Ronaldo Sousa
Universidade do Minho, Biology, Faculty Member
A major challenge for ecologists is understanding ecosystem dynamics and function under environmental and anthropogenic stresses. An approach for addressing this challenge is the analysis of the different components contributing to... more
A major challenge for ecologists is understanding ecosystem dynamics and function under environmental and anthropogenic stresses. An approach for addressing this challenge is the analysis of the different components contributing to secondary production (ie, consumer incorporation of organic matter or energy per time unit) and how this production is influenced by external factors.
Abstract Invasive bivalves may cause great ecological, evolutionary, and economic impacts in freshwater ecosystems. Species such as Corbicula fluminea, Dreissena bugensis, Dreissena polymorpha, Limnoperna fortunei, and Sinanodonta... more
Abstract Invasive bivalves may cause great ecological, evolutionary, and economic impacts in freshwater ecosystems. Species such as Corbicula fluminea, Dreissena bugensis, Dreissena polymorpha, Limnoperna fortunei, and Sinanodonta woodiana are widely distributed hyper-successful invaders, but several others not yet invasive (or at least not considered as such) may become so in the near future.
Vlaams Instituut voor de Zee. VLIZ. Informatie over marien en kustgebonden onderzoek & beleid in Vlaanderen.
Aim The indirect consequences of biotic homogenization, the process of a gradual increase in the similarity of regional biotas driven by the combined effects of species invasions and extinctions, are still poorly understood. In this... more
Aim The indirect consequences of biotic homogenization, the process of a gradual increase in the similarity of regional biotas driven by the combined effects of species invasions and extinctions, are still poorly understood. In this study, we aimed to assess the ability of a native affiliate species to maintain its host resources under the condition of biotic homogenization of host communities.
Summary This study evaluated the habitat modifications of sea lampreys (Petromyzon marinus) during their spawning season. Males are responsible for digging circular or oval shape nests with lengths varying between 0.80 and 2.25 m (mean... more
Summary This study evaluated the habitat modifications of sea lampreys (Petromyzon marinus) during their spawning season. Males are responsible for digging circular or oval shape nests with lengths varying between 0.80 and 2.25 m (mean 1.49 m±0.43 SD). Females join later during the final phase of the process. Nest depth varies between 0.20 and 0.40 m (mean 0.28 m±0.07 SD).
The spatial distribution of bivalves in relation to environmental conditions was studied along a second-and third order stream—medium-sized river (River Ipoly)—large river (River Danube) continuum in the Hungarian Danube River system.... more
The spatial distribution of bivalves in relation to environmental conditions was studied along a second-and third order stream—medium-sized river (River Ipoly)—large river (River Danube) continuum in the Hungarian Danube River system. Quantitative samples were collected four times in 2007 and a total of 1662 specimens, belonging to 22 bivalve species were identified. Among these species, two are endangered (Pseudanodonta complanata, Unio crassus) and five are invasive (Dreissena polymorpha, D.
ABSTRACT 1. Southern European populations of Margaritifera margaritifera (L., 1758) are under-studied. From 1986 to 2001 this species was considered extinct in Portugal but between 2001 and 2002 six northern populations were found, five... more
ABSTRACT 1. Southern European populations of Margaritifera margaritifera (L., 1758) are under-studied. From 1986 to 2001 this species was considered extinct in Portugal but between 2001 and 2002 six northern populations were found, five of which were previously unknown.
ABSTRACT 1. Procambarus clarkii (Girard, 1852) is a well-established invasive species in many worldwide aquatic ecosystems and is responsible for several ecological and economic impacts. This study examines the major factors responsible... more
ABSTRACT 1. Procambarus clarkii (Girard, 1852) is a well-established invasive species in many worldwide aquatic ecosystems and is responsible for several ecological and economic impacts. This study examines the major factors responsible for its invasive dynamics in the international section of the River Minho (north-west Iberian Peninsula).
Abstract Large-scale mortality of invasive bivalves was observed in the River Danube basin in the autumn of 2011 due to a particularly low water discharge. The aim of this study was to quantify and compare the biomass of invasive and... more
Abstract Large-scale mortality of invasive bivalves was observed in the River Danube basin in the autumn of 2011 due to a particularly low water discharge. The aim of this study was to quantify and compare the biomass of invasive and native bivalve die-offs amongst eight different sites and to assess the potential role of invasive bivalve die-offs as a resource subsidy for the adjacent terrestrial food web.
