Estudio del ecosistema urbano de San José. Protocolo de monitoreo de aves y naturalización del Parque La Sabana

El papel de la ciudad en el futuro de la humanidad será transcendente, y es que el crecimiento actual de los espacios urbanos tiende, en general, a desbordar el sitio original de las ciudades, abarcando territorios cada vez más extensos y discontinuos. Y por este motivo es de vital importancia el estudio de la ciudad y de su entorno, el cual es sinónimo de ecosistema urbano. En el siguiente estudio se evalúa el ecosistema urbano de San José, capital de Costa Rica, dando énfasis en las zonas verdes presentes, en las relaciones con los ecosistemas naturales circundantes y como mejorar su capacidad ecológica. Por este motivo se ha analizado un proceso de rearborización en el Parque Metropolitano La Sabana, principal nódulo de carga de la trama urbana. Este esfuerzo de naturación dotará al parque de una mayor naturalización, con lo que se espera un aumento de la biodiversidad faunística. Para conocer estos cambios se crea un programa de monitoreo de aves con su respectivo protocolo.

Analisi de compostos orgànics persistents i estudi de la procedència d'hidrocarburs en sediments del mar Mediterrani català

Els sediments del fons marí són molt importants en els ecosistemes aquàtics. Aquests sediments són considerats absorbents naturals, ja que s’hi acumulen moltes substàncies nocives, com ara metalls pesants i contaminants orgànics persistents (COPs). En aquest estudi s’han analitzat mostres de sediments del mar Mediterrani amb la finalitat d’examinar els COPs i la possible procedència d’hidrocarburs derivats del petroli. Les mostres han estat extretes davant de la desembocadura del riu Besòs (se n’ha fet una extracció a 8 km i una altra a 54 km de distància respecte la costa) i davant del municipi català anomenat Vilanova i la Geltrú (se n’ha fet, també, una extracció a 8-10 km i una altra a 30-40 km de distància respecte la costa). D’aquestes mostres, obtingudes per perforació, se n’han analitzat el primer i segon centímetres. S’han quantificat els hidrocarburs aromàtics policíclics (PAHs), els bifenils policlorats (PCBs) i els compostos organoclorats (OCPs) utilitzats antigament com a pesticides. S’ha posat de manifest que en les zones més properes a la costa, les concertacions COPs són més elevades a la regió més meridional, tot i estar davant de la desembocadura del riu Besòs. Segurament això és degut a la influència de la deriva litoral (corrent costaner marí en direcció NE-SW). Finalment, l’índex Phytane/Pristane, l’índex de preferència de carboni o, en anglès Carbon Preference Index (CPI) i la barreja complexa sense resoldre o, en anglès, Unresolved Complex Mixture (UCM) apunten a la conclusió que l’origen dels hidrocarburs analitzats (n-alcans) podria ser petrogènic.

Seguiment de l'evolució de la recuperació del bosc de ribera en la zona afectada per l'incendi del riu Canaletes del 20/07/2009. Proposta de campanya de voluntariat ambiental en rius per la custòdia i recuperació fluvial

El riu Canaletes va resultar afectat per l’ incendi que es va produir a Horta de Sant Joan el juliol de l’any 2009. El foc va malmetre bona part de la flora i fauna de la zona, però un dels ecosistemes que en va sortir més perjudicat va ser el del bosc de ribera, ecosistema molt fràgil en front de pertorbacions d’aquest tipus, ja que la seva capacitat de regeneració no és tant senzilla ni ràpida com en altres ecosistemes mediterranis com podrien ser els boscos de pi blanc. No obstant, si que existeixen algunes espècies de ribera que presenten una ràpida resposta als incendis com és el cas dels salzes o alguns pollancres o àlbers, que en aquest cas, poc temps després del foc ja presentaven rebrots, segons observacions realitzades al camp. Per comprovar l’evolució de la recuperació del bosc de ribera en la zona afectada per l’incendi, es van realitzar diverses sortides de camp. D’aquestes observacions, es va poder deduir que actualment el bosc de ribera de la zona estudiada, evoluciona segons les previsions realitzades en estudis immediatament posteriors al foc, de manera que hi estan proliferant de manera ràpida bardisses amb esbarzer, gavarrera, roldor i sanguinyol, en aquells llocs que abans de l’incendi eren ocupats per arbres caducifolis.

