Environmental Design Guidelines for Low Crested Coastal Structures, 2007
The species pool in a particular locality is determined by its biogeographic context. The evoluti... more The species pool in a particular locality is determined by its biogeographic context. The evolution of the species pool is a dynamic and ongoing process. Biodiversity patterns on a broad-scale are the functions of adaptation, extinction, and speciation. The species pool may also change following the introduction of alien species, often through human activities. Broad-scale biodiversity patterns are influenced by major physical factors, such as climate, currents, upwelling, tidal elevation, wave climate, salinity, coastal topography, and seabed composition, which can all vary with geographical location. The environmental impact of any amount of cases can be predicted by numerical modeling. The result for each case is a set of BioMar class values for physical parameters being designated for each cell. A procedure is then applied that selects the biotopes that can occur within the predicted set of parameter class values for each cell. Biotopes recorded in the field during baseline data survey can be compared with those predicted by the model. This enables calibration of the model to the present situation and allows evaluation of the type and magnitude of changes for each computed case in a straightforward fashion. These initial trials with the model are encouraging, and the model is still being refined to develop a tool to more accurately predict change in the identity and extent of biotopes because of the addition of breakwaters.
ABSTRACT The study of the relationships between vascular aquatic macrophyte occurrence, species r... more ABSTRACT The study of the relationships between vascular aquatic macrophyte occurrence, species richness and the local environment are central for suitable ecosystem quality assessments, freshwater bodies management and assistance for macrophyte restoration. Here we quantify the importance of the local factors, both water column and sediment, to provide tools for lentic water systems management and conservation in a Mediterranean region. We surveyed 90 water bodies along a 2500 m altitudinal gradient in Catalonia (NE Spain). Despite its relatively small scale, the area of study exhibits large-scale environmental gradients mainly related to a diverse geology and climate. In consequence, the response of aquatic macrophytes to a broad range of environmental conditions can be studied without interference of biogeographical clines. We identified all vascular aquatic macrophytes and analyzed 35 environmental variables at each site. Local environmental factors accounted for only 19% of variance in aquatic macrophyte distribution. Even though water column variables explained more variance than sediment variables in a variance partitioning analysis (pCCA), a mixed model integrating variables of both compartments performed better. The most important variables driving aquatic macrophyte distribution were water conductivity, water DOC, water K, water pH, water Na, sediment organic matter, sediment Na and water nitrate. CCA between species and water and sediment variables clearly segregated coastal lagoons, temporary pools and alpine lakes over two main gradients: ionic content and water body productivity. Species richness was low (4.2 species per water body on average) and GAM showed weak correlations with sediment and most water column variables. The best factor explaining species richness was the geomorphological typology, but only temporary pools were significantly different from the other types and had the highest species richness. Thus, temporary pools were unique and displayed a high biodiversity, strengthening the need for their preservation.
Page 1. Limnol. Oceanogr., 47(1), 2002, 23-32 ? 2002, by the American Society of Limnology and Oc... more Page 1. Limnol. Oceanogr., 47(1), 2002, 23-32 ? 2002, by the American Society of Limnology and Oceanography, Inc. Carbon and nutrient deposition in a Mediterranean seagrass (Posidonia oceanica) meadow Esperanqa Gacia1 ...
Environmental Design Guidelines for Low Crested Coastal Structures, 2007
The species pool in a particular locality is determined by its biogeographic context. The evoluti... more The species pool in a particular locality is determined by its biogeographic context. The evolution of the species pool is a dynamic and ongoing process. Biodiversity patterns on a broad-scale are the functions of adaptation, extinction, and speciation. The species pool may also change following the introduction of alien species, often through human activities. Broad-scale biodiversity patterns are influenced by major physical factors, such as climate, currents, upwelling, tidal elevation, wave climate, salinity, coastal topography, and seabed composition, which can all vary with geographical location. The environmental impact of any amount of cases can be predicted by numerical modeling. The result for each case is a set of BioMar class values for physical parameters being designated for each cell. A procedure is then applied that selects the biotopes that can occur within the predicted set of parameter class values for each cell. Biotopes recorded in the field during baseline data survey can be compared with those predicted by the model. This enables calibration of the model to the present situation and allows evaluation of the type and magnitude of changes for each computed case in a straightforward fashion. These initial trials with the model are encouraging, and the model is still being refined to develop a tool to more accurately predict change in the identity and extent of biotopes because of the addition of breakwaters.
ABSTRACT The study of the relationships between vascular aquatic macrophyte occurrence, species r... more ABSTRACT The study of the relationships between vascular aquatic macrophyte occurrence, species richness and the local environment are central for suitable ecosystem quality assessments, freshwater bodies management and assistance for macrophyte restoration. Here we quantify the importance of the local factors, both water column and sediment, to provide tools for lentic water systems management and conservation in a Mediterranean region. We surveyed 90 water bodies along a 2500 m altitudinal gradient in Catalonia (NE Spain). Despite its relatively small scale, the area of study exhibits large-scale environmental gradients mainly related to a diverse geology and climate. In consequence, the response of aquatic macrophytes to a broad range of environmental conditions can be studied without interference of biogeographical clines. We identified all vascular aquatic macrophytes and analyzed 35 environmental variables at each site. Local environmental factors accounted for only 19% of variance in aquatic macrophyte distribution. Even though water column variables explained more variance than sediment variables in a variance partitioning analysis (pCCA), a mixed model integrating variables of both compartments performed better. The most important variables driving aquatic macrophyte distribution were water conductivity, water DOC, water K, water pH, water Na, sediment organic matter, sediment Na and water nitrate. CCA between species and water and sediment variables clearly segregated coastal lagoons, temporary pools and alpine lakes over two main gradients: ionic content and water body productivity. Species richness was low (4.2 species per water body on average) and GAM showed weak correlations with sediment and most water column variables. The best factor explaining species richness was the geomorphological typology, but only temporary pools were significantly different from the other types and had the highest species richness. Thus, temporary pools were unique and displayed a high biodiversity, strengthening the need for their preservation.
Page 1. Limnol. Oceanogr., 47(1), 2002, 23-32 ? 2002, by the American Society of Limnology and Oc... more Page 1. Limnol. Oceanogr., 47(1), 2002, 23-32 ? 2002, by the American Society of Limnology and Oceanography, Inc. Carbon and nutrient deposition in a Mediterranean seagrass (Posidonia oceanica) meadow Esperanqa Gacia1 ...
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