Now showing items 31-50 of 80

    Fire legacies in Mediterranean streams: the key roles of the riparian canopy and the top predator on food webs 

    Rodríguez Lozano, Pablo (Date of defense: 2016-01-29)

    Wildfires are expected to increase in frequency and intensity because of climate change and changes in land use and management. In last decades, the research on fire effects on aquatic systems has grown, but it has been ...

    Fish as local stressors of Pyrenean high mountain lakes: Arrival process and impact on amphibians and other organisms 

    Miró Pastó, Alexandre (Date of defense: 2016-01-08)

    Pyrenean high mountain lakes are naturally fishless due to natural barriers that have prevented the natural colonisation of fish species from lower streams. However, there have been numerous trout introductions to such ...

    Flora and vegetation of the Guayana highlands : past dynamics, global warming and conservation guidelines = Flora i vegetació de les Terres de Guayana : dinàmica del passat, escalfament global i directrius de conservació 

    Safont Crespo, Elisabet (Date of defense: 2016-02-09)

    This thesis is aimed at the study of the flora and vegetation of the Guayana Highlands (GH), a set of -50 table mountains (called tepuis) located in the Guayana Shield of northern South America. Special emphasis is put on ...

    Freshwater meiofauna in Mediterranean lotic systems: community structure, adaptations and contribution to functional processes / Meiofauna d’aigua dolça en sistemes lòtics mediterranis:estructura de les seves comunitats, adaptacions i contribució en els processos funcionals 

    Gaudes Saez, Ainhoa (Date of defense: 2011-07-07)

    This thesis focuses on the study of the meiofaunal community in streams and rivers of the Mediterranean region. It approaches to a community level from a functional point of view, studying their response as a whole to ...

    From flood to drought: Transport and reactivity of dissolved organic matter along a Mediterranean river 

    Ejarque Gonzalez, Elisabet (Date of defense: 2014-11-17)

    Rivers play a key role in the global biogeochemical functioning, as they link the biogeochemical cycles of the terrestrial and oceanic systems. In the framework of the carbon cycle, streams and rivers receive dissolved ...

    The functional role of emergent macrophytes in nature-based solutions (NBS) aiming to mitigate nutrient loading in freshwater ecosystems 

    Nikolakopoulou, Myrto-Georgia (Date of defense: 2021-01-29)

    Freshwater degradation has been largely attributed to excess nutrient concentrations of anthropogenic origin. Freshwater degradation in combination with water scarcity are the reason of severe stress on water resources ...

    Global changes in headwater streams: effects of hydrological and nutrient fluctuations on the quality of basal resources = Canvis globals en rius de capçalera: efectes de les fluctuacions hidrològiques i dels nutrients en la qualitat dels recursos basals 

    Sanpera Calbet, Isis (Date of defense: 2014-04-11)

    Streams are complex and highly diverse ecosystems. Within the stream network, headwater streams (1st to 3rd order) are highly important. Headwaters represent most of the total length, influence the structure and functioning ...

    Heterotrophic and autotrophic metabolism in Mediterranean streams 

    Romaní i Cornet, Anna M. (Date of defense: 1997-10-21)

    Helerotrophic (cetoenzymatic and respiratory activities) and autotrophic (photosynthetic activity) metabolism on epilithic strearn biofilms have been measured, analyzed and studied in this thesis.<br/><br/>The main objective ...

    Impacte de l'accident miner d'Aznalcóllar sobre el riu Guadiamar. Recuperació de la comunitat de macroinvertebrats i bioacumulació de metalls pesants. 

    Solà Ortega, Carolina (Date of defense: 2004-07-21)

    L'abril de 1998, durant l'accident miner d'Aznalcóllar, més de 6 milions de m3 de llots i aigües àcides altament contaminades amb metalls pesants van ser vessats al riu Guadiamar (Sevilla), destruint els ecosistemes fluvials ...

    Influence of hydrology on dissolvedorganic matter quantity and properties in a temporal Mediterranean stream = Influència de la hidrologia sobre la quantitat i disponibilitat de la matèria orgànica dissolta en una riera temporal mediterrània 

    Vázquez Garcia, Eusebi (Date of defense: 2013-10-11)

    The studies presented in this thesis focus on the biogeochemistry of dissolved organic matter (DOM) in an intermittent stream in a Mediterranean climate zone, with great emphasis on extreme hydrologic events: floods and ...

