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Carla Morri - One of the best experts on this subject based on the ideXlab platform.
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Seagrass on the rocks: Posidonia oceanica settled on shallow-water hard substrata withstands wave stress beyond predictions
Estuarine Coastal and Shelf Science, 2016Co-Authors: Monica Montefalcone, Roberto Cabella, Chiara Francesca Schiaffino, Carlo Nike Bianchi, Carla Morri, Matteo Vacchi, Cristina Carbone, Franco Marco Elter, Marco FerrariAbstract:A multidisciplinary approach was applied to investigate the role of abiotic constraints in the settlement of Posidonia oceanica on shallow rocks in two coastal areas of the Ligurian Sea (Italy, NW Mediterranean). Meadows developed very shallow upper limits, at 1.5 m depth in both areas, and with a distinctive morphology of stripes growing on rocky outcrops orthogonal to the coastline. Application of a predictive model to indicate the reference condition zone for the Meadow upper limit, already validated on Meadows developing on soft-bottoms, was not adequate for these rocky substrata as the Meadow upper limits were found shallower than model predictions (>5 m depth). Geological and geomorphological characteristics of the rocky shores were analysed through geomechanic and petrographic analyses (i.e. thin sections, SEM analyses, rock hardness tests) whilst the shape and the features of the Meadows (i.e. shoot density and maximum leaf length) were assessed through scuba diving surveys. Among the different lithotypes occurring at the sites in the alternating and interbedded outcrops, P. oceanica was passively selected (i.e. due to the seedlings survival and settlement there) on the strongest (i.e. less erodible) lithotypes, whilst the comparatively weaker and more erodible rocks remained unvegetated and covered by a layer of soft-sediments. P. oceanica, settling on specific rocky substrata with favourable lithological and geomechanical characteristics, is able to establish outside the theoretical reference zone predicted by the model for soft sediments due to greater attachment strength and possible resistance to hydrodynamic forces. Combining biological, ecological, mineralogical, geological and geomorphological approaches was effective for explaining the primary role of substratum nature in the spatial variability of seagrass Meadows, with geomechanical and lithological characteristics of the rocks being equally important abiotic factors than sedimentological features. (C) 2016 Elsevier Ltd. All rights reserved.
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The influence of coastal dynamics on the upper limit of the Posidonia oceanica Meadow
Marine Ecology, 2010Co-Authors: Monica Montefalcone, Carla MorriAbstract:Abstract The recognized ecological importance of Posidonia oceanica, the most important seagrass of the Mediterranean Sea, makes it crucial to assess the state of health of its Meadows, discriminating natural from anthropogenic impacts. In this paper, the hydrodynamic conditions at the upper limit of P. oceanica Meadows along the Ligurian coast (NW Mediterranean Sea) were investigated. A relationship between the distance of the upper limit of the Meadow from the shoreline and the morphodynamic domain of the beach (i.e. distinctive types of beach produced by the topography, wave climate and sediment composition) was found. A zonation of the state of the shallow portions of the Meadows down the submerged beach profile was identified. Zone a, from the shoreline to the breaking limit, is naturally critical for the development of the Meadow. Zone b, from the breaking limit to the closure depth, is subjected to natural and human impacts. Zone c, below the closure depth, is little influenced by coastal dynamics. This study quantifies for the first time how much the status of the shallow portions of P. oceanica Meadows is dependent on coastal dynamics, which is important for their proper management.
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Measuring change of Mediterranean coastal biodiversity: diachronic mapping of the Meadow of the seagrass Cymodocea nodosa (Ucria) Ascherson in the Gulf of Tigullio (Ligurian Sea, NW Mediterranean)
Hydrobiologia, 2007Co-Authors: Mattia Barsanti, Carlo Nike Bianchi, Ivana Delbono, Ornella Ferretti, Andrea Peirano, Carla MorriAbstract:Monitoring the extension of seagrass Meadows over time is of primary importance for the surveillance of marine coastal biodiversity. Here, we analyse the evolution of the Meadow of Cymodocea nodosa in the Gulf of Tigullio, a coastal tract of naturalistic interest but subjected to high anthropogenic pressure. Historical maps at a scale 1:25,000 of C. nodosa Meadow drawn in 1986, 1991 and 2001 were processed with GIS (Geographical Information System), using overlay vector methods. Diachronic analyses allowed the measurements of temporal changes, in term of percentage gain or loss of Meadow extension, through concordance and discordance maps. A general increase in the extension of the Meadow from 1986 to 1991 was evidenced, but the disparity of mapping methods (SCUBA diving in 1986, Side Scan Sonar in 1991) in the two surveys imposes caution when interpreting this result. On the other hand, the comparison of 1991 and 2001 maps, both derived from Side Scan Sonar surveys, showed a regression of the Meadow of about 60% in the northern area, and modifications in the upper and lower limits of the Meadow due to the impact of coastal works. C. nodosa Meadow showed the only enlargement in front of the mouth of the Entella River, due to the increase in nutrient contents for rainfall in the period 1988–1994. The overall analysis evidenced a net decrease in seagrass Meadow extension, an early warning of risk for marine coastal biodiversity in the Gulf of Tigullio.
