193 research outputs found
O Estudo de aves marinhas em Portugal
In this paper we review some of the most important\ud
studies of seabirds of Madeira, Azores and Portugal.\ud
There has been a considerable increase in the interest\ud
in seabirds in the last ten years, resulting in a high\ud
number of papers published in this period. A project\ud
conceming the study of Cory's Shearwater breeding\ud
in Portugal is also presented
Coastal waters of a marine protected area of the Bijagós Archipelago, West Africa, shelter juvenile fishes of economic and ecological importance
In many marine ecosystems small pelagic fish exert a crucial role in controlling the dynamics of the
community, mainly due to their high biomass at intermediate levels of the food web. These fish use
coastal marine ecosystems as nursery areas, but also to forage and to avoid predation or competition.
We studied spatial, seasonal, lunar and diel variations in a coastal fish community from a marine
protected area of the Bijagós Archipelago, Guinea-Bissau. Fish were sampled with 46 beach seine net
sessions in 2015 and 2016. A total of 35 fish species of 25 families were captured. Fish abundance
varied between years and seasons, with a higher abundance in the dry season, but not by lunar tide.
Nonetheless, the community composition was broadly similar over the seasons, among islands and
between lunar tides. Clupeidae, Haemulidae and Gerreidae were the most abundant fish families.
Sardinella maderensis highly dominated the captures throughout the year, with catches much higher
than any other species. The differences in abundance between seasons and years may be related with
movements to or from the shore due to feeding activity or to avoid predation, or else to differences in
recruitment between years. There were no significant diel differences in species richness and diversity,
although higher numbers of fish were captured during daytime. For most species the majority of
individuals captured were immature, highlighting the importance of the archipelago as nursery area
for several species. These small pelagics, and particularly Sardinella maderensis, represent the main
prey for several marine predators. Thus, the conservation of such fish species may be key for the
management of the Bijagós Archipelago.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio
Beached bird surveys in Portugal 1990-1996
Between 1990 and 1996 a large proportion of the Portuguese coast was systematically surveyed for dead seabirds during the winter (October to March). About 5330 Km of beaches were walked during this period and 2660 dead seabirds were recorded. Razorbill Alca torda was the most common species, followed by Gannet Morus bassanus, Yellow-legged Gull Larus cachinnans and Lesser Black-backed Gull L. fuscus. Together, these species accounted for 73.7% of all corpses found. Most casualties were found in the central area of the Portuguese coast. Beaches in these regions face predominant northwesterly winds and are close to an important upwelling area which represents a potentially good feeding zone for seabirds. Oil contamination of the corpses was generally low, especially when compared with those recorded in similar surveys in some northern European countries. Deaths due to entanglement in fishing gear were significantly lower than those reported in previous surveys and they apparently no longer represent a major threat to seabirds in the Portuguese coast
Thermochromic Paints on External Surfaces: Impact Assessment for a Residential Building through Thermal and Energy Simulation
This work addresses the effect of using thermochromic paints in residential buildings. Two different thermochromic paint types were considered: One that changes properties through a step transition at a certain temperature, and another that changes properties in a gradual/linear manner throughout a temperature range. The studied building was a two-floor villa, virtually simulated through a digital model with and without thermal insulation, and considering thermochromic paints applied both on external walls and on the roof. The performance assessment was done through the energy use for heating and cooling (in conditioned mode), as well as in terms of the indoor temperature (in free-floating mode). Three different cities/climates were considered: Porto, Madrid, and Abu Dhabi. Results showed that energy savings up to 50.6% could be reached if the building is operated in conditioned mode. Conversely, when operated in free-floating mode, optimally selected thermochromic paints enable reductions up to 11.0 degrees C, during summertime, and an increase up to 2.7 degrees C, during wintertime. These results point out the great benefits of using optimally selected thermochromic paints for obtaining thermal comfort, and also the need to further develop stable and cost-effective thermochromic pigments for outdoor applications, as well as to test physical models in a real environment
Invisible trophic links?:Quantifying the importance of non-standard food sources for key intertidal avian predators in the Eastern Atlantic
