su evolución a lo largo de la historia, desde la aparición del primer satélite hasta nuestros días, así como mostrar las partes que lo componen y su proceso de lanzamiento. Todo este capítulo, sirve de base para poder entender mejor las siguientes partes del proyecto. En la segunda parte de esta memoria, se entra más en detalle y se desarrollan los temas principales de este documento. Podríamos decir que este segundo capítulo se divide a su vez en dos subpartes claramente diferenciadas: En la primera, se analiza la estructura de un sistema de comunicaciones por satélite, los diferentes tipos de satélites según su órbita o según su finalidad, viendo unos claros ejemplos de cada uno de ellos, así como las bandas de frecuencias en las que trabajan. Para concluir esta sección se habla de los diferentes tipos de servicios que ofrecen las comunicaciones por satélite para centrarnos más adelante en los servicios aeronáuticos. En la segunda parte, se habla de la aplicación de la tecnología EGNOS como ayuda a la navegación aeronáutica. Para ello, primero se explican los diferentes sistemas de navegación que usan las aeronaves, entre los que se encuentran los sistemas VOR, DME, ADF y TACAN, y después se introduce al usuario a la tecnología EGNOS, viendo su arquitectura y explicando su funcionamiento. Como ejemplo de aplicabilidad de esta tecnología se explica el novedoso sistema SLS que llevan las aeronaves. Toda esta segunda parte constituye el cuerpo del proyecto y el punto más importante de esta memoria. Para finalizar, en la última parte del Proyecto Fin de Carrera, se habla del presente y futuro del sistema EGNOS evaluando sus principales ventajas y las conclusiones que se han sacado al hacer esta memoria. ABSTRACT. This thesis has as main objective to analyze the evolution of satellite communication systems, as well as to inform the reader about EGNOS technology and its applicability as an aid to aeronautical navigation. This document will begin with a first part, which is dedicated to know what a satellite is and how has its evolution been throughout history, from the appearance of the first satellite until nowadays, as well as showing the parts that it is composed of and different launch processes. This chapter serves as a base to a better understanding of these parts of the project. In the second part of this report, more detail is introduced and it is developed the main themes of this document. We could say that this second chapter is divided in two clearly differentiated subparts: The first, analyzes the structure of a communications system by satellite, different types of satellites according to its orbit or according to their purpose, seeing some clear examples of each of them, as well as the frequency bands in which they work. To conclude, this section refers to different types of services offered by satellite communications to focus later in the aeronautical services. In the second part, application of EGNOS technology is referred as an aid to the aeronautical navigation. To do this, first they are explained the different navigation systems that the aircraft uses, which include VOR, DME, ADF and TACAN systems, and then EGNOS technology is introduced to the user, seeing its architecture and explaining its operation. As an example of applicability of this technology, the new system SLS carried by the aircraft is explained. Throughout this second part it is constituted the body of the project and the most important point of this report. Finally, in the last part of the thesis, the present and future of the EGNOS system are analyzed evaluating the main advantages and conclusions that have been obtained to make this memory