948 resultados para Urban ecology (Biology)


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Mistletoes constitute an important food resource for animals in many ecosystems. However, these plants are considered pests in urban areas because of deleterious effects they have on the host trees. Studies in urban areas were mostly focused on listing host species or procedures to control the "pest". In this sense, broader studies including several aspects of mistletoes ecology in urban ecosystems are still missing. We studied the interaction of the mistletoe, Phoradendron affine, with its dispersers and hosts in two urban sites in Uberlandia, Brazil. Phoradendron affine fruits were consumed almost exclusively by Euphonia chlorotica, which was crucial for seed germination. Parasitism was recorded in five hosts, two native (Handroanthus chrysotrichus and Tabebuia roseoalba) and three exotic species (Spathodea campanulata, Ligustrum lucidum and Melia azedarach). Mistletoes were found parasitizing larger host trees, a trend commonly reported for mistletoe-host interaction. Mistletoe seed germination was not affected by the trees species, whether host or non-host, but the radicle of germinated seeds could not penetrate the bark and seedlings invariably died in non-host species. We found a high prevalence of parasitism in our study, in comparison to what previous studies reported for natural areas. The spatial distribution of the hosts and high light incidence on isolated host trees may lead to this high prevalence in urban areas. Rather than eradicated, mistletoes in urban areas should be ecologically managed and their importance for bird species conservation must be considered. More studies to determine which bird species are favoured by mistletoe presence in urban areas will be essential for, this purpose. (C) 2012 Elsevier GmbH. All rights reserved.

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Mode of access: Internet.

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Black band disease of corals consists of a microbial community dominated by the cyanobacteriurn Phormidium corallyticum. The disease primarily affects reef-framework coral species, Active black band disease continually opens up new substrate in reef environments by destroying coral tissue as the disease line advances across the surface of infected colonies. A field study was carried out to determine the abundance and distribution of black band disease on the reef building corals in the Florida Keys. During July of 1992 and 1993, up to 0.72% of coral colonies were infected with black band disease. Analysis of the distribution showed that the disease was clumped. Seasonal patters varied, with some coral colonies infected year round, others exhibiting reinfection from summer 1992 to summer 1993, and some colonies infected for one year only. Statistical analysis of black band disease incidence in relation to various environmental parameters revealed that black band disease was associated with relatively shallow water depths, higher temperatures, elevated nitrite levels, and decreased ortho-phosphate levels. Additional field studies determined recovery of scleractinian coral colonies damaged or killed through the activities of black band disease over a five-year period. These studies determined if the newly exposed substrate was recolonized through scleractinian recruitment, if there was overgrowth of the damaged areas by the formerly diseased colony, or if coral tissue destruction continued after the cessation of black band disease activity. Tissue loss continued on all coral colonies with only one colony exhibiting new tissue growth. The majority of recolonization was by non-reef-framework corals and octocorallians, limited recruitment by framework species was observed. Physiological studies of P. corallyticum were carried out to investigate the photosynthetic capacity of this cyanobacterium, and to determine if this species has the ability to fix dinitrogen. The results of this research demonstrated that P. corallyticum reaches maximum photosynthetic rates at very low light intensities (27.9 μE/m/sec), and that P. corallyticum is able to carry out oxygenic photosynthesis in the presence of sulfide, an ability that is uncommon in prokaryotic organisms. ^

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There is growing urgency to enhance the sustainability of existing and emerging cities. The science of ecology, especially as it interacts with disciplines in the social sciences and urban design, has contributions to make to the sustainable transformation of urban systems. Not all possible urban transformations may lead toward sustainability. Ecological science helps identify components of resilience that can favor transformations that are more sustainable. To summarize the dynamics and choices involved in sustainable transformations, a “metacity” framework is presented, embracing ecological processes in cities as complementary to those involving society, power, and economy.