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A new synthetic index and a protocol for monitoring the status ofPosidonia oceanica Meadows: a case study at Sanremo (Ligurian Sea, NW Mediterranean)
Aquatic Conservation: Marine and Freshwater Ecosystems, 2006Co-Authors: Monica Montefalcone, Giancarlo Albertelli, Carlo Nike-Bianchi, Mauro Mariani, Carla MorriAbstract:1. The status of a Posidonia oceanica Meadow in front of the town of Sanremo, Italy, was studied through a combined use of benthic mapping and synthetic indices. 2. Mapping was accomplished by integrating side scan sonar imagery and data collected by scuba diving along transects placed perpendicularly to the coastline. A thematic map (scale 1:5000) was produced. Extent of the Meadow, occurrence of dead matte areas, and morphology of the lower limit (with new definition) are all described. 3. Two synthetic environmental indices were applied to transect data in order to quantify the status of the Meadow: the Conservation Index and the Substitution Index. The former is related to the proportion of dead matte; the latter is a novel index measuring the amount of replacement of the ‘constructional’ seagrass P. oceanica by the ‘non-constructional’ seagrass Cymodocea nodosa. The potential of a ‘phase shift’ in Ligurian Sea seagrass Meadows is discussed. 4. The approach here proposed, based on detailed mapping plus synthetic indices, may provide immediate information to evaluate the state of Mediterranean Posidonia oceanica for monitoring and management.
Lorenzo Marini - One of the best experts on this subject based on the ideXlab platform.
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high mobility reduces beta diversity among orthopteran communities implications for conservation
Insect Conservation and Diversity, 2012Co-Authors: Lorenzo Marini, Erik Ockinger, Andrea Battisti, Riccardo BommarcoAbstract:. 1. The analysis of β-diversity, i.e. species turnover, across space is central to a wide array of ecological and evolutionary topics, also providing critical information to conservation planning. Although dispersal limitation has been demonstrated to play an important role in determining insect community structure, very little research has been done to test whether mobility might affect the diversity distribution of species across multiple spatial scales. 2. We considered orthopterans (Ensifera and Caelifera) inhabiting hay Meadows to test whether species mobility modifies β-diversity patterns across three nested spatial scales (1-m2 plots within Meadow, 1000-m2 Meadows within landscape, and 19.6-km2 landscapes within a region) and along a gradient of management intensity. 3. Orthopteran community composition varied most significantly over broader spatial scales. Larger proportion of regional γ-diversity was mainly composed of β-diversity at the landscape scale, whereas this proportion was smaller at the plot and Meadow scale. 4. Mobility, but not management, strongly modified β-diversity patterns. Sedentary species contributed to a greater proportion of β-diversity across all the investigated scales compared with mobile species. 5. Measures currently included in most agri-environment schemes have only focused on the extensive management at the field scale. Our results imply that orthopteran diversity would benefit from maintaining extensively managed Meadows scattered throughout the whole region, as the loss of species-rich isolated grassland patches due to abandonment or eutrophication might cause severe reductions of the regional species pool. Increasing connectivity might be also considered as a complementary measure to increase species occupancy and population persistence, particularly for sedentary species.
