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[ES] El presente Trabajo de Fin de Grado tiene como objetivo el análisis particular del art. 541 CC, referente a la constitución por destino del padre de familia o por signo aparente. Puesto que el precepto no se sitúa ni entre los artículos correspondientes a las servidumbres legales, ni a las servidumbres voluntarias, se ha suscitado un permanente debate acerca de su naturaleza jurídica, unas veces entendiéndose la servidumbre del art. 541 CC constituida de forma automática o ex lege por la concurrencia de los requisitos que menciona el precepto, y otras, por voluntad de las partes, buscando ese plus de constatación de las voluntades. Es por ello que, se realiza un análisis individual de cada requisito del precepto, así como de la consideración acerca de su naturaleza, todo ello conforme a doctrina de distintos autores, jurisprudencia del Tribunal Supremo y jurisprudencia menor de las Audiencias para su interpretación y aplicación.

Land use change and nutrient pollution are two pervasive stressors that can modify carbon cycling, as they influence the inputs and the transformation of detritus. Understanding their impact on stream food webs and on diversity is particularly pressing, as streams are largely fuelled by detrital material received from the adjacent riparian environment. Here we assess how a switch from native deciduous forest to Eucalyptus plantations and nutrient enrichment alter the size distribution of stream detritivore communities and decomposition rates of detritus. As expected, more detritus resulted in higher size-independent, or overall, abundance (i.e. higher intercept of size spectra). This change in overall abundance was mainly driven by a change of the relative contribution of large taxa (Amphipoda and Trichoptera), which changed from an average relative abundance of 55.5 to 77.2 % between the sites compared for resource quantity differences in our study. In contrast, detritus quality modified the relative abundance of large vs small individuals (i.e. size spectra slopes), with shallow slopes of size spectra (proportionately more large individuals) associated with sites with nutrient-richer waters and steeper slopes (proportionately fewer large individuals) associated with sites draining Eucalyptus plantations. Decomposition rates of alder leaves due to macroinvertebrates increased from 0.0003 to 0.0142 when relative contribution of large organisms increased (modelled slopes of size spectra: −1.00 and − 0.33, respectively), highlighting the importance of large sized individuals for ecosystem functioning. Our study reveals that land use change and nutrient pollution can greatly impair the transfer of energy through the detrital or ‘brown’ food web by means of intra- and inter-specific responses to quality and quantity of the detritus. These responses enable linking land use change and nutrient pollution to ecosystem productivity and carbon cycling.

Ongoing global warming is expected to alter temperature-dependent processes. Nevertheless, how co-occurring local drivers will influence temperature sensitivity of plant litter decomposition in lotic ecosystems remains uncertain. Here, we examined the temperature sensitivity of microbial-mediated decomposition, microbial respiration, fungal biomass and leaf nutrients of two plant species varying in litter quality. We also assessed whether the type of microbial community and stream water characteristics influence such responses to temperature. We incubated alder (Alnus glutinosa) and eucalypt (Eucalyptus globulus) litter discs in three streams differing in autumn–winter water temperature (range 4.6–8.9 °C). Simultaneously, in laboratory microcosms, litter discs microbially conditioned in these streams were incubated at 5, 10 and 15 °C with water from the conditioning stream and with a water control from an additional stream. Both in the field and in the laboratory, higher temperatures enhanced litter decomposition rates, except for eucalypt in the field. Leaf quality modified the response of decomposition to temperature in the field, with eucalypt leaf litter showing a lower increase, whereas it did not in the laboratory. The origin of microbial community only affected the decomposition rates in the laboratory, but it did not modify the response to temperature. Water quality only defined the phosphorus content of the leaf litter or the fungal biomass, but it did not modify the response to temperature. Our results suggest that the acceleration in decomposition by global warming will be shaped by local factors, mainly by leaf litter quality, in headwater streams.