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Social structure is a key determinant of population biology and is central to the way animals exploit their environment. The risk of predation is often invoked as an important factor influencing the evolution of social structure in cetaceans and other mammals, but little direct information is available about how cetaceans actually respond to predators or other perceived threats. The playback of sounds to an animal is a powerful tool for assessing behavioral responses to predators, but quantifying behavioral responses to playback experiments requires baseline knowledge of normal behavioral patterns and variation. The central goal of my dissertation is to describe baseline foraging behavior for the western Atlantic short-finnned pilot whales (Globicephala macrohynchus) and examine the role of social organization in their response to predators. To accomplish this I used multi-sensor digital acoustic tags (DTAGs), satellite-linked time-depth recorders (SLTDR), and playback experiments to study foraging behavior and behavioral response to predators in pilot whales. Fine scale foraging strategies and population level patterns were identified by estimating the body size and examining the location and movement around feeding events using data collected with DTAGs deployed on 40 pilot whales in summers of 2008-2014 off the coast of Cape Hatteras, North Carolina. Pilot whales were found to forage throughout the water column and performed feeding buzzes at depths ranging from 29-1176 meters. The results indicated potential habitat segregation in foraging depth in short-finned pilot whales with larger individuals foraging on average at deeper depths. Calculated aerobic dive limit for large adult males was approximately 6 minutes longer than that of females and likely facilitated the difference in foraging depth. Furthermore, the buzz frequency and speed around feeding attempts indicate this population pilot whales are likely targeting multiple small prey items. Using these results, I built decision trees to inform foraging dive classification in coarse, long-term dive data collected with SLTDRs deployed on 6 pilot whales in the summers of 2014 and 2015 in the same area off the coast of North Carolina. I used these long term foraging records to compare diurnal foraging rates and depths, as well as classify bouts with a maximum likelihood method, and evaluate behavioral aerobic dive limits (ADLB) through examination of dive durations and inter-dive intervals. Dive duration was the best predictor of foraging, with dives >400.6 seconds classified as foraging, and a 96% classification accuracy. There were no diurnal patterns in foraging depth or rates and average duration of bouts was 2.94 hours with maximum bout durations lasting up to 14 hours. The results indicated that pilot whales forage in relatively long bouts and the ADLB indicate that pilot whales rarely, if ever exceed their aerobic limits. To evaluate the response to predators I used controlled playback experiments to examine the behavioral responses of 10 of the tagged short-finned pilot whales off Cape Hatteras, North Carolina and 4 Risso’s dolphins (Grampus griseus) off Southern California to the calls of mammal-eating killer whales (MEK). Both species responded to a subset of MEK calls with increased movement, swim speed and increased cohesion of the focal groups, but the two species exhibited different directional movement and vocal responses. Pilot whales increased their call rate and approached the sound source, but Risso’s dolphins exhibited no change in their vocal behavior and moved in a rapid, directed manner away from the source. Thus, at least to a sub-set of mammal-eating killer whale calls, these two study species reacted in a manner that is consistent with their patterns of social organization. Pilot whales, which live in relatively permanent groups bound by strong social bonds, responded in a manner that built on their high levels of social cohesion. In contrast, Risso’s dolphins exhibited an exaggerated flight response and moved rapidly away from the sound source. The fact that both species responded strongly to a select number of MEK calls, suggests that structural features of signals play critical contextual roles in the probability of response to potential threats in odontocete cetaceans.

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Understanding the dynamics of urban ecosystem services is a necessary requirement for adequate planning, management, and governance of urban green infrastructure. Through the three-year Urban Biodiversity and Ecosystem Services (URBES) research project, we conducted case study and comparative research on urban biodiversity and ecosystem services across seven cities in Europe and the United States. Reviewing > 50 peer-reviewed publications from the project, we present and discuss seven key insights that reflect cumulative findings from the project as well as the state-of-the-art knowledge in urban ecosystem services research. The insights from our review indicate that cross-sectoral, multiscale, interdisciplinary research is beginning to provide a solid scientific foundation for applying the ecosystem services framework in urban areas and land management. Our review offers a foundation for seeking novel, nature-based solutions to emerging urban challenges such as wicked environmental change issues.