Treeline and climate change : analyzing and modeling patterns and shifts in the Swiss Alps

Summary: Global warming has led to an average earth surface temperature increase of about 0.7 °C in the 20th century, according to the 2007 IPCC report. In Switzerland, the temperature increase in the same period was even higher: 1.3 °C in the Northern Alps anal 1.7 °C in the Southern Alps. The impacts of this warming on ecosystems aspecially on climatically sensitive systems like the treeline ecotone -are already visible today. Alpine treeline species show increased growth rates, more establishment of young trees in forest gaps is observed in many locations and treelines are migrating upwards. With the forecasted warming, this globally visible phenomenon is expected to continue. This PhD thesis aimed to develop a set of methods and models to investigate current and future climatic treeline positions and treeline shifts in the Swiss Alps in a spatial context. The focus was therefore on: 1) the quantification of current treeline dynamics and its potential causes, 2) the evaluation and improvement of temperaturebased treeline indicators and 3) the spatial analysis and projection of past, current and future climatic treeline positions and their respective elevational shifts. The methods used involved a combination of field temperature measurements, statistical modeling and spatial modeling in a geographical information system. To determine treeline shifts and assign the respective drivers, neighborhood relationships between forest patches were analyzed using moving window algorithms. Time series regression modeling was used in the development of an air-to-soil temperature transfer model to calculate thermal treeline indicators. The indicators were then applied spatially to delineate the climatic treeline, based on interpolated temperature data. Observation of recent forest dynamics in the Swiss treeline ecotone showed that changes were mainly due to forest in-growth, but also partly to upward attitudinal shifts. The recent reduction in agricultural land-use was found to be the dominant driver of these changes. Climate-driven changes were identified only at the uppermost limits of the treeline ecotone. Seasonal mean temperature indicators were found to be the best for predicting climatic treelines. Applying dynamic seasonal delimitations and the air-to-soil temperature transfer model improved the indicators' applicability for spatial modeling. Reproducing the climatic treelines of the past 45 years revealed regionally different attitudinal shifts, the largest being located near the highest mountain mass. Modeling climatic treelines based on two IPCC climate warming scenarios predicted major shifts in treeline altitude. However, the currently-observed treeline is not expected to reach this limit easily, due to lagged reaction, possible climate feedback effects and other limiting factors. Résumé: Selon le rapport 2007 de l'IPCC, le réchauffement global a induit une augmentation de la température terrestre de 0.7 °C en moyenne au cours du 20e siècle. En Suisse, l'augmentation durant la même période a été plus importante: 1.3 °C dans les Alpes du nord et 1.7 °C dans les Alpes du sud. Les impacts de ce réchauffement sur les écosystèmes - en particuliers les systèmes sensibles comme l'écotone de la limite des arbres - sont déjà visibles aujourd'hui. Les espèces de la limite alpine des forêts ont des taux de croissance plus forts, on observe en de nombreux endroits un accroissement du nombre de jeunes arbres s'établissant dans les trouées et la limite des arbres migre vers le haut. Compte tenu du réchauffement prévu, on s'attend à ce que ce phénomène, visible globalement, persiste. Cette thèse de doctorat visait à développer un jeu de méthodes et de modèles pour étudier dans un contexte spatial la position présente et future de la limite climatique des arbres, ainsi que ses déplacements, au sein des Alpes suisses. L'étude s'est donc focalisée sur: 1) la quantification de la dynamique actuelle de la limite des arbres et ses causes potentielles, 2) l'évaluation et l'amélioration des indicateurs, basés sur la température, pour la limite des arbres et 3) l'analyse spatiale et la projection de la position climatique passée, présente et future de la limite des arbres et des déplacements altitudinaux de cette position. Les méthodes utilisées sont une combinaison de mesures de température sur le terrain, de modélisation statistique et de la modélisation spatiale à l'aide d'un système d'information géographique. Les relations de voisinage entre parcelles de forêt ont été analysées à l'aide d'algorithmes utilisant des fenêtres mobiles, afin de mesurer les déplacements de la limite des arbres et déterminer leurs causes. Un modèle de transfert de température air-sol, basé sur les modèles de régression sur séries temporelles, a été développé pour calculer des indicateurs thermiques de la limite des arbres. Les indicateurs ont ensuite été appliqués spatialement pour délimiter la limite climatique des arbres, sur la base de données de températures interpolées. L'observation de la dynamique forestière récente dans l'écotone de la limite des arbres en Suisse a montré que les changements étaient principalement dus à la fermeture des trouées, mais aussi en partie à des déplacements vers des altitudes plus élevées. Il a été montré que la récente déprise agricole était la cause principale de ces changements. Des changements dus au climat n'ont été identifiés qu'aux limites supérieures de l'écotone de la limite des arbres. Les indicateurs de température moyenne saisonnière se sont avérés le mieux convenir pour prédire la limite climatique des arbres. L'application de limites dynamiques saisonnières et du modèle de transfert de température air-sol a amélioré l'applicabilité des indicateurs pour la modélisation spatiale. La reproduction des limites climatiques des arbres durant ces 45 dernières années a mis en évidence des changements d'altitude différents selon les régions, les plus importants étant situés près du plus haut massif montagneux. La modélisation des limites climatiques des arbres d'après deux scénarios de réchauffement climatique de l'IPCC a prédit des changements majeurs de l'altitude de la limite des arbres. Toutefois, l'on ne s'attend pas à ce que la limite des arbres actuellement observée atteigne cette limite facilement, en raison du délai de réaction, d'effets rétroactifs du climat et d'autres facteurs limitants.