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High mobility reduces beta-diversity among orthopteran communities – implications for conservation
Insect Conservation and Diversity, 2011Co-Authors: Lorenzo Marini, Erik Ockinger, Andrea Battisti, Riccardo BommarcoAbstract:. 1. The analysis of β-diversity, i.e. species turnover, across space is central to a wide array of ecological and evolutionary topics, also providing critical information to conservation planning. Although dispersal limitation has been demonstrated to play an important role in determining insect community structure, very little research has been done to test whether mobility might affect the diversity distribution of species across multiple spatial scales. 2. We considered orthopterans (Ensifera and Caelifera) inhabiting hay Meadows to test whether species mobility modifies β-diversity patterns across three nested spatial scales (1-m2 plots within Meadow, 1000-m2 Meadows within landscape, and 19.6-km2 landscapes within a region) and along a gradient of management intensity. 3. Orthopteran community composition varied most significantly over broader spatial scales. Larger proportion of regional γ-diversity was mainly composed of β-diversity at the landscape scale, whereas this proportion was smaller at the plot and Meadow scale. 4. Mobility, but not management, strongly modified β-diversity patterns. Sedentary species contributed to a greater proportion of β-diversity across all the investigated scales compared with mobile species. 5. Measures currently included in most agri-environment schemes have only focused on the extensive management at the field scale. Our results imply that orthopteran diversity would benefit from maintaining extensively managed Meadows scattered throughout the whole region, as the loss of species-rich isolated grassland patches due to abandonment or eutrophication might cause severe reductions of the regional species pool. Increasing connectivity might be also considered as a complementary measure to increase species occupancy and population persistence, particularly for sedentary species.
Riccardo Bommarco - One of the best experts on this subject based on the ideXlab platform.
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high mobility reduces beta diversity among orthopteran communities implications for conservation
Insect Conservation and Diversity, 2012Co-Authors: Lorenzo Marini, Erik Ockinger, Andrea Battisti, Riccardo BommarcoAbstract:. 1. The analysis of β-diversity, i.e. species turnover, across space is central to a wide array of ecological and evolutionary topics, also providing critical information to conservation planning. Although dispersal limitation has been demonstrated to play an important role in determining insect community structure, very little research has been done to test whether mobility might affect the diversity distribution of species across multiple spatial scales. 2. We considered orthopterans (Ensifera and Caelifera) inhabiting hay Meadows to test whether species mobility modifies β-diversity patterns across three nested spatial scales (1-m2 plots within Meadow, 1000-m2 Meadows within landscape, and 19.6-km2 landscapes within a region) and along a gradient of management intensity. 3. Orthopteran community composition varied most significantly over broader spatial scales. Larger proportion of regional γ-diversity was mainly composed of β-diversity at the landscape scale, whereas this proportion was smaller at the plot and Meadow scale. 4. Mobility, but not management, strongly modified β-diversity patterns. Sedentary species contributed to a greater proportion of β-diversity across all the investigated scales compared with mobile species. 5. Measures currently included in most agri-environment schemes have only focused on the extensive management at the field scale. Our results imply that orthopteran diversity would benefit from maintaining extensively managed Meadows scattered throughout the whole region, as the loss of species-rich isolated grassland patches due to abandonment or eutrophication might cause severe reductions of the regional species pool. Increasing connectivity might be also considered as a complementary measure to increase species occupancy and population persistence, particularly for sedentary species.
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High mobility reduces beta-diversity among orthopteran communities – implications for conservation
Insect Conservation and Diversity, 2011Co-Authors: Lorenzo Marini, Erik Ockinger, Andrea Battisti, Riccardo BommarcoAbstract:. 1. The analysis of β-diversity, i.e. species turnover, across space is central to a wide array of ecological and evolutionary topics, also providing critical information to conservation planning. Although dispersal limitation has been demonstrated to play an important role in determining insect community structure, very little research has been done to test whether mobility might affect the diversity distribution of species across multiple spatial scales. 2. We considered orthopterans (Ensifera and Caelifera) inhabiting hay Meadows to test whether species mobility modifies β-diversity patterns across three nested spatial scales (1-m2 plots within Meadow, 1000-m2 Meadows within landscape, and 19.6-km2 landscapes within a region) and along a gradient of management intensity. 3. Orthopteran community composition varied most significantly over broader spatial scales. Larger proportion of regional γ-diversity was mainly composed of β-diversity at the landscape scale, whereas this proportion was smaller at the plot and Meadow scale. 4. Mobility, but not management, strongly modified β-diversity patterns. Sedentary species contributed to a greater proportion of β-diversity across all the investigated scales compared with mobile species. 5. Measures currently included in most agri-environment schemes have only focused on the extensive management at the field scale. Our results imply that orthopteran diversity would benefit from maintaining extensively managed Meadows scattered throughout the whole region, as the loss of species-rich isolated grassland patches due to abandonment or eutrophication might cause severe reductions of the regional species pool. Increasing connectivity might be also considered as a complementary measure to increase species occupancy and population persistence, particularly for sedentary species.
Heidi Nepf - One of the best experts on this subject based on the ideXlab platform.