    Insights into seascape ecology: landscape patterns as drivers in coastal marine ecosystems = Perspectives en l'ecologia del paisatge marí: els patrons del paisatge com a factors de control en els ecosistemes marins costaners 

    Martínez Ricart, Aurora (Date of defense: 2016-04-08)

    Habitats commonly occur as more or less interconnected patches constituting spatial heterogeneous mosaics. Connectivity and interactions among habitats can determine their functioning. Therefore, ecological patterns and ...

    Invertebrate community responses to pollutants in mediterranean basins : insights from ecotoxicological approaches = Respostes de la comunitat d'invertebrats als contaminants en conques mediterrànies: aproximacions ecotoxicològiques 

    Castro Català, Núria de (Date of defense: 2016-02-05)

    Aquatic systems are under pressure from multiple stressors that affect the structure, the functioning, and the health of species, communities and ecosystems. One of the main human pressures affecting the Earth’s ecosystems ...

    Irreversibility and Criticality in the Biosphere 

    Pueyo Puntí, Salvador (Date of defense: 2003-03-25)

    This work is the result of a search for general (or nearly general) regularities at ecosystem level, and an exploration of their practical relevance in our relations with the environment.<br/>I began by adding some new ...

    La colonización del mejillón cebra, Drcissena polymorpha (Bivalvia: Dreisscnidae) en el tramo final del río Ebro: factores que controlan su distribución y abundancia 

    Muñoz Camarillo, Gloria (Date of defense: 2013-04-05)

    El mejillón cebra, Dreissena polymorpha (Pallas, 1771), es conocido por ser una de las especies invasoras de agua dulce más dañinas, tanto desde el punto de vista ecológico como económico, a nivel mundial. Este exitoso ...

    Lake macroinvertebrates and the altitudinal gradient in the Pyrenees / Los macroinvertebrados lacustres y el gradiente altitudinal en los Pirineos 

    Mendoza Barberá, Guillermo de (Date of defense: 2013-06-20)

    “Lake macroinvertebrates and the altitudinal gradient in the Pyrenees [Los macroinvertebrados lacustres y el gradiente altitudinal en los Pirineos]” is a thesis about freshwater macroinvertebrate communities inhabitting ...

    Landscape fragmentation and resilience in seagrass meadows / Fragmentación del paisaje y resiliencia en praderas de fanerógamas marinas 

    Gera, Alessandro (Date of defense: 2013-06-21)

    Overall, this thesis is an attempt at approaching seagrass ecosystems from a landscape perspective, with the aim of increasing knowledge about the processes generating patterns at large spatial scales, and understanding ...

    Lévy Processes in Animal Movement and Dispersal 

    Bartumeus i Ferré, Frederic (Date of defense: 2005-06-17)

    ENGLISH ABSTRACT:<br/><br/>The general aim of this thesis was to develop a theoretical framework in order to study large-scale animal movements and/or dispersal processes as random search strategies. The framework was ...

    Limnologia de la part baixa del riu Ebre i els canals de reg: els factors físico-químics, el fitoplàncton i els macroinvertebrats bentònics 

    Muñoz Gràcia, Isabel (Date of defense: 1990-02-23)

    La major part de la concentració de carboni i nitrogen que arriba al Mediterrani des de l'Ebre és en forma dissolta, mentre que en el cas del fòsfor la concentració en la forma particulada pot ser més important, especialment ...

    Limnología del embalse de Sau. Relaciones del zooplancton, la clorofila y los sólidos en suspensión con el clima lumínico del agua 

    Ordóñez Salinas, Jaime (Date of defense: 2010-09-21)

    La disponibilidad y calidad del agua que se encuentra en los embalses depende de factores relacionados directamente con las características de la cuenca a la que pertenece el río embalsado, como las cargas de nutrientes ...

    Magnitude of herbivory in "Poseidonia oceanica" (L.) Delile and factors responsible for spatial variation 

    Prado Villegas, Patricia (Date of defense: 2007-02-23)

    La revaluació a gran escala espacial (> de 300 Km) i mitjançant mètodes de quantificació directa, del impacte de l'herbivorisme en els ecosistemes de <i>Posidonia oceanica</i> va revelar pèrdues de biomassa foliar molt ...