Search results for "MEDITERRANEAN SEA"
showing 10 items of 876 documents
Food selection of a generalist herbivore exposed to native and alien seaweeds
2018
Understanding which factors influence the invasion of alien seaweed has become a central concern in ecology. Increasing evidence suggests that the feeding preferences of native herbivores influence the success of alien seaweeds in the new community. We investigated food selection of a generalist native grazer Paracentrotus lividus, in the presence of two alien seaweeds (Caulerpa cylindracea and Caulerpa taxifolia var. distichophylla) and two native seaweeds (Dictyopteris membranacea and Cystoseira compressa). Sea urchins were fed with six experimental food items: C. cylindracea, C. taxifolia var. distichophylla, a mixture of C. cylindracea and C. taxifolia var. distichophylla, D. membranace…
New historical data for long-term swordfish ecological studies in the Mediterranean Sea
2021
Abstract. Management of marine fisheries and ecosystems is constrained by knowledge based on datasets with limited temporal coverage. Many populations and ecosystems were perturbed long before scientific investigations began. This situation is particularly acute for the largest and commercially most valuable species. We hypothesized that historical trap fishery records for bluefin tuna (Thunnus thynnus Linnaeus, 1758) could contain catch data and information for other, bycatch species, such as swordfish (Xiphias gladius Linnaeus, 1758). This species has a long history of exploitation and is presently overexploited, yet indicators of its status (biomass) used in fishery management only start…
Native predators control the population of an invasive crab in no-take marine protected areas
2018
1. The resistance of an ecosystem to species invasion is considered to be related to the abundance and diversity of native species i.e. biotic resistance hypothesis). Theory predicts that the high native diversity in pristine systems can hinder the establishment and/or the spread of non‐native species through direct and indirect mechanisms (e.g. through competitive and/or predatory interactions). 2. Here we tested whether predation provides higher resistance to invasion by the Percnidae crab Percnon gibbesi (H. Milne Edwards, 1853) in protected native communities, compared with exploited ones. Specifically, this study aimed to compare: (i) the abundance and diversity of potential predator a…
Limited potential for bird migration to disperse plants to cooler latitudes
2021
Climate change is forcing the redistribution of life on Earth at an unprecedented velocity1,2. Migratory birds are thought to help plants to track climate change through long-distance seed dispersal3,4. However, seeds may be consistently dispersed towards cooler or warmer latitudes depending on whether the fruiting period of a plant species coincides with northward or southward migrations. Here we assess the potential of plant communities to keep pace with climate change through long-distance seed dispersal by migratory birds. To do so, we combine phenological and migration information with data on 949 seed-dispersal interactions between 46 bird and 81 plant species from 13 woodland communi…
Marine caves of the Southern Tyrrhenian Sea: a First Census of Benthic Biodiversity
2017
This is the first paper documenting research on a selection of marine caves located along the coast of Capo Milazzo in the southern Tyrrhenian Sea. Three submarine and one semi-submerged caves were surveyed and sampled using underwater photo sampling. Surveys have only taken into account the sessile species belonging to the main taxa: Porifera, Anthozoa, Bryozoa and Polychaeta. Diversity indices and abundances were calculated for three sections within each explored cave: the Entrance Zone, Intermediate Zone and Bottom Zone. The richest group was Porifera with 21 taxa, followed by cnidarians, (Anthozoa), with 8 taxa, Polychaeta (5 taxa), and Bryozoa (5 taxa). Among Porifera, the presence of …
Functional trait-based layers - an aquaculture siting tool for the Mediterranean Sea
2021
Abstract Aquaculture, the current fastest-growing food sector, is one of the major opportunities that could be reaped to cope with the increased demand for proteins from the sea and simultaneously generate economic growth while ensuring sustainable use of natural resources. The number of tools and approaches suggested to promote the selection of suitable areas - focusing mostly on the management of potential conflicting uses at sea - is rapidly increasing. However, to date, there is a lack of information regarding spatial planning according to a trait-based approach encompassing the functional and biological data of farmed species; a gap that may lead to selecting unsuitable areas for farmi…
Diel feeding habits of juveniles of Mullus surmuletus (Linneo, 1758) in the lagoon of the Stagnone di Marsala (Western Sicily, Italy)
1999
Diet composition, feeding rhythm, gastric evacuation rate and daily ration were investigated in juvenile Mulhis surmuletus (Linneo, 1758). Fish were collected in the lagoon of the Stagnone di Marsala in western Sicily, in July 1995, during a 24 h sampling period. Copepoda, Polychaeta, Amphipoda and Tanaidacea were shown to be the most frequent prey items. The feeding index values showed two different daily feeding times. A unimodal trend in the daily rhythm of food consumption was derived, with a peak in feeding between 1200 and 2000 h. Gastric evacuation in juvenile M. surmuletus is best described by an exponential model, with a gastric evacuation rate R = 0.66 g h-1 (r = 0.88) (T = 24.45 …
The Stagnone of Marsala lagoon
2009
The Stagnone of Marsala is an oligotrophic lagoon situated on the western coast of Sicily. The area has been under study since the mid-nineteenth century. Research has focused on its physiographic, chemical-physical, biological, ecological features and, particularly, on submerged vegetation. Its main biotic component, a meadow of Posidonia oceanica, is distributed among peculiar reef formations inside and outside the lagoon, which are extremely interesting from an ecological and environmental point of view. The seagrass grows near to its thermal and salinity tolerance level in the inner lagoon, where it is partially replaced by Cymodocea nodosa and Caulerpa prolifera meadows. Algal assembla…
Assessment of the ecological status of transitional waters in Sicily (Italy): first characterisation and classification according to a multiparametri…
2010
A 1-year cycle of observations was performed in four Sicilian transitional water systems (Oliveri-Tindari, Cape Peloro, Vendicari and Marsala) to characterise their ecological status. A panel of variables among which trophic and microbial (enzyme activities, abundance of hetetrophic bacteria and of bacterial pollution indicators) parameters, were selected. Particulate organic carbon (POC) and nitrogen (PON) and chlorophyll-. a (Chl-. a) contents defined the trophic state, while microbial hydrolysis rates and abundance gave insights on microbial community efficiency in organic matter transformation and on allochthonous inputs. To classify the trophic state of examined waters, the synthetic t…
Scuba diver behaviour and its effects on the biota of a Mediterranean marine protected area
2009
The effects of diving activity in different Mediterranean subtidal habitats are scarcely known. This study evaluates diver behaviour (for example time spent in each habitat), use (contacts made with the substrate) and immediate effects of diver contact on benthic species in a marine protected area (MPA) in Sicily. Over a two-year period, intentions of 105 divers were observed within seven subtidal habitats: algae on horizontal substrate, algae on vertical substrate, Posidonia oceanica, encrusted walls, caves, sand and pebbles. Divers selected a habitat in proportion to its availability along the scuba trail. On average, each diver made 2.52 contacts every seven minutes, and no differences w…