Canvis ambientals i relacions tròfiques en rius mediterranis

Els rius i rieres mediterranis són ecosistemes que es caracteritzen per fortes oscil•lacions de cabal i temperatura al llarg de l’any. Aquestes oscil•lacions provoquen canvis ambientals en l'hàbitat i en els recursos que afecten directament o indirecta la biota que habita aquests ecosistemes, la qual, per tant, ha de presentar adaptacions a aquestes oscil•lacions ambientals. L'escenari actual de canvi climàtic preveu una intensificació dels fenòmens de sequera i augment de temperatura. Entendre com la biota dels rius respon a aquestes fluctuacions és de gran importància per poder anticipar les respostes d'aquests sistemes als imminents canvis ambientals així com per gestionar adequadament els recursos hídrics en un futur. Els objectius principals d'aquesta tesi eren: caracteritzar estructural i funcionalment dues rieres intermitents mediterrànies al llarg dels diferents períodes característics del cicle anual i veure els efectes d'un augment de la sequera; veure com aquests efectes podien afectar l'ecosistema ripari circumdant i establir com diferències en la qualitat de la matèria orgànica derivades del canvi climàtic pot afectar el fitness i desenvolupament dels invertebrats. Aquests objectius s'han pogut complir només parcialment, ja que adversitats climàtiques van impedir finalitzar amb èxit la manipulació del cabal al camp i la resolució d'algunes dades no ha estat prou bona com per aplicar els models corresponents. Aquests contratemps s'han solucionat amb la incorporació de dos nous experiments (un encara s'ha de realitzar), fet que ha fet enlentir la finalització de la tesi.

