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Henrique N Cabral - One of the best experts on this subject based on the ideXlab platform.
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connectivity between Estuaries and marine environment integrating metrics to assess estuarine nursery function
Ecological Indicators, 2011Co-Authors: Rita P Vasconcelos, Patrick Reissantos, Maria Jose Costa, Henrique N CabralAbstract:Natural or anthropogenic induced variations in Estuaries and the dynamics of marine fish populations potentially promote differences in connectivity between Estuaries and marine areas, i.e. in their importance as nursery grounds. Within this context, an integrated assessment of the differential nursery function of the main Estuaries along the Portuguese coast for commercial fish species common sole Solea solea, Senegalese sole Solea senegalensis, flounder Platichthys flesus and sea bass Dicentrarchus labrax was performed through several indicators based on available data. Contribution of individual Estuaries to marine subpopulations was measured with potential metrics (juvenile density, habitat quantity, juvenile number and habitat quality within Estuaries) and effective metrics (estuarine source of young adults in marine environment measured via otolith elemental fingerprints). The relationship between the two types of metrics was also assessed. Estuaries identified as important nursery and/or effective juvenile habitat (EJH) differed with species and no single estuary was best for all, highlighting species-specific regulation of nursery function. Multiple species assessment of nursery and EJH function differed among Estuaries. Management and conservation of Estuaries should focus on sites with higher contributions to adult subpopulations of multiple species. The importance of defining precise scientific and management objectives was emphasized by the different rankings of Estuaries obtained with nursery or EJH criteria. Potential and effective contribution of Estuaries were not significantly correlated, but in a quantitative analysis juvenile densities and number of juveniles seem related with effective contribution in some species. An agreement between potential and effective contributions of Estuaries is concurrent with the acknowledged minor role of juvenile stage processes in regulation of recruitment to adult subpopulations.
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inter and intra estuarine fish assemblage variability patterns along the portuguese coast
Estuarine Coastal and Shelf Science, 2011Co-Authors: Susana Franca, Marco Costa, Henrique N CabralAbstract:Abstract Estuaries along the Portuguese coast differ considerably in terms of their structure, geomorphologic and hydrologic characteristics. They play an important ecological role for different fish species, namely acting as important nursery areas. The fish assemblages of nine Estuaries of the Portuguese coast were investigated in order to evaluate their main inter- and intra-estuarine variability patterns. Fish sampling surveys were conducted in May and July 2006, covering the full estuarine gradient. The different saline areas in each estuary were mapped using a Geographic Information System and fish assemblages’ were described and compared using a functional guilds approach. Generalized linear models were used to relate fish species richness to geomorphologic, hydrologic and environmental characteristics of the Estuaries considered and correspondence analyses were performed to evaluate similarities in fish assemblages’ structure. At a large scale, river flow was the most important factor explaining the variability in species richness in Estuaries along the Portuguese coast. At a regional scale, different abiotic factors explained the occurrence and abundance of fish species in the Estuaries. Nonetheless, the overall role of the estuary was strongly related with the dominant saline zone within each estuary.
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assessing anthropogenic pressures on estuarine fish nurseries along the portuguese coast a multi metric index and conceptual approach
Science of The Total Environment, 2007Co-Authors: Rita P Vasconcelos, Marco Costa, Susana Franca, Patrick Reissantos, Catarina Vinagre, Vanessa F Fonseca, Anabela Maia, M Ruano, Henrique N CabralAbstract:Estuaries are among the most productive ecosystems and simultaneously among the most threatened by conflicting human activities which damage their ecological functions, namely their nursery role for many fish species. A thorough assessment of the anthropogenic pressures in Portuguese estuarine systems (Douro, Ria de Aveiro, Mondego, Tejo, Sado, Mira, Ria Formosa and Guadiana) was made applying an aggregating multi-metric index, which quantitatively evaluates influences from key components: dams, population and industry, port activities and resource exploitation. Estuaries were ranked from most (Tejo) to least pressured (Mira), and the most influential types of pressure identified. In most Estuaries overall pressure was generated by a dominant group of pressure components, with several systems being afflicted by similar problematic sources. An evaluation of the influence of anthropogenic pressures on the most important sparidae, soleidae, pleuronectidae, moronidae and clupeidae species that use these Estuaries as nurseries was also performed. To consolidate information and promote management an ecological conceptual model was built to identify potential problems for the nursery function played by these Estuaries, identifying pressure agents, ecological impacts and endpoints for the anthropogenic sources quantified in the assessment. This will be important baseline information to safeguard these vital areas, articulating information and forecasting the potential efficacy of future management options.