The Asian clam Corbicula fluminea is one of the most invasive species in brackish and freshwater ecosystems. In the Minho estuary (NW of the Iberian Peninsula) this invasive species can reach densities up to 4000 ind m− 2, occurring over... more
The Asian clam Corbicula fluminea is one of the most invasive species in brackish and freshwater ecosystems. In the Minho estuary (NW of the Iberian Peninsula) this invasive species can reach densities up to 4000 ind m− 2, occurring over large areas. C. fluminea can significantly alter the physical structure of the benthic environment, and the structure and functioning of this estuarine community. In this context, this work aimed to evaluate the correlation of different densities of C. fluminea on the macrozoobenthos across five sites in the Minho estuary during three distinct periods of 2009 (winter, spring and summer). The comparative analysis indicate that macrozoobenthic density, biomass and diversity positively respond to increasing density of C. fluminea, with abiotic conditions also playing an important role in the observed patterns, both in brackish and freshwater settings. Crustacea, Insecta and Gastropoda are the main faunal groups responding positively to C. fluminea increasing density. The mechanisms responsible for these positive trends still needs to be established although engineering activities and the increase in waste products may play essential roles. Nevertheless, despite such positive effects, earlier studies have showed that the density, biomass and spatial distribution of some species, especially native bivalves dramatically decreased after C. fluminea introduction.► Bivalves can contribute to particularly important impacts in shallow-water areas. ► The Asian clam Corbicula fluminea is one of the most invasive species. ► In Minho estuary this species can reach densities up to 4000 ind m− 2. ► C. fluminea can significantly alter the physical structure of the benthic environment.
Research Interests: Oceanography, Invasive Species, Biological invasions, Biological Sciences, Protein Structure and Function, and 15 moreEnvironmental Sciences, Estuaries, Ecosystems, Comparative Analysis, Iberian Peninsula, Biological Invasion, Spatial Distribution, Sea, Ecosystem engineer, Benthos, Ecosystem service, Ecosystem Function, Ecosystem Functioning, Aquatic Animals, and Biological Invasions and Ecosystem Functioning
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Research Interests: Earth Sciences, Conservation, Biomass, Ecology, Population Dynamics, and 17 moreConservation planning, Estuarine Ecology, Biological Sciences, Aquatic Ecosystem, Environmental Sciences, Bivalvia, Freshwater bivalves, Aquatic Biology, Abundance, Spatial Distribution, Bivalve, Organic Matter, Minho estuary, Pisidium, Pisidium amnicum, Abiotic factors, and Multiple regression Model
Pisidium amnicum is an important indigenous species in the freshwater tidal portion of the River Minho estuary and until the introduction of the non-indigenous invasive species Corbicula fluminea was the most abundant bivalve in this... more
Pisidium amnicum is an important indigenous species in the freshwater tidal portion of the River Minho estuary and until the introduction of the non-indigenous invasive species Corbicula fluminea was the most abundant bivalve in this ecosystem. Between January 2005 and August 2006 monthly samples were collected in three sites to study the abundance, biomass, growth and production of P. amnicum. Results indicate that P. amnicum has continuous growth throughout its life span and growth rates were higher during the early phases of development, coincident with the spring and summer months. Life span estimated was 24 months. The annual 2005 growth production of P. amnicum estimated was 2.339 g AFDW m−2 year−1, and the mean annual biomass was 1.594 g AFDW m−2, resulting in a P/B¯ ratio of 1.47 year−1 and a turnover time of 248.7 days. The annual 2005 elimination production estimated was 7.541 g AFDW m−2 year−1, resulting in an E/B¯ ratio of 4.73 year−1. It is concluded that P. amnicum continues to play an important role in the food web in areas where it coexists with C. fluminea. Previous studies showed declines in the indigenous population after the introduction of C. fluminea and currently, areas of high abundance are restricted to small patches in the upper limit of the tidal influence. Consequently, P. amnicum is now under considerable pressure and this situation requires ecological and conservational attention.
