Now showing items 31-50 of 80
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...