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Forested areas within cities host a large number of species, responsible for many ecosystem services in urban areas. The biodiversity in these areas is influenced by human disturbances such as atmospheric pollution and urban heat island effect. To ameliorate the effects of these factors, an increase in urban green areas is often considered sufficient. However, this approach assumes that all types of green cover have the same importance for species. Our aim was to show that not all forested green areas are equal in importance for species, but that based on a multi-taxa and functional diversity approach it is possible to value green infrastructure in urban environments. After evaluating the diversity of lichens, butterflies and other-arthropods, birds and mammals in 31 Mediterranean urban forests in south-west Europe (Almada, Portugal), bird and lichen functional groups responsive to urbanization were found. A community shift (tolerant species replacing sensitive ones) along the urbanization gradient was found, and this must be considered when using these groups as indicators of the effect of urbanization. Bird and lichen functional groups were then analyzed together with the characteristics of the forests and their surroundings. Our results showed that, contrary to previous assumptions, vegetation density and more importantly the amount of urban areas around the forest (matrix), are more important for biodiversity than forest quantity alone. This indicated that not all types of forested green areas have the same importance for biodiversity. An index of forest functional diversity was then calculated for all sampled forests of the area. This could help decision-makers to improve the management of urban green infrastructures with the goal of increasing functionality and ultimately ecosystem services in urban areas.

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Urbanization is associated with global biodiversity loss of macrophauna and flora through direct and indirect mechanisms, but to date few studies have examined urban soil microbes. Although there are numerous studies on the influence of agricultural management on soil microbial community composition, there has been no global-scale study of human control over urban soil microbial communities. This thesis extends the literature of urban ecology to include soil microbial communities by analyzing soils that are part of the Global Urban Soil Ecology and Education Network (GLUSEEN). Chapter 1 sets the context for urban ecology; Chapters 2 addresses patterns of community assembly, biodiversity loss, and the phylogenetic relationships among community members; Chapter 3 addresses the metabolic pathways that characterize microbial communities existing under different land-uses across varying geographic scales; and Chapter 4 relates Chapter 2 and 3 to one another and to evolutionary theory, tackling assumptions that are particular to microbial ecology.

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Fire ephemerals are short-lived plants that primarily germinate after fire. Fresh and laboratory-stored seeds are difficult to germinate ex situ, even in response to fire-related cues such as heat and smoke. Seeds of eight Australian fire ephemeral species were buried in unburnt and recently burnt sites of natural bushland during autumn. Seeds were exhumed after 6 and 12 months and incubated in water and smoke water, either with or without a heat treatment at 70 degrees C for 1 h. Generally, germination did not increase after 6 months of burial, but after 12 months of burial germination was enhanced in seven of the eight species. Actinotus leucocephalus produced higher germination following 12 months of burial without any further treatment, and smoke water and heat further improved germination. The four Gyrostemonaceae species, Codonocarpus cotinifolius, Gyrostemon racemiger, Gyrostemon ramulosus and Tersonia cyathiflora, only germinated in the presence of smoke water, and their germination was enhanced by burial. Burial improved germination in response to a heat treatment in Grevillea scapigera and Alyogyne huegelii seeds, but did not enhance Alyogyne hakeifolia germination. During concurrent dry laboratory storage of seeds at 15 degrees C, only Actinotus leucocephalus produced increased germination in response to smoke water and heat over time. In summary, soil burial can alter the dormancy status of a number of Australian fire ephemeral seeds, rendering them more responsive to germination cues such as smoke water and heat. The requirement for a period of burial before seeds become responsive to smoke and/or heat would ensure that seeds persist in the soil until a subsequent fire, when there is an increase in nutrients available for growth and reduced competition from other plants.