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Wave damping by flexible vegetation: Connecting individual blade dynamics to the Meadow scale
Coastal Engineering, 2019Co-Authors: Heidi NepfAbstract:Abstract Aquatic vegetation provides ecosystem services of great value, including the damping of waves, which protects shorelines and reduces resuspension. This study proposes a physically-based model to predict the wave decay associated with a submerged Meadow as a function of plant morphology, flexibility, and shoot density. In particular, the study considers both the rigid (sheath) and flexible (blade) segments of the plant. Flexible plants reconfigure in response to wave orbital velocity, which diminishes wave decay relative to a rigid plant of the same morphology. The impact of reconfiguration on wave decay can be characterized using an effective blade length, l e , which represents the length of a rigid blade that generates the same drag as the flexible blade of length l . The effective blade length depends on the Cauchy number, which defines the ratio of hydrodynamic drag to blade stiffness, and the ratio of blade length to wave orbital excursion. This laboratory study considered how the scaling laws determined for individual blades can be used to predict the wave decay over a Meadow of multiple plants, each consisting of multiple blades attached at a rigid stem (sheath). First, the drag force on and motion of individual model blades (made of low-density polyethylene) was studied for a range of wave conditions to provide empirical coefficients for the theoretically determined scaling laws for effective blade length, l e . Second, the effective blade length predicted for individual blades was incorporated into a Meadow-scale model to predict wave decay over a Meadow. The Meadow-scale model accounts for both the rigid and flexible parts of individual plants. Finally, wave decay was measured over Meadows of different plant density (shoots per bed area), and the measured decay was used to validate the wave-decay model. Wave decay was shown to be similar over Meadows with regular and random arrangements of plants.
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particle retention in a submerged Meadow and its variation near the leading edge
Estuaries and Coasts, 2018Co-Authors: Elizabeth Follett, Heidi NepfAbstract:The retention of particles within Meadows of submerged aquatic vegetation impacts the fate of organic matter, pollen, and larvae. Because flow conditions near the leading edge differ from those over the bulk of the canopy, particle retention is likely to differ as well. In particular, near the leading edge of a wide Meadow, flow deceleration generates a vertical updraft, which impacts particle fate. In the fully developed region of the Meadow, shear layer vortices at the top of the Meadow may also influence particle fate. In this study, the retention of particles was measured along the length of a 10-m model Meadow (height h = 0.1 m) and was connected to the evolving flow field. Two particle sizes, with settling velocity w s50 = 0.00075 , 0.018 m s−1, were released at two heights within the model Meadow \( \left(\frac{Z_{rel}}{h}=0.31,0.81\right). \) The retention of particles was measured using microscope slides distributed along the flume bed. Retention increased with distance from the leading edge, associated with the decrease in vertical updraft. Retention was also greater for the particles with higher settling velocity. In the fully developed region of the Meadow, particle retention was lower for particles influenced by the shear layer vortices at the top of the Meadow (\( \frac{Z_{rel}}{h}=0.81 \)).
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Particle Retention in a Submerged Meadow and Its Variation Near the Leading Edge
Estuaries and Coasts, 2017Co-Authors: Elizabeth Follett, Heidi NepfAbstract:The retention of particles within Meadows of submerged aquatic vegetation impacts the fate of organic matter, pollen, and larvae. Because flow conditions near the leading edge differ from those over the bulk of the canopy, particle retention is likely to differ as well. In particular, near the leading edge of a wide Meadow, flow deceleration generates a vertical updraft, which impacts particle fate. In the fully developed region of the Meadow, shear layer vortices at the top of the Meadow may also influence particle fate. In this study, the retention of particles was measured along the length of a 10-m model Meadow (height h = 0.1 m) and was connected to the evolving flow field. Two particle sizes, with settling velocity ws50 = 0.00075 , 0.018 m s−1, were released at two heights within the model Meadow Zrelh=0.310.81.$$ \left(\frac{Z_{rel}}{h}=0.31,0.81\right). $$ The retention of particles was measured using microscope slides distributed along the flume bed. Retention increased with distance from the leading edge, associated with the decrease in vertical updraft. Retention was also greater for the particles with higher settling velocity. In the fully developed region of the Meadow, particle retention was lower for particles influenced by the shear layer vortices at the top of the Meadow (Zrelh=0.81$$ \frac{Z_{rel}}{h}=0.81 $$).
Monica Montefalcone - One of the best experts on this subject based on the ideXlab platform.