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The epibenthic community of the Minho Estuary was studied during the summer of 2006. Diversity was generally low and a total of 14 fish and five crustacean taxa were identified. Multivariate analysis revealed two site clusters (A and B).... more
The epibenthic community of the Minho Estuary was studied during the summer of 2006. Diversity was generally low and a total of 14 fish and five crustacean taxa were identified. Multivariate analysis revealed two site clusters (A and B). Water conductivity and percentage of fine sand were the abiotic variables that most contributed to the spatial distinction between clusters. The species contributing the most to the average similarity within Cluster A were Crangon crangon and Pomatoschistus microps, while in Cluster B was Atyaephyra desmarestii. Possible factors responsible for the low diversity of the epibenthic community in Minho Estuary were the low macrozoobenthic abundance and diversity, and the high abiotic oscillations between tides (mainly salinity) acting on the ecosystem.
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Research Interests: Oceanography, Invasive Species, Biological invasions, Biological Sciences, Protein Structure and Function, and 15 moreEnvironmental Sciences, Estuaries, Ecosystems, Comparative Analysis, Iberian Peninsula, Biological Invasion, Spatial Distribution, Sea, Ecosystem engineer, Benthos, Ecosystem service, Ecosystem Function, Ecosystem Functioning, Aquatic Animals, and Biological Invasions and Ecosystem Functioning
Research Interests: Oceanography, Invasive Species, Biological invasions, Biological Sciences, Protein Structure and Function, and 15 moreEnvironmental Sciences, Estuaries, Ecosystems, Comparative Analysis, Iberian Peninsula, Biological Invasion, Spatial Distribution, Sea, Ecosystem engineer, Benthos, Ecosystem service, Ecosystem Function, Ecosystem Functioning, Aquatic Animals, and Biological Invasions and Ecosystem Functioning
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Extirpation or even extinction of freshwater invertebrate species is a neglected conservation issue; declines in abundance and spatial distribution for freshwater invertebrates are far less documented than for vertebrate species. One of... more
Extirpation or even extinction of freshwater invertebrate species is a neglected conservation issue; declines in abundance and spatial distribution for freshwater invertebrates are far less documented than for vertebrate species. One of the faunal freshwater groups more threatened are bivalves. In this study, we used a long data set (from 2004 to 2011) with samples collected annually over a large area (comprising 16 different sites) to document a rapid decline of the bivalve Pisidium amnicum in the Minho River tidal freshwater ...
We present a report of a patient with systemic lupus erythematosus who subsequently developed hemichorea associated with increased anti-phospholipid antibodies values.
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Research Interests: Communication, Public Opinion, Social Sciences, Conservation Biology, Ecology, and 13 moreInvasive Species, Biodiversity, Biological Sciences, Environmental Sciences, Uncertainty, Society, World, Animals, Resource Management, Introduced species, Environmental Impact, Conservation of Natural Resources, and Opinions
Green coconut shells were treated with acid, base and hydrogen peroxide solutions for 3, 6, 12 and 24 h for removing toxic metals from synthetic wastewater. The removal of ions by the adsorbent treated with 0.1 mol L-1 NaOH/ 3h was 99.5%... more
Green coconut shells were treated with acid, base and hydrogen peroxide solutions for 3, 6, 12 and 24 h for removing toxic metals from synthetic wastewater. The removal of ions by the adsorbent treated with 0.1 mol L-1 NaOH/ 3h was 99.5% for Pb2+ and 97.9% for Cu2+. The removal of Cd2+, Ni2+, Zn2+, using adsorbent treated with 1.0 mol L-1 NaOH/3 h, was 98.5, 90.3 and 95.4%, respectively. Particle size, adsorbent concentration and adsorption kinetics were also studied. An adsorbent size of 60-99 mesh and a concentration of 30-40 g/L for 5 min exposure were satisfactory for maximum uptake of Pb2+, Ni2+, Cd2+, Zn2+ and Cu2+ and can be considered as promising parameters for treatment the aqueous effluents contaminated with toxic metals.
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Monitoring biotic factors is gaining in importance within Europe, due in large extent to the ecological approach of the European Water Framework Directive (WFD) and the importance attributed to biological elements in the assessment of... more
Monitoring biotic factors is gaining in importance within Europe, due in large extent to the ecological approach of the European Water Framework Directive (WFD) and the importance attributed to biological elements in the assessment of quality status. Despite its ecological importance, the Lima Estuary is subjected to a range of perturbations, including urban, agricultural and industrial waste discharge, dredging activities, and introduction of non-indigenous invasive species. This work uses macrozoobenthic data to study the ecological status of the lower Lima Estuary where most disturbance factors are concentrated. We were able to verify consistent differences along space, and to identify different degrees of disturbance in the estuarine area. These results allow us to suggest cost-effective approaches to monitor this estuarine area, aiming on contributing to effective management actions.