Alternativas tecnológicas para la recuperación y valorización del nitrógeno presente en los residuos orgánicos

La conciencia de los problemas asociados a la gestión de los residuos orgánicos y el interés por las oportunidades de su recuperación y valorización han ido tomando importancia en los últimos años, tanto en el campo de las deyecciones ganaderas como en el sector de las aguas residuales. Consecuentemente, las combinaciones tecnológicas que permitan cerrar los ciclos de los nutrientes y la recuperación energética han adquirido mayor importancia en la investigación así como en las nuevas normativas sectoriales. En este contexto se sitúa el trabajo realizado durante el periodo becado (octubre 2010 - noviembre 2011). En una primera etapa de estudio bibliográfico se identificaron i) el aumento de la eficiencia en el uso del nitrógeno en la agricultura y en la ganadería, ii) la reutilización del nitrógeno en los mismos ecosistemas agrícolas y iii) el tratamiento de las deyecciones para redistribuir el nitrógeno a zonas con poca disponibilidad, como las tres direcciones principales hacia las cuales se está focalizando el interés del sector agrícola. Se puso en marcha una planta piloto de stripping y absorción para estudiar la posibilidad de recuperar y valorizar el amoniaco presente en los purines en forma de solución amoniacal para la industria de fertilizantes. Los resultados obtenidos evidenciaron el rol fundamental de las características iníciales del substrato en el rendimiento global del proceso. En particular, elevados contenidos en materia orgánica resultaron en bajas eficiencias y en elevadas contaminaciones del producto obtenido. Finalmente, considerando sus potenciales ventajas tanto en la gestión de los residuos ganaderos como de las aguas residuales y focalizándose en las perdidas de nitrógeno se estudió un sistema descentralizado de separación de orina instalado en un centro de investigación. Los resultados preliminares permitieron caracterizar los principales procesos que ocurren en el sistema e identificar las posibles líneas futuras de investigación.

Trapping Triatominae in Silvatic Habitats

Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Live-baited adhesive traps were tested in various ecosystems and different triatomine habitats (arboreal and terrestrial). The trials were always successful, with a rate of positive habitats generally over 20% and reaching 48.4% for palm trees of the Amazon basin. Eleven species of Triatominae belonging to the three genera of public health importance (Triatoma, Rhodnius and Panstrongylus) were captured. This trapping system provides an effective way to detect the presence of triatomines in terrestrial and arboreal silvatic habitats and represents a promising tool for ecological studies. Various lines of research are contemplated to improve the performance of this trapping system.

Modelación de la distribución de especies y ecosistemas en el tiempo y en el espacio: una revisión de las nuevas herramientas y enfoques disponibles

This article aims to present the conceptual and methodological framework in which models techniques for species and ecosystems distribution are developed. An historical review of concepts behind these techniques is made as well as the presentation of the major methodological steps involved in these tests. A discussion on how these approaches are useful for the development of new questions in the field of biogeography and biological conservation is generated. Finally, an application of distribution modeling techniques, using the specie Beilschmiedia miersii (belloto Del Norte) as a study case, is presented. This conceptual and methodological review as well as the example applied, seeks to clarify the usefulness and potential of distribution models techniques, with the objective to go forward in biogeography research and thus, farther progress in understanding spatial and temporal patterns of organism's distribution

Triatoma vandae sp. n. do complexo oliveirai encontrada no estado de Mato Grosso, Brasil (Hemiptera: Reduviidae: Triatominae)

There are several specific complexes belonging to the genus Triatoma Laporte, 1832, which are generally associated to specific geographic areas. Recent publications have linked the oliveirai complex to ecosystems of Mato Grosso, which are also present in other Brazilian states and even in other bordering countries as eastern Paraguay. The study of the abundant material collected during the last years allowed the description of several new species of the oliveirai complex: T. jurbergi Carcavallo, Galvão & Lent, 1998; T. baratai Carcavallo & Jurberg, 2000 and T. klugi Carcavallo, Jurberg, Lent & Galvão, 2001. Another new species belonging to the same complex is described here as T. vandae sp.n. It originates from the state of Mato Grosso, and has been reared in the insectary of the Laboratório Nacional e Internacional de Referência em Taxonomia de Triatomíneos, Departamento de Entomologia, Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro.