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relative importance of estuarine flatfish nurseries along the portuguese coast
Journal of Sea Research, 2007Co-Authors: Henrique N Cabral, Susana Franca, Rita P Vasconcelos, Patrick Reissantos, Catarina Vinagre, Vanessa F Fonseca, Anabela Maia, Marta B Lopes, M Ruano, Joana CamposAbstract:The relative importance of nursery areas and their relationships with several environmental variables were evaluated in nine estuarine systems along the Portuguese coast based on trawl surveys. Historical data were used to outline changes and trends in the nursery function of some of these Estuaries over the past decades. The dominant flatfish species in Portuguese Estuaries were Platichthys flesus (Linnaeus, 1758), Solea solea (Linnaeus, 1758), Solea senegalensis Kaup, 1858 and Monochirus hispidus Rafinesque, 1814, but their occurrence differed among the Estuaries. P. flesus only occurred in Estuaries north of the Tejo estuary (39°N), S. solea was quite rare along the southern Portuguese coast (south of 37°30′N), S. senegalensis occurred in Estuaries throughout the coast, but its abundance varied considerably, and the occurrence of M. hispidus was limited to the Sado estuary and Ria Formosa. A Correspondence Analysis was performed to evaluate the relationships between flatfish species abundance and geomorphologic and hydrologic characteristics of Estuaries (latitude, freshwater flow, estuarine area, intertidal area, mean depth and residence time). Abiotic characteristics (depth, temperature, salinity, sediment type) of nursery grounds of each flatfish species were also evaluated. Results showed that some Estuaries along the Portuguese coast have nursery grounds used by several flatfish species (e.g. Ria de Aveiro, Sado estuary), while in other systems a segregation was noticed, with juveniles of different species occurring in distinct estuarine areas (e.g. Minho and Mondego Estuaries). This emphasizes the relevance of niche overlap, but the potential for competition may be considerably minimized by differences in resource use patterns and by an extremely high abundance of resources. Peak densities of flatfishes recorded in nurseries areas along the Portuguese coast were within the range of values reported for other geographical areas. Inter-annual abundance variability of all the species in the Tejo and Sado Estuaries was extremely high, with a drastic decrease in P. flesus in the Tejo estuary, probably related to higher water temperature in recent years due to global climate change.
Marcus Sheaves - One of the best experts on this subject based on the ideXlab platform.
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importance of mangrove carbon for aquatic food webs in wet dry tropical Estuaries
Estuaries and Coasts, 2015Co-Authors: Kátya G. Abrantes, Ross Johnston, Rod M Connolly, Marcus SheavesAbstract:Mangroves are traditionally considered to provide important nutrition to tropical estuarine consumers. However, there is still controversy about this, and the extent and importance of these inputs are largely unquantified. In particular, there is no information for food webs of small Estuaries that dominate wet–dry tropical coasts, where freshwater inflow is intermittent, leading to highly seasonal inputs of nutrients from terrestrial systems. Since the relative importance of the different sources depends on the type and extent of different habitats and on hydrological and topographic conditions, results from other regions/type of systems cannot be extrapolated to these Estuaries. Here, δ13C is used to determine the importance of mangrove-derived carbon for Penaeus merguiensis (detritivore; shrimp), Ambassis vachellii (planktivore; fish), and Leiognathus equulus (benthivore; fish) from six small wet–dry tropical Estuaries that differ in mangrove (C3) cover and in type of terrestrial vegetation adjacent to the estuary. Bayesian mixing models confirmed that mangrove material was important to consumers in all Estuaries. There was a gradient in this importance that agreed with the extent of mangrove forests in the Estuaries, as C3 sources were the most important contributors to animals from the three Estuaries with the greatest (>40 %) mangrove cover. There was also evidence of incorporation of C3 material for the three Estuaries with lower (<30 %) mangrove cover. Since these latter Estuaries had no adjacent terrestrial C3 forests, the detected C3 influence can only be of mangrove origin. This shows that mangroves are important contributors to these food webs, underlining the importance of mangroves in supporting estuarine nursery ground value and fisheries productivity.
