102,616 research outputs found
Il macrozoobenthos: uno dei possibili descrittori di stato ecologico nel monitoraggio delle aree di transizione siciliane.
No full textSeabird influence on ecological processes in coastal marine ecosystems: An overlooked role? A critical review
No full textSeabirds are vital, but overlooked, components of coastal marine ecosystems and may connect the marine and terrestrial environment at a global scale, significantly contributing to inter-habitat connectivity and the provision of multiple ecosystem services. Although the ecological and functional role of birds in terrestrial areas, islands in particular, has been deeply studied since the last century, the same does not hold true for coastal marine areas. Given the importance of coastal areas for seabirds worldwide and, at the same time, the high vulnerability of both, looking into the role of seabirds in influencing the ecosystem functioning in coastal areas is needed nowadays. Here, we review the current knowledge regarding the role of seabirds on coastal ecological processes giving particular emphasis on the linkage between the seabird functions that are crucial in influencing the ecological processes and the provision of ecosystem services, and disservices, for the human well-being. Seabirds can contribute to shaping coastal ecological processes and services in a multitude of ways, among which directly influencing trophic status, environmental contamination, biodiversity and food webs through trophic (bottom-up or top-down) and non-trophic processes. We identified areas for future research to further clarify this linkage and promote seabird conservation
Development of the wing buds in Megoura viciae: a morphological study
No full textThis study describes the initial phases of wing morphogenesis of Megoura viciae. We evaluated the development of wing buds in males (winged) and parthenogenetic females (presumed to become wingless) of M. viciae from birth to IV instar. Wing bud epithelium in males is initially simple, becoming bistratified and then progressing to stratify. Mitotic activity is more intense in the proximal region of bud, and its behaviour seems to be synchronous. In parthenogenetic females, from birth to I instar, the buds resemble those of males at the same stages, but subsequently the epithelium returns to the simple state, and from the III instar stage, it cannot be distinguished from the adjacent epithelium.This study moreover defines distinctive wing bud features that can be used to identify these buds during development in other aphid species
Aquaculture of emerging species in North-Eastern Atlantic and Mediterranean Sea: a systematic review on sea cucumber farming and potential development
No full textSea cucumbers are considered a traditional food delicacy in Asian countries. In last decades high market demand, uncontrolled exploitation and inadequate management have led to stock overexploitation, driving commercial interest in new target species and new areas. In recent years, Mediterranean and North-East Atlantic sea cucumbers have become fishing targets, and, due to overfishing, a significant decline of wild populations have been observed, with detrimental effects on benthic communities and ecosystems. Indeed, in addition to being an important economic resource, sea cucumbers play a key ecological role in benthic dynamics where they are involved as ecosystem engineers in the processing of organic matter in the detrital food web pathway. In this context, aquaculture can play a crucial role in supporting the conservation of natural stocks by reducing harvesting pressure on wild populations and enabling restoration programmes for depleted stocks. Commercial sea cucumber farming is already an established reality in the Indo-Pacific region, where it has become one of the most profitable sectors of aquaculture production. In Europe, on the other hand, sea cucumber aquaculture is still an emerging sector, whose development is hampered by poor and fragmented information on the farming requirements of native species. In this context, this systematic review was carried out with the aim of providing a comprehensive summary of the state of the art of farming practices of the European sea cucumbers considered as a target of commercial fisheries. A total of 34 original articles were included in this review, after title, abstract and full-text screening. The results highlighted a sharp increase in the number of studies over the last six years. Portugal, Turkey and Italy are the countries where most research has been carried out. Among the selected species, Holothuria tubulosa was the most studied, while only one article was found on Parastichopus regalis. The main aims of this review were i) to gather all available literature on the farming practices of North-East Atlantic and Mediterranean sea cucumber species, ii) to outline the most common farming practices, iii) to identify gaps and future directions in this emerging aquaculture sector
Certissima Signa. Manoscritti astronomici illustrati