Aptian to Cenomanian deeper-water hiatal stromatolites from the northern Tethyan margin

A suite of deeper-water hiatal (DWH) stromatolites has been identified in the phosphatic and glauconitic sediments of Aptian to Cenomanian age in the alpine Helvetic thrust-and-fold belt, which represents the former northern Tethyan margin. The most important occurrences date from the latest Early to Late Aptian, the late Early to early middle Albian, and the Early Cenomanian. They are invariably associated with condensed phosphatic beds and occur preferentially on top of hardgrounds or on reworked pebbles and fossils. The zone of optimal stromatolite growth and preservation coincides with the zone of maximal sedimentary condensation, in the deeper parts of phosphogenic areas. The DWH stromatolites show variable morphologies, ranging from isolated laminae ("films") to internally laminated columns and crusts. They reach thicknesses of maximal 10 cm and are either preserved in phosphate or micrite. In the latter case, they may show peripheral impregnations of phosphate or iron oxyhydroxides. The quasi-complete lack of macroscopic sessile organisms suggests that the DWH stromatolites grew close to the upper boundary of an oxygen-minimum zone. Electron-scanning microscopic images show that the Early Cenomanian examples preserved in micrite consist of filamentous structures, which form spaghetti-like assemblages. They are. interpreted as the remains of poikiloaerobic, heterotrophic microbes. Coeval DWH stromatolites are known from the entire European segment of the northern Tethyan margin, and shallow-water counterparts are commonplace on Tethyan carbonate platforms. This indicates that, in general, paleoceanographic and paleoenvironmental conditions were appropriate for stromatolite growth and preservation. The here-described DWH stromatolites proliferated especially in time windows, which followed upon the oceanic anoxic periods OAE la (Early Aptian), lb (latest Aptian and earliest Albian), and Id (latest Albian). They may represent pioneer ecosystems, which thrived during the recovery phases following the "mid"-Cretaceous OAEs.

Horizontal stratification of the sand fly fauna (Diptera: Psychodidae) in a transitional vegetation between caatinga and tropical rain forest, state of Bahia, Brazil

A study about the horizontal stratification of the sand fly fauna in two distinct ecosystems, caatinga area, endemic for visceral leishmaniasis, and the tropical rain forest area, endemic for cutaneous leishmaniasis, was performed in the state of Bahia, Brazil. Lutzomyia longipalpis was predominant in the caatinga, and following it came the species L. capixaba and L. oswaldoi. In the tropical rain forest other species were found, such as L. intermedia, L. migonei, L. whitmani, L. yuilli, L.fischeri, L. damascenoi, L. evandroi, L. monticola, and L. lenti. It was found that the geographical limits of the vector species of visceral and cutaneous leishmaniasis are clearly defined by the biological and phytogeographic characteristics.

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In the case of such a very special building project, the crucial stake for sustainable development is the fact that space systems are extreme cases of environmental constraints. In- deed, they constitute an interesting model as an analogy can be made between Martian utmost conditions and some of the possible extreme one's that Earth might soon face. The didactic ob- jective of the project is to use the context of a building on Mars to teach an approach which raises the students awareness to design and plan all steps of a building in a sustainable way, i.e. build, with the available resources, living spaces that satisfy human needs and leave as intact as possible the external environment. The paper presents the approach and the feedback of this student project, more specifically ENAC Learning Unit", which involved 17 students from envi- ronmental, civil engineering and architecture sections from EPFL. All the same, it involved pro- fessors from all three domains, as well as aerospace and Mars specialists, which gave seminars during the course of the semester. The students were separated in groups, and the project con- sisted of two phases: 1) analysis of the context and resources, 2) project design and critic. Both organisational, technical and pedagogical aspects of the experience are presented. The outcome was very positive, with students experiencing for their first time multidisciplinary work and the iterative process of design under multiple constraints.

