17 resultados para species list

em Universidade dos Açores - Portugal


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World Congress of Malacology, Ponta Delgada, July 22-28, 2013.

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Copyright © 2014 The Authors. Oikos © 2014 Nordic Society Oikos.

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Deep Ocean Species. The little that is known mostly comes from collected specimens. L.A. Rocha et al. Letter "Specimen collection: An essential tool" (23 May, 344: 814) brilliantly discuss the importance of specimen collection and present the evolution of collecting since the mid-19th century until our present strict codes and conducts. However, it is also important to emphasize the fact that the vast majority of deep ocean macro-organisms are only known to us because of collection and this is a strong argument that should be present in our actions as scientists. If the deep is considered the least known of Earth’s habitats (1% or so according to recent estimates) then what awesome collection of yet to discover species are still there to be properly described? As the authors point citing (1), something around 86% of species remain unknown. Voucher specimens are fundamental for the reasons pointed out and perhaps the vast depths of the World’s oceans are the best example of that importance. The resumed report of 2010 Census of Marine Life (2) showed that among the millions of specimens collected in both familiar and seldom-explored waters, the Census found more than 6,000 potentially new species and completed formal descriptions of more than 1,200 of them. It also found that a number of rare species are in fact common. Voucher specimens are essential and, again agreeing with L.A. Rocha et al. Letter (see above), the modern approach for collecting will not be a cause for extinctions but instead a valuable tool for knowledge, description and even, as seen above, a way to find out that supposed rare species may not be that rare and even prove to reach abundant populations.

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Dissertação de Mestrado, Estudos Integrados dos Oceanos, 25 de Março de 2013, Universidade dos Açores.

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Dissertação de Mestrado, Biodiversidade e Ecologia Insular, 4 de Abril de 2014, Universidade dos Açores.

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Copyright: © 2014 Aranda et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Tese de Doutoramento, Ciências do Mar (Biologia Marinha)

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The species abundance distribution (SAD) has been a central focus of community ecology for over fifty years, and is currently the subject of widespread renewed interest. The gambin model has recently been proposed as a model that provides a superior fit to commonly preferred SAD models. It has also been argued that the model's single parameter (α) presents a potentially informative ecological diversity metric, because it summarises the shape of the SAD in a single number. Despite this potential, few empirical tests of the model have been undertaken, perhaps because the necessary methods and software for fitting the model have not existed. Here, we derive a maximum likelihood method to fit the model, and use it to undertake a comprehensive comparative analysis of the fit of the gambin model. The functions and computational code to fit the model are incorporated in a newly developed free-to-download R package (gambin). We test the gambin model using a variety of datasets and compare the fit of the gambin model to fits obtained using the Poisson lognormal, logseries and zero-sum multinomial distributions. We found that gambin almost universally provided a better fit to the data and that the fit was consistent for a variety of sample grain sizes. We demonstrate how α can be used to differentiate intelligibly between community structures of Azorean arthropods sampled in different land use types. We conclude that gambin presents a flexible model capable of fitting a wide variety of observed SAD data, while providing a useful index of SAD form in its single fitted parameter. As such, gambin has wide potential applicability in the study of SADs, and ecology more generally.

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The Desertas Islands (Madeira, Portugal) are the sole home of one of the largest and rarest wolf spiderspecies, Hogna ingens (Blackwall 1857) (Araneae, Lycosidae). Despite its size, it inhabits a single valleyin the North of the Deserta Grande Island, Vale da Castanheira, currently invaded by the herb Phalarisaquatica. This invasive species competes with the native flora and was subject to several eradicationexperiments, namely through fire and chemicals. The objectives of this work were to: (1) estimate thecurrent distribution and abundance of H. ingens and respective trends; (2) evaluate the impact of theinvasive plant and eradication methods on the spider population; (3) suggest future measures for therecovery of the species; and (4) evaluate its conservation status according to the IUCN criteria. The current distribution of H. ingens covers 23 ha, a recent reduction from its original 83 ha, correspond-ing to the entire Vale da Castanheira. A total of 4447 and 4086 adults and 71,832 and 24,635 juvenileswere estimated to live in the valley during 2011 and 2012, respectively. We found a significant negativeimpact of P. aquatica cover on the presence and abundance of H. ingens and that chemical treatmentspecifically directed towards the invasive plant species may be the only way to effectively recover thespider's habitat. We suggest (1) regular monitoring; (2) extend chemical treatments; (3) ex-situ conserva-tion with future reintroduction of adults. Based on the current area of occupancy (AOO) of H. ingens and itsrecent decline in both AOO and number of individuals, it was recently classified as Critically Endangeredby IUCN and we suggest its urgent inclusion in the Habitats Directive species lists.

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This paper presents and describes the first confirmed occurrence of the Yellow-crowned Night Heron Nyctanassa violacea in the Azores, which also represents the first record for Europe and the Western Palearctic. We also present and discuss subsequent reports of the species in Macaronesia. Several hypotheses may help to explain the occurrence of this species in this part of the Atlantic, including disorientation caused by strong winds and increasing observation pressure. However, further studies are necessary to assess the part played by the different factors in the occurrence of new vagrant individuals/species in Macaronesia.

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Studies on the feeding habits of aquatic organisms are a requirement for the management and sustainable use of marine ecosystems. The aim of the present research was to analyze the habits and trophic similarities of decapods, starfish and fish in order to propose trophic relationships between taxa, using Hennigian methods of phylogenetic systematics. This new grouping hypothesis, based on shared and exclusive food items and food types, corresponds to the broad taxonomic groups used in the analysis. Our results indicate that algae, Mollusca, Polychaeta, Crustacea, Echinodermata and Actinopterygii are the most exploited common resources among the species studied. Starfish were differentiated from other organisms for being stenophagic, and were grouped for feeding on bivalve mollusks. A larger group of fish and crustaceans shares algae and mainly crustaceans as food items. A third group united all eight species of Actinopterygii. This largest subgroup of fish is typically carnivorous, feeding on Anthozoa and a great quantity of Crustacea. Synodus foetens has a special position among fishes, due to its unique feeding on nematodes. A Euclidean distance dendrogram obtained in a previous publication grouped S. foetens with starfish. That result was based on a few non-exclusive shared similarities in feeding modes, as well as on shared absences of items, which are not an adequate grouping factor. Starfish are stenophagic, eating bivalves almost exclusively. Synodus foetens and Isopisthus parvipinnis have restricted food items, and are thus intermediary in relation to starfish, decapods, and other fish, which are euryphagous. The trophic cladogram displays details of food items, whether or not shared by all species. The resulting trophic analysis is consistent with known historical relationships.

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Malacoctenus carrowi is described on the basis of three specimens from the Cape Verde Islands. The species is most similar to the only other eastern Atlantic species of the same genus, Malacoctenus africanus Cadenat, 1951. M. carrowi differs in colouration, a more elongated body, longer snout length, lower lateral line scale count and the absence of scales on the breast and is probably endemic to the Cape Verde Islands. A key to the Atlantic species of Malacoctenus is provided.

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The hoverfly fauna of the Azores currently comprises 23 species (Smit 2010), but the current state of knowledge concerning these species differs for each island. In the year 1938, R. Frey and R. Storå recorded the first seven hoverfly species on Pico Island (Frey 1945), and these very same ones were still mentioned by Rojo et al. (1997). Smit (2010) added one more species to this list (Table 1). In the summer of 2014, the author of this article sampled hoverflies on Pico Island in several habitats. In this paper, the results will be presented.