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Importance of Mangrove Carbon for Aquatic Food Webs in Wet–Dry Tropical Estuaries
Estuaries and Coasts, 2015Co-Authors: Kátya G. Abrantes, Ross Johnston, Rod M Connolly, Marcus SheavesAbstract:Mangroves are traditionally considered to provide important nutrition to tropical estuarine consumers. However, there is still controversy about this, and the extent and importance of these inputs are largely unquantified. In particular, there is no information for food webs of small Estuaries that dominate wet–dry tropical coasts, where freshwater inflow is intermittent, leading to highly seasonal inputs of nutrients from terrestrial systems. Since the relative importance of the different sources depends on the type and extent of different habitats and on hydrological and topographic conditions, results from other regions/type of systems cannot be extrapolated to these Estuaries. Here, δ^13C is used to determine the importance of mangrove-derived carbon for Penaeus merguiensis (detritivore; shrimp), Ambassis vachellii (planktivore; fish), and Leiognathus equulus (benthivore; fish) from six small wet–dry tropical Estuaries that differ in mangrove (C_3) cover and in type of terrestrial vegetation adjacent to the estuary. Bayesian mixing models confirmed that mangrove material was important to consumers in all Estuaries. There was a gradient in this importance that agreed with the extent of mangrove forests in the Estuaries, as C_3 sources were the most important contributors to animals from the three Estuaries with the greatest (>40 %) mangrove cover. There was also evidence of incorporation of C_3 material for the three Estuaries with lower (
Kátya G. Abrantes - One of the best experts on this subject based on the ideXlab platform.
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importance of mangrove carbon for aquatic food webs in wet dry tropical Estuaries
Estuaries and Coasts, 2015Co-Authors: Kátya G. Abrantes, Ross Johnston, Rod M Connolly, Marcus SheavesAbstract:Mangroves are traditionally considered to provide important nutrition to tropical estuarine consumers. However, there is still controversy about this, and the extent and importance of these inputs are largely unquantified. In particular, there is no information for food webs of small Estuaries that dominate wet–dry tropical coasts, where freshwater inflow is intermittent, leading to highly seasonal inputs of nutrients from terrestrial systems. Since the relative importance of the different sources depends on the type and extent of different habitats and on hydrological and topographic conditions, results from other regions/type of systems cannot be extrapolated to these Estuaries. Here, δ13C is used to determine the importance of mangrove-derived carbon for Penaeus merguiensis (detritivore; shrimp), Ambassis vachellii (planktivore; fish), and Leiognathus equulus (benthivore; fish) from six small wet–dry tropical Estuaries that differ in mangrove (C3) cover and in type of terrestrial vegetation adjacent to the estuary. Bayesian mixing models confirmed that mangrove material was important to consumers in all Estuaries. There was a gradient in this importance that agreed with the extent of mangrove forests in the Estuaries, as C3 sources were the most important contributors to animals from the three Estuaries with the greatest (>40 %) mangrove cover. There was also evidence of incorporation of C3 material for the three Estuaries with lower (<30 %) mangrove cover. Since these latter Estuaries had no adjacent terrestrial C3 forests, the detected C3 influence can only be of mangrove origin. This shows that mangroves are important contributors to these food webs, underlining the importance of mangroves in supporting estuarine nursery ground value and fisheries productivity.