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La hipótesis de la compensación plantea la posibilidad de que los individuos que viven en centros urbanos densos tengan una mayor propensión a disponer de una segunda residencia y/o llevar a cabo desplazamientos más frecuentes hacia destinos más alejados durante los fines de semana y las vacaciones que los individuos que viven en zonas poco densas. En este contexto, no está claro cuál es el efecto neto de la densidad en términos ambientales. En esta investigación se contrasta la hipótesis de la compensación en la Región Metropolitana de Barcelona utilizando como indicador de impacto ambiental la huella ecológica de la movilidad y de la vivienda. Los resultados obtenidos rechazan la hipótesis de la compensación en un sentido fuerte, pero se detecta la existencia de un nivel máximo de densidad a partir del cual ejerce un impacto de signo positivo.

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La finalitat del projecte consisteix en establir les pautes per a la implantació d’un model d’ecobarri al Pla d’en Serra, un barri situat a l’est del municipi de Sant Gregori, el qual, com a conseqüència de la crisi, es troba urbanitzat i pendent d’edificació. Per tal d’assolir l’objectiu proposat es fa èmfasi en aspectes d’usos del sòl, mobilitat, metabolisme i governança. Inclou un estudi previ amb la diagnosi de l’estat actual de la zona i dels Plans influents, enquesta a la població, diagnosi de conflictes i potencialitats entre el model d’ecobarri i el model tradicional.El model que resulta de l’elaboració d’aquest projecte és el d’un barri més sostenible, més respectuós amb el medi ambient, proporciona una major comoditat i qualitat de vida per als futurs habitants de la comunitat en comparació a les perspectives que se li donen actualment a la zona

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Quality of life is increasingly becoming a concept researched empirically and theoretically in the field of economics. In urban economics in particular, this increasing interest stems mainly from the fact that quality of life affects urban competitiveness and urban growth: research shows that when households and businesses decide where to locate, quality of life considerations can play a very important role. The purpose of the present paper is to examine the way economic literature and urban economic literature in particular, have adopted quality of life considerations in the economic thinking. Moreover, it presents the ways various studies have attempted to capture the multidimensional nature of the concept, and quantify it for the purposes of empirical research. Additionally we focus on the state of the art in Spain. Looking at the experiences in the last years we see very important possibilities of developing new studies in the field.

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En el presente artículo se hace un breve repaso de las circunstancias académicas, institucionales y de algunos de los avatares que han venido sucediendo hasta dar lugar a la constitución de la Asociación de Psicología Ambiental (PSICAMB) y sus primeros años. Junto a este recorrido, también se ha prestado atención a los trabajos que se han presentado en las doce jornadas y congresos bianuales que se han celebrado hasta la actualidad. Para ello se ha llevado a cabo un análisis de contenido de los 1065 títulos recogidos en estos eventos. Por lo que respecta al nivel de participación se observa que cada vez este es más alto tanto en el número trabajos presentados cómo en los autores que los avalan. Por lo que respecta al análisis de los títulos, se observó que las quince categorías utilizadas se subsumían en cinco: 'aspectos teóricos, conceptuales y metodológicos', 'medio construido' 'medio natural' la 'psicología de la conservación' 'los riesgos y los desastres'. Los resultados del análisis muestran un alto volumen en cada una de estas categorías salvo en el 'medio natural' y se observa como con el devenir de los años se ha ido prestando atención más a unos temas que a otros.

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El mito al que se refiere el título no es una creación contemporánea. La idea de las infraestructuras como una fuerza con la virtud, por si misma, de iniciar procesos de desarrollo ha revestido rasgos típicos de 'mito' desde hace al menos siglo y medio, La fiebre ferroviaria del siglo XIX constituyen dos buenos ejemplos de la fuerza que ha tenido el mito en España: en ambos casos, las infraestructuras se percibieron, casi sin discusión, como solución definitiva a los problemas del país, y como tales entraron a formar parte del discurso político de la época.

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Kirjallisuusarvostelu