No full textPresentation of Certissima Signa (http://certissimasigna.sns.it), a website created by the Astronomical Illustrated Manuscripts Research Group operating at the Scuola Normale Superiore, Pisa, Italy (http://www.sns.it/en/ricerca/lettere/manoscrittiastronomici)
First assessment of total organic carbon/macrofauna relation in Sicilian coastal lagoons
No full textCoexisting with the alien: Evidence for environmental control on trophic interactions between a native (Atherina boyeri) and a non-indigenous fish species (Gambusia holbrooki) in a Mediterranean coastal ecosystem
No full textBiological invasions are a widespread problem worldwide, as invasive non-indigenous species (NIS) may affect native populations through direct (e. g., predation) or indirect (e.g., competition) trophic interactions, leading to changes in the food web structure. The trophic relationships of the invasive eastern mosquitofish Gambusia holbrooki and the native big-scale sand smelt Atherina boyeri coexisting in three Mediterranean coastal ponds characterized by different trophic statuses (from oligotrophic to hypereutrophic) were assessed in spring through isotopic niche analysis and Bayesian mixing models. The two fish relied on the distinctive trophic pathways in the different ponds, with the evidence of minimal interspecific niche overlap indicating site-specific niche divergence mechanisms. In more detail, under hypereutrophic and mesotrophic conditions, the two species occupied different trophic positions but relying on a single trophic pathway, whereas, under oligotrophic conditions, both occupied a similar trophic position but belonging to distinct trophic pathways. Furthermore, the invaders showed the widest niche breadth while the native species showed a niche compression and displacement in the ponds at a higher trophic status compared to the oligotrophic pond. We argue that this may be the result of an asymmetric competition arising between the two species because of the higher competitive ability of G. holbrooki and may have been further shaped by the trophic status of the ponds, through a conjoint effect of prey availability and habitat complexity. While the high trophic plasticity and adaptability of both species to different environmental features and resource availability may have favored their coexistence through site-specific mechanisms of niche segregation, we provide also empirical evidence of the importance of environmental control in invaded food webs, calling for greater attention to this aspect in future studies
Seabird influence on ecological processes in coastal marine ecosystems: an overlooked role?
No full textCoastal marine ecosystems and especially transitional environments host a large variety of birds, functioning as nesting sites for resident species and corridors for migratory ones. Seabirds activity may trigger movement of nutrients and organic matter between coastal boundaries, affecting their availability and processing. Consequently seabirds are often labelled as biotic vectors. While attention has been focused on the study of biodiversity level and migratory patterns of avifauna, there is little information on the effects of seabirds on ecological features (i.e. trophic status, biodiversity level, food web patterns, transfer of contaminants) in coastal marine ecosystems.
To address these knowledge gaps, in this presentation we will firstly review the available information on the role of seabird derived-subsidies (i.e. nutrients) in coastal marine ecosystems and then we will present a case study from a Mediterranean transitional environment (Marinello ponds, Sicily, Italy). This area may be considered a field laboratory where to study the ecological role of seabirds due to the presence of several small (1-2 ha) and adjoining ponds that differ strongly in the amount of subsidies they receive from seabird guano. We will summarize data on trophic condition, benthic biodiversity, isotopically constructed-food webs and trace element contamination and biomagnification. The results provide evidence of the important ecological role of seabirds in driving ecosystem structure and functioning; indeed the pond affected by gull guano showed a higher trophic status and trace element contamination, lower biodiversity of benthic communities and simpler food webs. This overall picture highlights that avifauna may exert a noteworthy, though so far neglected, ecological role in coastal marine ecosystems, and especially in transitional environments, deserving more attention
Catalogue des Manuscrits Alchimiques Grecs, t. VIII : Alchemistica signa digessit et explanavit Zuretti (G. O.)
No full textJosserand Ch. Catalogue des Manuscrits Alchimiques Grecs, t. VIII : Alchemistica signa digessit et explanavit Zuretti (G. O.). In: Revue belge de philologie et d'histoire, tome 12, fasc. 4, 1933. p. 1110
Effects of a small seagull colony on trophic status and primary production in a Mediterranean coastal system (Marinello ponds, Italy)
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