Coastal wetlands are heterogeneous systems with multiple inputs and complex interactionswithin local food webs. Interpreting such complexity is limited by incomplete knowledgeof trophic interactions among organisms. Although widely recognized as secondary consumersand predators of intertidal macroinvertebrates, shorebirds can also consume lower-trophic-levelfood sources, and frequently forage in adjacent supratidal habitats. To ascertain potential trophiclinks between overwintering shorebirds and alternative non-standard food sources, we collectedcarbon and nitrogen stable isotope data of shorebirds and benthic organisms from 4 coastal wetlandsalong the Eastern Atlantic: Tejo Estuary, Portugal; Sidi-Moussa, Morocco; Banc d’Arguin,Mauritania; and Bijagós Archipelago, Guinea-Bissau. Using dual-isotope Bayesian mixing models,we evaluated the relative importance of intertidal benthic macroinvertebrates and 3 otherpotential food sources (biofilm and seagrass rhizomes from intertidal areas, and saltpan macroinvertebrates)in the diet of wintering shorebirds. Although intertidal macroinvertebrates form themain part of most shorebird species’ diet, our data revealed that supratidal saltpans can contributeto >30% of the biomass ingested by several shorebird species. Seagrass rhizomes represented>10% of the diet of several species in Banc d’Arguin and in Sidi Moussa. Little stint Calidris minutaappears to consume biofilm on all 3 wetlands where they were sampled, which is the first timebiofilm consumption by shorebirds has been detected along the East Atlantic Flyway. Empiricalevidence for generalized consumption of alternative food sources by intertidal avian predatorsshow the greater complexity and food web connectivity in and of intertidal habitats, and also withthe surrounding habitats
Pulmonary Metastasis in a Cardiac Angiosarcoma. Case Report and Discussion
Apresenta-se um caso clínico referente a doente de 35 anos, do sexo masculino sem antecedentes pessoais relevantes, admitido no serviço de urgência por quadro de toracalgia e tosse produtiva com alterações
electrocardiográficas sugestivas de pericardite. Inicialmente admitido pelo Serviço de Cardiologia, com melhoria do quadro clínico após terapêutica anti-
-inflamatória; contudo, no internamento houve como intercorrência pneumonia de provável etiologia bacteriana, complicada por derrame pleural. Após a alta,foi referenciado à consulta de pneumologia, onde se manteve o estudo etiológico do derrame persistente, tendo vindo a complicar-se o seu quadro com alterações das cavidades cardíacas e múltiplos nódulos pulmonares,
sugestivos de endocardite subaguda com
embolização séptica pulmonar. Internado no serviço de Pneumologia e submetido a videotoracoscopia, foi-lhe diagnosticado angiossarcoma cardíaco com metastização pulmonar. Assistiu-se a uma rápida evolução
do quadro clínico, quase fulminante, com falência cardíaca e óbito do doente sem ter iniciado radioterapia ou quimioterapia adjuvante
Use of stable isotope fingerprints to assign wintering origin and trace shorebird movements along the East Atlantic Flyway
Migratory connectivity can be defined as the flux of individuals or populations among areas between stages of an animal's life cycle. Many shorebird species perform long-distance migrations and while moving between breeding and wintering grounds, they depend on a network of intermediate wetlands (stopover sites) where populations of different origins extensively overlap. The difficulty to discriminate such populations represents a serious obstacle to the identification of the links between breeding or wintering areas and stopover sites, and also precludes the estimation of demographic parameters for each population. In this study, we test if linear discriminant models based on stable carbon and nitrogen isotope ratios in toenails can he used to identify populations of several shorebird species of different wintering origins overlapping at two stopover sites of the East Atlantic Flyway. In addition, we evaluate the ability of this approach to infer migratory phenological patterns of shorebirds. Linear discriminant analyses performed overall well in distinguishing the isotopic signals of birds from wintering areas (in France, Portugal, Morocco, Mauritania and Guinea-Bissau) most species, correctly classifying over 80% (n = 542) of all wintering individuals sampled at these areas. Assignment rates of shorebirds captured during spring migration were also high (96%, n=323) at the Tejo estuary, Portugal, but lower (40%, 0 = 185) at Marennes-Oleron Bay in France, and also differed among species. A large proportion of spring migrants captured in Portugal and France were assigned to Banc d' Arguin in Mauritania, the most important wintering area in the flyway. Phenological patterns derived for dunlins (Calidris alpina), common ringed plovers (Charadrius hiaticula) and grey plovers (Pluvialis squatarola) suggest that the first northward migrants started arriving at the Tejo estuary during the second half of March, with peaking numbers occurring during April or May.</p
Structure and functioning of intertidal food webs along an avian flyway:A comparative approach using stable isotopes
