Engenharia biológica : uma ferramenta para a conservação

A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.Com o aumento da concentração humana em zonas litorais, que se tem vindo a assistir no ultimo século, as comunidades biológicas costeiras ficaram expostas a uma elevada pressão. Assim, quer uma série de actividades económicas e recreativas, quer a urbanização crescente das zonas costeiras provocam a destruição de habitats. Partes significativas da orla costeira são progressivamente substituídas por estruturas artificiais (portos, marinas, pontões, molhes, etc.,), o que e considerado, pela comunidade cientifica, como uma das principais razoes para a degradação dos ecossistemas costeiros. […]. Conscientes desta realidade, a Universidade dos Açores, em colaboração com investigadores do Reino Unido, desenvolveu um estudo em que testou a seguinte hipótese: seria possível aumentar a abundância de espécies ecologicamente importantes e com elevado interesse económico, em estruturas artificiais, recorrendo a engenharia biológica? Ou seja, através da inclusão experimental de micro-habitat nas estruturas artificiais, potenciar a abundância das espécies alvo. […].info:eu-repo/semantics/publishedVersio

COMMUNITY STRUCTURE AND DYNAMICS OF THE AZOREAN ROCKY INTERTIDAL: EXPLOITATION OF KEYSTONE SPECIES

Experimental work has shown the importance of grazing by patellid limpets in structuring intertidal assemblages. Little is known, however, about the effects of a largescale and chronic removal of limpets. Here I investigate the ecology of Patella candei, a seldom-studied limpet endemic to Macaronesia, and how its long-term fishery impacts the Azorean rocky intertidal. The specific aims of this thesis are to: examine the processes that affect the distribution of limpets in the Azores at a range of spatial scales; investigate the role of grazing by P. candei in structuring the Azorean rocky intertidal and if its harvesting has impacted the dynamics and functioning of this ecosystem. The distribution of limpets was variable at a range of spatial scales. At the scale of islands, inter-island variation in harvesting intensity affected the abundance and size structure of populations of limpets as well as the balance between grazers, algae and barnacles. Stocks of limpets showed clear signs of exploitation and there was evidence that current legislation, including limpet protected zones, have been largely ineffective in protecting these populations. At smaller spatial scales, substratum micro-topography influenced the distribution and sui-vival of limpets. I also showed that the experimental provision of microhabitats could be used as a measure to mitigate the effects of coastal urbanisation, whilst promoting a local enhancement of the stocks of limpets. Overall my results provide evidence for the population and community level effects of limpet harvesting and show that limpet harvesting has a strong impact on the structure and fiinctioning of the Azorean rocky intertidal.University of the Azores. Marine Biological Association of the U

Speaker change detection using BIC: a comparison on two datasets

Abstract — This paper addresses the problem of unsupervised speaker change detection. We assume that there is no prior knowledge on the number of speakers or their identities. Two methods are tested. The first method uses the Bayesian Information Criterion (BIC), investigates the AudioSpectrumCentroid and AudioWaveformEnvelope features, and implements a dynamic thresholding followed by a fusion scheme. The second method is a real-time one that uses a metric-based approach employing line spectral pairs (LSP) and the BIC criterion to validate a potential change point. The experiments are carried out on two different datasets. The first set was created by concatenating speakers from the TIMIT database and is referred to as the TIMIT data set. The second set was created by using recordings from the MPEG-7 test set CD1 and broadcast news and is referred to as the INESC dataset. I

Lapas : pequenas Ilhas de diversidade

A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.[…]. Um estudo recente feito por investigadores do Centro de Investigação em Recursos Naturais da Universidade dos Açores examinou a diversidade de organismos que vivem sob as conchas da lapa Patella aspera. As lapas desempenham um papel importante nos ecossistemas uma vez que controlam a abundancia de algas prevenindo desta forma que estas monopolizem o espaço, permitindo assim a fixação de outro tipo de organismos como por exemplo a pequena craca Chthamalus stellatus. No entanto, o presente estudo mostrou que para alem do papel importante na ecologia das nossas costas, as lapas desempenham ainda um outro papel ao suportarem em si mesmas uma extraordinária diversidade. Foram observados um total de 707 conchas de lapa recolhidas em todas as ilhas do arquipélago nas quais se registaram uns surpreendentes 190 registos de espécies diferentes. […].info:eu-repo/semantics/publishedVersio