[EN] Biodiversity loss is known to affect the two fundamental and opposite processes controlling carbon and nutrient cycles globally, that is, primary production and decomposition, which are driven by green and brown food web compartments, respectively. However, biodiversity in these two food web compartments has been mostly studied independently, and potential reciprocal effects of biodiversity loss on ecosystem processes remain unclear. We conducted a 35-day stream mesocosm experiment with two levels of algal diversity (natural and diluted periphyton communities) and three levels of litter diversity (no litter, monocultures of poplar, maple, and oak, and the three-spp. mixture) to simulate changes in biodiversity in both the green and brown pathways of an aquatic food web. We then measured multiple ecosystem processes pertaining to carbon cycling. We predicted that algal diversity would enhance decomposition and sporulation of fungal decomposers, while litter diversity would enhance algal growth and net primary production, due to the more diverse algal exudates or litter nutrients being released from more diverse mixtures. In contrast to this hypothesis, we only found biodiversity effects on an ecosystem process within the green pathway: there was a relationship between algal diversity and biofilm carrying capacity. Nevertheless, we found that this relationship was affected by the presence or absence of litter (algal diversity increased the carrying capacity in presence of litter and decreased it in its absence), which also influenced the algal community structure. Our mesocosm experiment did not evidence relationships between biodiversity and ecosystem processes across different food web compartments, but further studies in more realistic conditions would be necessary to confirm this result. If supported, the lack of biodiversity-ecosystem functioning relationships across compartments would facilitate the prediction of the impacts of biodiversity loss on ecosyste

En este trabajo, ofrecemos una visión general de la situación lingüística en España y de los principales elementos de los marcos jurídicos. A continuación, analizamos los problemas más significativos que han surgido en la aplicación de los modelos de diversidad lingüística establecidos a través de la Constitución y el Estatuto de Autonomía, así como la probabilidad de nuevos cambios., In this paper, we provide an overview of the linguistic situation in Spain and the main elements of the legal frameworks. We then discuss the most significant problems that have arisen in the implementation of the models of linguistic diversity as established through the Constitution and the Statute of Autonomy, as well as the likelihood of further changes.

Detritivores are pivotal in forest streams as they process detritus and promote secondary production. Many studies have addressed the preference of freshwater detritivores towards materials of differing quality. Nevertheless, few studies compare the resource preferences in the laboratory with the availability in the field. In the present study, feeding preferences of two stream detritivores (the caddisfly Sericostoma pyrenaicum and the amphipod Echinogammarus tarragonensis), over three native leaf species (alder, chestnut and oak) and an exotic species (eucalypt) were quantified in the laboratory. Preference for eucalypt leaves conditioned for 1, 2 and 3 weeks was also described. We then contrasted the preference patterns in the laboratory feeding experiments with a 15-month-long benthic standing stock time series of a stream below a native deciduous forest and another below a eucalypt plantation. Both detritivores preferred consuming alder leaves and more conditioned eucalypt leaves, although the amphipod was more selective than the caddisfly. The consumption preference in the laboratory was unmatched by the availability in the field, especially under eucalypt plantations and for the amphipod. Our results show that the strength of the preference for high-quality resources can differ among different taxa, which can modulate their response to land use changes.

The case-law issued so far by the Constitutional Court on the state of emergency addresses most of the fundamental issues that have been the subject ofacademic controversy surrounding the pandemic. In this paper the autor has tried to avoid a simple statement or account of the issues, facts and legal grounds on which the court bases its decision. Although always with reference to the decisions taken by the court —to which the autor is vey critical— it has been taken as an opportunity for an analysis of the issues that have been the subject of heated debate within the community of lawyers in recent times. In this way, it offers, at the same time, a defence of the rightness of the constitutional —and legal— provision of the state of alarm and of the interpretation which the autor considers should be defended., La jurisprudencia constitucional sobre el estado de alarma emitida hasta el momento afronta la mayoría de las cuestiones fundamentales que han sido objeto de controversia en el ámbito académico en torno a la pandemia. En este trabajo se ha tratado de eludir una simple exposición o relato de los asuntos, de los hechos y de los fundamentos de derecho en los que el Tribunal asienta su decisión. Aunque siempre teniendo como referencia las decisiones adoptadas por el Tribunal —sobre las que el autor es muy crítico—, se ha tratado de aprovecharlo como oportunidad para un análisis de las cuestiones que han sido objeto de encendidos debates en el seno de la comunidad de juristas. De esta forma, constituye, al mismo tiempo, una defensa del acierto de la previsión constitucional —y legal— del estado de alarma y, en relación con ello, de la interpretación que sobre esa regulación defiende el autor.