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Importance of Mangrove Carbon for Aquatic Food Webs in Wet–Dry Tropical Estuaries
Estuaries and Coasts, 2015Co-Authors: Kátya G. Abrantes, Ross Johnston, Rod M Connolly, Marcus SheavesAbstract:Mangroves are traditionally considered to provide important nutrition to tropical estuarine consumers. However, there is still controversy about this, and the extent and importance of these inputs are largely unquantified. In particular, there is no information for food webs of small Estuaries that dominate wet–dry tropical coasts, where freshwater inflow is intermittent, leading to highly seasonal inputs of nutrients from terrestrial systems. Since the relative importance of the different sources depends on the type and extent of different habitats and on hydrological and topographic conditions, results from other regions/type of systems cannot be extrapolated to these Estuaries. Here, δ^13C is used to determine the importance of mangrove-derived carbon for Penaeus merguiensis (detritivore; shrimp), Ambassis vachellii (planktivore; fish), and Leiognathus equulus (benthivore; fish) from six small wet–dry tropical Estuaries that differ in mangrove (C_3) cover and in type of terrestrial vegetation adjacent to the estuary. Bayesian mixing models confirmed that mangrove material was important to consumers in all Estuaries. There was a gradient in this importance that agreed with the extent of mangrove forests in the Estuaries, as C_3 sources were the most important contributors to animals from the three Estuaries with the greatest (>40 %) mangrove cover. There was also evidence of incorporation of C_3 material for the three Estuaries with lower (
Rod M Connolly - One of the best experts on this subject based on the ideXlab platform.
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umbrellas can work under water using threatened species as indicator and management surrogates can improve coastal conservation
Estuarine Coastal and Shelf Science, 2017Co-Authors: Ben L Gilby, Rod M Connolly, Andrew D Olds, Nicholas A Yabsley, Paul S Maxwell, Ian R Tibbetts, David S Schoeman, Thomas A SchlacherAbstract:Species surrogates, the use of particular species to index habitat condition or to represent ecological assemblages are commonly identified in many ecosystems, but are less tested, and therefore less employed in Estuaries. Estuaries provide important ecosystem goods (e.g. harvestable species) and services (e.g. carbon processing, coastal armouring), but require protection from multiple human activities, meaning that finding surrogates for estuarine condition or faunal assemblages is a significant knowledge gap. In this study, we test the efficacy of the threatened estuary ray Hemitrygon fluviorum, as a suitable indicator of ecosystem condition and management umbrella surrogate species for conservation prioritisation and monitoring purposes within Estuaries. We surveyed fish assemblages and ray presence at ten sites within each of 22 Estuaries in southeast Queensland, Australia, using one hour deployments of baited video arrays. We then tested for correlations between ray presence, a series of environmental variables considered important to ecosystem management within Estuaries (i.e. testing rays as indicator species), and the co-occurring fish species (i.e. testing rays as umbrella species). Estuary rays function as both umbrella species and ecological indicators of habitat status in subtropical Australian Estuaries. As umbrellas, ray occurrence concords with elevated species richness. As ecological indicators, ray distribution concords with habitats of good water quality (especially low turbidity) and more natural vegetation remaining in the catchment. These results highlight the potential for other threatened aquatic vertebrates that are both readily detectable and that are reliable proxies for ecosystems status to be become useful management tools in Estuaries. The protection of such large, threatened species in coastal seascapes allows managers to address multiple targets for conservation, especially; (1) protecting species of conservation concern; (2) maintaining diversity; and (3) protecting optimal habitats by better placing reserves.
