168 research outputs found
Developing a novel approach to analyse the regimes of temporary streams and their controls on aquatic biota
Temporary streams are those water courses that undergo the recurrent cessation of flow or the complete drying of their channel. The biological communities in temporary stream reaches are strongly dependent on the temporal changes of the aquatic habitats determined by the hydrological conditions. The use of the aquatic fauna structural and functional characteristics to assess the ecological quality of a temporary stream reach can not therefore be made without taking into account the controls imposed by the hydrological regime. This paper develops some methods for analysing temporary streams' aquatic regimes, based on the definition of six aquatic states that summarize the sets of mesohabitats occurring on a given reach at a particular moment, depending on the hydrological conditions: flood, riffles, connected, pools, dry and arid. We used the water discharge records from gauging stations or simulations using rainfall-runoff models to infer the temporal patterns of occurrence of these states using the developed aquatic states frequency graph. The visual analysis of this graph is complemented by the development of two metrics based on the permanence of flow and the seasonal predictability of zero flow periods. Finally, a classification of the aquatic regimes of temporary streams in terms of their influence over the development of aquatic life is put forward, defining Permanent, Temporary-pools, Temporary-dry and Episodic regime types. All these methods were tested with data from eight temporary streams around the Mediterranean from MIRAGE project and its application was a precondition to assess the ecological quality of these streams using the current methods prescribed in the European Water Framework Directive for macroinvertebrate communities
Carbon dioxide emissions of Antarctic tourism
The increase of tourism to the Antarctic continent may entail not only local but also global environmental impacts. These latter impacts, which are mainly caused by transport, have been generally ignored. As a result, there is a lack of data on the global impacts of Antarctic tourism in terms of energy consumption and carbon dioxide emissions. This paper presents and applies a methodology for quantifying CO2 emissions, both for the Antarctic vessel fleet as a whole and per passenger (both per trip and per day). The results indicate that the average tourist trip to Antarctica results in 5.44 t of CO2 emissions per passenger, or 0.49 t per passenger and day. Approximately 70% of these emissions are attributable to cruising and 30% to flying, which highlights the global environmental relevance of local transport for this type of touris
The ecodesign and planning of sustainable neighbourhoods : the Vallbona case study (Barcelona)
Global sustainability is increasingly an issue of urban sustainability, being essential to encourage more benign trajectories of urbanisation. For this, there is need for a framework that could aid in the process of designing and redesigning (retrofitting) cities. The aim of this paper is to present and describe the methodology of urban ecodesign, which is characterized by a systematic incorporation of environmental life cycle considerations into the design of urban systems. The paper presents a case study of neighbourhood ecodesign from the city of Barcelona (Vallbona neighbourhood). This practical experience shows that the inclusion of sustainability criteria at an early stage of the design and planning of urban systems is the best strategy for environmental protection.In addition; a methodological framework is described in order to provide planners with a structured way of designing urban settlements so as to move towards sustainable urban environments.La sostenibilidad global es cada vez más un tema de sostenibilidad urbana. Por este motivo, es necesario un marco de trabajo que pueda ayudar en el proceso de diseño y rediseño (rehabilitación) de nuestras ciudades. El objetivo de este trabajo es presentar y describir la metodología de ecodiseño adaptada a los entornos urbanos, la cual se caracteriza por la incorporación sistemática de las consideraciones ambientales a lo largo de su ciclo de vida. El documento presenta un caso de estudio de ecodiseño del barrio de Vallbona (Barcelona). Esta experiencia demuestra que la inclusión de criterios de sostenibilidad en las etapas iniciales de diseño y planificación de los sistemas urbanos es la mejor estrategia para la prevención ambiental. Además, se presenta un marco metodológico con el fin de proporcionar a los planificadores una forma estructurada de diseño de los asentamientos urbanos que les permita avanzar hacia entornos urbanos más sostenibles