A urbanização nos ecossistemas costeiros : implicações para a biodiversidade

A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.[…]. A urbanização dos habitats costeiros, incluindo a construção de estruturas de defesa costeiras, como paredões, quebra-mares ou espigões, tem vindo a aumentar como resposta às previsões para o aumento do nível do mar, maior ocorrência de tempestades e aumento do transporte marítimo. O efeito destes habitats artificiais numa variedade de organismos marinhos tem recebido pouca atenção, apesar de ser fundamental para estabelecer diretrizes para a correta gestão das áreas costeiras urbanizadas. Existe, por tanto, um claro interesse em compreender as consequências ambientais da urbanização, razão que esteve na base do desenvolvimento dum projeto de investigação levado a cabo pelo grupo de Investigação Aquática Macaronésia (IAM) entre os anos 2013 e 2015. O IAM, integrado no CIIMAR é composto por elementos do Departamento de Biologia da Universidade dos Açores, coordenou o projeto “Estruturas urbanas: um fator de mudança na biodiversidade dos ecossistemas costeiros”. O projeto foi financiado pela Fundação para a Ciência e a Tecnologia e contou com a Prof. Ana I. Neto como investigadora responsável e com a Faculty of Science and Environment da Universidade de Plymouth como entidade colaboradora externa. […].info:eu-repo/semantics/publishedVersio

Population structure in high shore littorinids: contrast between riprap and rocky shores

World Congress of Malacology, Ponta Delgada, July 22-28, 2013.The number of anthropogenic structures deployed in coastal areas has increased markedly in recent times and many studies have now shown that these structures seldom mimic the natural habitais they replace. To date, however, most such studies have focused on the numbers and relative abundance of species and little is known about how these structures affect the patterns of species aggregation and size structure, despite the fact that variations in these parameters may have important ecological consequences at population and community levels. Here we compare the relative abundance, patterns of aggregation and size structure of two high shore gastropod littorinids (Tectarius striatus and Melarhaphe neritoides) on riprap and adjacent rocky shores. While the relative abundance of T. striatus was similar on riprap and natural rocky shores, M. neritoides was significantly more abundant on rocky shores. At small spatial scales (cm’s) both littorinids specics showed more aggregated distributions on riprap. At larger scales (cm’s), both littorinids were also more aggregated on riprap although this was only significant for T. striatus. Habitat type influenced the size structure whith both species attaining a significantly larger size on riprap. Here we add to the wider literature by showing that anthropogenic structures can affect intertidal assemblages in ways other than richness or the relative abundance of organisms alone. The here documented variation in patterns of aggregation and size structure between habitats likely influence the population dynamics of these species and may have wider community level consequences

Influence of a breakwater on nearby rocky intertidal community structure

Copyright © 2009 Elsevier Ltd. All rights reserved.It is widely recognised that coastal-defence structures generally affect the structure of the assemblages they support, yet their impact on adjacent systems has been largely ignored. Breakwaters modify the nearby physical environment (e.g. wave action) suggesting a local impact on biological parameters. In the present study, an ACI (After-Control-Impact) design was used to test the general hypothesis that the artificial sheltering of an exposed coast has a strong effect on the structure and functioning of adjacent systems. The effects of a reduction in hydrodynamics were clear for a number of taxa and included the replacement of barnacles, limpets and frondose algae by an increasing cover of ephemeral algae. These effects were evident both at early and late successional stages. Results suggest that the artificial sheltering of naturally exposed coasts can have a strong impact promoting a shift from consumer- to producer-dominated communities, which has important ecological and energetic consequences for the ecosystem

A buil-in mixed-signal block observer (BIMBO) to improve observability in 1149.4 environments

This document proposes an extension to the IEEE 1149.4 test infrastructure, whereby a bank of sigma-delta first order modulators enables the simultaneous observation of several analog pins in a single component. The modulator output bit streams are shifted out and made available to an external test controller that comprises the corresponding bank of decimation filters and other decision and control logic. The architecture proposed is fully non-intrusive and may be used to support debug and test operations in mixed-signal environments