Screening of Brazilian basidiomycetes for antimicrobial activity

A total of 103 isolates of basidiomycetes, representing 84 species from different Brazilian ecosystems, were evaluated for their antifungal and antibacterial activity in a panel of pathogenic and non-pathogenic microorganisms. Tissue plugs of the fruiting bodies were cultivated in liquid media and the whole culture extracted with ethyl acetate. Crude extracts from Agaricus cf. nigrecentulus, Agrocybe perfecta, Climacodon pulcherrimus, Gloeoporus thelephoroides, Hexagonia hydnoides, Irpex lacteus, Leucoagaricus cf. cinereus, Marasmius cf. bellus, Marasmius sp., Nothopanus hygrophanus, Oudemansiella canarii, Pycnoporus sanguineus, Phellinus sp., and Tyromyces duracinus presented significant activity against one or more of the target microorganisms. Eight isolates were active only against bacteria while three inhibited exclusively the growth of fungi. Two extracts presented wide antimicrobial spectrum and were active against both fungi and bacteria. Differences in the bioactivity of extracts obtained from isolates from the same species were observed.

Arctic warming will promote Atlantic-Pacific fish interchange

Throughout much of the Quaternary Period, inhospitable environmental conditions above the Arctic Circle have been a formidable barrier separating most marine organisms in the North Atlantic from those in the North Pacific(1,2). Rapid warming has begun to lift this barrier(3), potentially facilitating the interchange of marine biota between the two seas(4). Here, we forecast the potential northward progression of 515 fish species following climate change, and report the rate of potential species interchange between the Atlantic and the Pacific via the Northwest Passage and the Northeast Passage. For this, we projected niche-based models under climate change scenarios and simulated the spread of species through the passages when climatic conditions became suitable. Results reveal a complex range of responses during this century, and accelerated interchange after 2050. By 2100 up to 41 species could enter the Pacific and 44 species could enter the Atlantic, via one or both passages. Consistent with historical and recent biodiversity interchanges(5,6), this exchange of fish species may trigger changes for biodiversity and food webs in the North Atlantic and North Pacific, with ecological and economic consequences to ecosystems that at present contribute 39% to global marine fish landings.

Climate change impact on biodiversity in Switzerland: a review. Journal for Nature Conservation

A noticeable increase in mean temperature has already been observed in Switzerland and summer temperatures up to 4.8 K warmer are expected by 2090. This article reviews the observed impacts of climate change on biodiversity and consider some perspectives for the future at the national level. The following impacts are already evident for all considered taxonomic groups: elevation shifts of distribution toward mountain summits, spread of thermophilous species, colonisation by new species from warmer areas and phenological shifts. Additionally, in the driest areas, increasing droughts are affecting tree survival and fish species are suffering from warm temperatures in lowland regions. These observations are coherent with model projections, and future changes will probably follow the current trends. These changes will likely cause extinctions for alpine species (competition, loss of habitat) and lowland species (temperature or drought stress). In the very urbanised Swiss landscape, the high fragmentation of the natural ecosystems will hinder the dispersal of many species towards mountains. Moreover, disruptions in species interactions caused by individual migration rates or phenological shifts are likely to have consequences for biodiversity. Conversely, the inertia of the ecosystems (species longevity, restricted dispersal) and the local persistence of populations will probably result in lower extinction rates than expected with some models, at least in 21st century. It is thus very difficult to estimate the impact of climate change in terms of species extinctions. A greater recognition by society of the intrinsic value of biodiversity and of its importance for our existence will be essential to put in place effective mitigation measures and to safeguard a maximum number of native species.