Quironómidos (Diptera, Chironomidae) de alta montaña de la Sierra de Estrela (Portugal) y adiciones a la fauna de Portugal y la Península Ibérica
A Chironomidae (Diptera) fauna list for headwater streams of high altitude areas in Serra da Estrela (Portugal) is presented, doubling the previously established species richness for the region. The findings include 17 new records for Portugal, which represent an increase to 219 species for the Continental Portugal Chironomidae fauna. Two new records were detected for the Iberian Peninsula: one species (Tvetenia duodenaria), and one subgenus –Psectrocladius (Mesopsectrocladius)–; and the presence of the genus Natarsia is confirmed. The last two occurrences correspond to monoespecific taxa of the Palearctic region. However, as taxonomic identification has been based on larval material, instead of pupae, pupal exuviae or imagoes, species level assignment is still uncertain.Se presenta una lista de especies de Chironomidae (Diptera) recolectadas en los ríos de cabecera de zonas de alta montaña en la Serra da Estrela (Portugal). Con esta aportación se duplica la riqueza de especies regional conocida hasta el momento y se eleva la fauna de quironómidos del Portugal continental a 219 especies. Se incluyen dos nuevas citas para la Península Ibérica, una especie (Tvetenia duodenaria) y un subgénero –Psectrocladius (Mesopsectrocladius)–, y se confirma la presencia del género Natarsia. En los dos últimos casos se trata de larvas de taxones hasta el momento monoespecíficos en la región paleárctica, pero al no haberse recolectado pupas o adultos no se puede asegurar la identificación específica
La recollida d'oli de cuina, analitzada
Què fer amb l'oli de cuina, com recollir-lo després de l'ús a les cuines domèstiques és un problema que encara no té una solució clara. Un estudi realitzat a l'ICTA i a Inèdit, spin off del Parc de Recerca de la UAB, ha utilitzat una metodologia quantitativa de l'Avaluació de la Sostenibilitat del Cicle de Vida (LCSA) per analitzar els diferents mètodes utilitzats fins ara per a la recollida d'oli de cuina usat: les deixalleries urbanes, el porta a porta i la recollida a les escoles. Aquest treball ha arribat a la conclusió que la utilització de les deixalleries urbanes, que recullen altres residus a més de l'oli, és el mètode més sostenible, encara que genera menys benefici social que d'altres sistemes de recollida. Els altres dos sistemes serien menys sostenibles però disposarien de més beneficis socials.Qué hacer con el aceite de cocina, cómo recogerlo después del uso en las cocinas domésticas es un problema que aún no tiene una solución clara. Un estudio realizado en el ICTA y en Inèdit, spin off del Parc de Recerca de la UAB, ha utilizado una metodología cuantitativa de la Evaluación de la Sostenibilidad del Ciclo de Vida (LCSA) para analizar los diferentes métodos utilizados hasta el momento para la recogida de aceite de cocina usado: los centros de recogida urbanos, el puerta a puerta y la recogida en las escuelas. Este trabajo ha llegado a la conclusión de que la utilización de los centros de recogida urbanos, que recogen otros residuos además del aceite, es el método más sostenible, aunque genera menos beneficio social que otros sistemas de recogida. Los otros dos sistemas serían menos sostenibles pero dispondrían de más beneficios sociales
A biological tool to assess flow connectivity in reference temporary streams from the Mediterranean Basin
Many streams in the Mediterranean Basin have temporary flow regimes. While timing for seasonal drought is predictable, they undergo strong inter-annual variability in flow intensity. This high hydrological variability and associated ecological responses challenge the ecological status assessment of temporary streams, particularly when setting reference conditions. This study examined the effects of flow connectivity in aquatic macroinvertebrates from seven reference temporary streams across the Mediterranean Basin where hydrological variability and flow conditions are well studied. We tested for the effect of flow cessation on two streamflow indices and on community composition, and, by performing random forest and classification tree analyses we identified important biological predictors for classifying the aquatic state either as flowing or disconnected pools. Flow cessation was critical for one of the streamflow indices studied and for community composition. Macroinvertebrate families found to be important for classifying the aquatic state were Hydrophilidae, Simuliidae, Hydropsychidae, Planorbiidae, Heptageniidae and Gerridae. For biological traits, trait categories associated to feeding habits, food, locomotion and substrate relation were the most important and provided more accurate predictions compared to taxonomy. A combination of selected metrics and associated thresholds based on the most important biological predictors (i.e. Bio-AS Tool) were proposed in order to assess the aquatic state in reference temporary streams, especially in the absence of hydrological data. Although further development is needed, the tool can be of particular interest for monitoring, restoration, and conservation purposes, representing an important step towards an adequate management of temporary rivers not only in the Mediterranean Basin but also in other regions vulnerable to the effects of climate change