1. Food webs and trophic dynamics of coastal systems have been the focus of intense research throughout the world, as they prove to be critical in understanding ecosystem processes and functions. However, very few studies have undertaken a quantitative comparison of entire food webs from a key consumer perspective across a broad geographical area, limiting relevant comparisons among systems with distinct biotic and abiotic components.2. We investigate the structure and functioning of food webs in four tidal ecosystems of international importance for migratory shorebirds along the East Atlantic Flyway: Tejo estuary in Portugal, Sidi Moussa in Morocco, Banc d'Arguin in Mauritania and Bijagós archipelago in Guinea-Bissau. Basal food sources, shorebirds and their prey (benthic invertebrates) were sampled in all areas, and Bayesian stable isotope mixing models and community-wide metrics were used in a comparative analysis among areas.3. Significant differences among study areas were found in the structure of food webs, as well as in the relative importance of basal resource pools supporting each food web. Overall, the food web of Banc d'Arguin was characterized by lower trophic diversity and higher functional redundancy than the other sites. This result might be explained by the low number of trophic pathways of organic matter transfer in this seagrass-dominated system which, as a fossil estuary, lacks inputs from both freshwater and nutrient-rich offshore oceanic waters.4. Structure of shorebird communities was consistent with the main organizational patterns found for each food web, highlighting the less diverse character of the community of Banc d'Arguin. At Banc d'Arguin and Bijagós archipelago, which displayed the smallest and largest isotopic niche widths in bird assemblage, respectively, mean niche overlap among species was low, suggesting high interspecific partitioning in resource use. Tropical systems typically offer comparatively lower harvestable prey biomass for shorebirds and might thus strengthen interspecific competition, leading to low niche overlap among species.5. Our study reveals relevant differences in the structure of food webs and shorebird communities in coastal areas along an avian flyway. While differences in trophic redundancy of food webs point to distinct levels of ecosystem resilience, contrasts in the organization of shorebird communities highlight the plasticity in the foraging behaviour of species inhabiting areas with distinct environmental conditions
Assessing bird exclusion effects in a wetland crossed by a railway (Sado estuary, Portugal)
L. Borda-de-Água et al. (eds.), Railway Ecology, Chapter 11, p. 179-195Linear transportation infrastructures may displace wildlife from nearby
areas that otherwise would provide adequate habitat conditions. This exclusion
effect has been documented in roads, but much less is known about railways. Here
we evaluated the potential exclusion effect on birds of a railway crossing a wetland
of international importance (Sado Estuary, Portugal). We selected 22 sectors representative
of locally available wetland habitats (salt pans, rice paddy fields, and
intertidal mudflats); of each, half were located either close to (0–500 m) or far from
(500–1500 m) the railway line. Water birds were counted in each sector between
December 2012 and October 2015, during two months per season (spring, summer,
winter, and autumn) and year, at both low and high tide. We recorded 46 species, of
which the most abundant (>70% of individuals) were black-headed gull, greater
flamingo, northern shoveler, black-tailed godwit, and lesser black-backed gull. Peak
abundances were found in autumn and winter. There was no significant variation
between sectors close to and far from the railway in species richness, total abundance,
and abundance of the most common species. Some species tended to be most abundant either close to or far from the railway albeit not significantly so but this
often varied across the tidal and annual cycles. Overall, our study did not find
noticeable exclusion effects of this railway on wetland birds, with spatial variation
in abundances probably reflecting habitat selection and daily movement patterns.
Information is needed on other study systems to assess the generality of our
findingsinfo:eu-repo/semantics/publishedVersio
Global political responsibility for the conservation of albatrosses and large petrels
Migratory marine species cross political borders and enter the high seas, where the lack of an effective global management framework for biodiversity leaves them vulnerable to threats. Here, we combine 10,108 tracks from 5775 individual birds at 87 sites with data on breeding population sizes to estimate the relative year-round importance of national jurisdictions and high seas areas for 39 species of albatrosses and large petrels. Populations from every country made extensive use of the high seas, indicating the stake each country has in the management of biodiversity in international waters. We quantified the links among national populations of these threatened seabirds and the regional fisheries management organizations (RFMOs) which regulate fishing in the high seas. This work makes explicit the relative responsibilities that each country and RFMO has for the management of shared biodiversity, providing invaluable information for the conservation and management of migratory species in the marine realm
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