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Seagrass on the rocks: Posidonia oceanica settled on shallow-water hard substrata withstands wave stress beyond predictions
Estuarine Coastal and Shelf Science, 2016Co-Authors: Monica Montefalcone, Roberto Cabella, Chiara Francesca Schiaffino, Carlo Nike Bianchi, Carla Morri, Matteo Vacchi, Cristina Carbone, Franco Marco Elter, Marco FerrariAbstract:A multidisciplinary approach was applied to investigate the role of abiotic constraints in the settlement of Posidonia oceanica on shallow rocks in two coastal areas of the Ligurian Sea (Italy, NW Mediterranean). Meadows developed very shallow upper limits, at 1.5 m depth in both areas, and with a distinctive morphology of stripes growing on rocky outcrops orthogonal to the coastline. Application of a predictive model to indicate the reference condition zone for the Meadow upper limit, already validated on Meadows developing on soft-bottoms, was not adequate for these rocky substrata as the Meadow upper limits were found shallower than model predictions (>5 m depth). Geological and geomorphological characteristics of the rocky shores were analysed through geomechanic and petrographic analyses (i.e. thin sections, SEM analyses, rock hardness tests) whilst the shape and the features of the Meadows (i.e. shoot density and maximum leaf length) were assessed through scuba diving surveys. Among the different lithotypes occurring at the sites in the alternating and interbedded outcrops, P. oceanica was passively selected (i.e. due to the seedlings survival and settlement there) on the strongest (i.e. less erodible) lithotypes, whilst the comparatively weaker and more erodible rocks remained unvegetated and covered by a layer of soft-sediments. P. oceanica, settling on specific rocky substrata with favourable lithological and geomechanical characteristics, is able to establish outside the theoretical reference zone predicted by the model for soft sediments due to greater attachment strength and possible resistance to hydrodynamic forces. Combining biological, ecological, mineralogical, geological and geomorphological approaches was effective for explaining the primary role of substratum nature in the spatial variability of seagrass Meadows, with geomechanical and lithological characteristics of the rocks being equally important abiotic factors than sedimentological features. (C) 2016 Elsevier Ltd. All rights reserved.
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The influence of coastal dynamics on the upper limit of the Posidonia oceanica Meadow
Marine Ecology, 2010Co-Authors: Monica Montefalcone, Carla MorriAbstract:Abstract The recognized ecological importance of Posidonia oceanica, the most important seagrass of the Mediterranean Sea, makes it crucial to assess the state of health of its Meadows, discriminating natural from anthropogenic impacts. In this paper, the hydrodynamic conditions at the upper limit of P. oceanica Meadows along the Ligurian coast (NW Mediterranean Sea) were investigated. A relationship between the distance of the upper limit of the Meadow from the shoreline and the morphodynamic domain of the beach (i.e. distinctive types of beach produced by the topography, wave climate and sediment composition) was found. A zonation of the state of the shallow portions of the Meadows down the submerged beach profile was identified. Zone a, from the shoreline to the breaking limit, is naturally critical for the development of the Meadow. Zone b, from the breaking limit to the closure depth, is subjected to natural and human impacts. Zone c, below the closure depth, is little influenced by coastal dynamics. This study quantifies for the first time how much the status of the shallow portions of P. oceanica Meadows is dependent on coastal dynamics, which is important for their proper management.
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A new synthetic index and a protocol for monitoring the status ofPosidonia oceanica Meadows: a case study at Sanremo (Ligurian Sea, NW Mediterranean)
Aquatic Conservation: Marine and Freshwater Ecosystems, 2006Co-Authors: Monica Montefalcone, Giancarlo Albertelli, Carlo Nike-Bianchi, Mauro Mariani, Carla MorriAbstract:1. The status of a Posidonia oceanica Meadow in front of the town of Sanremo, Italy, was studied through a combined use of benthic mapping and synthetic indices. 2. Mapping was accomplished by integrating side scan sonar imagery and data collected by scuba diving along transects placed perpendicularly to the coastline. A thematic map (scale 1:5000) was produced. Extent of the Meadow, occurrence of dead matte areas, and morphology of the lower limit (with new definition) are all described. 3. Two synthetic environmental indices were applied to transect data in order to quantify the status of the Meadow: the Conservation Index and the Substitution Index. The former is related to the proportion of dead matte; the latter is a novel index measuring the amount of replacement of the ‘constructional’ seagrass P. oceanica by the ‘non-constructional’ seagrass Cymodocea nodosa. The potential of a ‘phase shift’ in Ligurian Sea seagrass Meadows is discussed. 4. The approach here proposed, based on detailed mapping plus synthetic indices, may provide immediate information to evaluate the state of Mediterranean Posidonia oceanica for monitoring and management.