Spatial scale effects on taxonomic and biological trait diversity of aquatic macroinvertebrates in Mediterranean streams
We examined the effect of spatial scale on aquatic macroinvertebrate communities in Mediterranean streams from six basins distributed across southern Europe, including Spain, France, Italy, and Greece. We classified the studied streams according to their long-term aquatic regime into the three following types: (i) permanent (P), (ii) intermittent with summer pools (I-P), and (iii) intermittent with summer dry channels (I-D). For each stream type, we analyzed taxonomic and trait diversity, as well as the composition of the macroinvertebrate community, following a spatially nested design at three spatial scales of analysis: microhabitat (substratum patches), mesohabitat (pools vs. riffles), and macrohabitat (streams). In order to assess intrinsic seasonal variability in streams from the Mediterranean region, 20 Surber samples were taken from each stream according to meso- and microhabitat frequency in the wet and the dry season during 2010. Given the need for adaptation to specific hydrological conditions and the fact that microhabitats should encompass the niche requirements of particular taxa, we hypothesized that this spatial scale would have a greater influence on macroinvertebrate taxa composition and biological traits than the other two larger spatial scales in intermittent streams. We observed that patterns in the relative importance of variance components across hierarchical spatial scales changed with time because low flow or droughts altered both mesohabitat preva - lence and microhabitat composition. Our results confirm the importance of the microhabitat scale in I-P streams in the wet season but not in the dry one, when a loss of microhabitat diversity occurred. Stream-to-stream variability was more important in P and I-D streams. Our study also explored the relationships between traits and aquatic regimes. We found that aquatic macroinvertebrates inhabiting permanent streams exhibited traits related to the longer duration of life cycles in these rivers (e.g. large size of adult stages) and adaptations to flowing conditions (e.g. modes of aquatic dispersal), whereas aquatic macroinvertebrates inhabiting intermittent streams with summer pools had traits adapted to depositional conditions and ecological preferences for confined habitats (i.e. disconnected pools without flow). Finally, aquatic macroinvertebrates from intermittent streams with summer dry channels had adaptations conferring ability to survive periods with no water (e.g. modes of aerial dispersal, resistant stages). These results indicate that microhabitat conditions should not be neglected as they can play an important role in certain situations
Distribution, Abundance and Molecular Analysis of Genus Barbadocladius Cranston & Krosch (Diptera, Chironomidae) in Tropical, High Altitude Andean Streams and Rivers
The distribution of the genus Barbadocladius Cranston & Krosch (Diptera: Chironomidae), previously reported from Chile to Bolivia, has extended northwards. Larvae, pupae and pupal exuviae of this genus have been found in the high mountain tropical streams of Peru to 9°22′56″, but are restricted to very high altitude streams (altitudes over 3,278 m asl) compared to the lower altitude streams (below 1,100 m asl) in which the genus is reported in Chile and Argentina. Based on morphological studies, both described species in the genus, Barbadocladius andinus Cranston & Krosch and Barbadocladius limay Cranston & Krosch, have been found in Peru as pupae or pupal exuviae. Morphological analysis of the larvae and pupae revealed no differences between the two described species from Patagonia and Peru, which are of similar size and with a similar armament of hooklets and spines in pupal tergites and sternites. However, molecular analysis of larvae and pupae revealed that in Peru, there are at least two different evolutionary lines, one distributed widely and another restricted to one site. Phylogenetic analysis (using cox1 mitochondrial sequences) of all available sequences of Barbadocladius shows that the Chilean and Argentinean material differs from that of Peru. Therefore, a total of four molecular segregates are identified, although morphologically, neither larvae nor the pupae may be differentiated
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