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importance of mangrove carbon for aquatic food webs in wet dry tropical Estuaries
Estuaries and Coasts, 2015Co-Authors: Kátya G. Abrantes, Ross Johnston, Rod M Connolly, Marcus SheavesAbstract:Mangroves are traditionally considered to provide important nutrition to tropical estuarine consumers. However, there is still controversy about this, and the extent and importance of these inputs are largely unquantified. In particular, there is no information for food webs of small Estuaries that dominate wet–dry tropical coasts, where freshwater inflow is intermittent, leading to highly seasonal inputs of nutrients from terrestrial systems. Since the relative importance of the different sources depends on the type and extent of different habitats and on hydrological and topographic conditions, results from other regions/type of systems cannot be extrapolated to these Estuaries. Here, δ13C is used to determine the importance of mangrove-derived carbon for Penaeus merguiensis (detritivore; shrimp), Ambassis vachellii (planktivore; fish), and Leiognathus equulus (benthivore; fish) from six small wet–dry tropical Estuaries that differ in mangrove (C3) cover and in type of terrestrial vegetation adjacent to the estuary. Bayesian mixing models confirmed that mangrove material was important to consumers in all Estuaries. There was a gradient in this importance that agreed with the extent of mangrove forests in the Estuaries, as C3 sources were the most important contributors to animals from the three Estuaries with the greatest (>40 %) mangrove cover. There was also evidence of incorporation of C3 material for the three Estuaries with lower (<30 %) mangrove cover. Since these latter Estuaries had no adjacent terrestrial C3 forests, the detected C3 influence can only be of mangrove origin. This shows that mangroves are important contributors to these food webs, underlining the importance of mangroves in supporting estuarine nursery ground value and fisheries productivity.
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Importance of Mangrove Carbon for Aquatic Food Webs in Wet–Dry Tropical Estuaries
Estuaries and Coasts, 2015Co-Authors: Kátya G. Abrantes, Ross Johnston, Rod M Connolly, Marcus SheavesAbstract:Mangroves are traditionally considered to provide important nutrition to tropical estuarine consumers. However, there is still controversy about this, and the extent and importance of these inputs are largely unquantified. In particular, there is no information for food webs of small Estuaries that dominate wet–dry tropical coasts, where freshwater inflow is intermittent, leading to highly seasonal inputs of nutrients from terrestrial systems. Since the relative importance of the different sources depends on the type and extent of different habitats and on hydrological and topographic conditions, results from other regions/type of systems cannot be extrapolated to these Estuaries. Here, δ^13C is used to determine the importance of mangrove-derived carbon for Penaeus merguiensis (detritivore; shrimp), Ambassis vachellii (planktivore; fish), and Leiognathus equulus (benthivore; fish) from six small wet–dry tropical Estuaries that differ in mangrove (C_3) cover and in type of terrestrial vegetation adjacent to the estuary. Bayesian mixing models confirmed that mangrove material was important to consumers in all Estuaries. There was a gradient in this importance that agreed with the extent of mangrove forests in the Estuaries, as C_3 sources were the most important contributors to animals from the three Estuaries with the greatest (>40 %) mangrove cover. There was also evidence of incorporation of C_3 material for the three Estuaries with lower (
Rita P Vasconcelos - One of the best experts on this subject based on the ideXlab platform.
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connectivity between Estuaries and marine environment integrating metrics to assess estuarine nursery function
Ecological Indicators, 2011Co-Authors: Rita P Vasconcelos, Patrick Reissantos, Maria Jose Costa, Henrique N CabralAbstract:Natural or anthropogenic induced variations in Estuaries and the dynamics of marine fish populations potentially promote differences in connectivity between Estuaries and marine areas, i.e. in their importance as nursery grounds. Within this context, an integrated assessment of the differential nursery function of the main Estuaries along the Portuguese coast for commercial fish species common sole Solea solea, Senegalese sole Solea senegalensis, flounder Platichthys flesus and sea bass Dicentrarchus labrax was performed through several indicators based on available data. Contribution of individual Estuaries to marine subpopulations was measured with potential metrics (juvenile density, habitat quantity, juvenile number and habitat quality within Estuaries) and effective metrics (estuarine source of young adults in marine environment measured via otolith elemental fingerprints). The relationship between the two types of metrics was also assessed. Estuaries identified as important nursery and/or effective juvenile habitat (EJH) differed with species and no single estuary was best for all, highlighting species-specific regulation of nursery function. Multiple species assessment of nursery and EJH function differed among Estuaries. Management and conservation of Estuaries should focus on sites with higher contributions to adult subpopulations of multiple species. The importance of defining precise scientific and management objectives was emphasized by the different rankings of Estuaries obtained with nursery or EJH criteria. Potential and effective contribution of Estuaries were not significantly correlated, but in a quantitative analysis juvenile densities and number of juveniles seem related with effective contribution in some species. An agreement between potential and effective contributions of Estuaries is concurrent with the acknowledged minor role of juvenile stage processes in regulation of recruitment to adult subpopulations.