Avaliação do stock de Abalones: uma pesca sustentável

Jornadas "Ciência nos Açores – que futuro? Tema Ciências Naturais e Ambiente", Ponta Delgada, 7-8 de Junho de 2013.A falta de informação anterior ao início de uma exploração de uma espécie alvo é ponto comum à maior parte das pescarias. A maioria dos estudos só é iniciada após indícios claros de efeitos de um excesso de pesca. No entanto, esta situação é indicadora de que a pesca já causou alterações drásticas na estrutura das populações alvo e que, consequentemente, já não existe um ponto de referência que informe a gestão e a recuperação dos mananciais. A exploração do abalone nos Açores é virtualmente inexistente, ao contrário de muitas outras regiões onde a sua captura tem levado à ruptura dos mananciais. A espécie existente nos Açores, Haliotis tuberculata, é um recurso com elevado interesse gastronómico e económico e existem indícios de que tem sido gradualmente introduzida na gastronomia regional. Nos Açores os mananciais de H. tuberculata podem, à partida, ser considerados virgens, mas não existe informação sobre a sua abundância, biologia e ecologia. Concomitantemente, não existe qualquer tipo de restrição ou legislação regional relativamente à exploração deste marisco. O presente projecto tem como objectivo avaliar o estado actual das populações de H. tuberculata providenciando um ponto de referência para estudos futuros e garantindo deste modo uma avaliação rigorosa dos impactos de uma potencial pescaria. Neste projecto examinam-se aspectos da biologia e da ecologia de H. tuberculata que providenciarão dados úteis para garantir uma exploração sustentável deste recurso. O presente estudo providenciará também recomendações para a gestão desta pescaria baseadas na revisão bibliográfica e na informação recolhida.ABSTRACT: A common drawback in predicting the consequences of harvest rates is that there is no a priori information regarding the status of exploited populations. Most studies are done only when there is a perceived impact upon the targeted populations. In most situations, this means that fishing has already caused dramatic reductions in populations sizes and changes in the population structure so that a reference state against which to compare and predict the resilience or recovery of target populations does not exist. In the Azores unlike there has been little impact on the stocks of the abalone Haliotis tuberculata. However, H. tuberculata is a valuable and highly regarded resource and there is now evidence that it is slowly being introduced into the regional gastronomy. Although Azorean abalone stocks may be considered relatively virgin, there is yet no information regarding the local abundance, biology or ecology of this species. Similarly, there is no regional legislation regarding the exploitation of this shellfish. The present project aims to provide a reference state to which future studies can be compared and thus accurately assess the impact of a potential fishery. This involves examining the biology and ecology of H. tuberculata, creating a dynamic population model that will inform the authorities and provide valuable information that fosters sustainable harvest rates. The present project will also provide recommendations for the future management of the fishery based on a literature review and the field information collected

Genetic population structure and connectivity of Azorean limpets

Ocean Science Meeting. Hawaii Convention Center, Honolulu, Hawaii, USA, 23-28 de Fevereiro.There is growing consensus that anthropogenic activities significantly rarefy the structure and functioning of marine ecosystems. Oceanic islands such as the Azores (NE Atlantic) constitute unique habitats with fragile communities, which are highly susceptible to degradation and ecosystem disruption. . Patellid limpets have traditionally been collected as a food resource and in 1988 the limpet fishery in São Miguel Island collapsed, and after a one-year ban throughout the archipelago, the stocks were allowed to recover, avoiding catastrophic overexploitation effects. In 1993, legislation was passed to protect this resource, i.e. limpet no-take areas were created, seasonal harvesting restrictions were applied and minimum legal catch sizes were established. However, a recent survey has shown that limpet populations still show clear signs of overexploitation and some populations are virtually extinct in some islands. Here we have developed new multiplexed and described microsatellite markers for the species Patella aspera and P. candei and have examined their genetic diversity, gene flow and population connectivity in the Azores Archipelago. Overall, such information is a fundamental asset to inform conservation strategies and to promote the sustainable exploitation of macaronesian limpets.FC