Research Interests: Invertebrates, Ecology, Invasive Species, Risk Management, Rivers, and 14 moreRisk assessment, Biodiversity, Environmental Pollution, Multidisciplinary, Urban Agriculture, Portugal, Animals, Cost effectiveness, Quality assessment, Anthropogenic impact, Industrial Waste, Risk Assessment, Conservation of Natural Resources, and Oceans and Seas
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Research Interests: Earth Sciences, Conservation, Biomass, Ecology, Population Dynamics, and 17 moreConservation planning, Estuarine Ecology, Biological Sciences, Aquatic Ecosystem, Environmental Sciences, Bivalvia, Freshwater bivalves, Aquatic Biology, Abundance, Spatial Distribution, Bivalve, Organic Matter, Minho estuary, Pisidium, Pisidium amnicum, Abiotic factors, and Multiple regression Model
Research Interests: Earth Sciences, Conservation, Biomass, Ecology, Population Dynamics, and 17 moreConservation planning, Estuarine Ecology, Biological Sciences, Aquatic Ecosystem, Environmental Sciences, Bivalvia, Freshwater bivalves, Aquatic Biology, Abundance, Spatial Distribution, Bivalve, Organic Matter, Minho estuary, Pisidium, Pisidium amnicum, Abiotic factors, and Multiple regression Model
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Research Interests: Oceanography, Invasive Species, Biological invasions, Biological Sciences, Protein Structure and Function, and 15 moreEnvironmental Sciences, Estuaries, Ecosystems, Comparative Analysis, Iberian Peninsula, Biological Invasion, Spatial Distribution, Sea, Ecosystem engineer, Benthos, Ecosystem service, Ecosystem Function, Ecosystem Functioning, Aquatic Animals, and Biological Invasions and Ecosystem Functioning
The identification of different species inside the Corbicula genus is complicated due to the high variation of shell shape, colour and sculpture of the individuals. The species Corbicula fluminea has been present in the River Minho... more
The identification of different species inside the Corbicula genus is complicated due to the high variation of shell shape, colour and sculpture of the individuals. The species Corbicula fluminea has been present in the River Minho estuary (NW Portugal) at least since 1989. More recently, individuals of the same genus colonized an adjacent estuary (River Lima estuary). Although appearing also to be C. fluminea, the individuals of the Lima estuary differ from those of Minho estuary in the colour and shape of the shell. Therefore, the two populations were compared by conventional morphometric measures (shell length, width and height), geometric morphometric methods (landmarks analysis using the interior of the shell) and genetic analysis (based on the mitochondrial cytochrome c oxidase subunit I gene sequence). Genetic analysis showed an identical mtCOI sequence indicating that both populations belong to the species C. fluminea. However, results of conventional and geometric morphometric analysis showed significant differences in shell shape between individuals from the two populations. These differences may be due to (a) phenotypical plasticity in response to different environmental and/or ecological conditions existing in the two estuaries, (b) different origins of the populations and/or distinct routes until reaching the two estuaries and (c) inter-population genetic differences caused by processes occurring after the introduction of the species in the two estuaries (e.g. differential selection).
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Research Interests: Oceanography, Invasive Species, Biological invasions, Biological Sciences, Protein Structure and Function, and 15 moreEnvironmental Sciences, Estuaries, Ecosystems, Comparative Analysis, Iberian Peninsula, Biological Invasion, Spatial Distribution, Sea, Ecosystem engineer, Benthos, Ecosystem service, Ecosystem Function, Ecosystem Functioning, Aquatic Animals, and Biological Invasions and Ecosystem Functioning
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Extirpation or even extinction of freshwater invertebrate species is a neglected conservation issue; declines in abundance and spatial distribution for freshwater invertebrates are far less documented than for vertebrate species. One of... more
Extirpation or even extinction of freshwater invertebrate species is a neglected conservation issue; declines in abundance and spatial distribution for freshwater invertebrates are far less documented than for vertebrate species. One of the faunal freshwater groups more threatened are bivalves. In this study, we used a long data set (from 2004 to 2011) with samples collected annually over a large area (comprising 16 different sites) to document a rapid decline of the bivalve Pisidium amnicum in the Minho River tidal freshwater ...
We present a report of a patient with systemic lupus erythematosus who subsequently developed hemichorea associated with increased anti-phospholipid antibodies values.