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assessing anthropogenic pressures on estuarine fish nurseries along the portuguese coast a multi metric index and conceptual approach
Science of The Total Environment, 2007Co-Authors: Rita P Vasconcelos, Marco Costa, Susana Franca, Patrick Reissantos, Catarina Vinagre, Vanessa F Fonseca, Anabela Maia, M Ruano, Henrique N CabralAbstract:Estuaries are among the most productive ecosystems and simultaneously among the most threatened by conflicting human activities which damage their ecological functions, namely their nursery role for many fish species. A thorough assessment of the anthropogenic pressures in Portuguese estuarine systems (Douro, Ria de Aveiro, Mondego, Tejo, Sado, Mira, Ria Formosa and Guadiana) was made applying an aggregating multi-metric index, which quantitatively evaluates influences from key components: dams, population and industry, port activities and resource exploitation. Estuaries were ranked from most (Tejo) to least pressured (Mira), and the most influential types of pressure identified. In most Estuaries overall pressure was generated by a dominant group of pressure components, with several systems being afflicted by similar problematic sources. An evaluation of the influence of anthropogenic pressures on the most important sparidae, soleidae, pleuronectidae, moronidae and clupeidae species that use these Estuaries as nurseries was also performed. To consolidate information and promote management an ecological conceptual model was built to identify potential problems for the nursery function played by these Estuaries, identifying pressure agents, ecological impacts and endpoints for the anthropogenic sources quantified in the assessment. This will be important baseline information to safeguard these vital areas, articulating information and forecasting the potential efficacy of future management options.
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relative importance of estuarine flatfish nurseries along the portuguese coast
Journal of Sea Research, 2007Co-Authors: Henrique N Cabral, Susana Franca, Rita P Vasconcelos, Patrick Reissantos, Catarina Vinagre, Vanessa F Fonseca, Anabela Maia, Marta B Lopes, M Ruano, Joana CamposAbstract:The relative importance of nursery areas and their relationships with several environmental variables were evaluated in nine estuarine systems along the Portuguese coast based on trawl surveys. Historical data were used to outline changes and trends in the nursery function of some of these Estuaries over the past decades. The dominant flatfish species in Portuguese Estuaries were Platichthys flesus (Linnaeus, 1758), Solea solea (Linnaeus, 1758), Solea senegalensis Kaup, 1858 and Monochirus hispidus Rafinesque, 1814, but their occurrence differed among the Estuaries. P. flesus only occurred in Estuaries north of the Tejo estuary (39°N), S. solea was quite rare along the southern Portuguese coast (south of 37°30′N), S. senegalensis occurred in Estuaries throughout the coast, but its abundance varied considerably, and the occurrence of M. hispidus was limited to the Sado estuary and Ria Formosa. A Correspondence Analysis was performed to evaluate the relationships between flatfish species abundance and geomorphologic and hydrologic characteristics of Estuaries (latitude, freshwater flow, estuarine area, intertidal area, mean depth and residence time). Abiotic characteristics (depth, temperature, salinity, sediment type) of nursery grounds of each flatfish species were also evaluated. Results showed that some Estuaries along the Portuguese coast have nursery grounds used by several flatfish species (e.g. Ria de Aveiro, Sado estuary), while in other systems a segregation was noticed, with juveniles of different species occurring in distinct estuarine areas (e.g. Minho and Mondego Estuaries). This emphasizes the relevance of niche overlap, but the potential for competition may be considerably minimized by differences in resource use patterns and by an extremely high abundance of resources. Peak densities of flatfishes recorded in nurseries areas along the Portuguese coast were within the range of values reported for other geographical areas. Inter-annual abundance variability of all the species in the Tejo and Sado Estuaries was extremely high, with a drastic decrease in P. flesus in the Tejo estuary, probably related to higher water temperature in recent years due to global climate change.
