643 research outputs found
Typification of<i>Octaviania rubescens</i>(<i>Paxillineae</i>,<i>Boletales</i>) and phylogenetic hypotheses for genus<i>Alpova</i>
No full textThere are no usable herbarium specimens for the type of Alpova rubescens; therefore a lectotype and an epitype are designated hereby to preserve current usage of the name. As lecotype the Vittadini's Fig. XII E/Tab. IV (from Monographia Tubercearum) was selected. The epitype chosen for A. rubescens is a recent. large collection from Liguria (Italy). Furthermore to investigate the phylogenetic position of A. rabescens among Alpova spp. comparative 28S-rDNA gene sequence analyses were conducted. The new combination Rhizopogon atexsmithii (Trappe) Vizzini & Zotti is proposed.</p
Chromosera viola (J. Geesink & Bas) Vizzini & Ercole 2012, una espectacular especie localizada en Cataluña
No full textChromosera viola (J. Geesink & Bas) Vizzini & Ercole 2012. Un interessant taxón dels
Hygrophoraceae trobat a Catalunya, es descriu, comenta e il·lustraChromosera viola (J. Geesink & Bas) Vizzini & Ercole 2012. An interesting taxon
of Hygrophoraceae found in Catalonia is described, commented and illustrated.Chromosera viola (J. Geesink & Bas) Vizzini & Ercole 2012. Un interesante taxón
de Hygrophoraceae hallado en Cataluña, se describe, comenta e ilustra
The trophic structure of a pipefish community (Pisces: Syngnathidae) from a western Mediterranean seagrass meadow based on stable isotope analysis
No full textSyngnathus abaster and S. typhle (Pisces. Syngnathidae) from a dense Cymodocea nodosa meadow in the western Mediterranean Stagnone di Marsala (Italy) were studied using δ13C and δ15N analysis. Because of the presence of these two species in the same habitat and the specialized parental care by the male, the effect of species and sex on the isotopic composition was also studied to investigate the different feeding strategies between and within species. S. abaster and S. typhle exhibited enriched 13C and 15N values throughout the sampling period (δ13C mean ± s.e. = -10.5 ± 1.8‰ and -10.8 ± 2.0‰, δ15N mean ± s.e. = 11.9 ± 0.7‰ and 10.6 ± 1.0‰ respectively), suggesting that these species receive their energy mainly from mixed sources, particularly from sedimentary and particulate organic matter and the seagrass C, nodosa as ultimate organic matter sources. ANOVA results demonstrated that the interaction between season, species and sex significantly affected the isotopic composition of the pipefish (P<0.001 for both δ13C and δ15N). Differences between species and sex, although significant, were smaller than the values generally reported for trophic level differences (~1‰ and ~3.5‰ for δ13C and δ15N respectively) and change in foraging habitat. Slight isotopic differences may mirror small differences in resource exploitation and resource partitioning. Evidence from stomach content analysis from the literature coupled with stable isotope measurements, while disagreeing somewhat, provide additional knowledge of pipefish feeding strategies
Analysis of the trophic role of Mediterranean seagrasses in marine coastal ecosystems: a review
No full textSeagrasses form high-productivity coastal ecosystems, providing habitats for many organisms, including species of commercial value. They play a significant role as a direct food source for herbivores and enter detrital food webs. In this review the trophic ecology of Mediterranean seagrass ecosystems is revised, with major emphasis on Posidonia oceanica, the most extensively studied seagrass. The major topics are the role of herbivory and detritus, the contribution to littoral fish production, exportation to other ecosystems and their role as vectors of anthropogenic nutrients into food webs, and are discussed by analysing both conventional knowledge and new insights derived from the application of carbon and nitrogen stable isotope analysis. In conclusion, perspectives for future research are highlighted, with particular emphasis on areas demanding further study and on the effects of seagrass decline on trophic organization in coastal environments
Study of the trophic and functional organization of fish assemblages in submarine shallow CO2 vents
No full textNaturally acidified marine ecosystems are currently investigated to evaluate the effects of ocean acidification on species, communities and ecological processes. Among these, submarine shallow CO2 vents represent a sort of natural mesocosms, where at small spatial scales marked gradient of pH are present. The aim of this project is to study the responses of fish assemblages to pH reduction in Mediterranean shallow CO2 vents by using several descriptors such as community structure, trophic organization, chemical characteristics and composition of carbonic structures. Moreover as in CO2 vents concentration and bio-availability of several trace elements, also toxic ones, may increase due to direct input from the vents and/or to peculiar pH and Eh conditions, another aim is the evaluation of trace element bioaccumulation and biomagnification. As scant information is available in the literature on this topic, the results of this research will contribute to bridge the gap to predict the ecological effects of ocean acidification on fishes, a key biological component whose monitoring is relevant not only from the ecological standpoint but also for the economic one and for the implications on human health
Seasonal variations in the stable carbon and nitrogen isotope ratios (13C/12C and 15N/14N) of primary producers and consumers in a western Mediterranean coastal lagoon
No full textStable carbon and nitrogen isotope ratios (13C/12C and 15N/14N) of primary producers and consumers were investigated seasonally throughout 1999, in order to describe the food web in a western Mediterranean coastal lagoon (Lake of Sabaudia, central Italy). Particulate organic matter and algal material (seagrass epiphytes and macroalgae) seem to constitute the main food sources for primary consumers (zooplankton and small benthic invertebrates, respectively) throughout the sampling year, while the seagrass Cymodocea nodosa appears to play a negligible trophic role. As regards the ichthyofauna, carbon stable isotopes differentiated between planktivore and benthivore fish species. However, a benthic-pelagic coupling seems to occur, with some fish of higher trophic levels feeding both on benthic and pelagic materials. Analysis of variance showed that the interaction between the three main factors (speciesxsizexseason) significantly affects the isotopic composition of fish, suggesting the presence of intra- and inter-specific resource partitioning. Wide seasonal variations in the isotopic composition were observed in organic matter sources, invertebrates and fish, with a general trend towards depleted values in winter and enriched values in summer. The winter depletion of organic matter sources may be due to several environmental factors and seems to be mirrored in the upper trophic levels. Primary producers and invertebrates are known to have shorter time-integrated isotopic signatures than vertebrates, yet fish also exhibited seasonal isotopic differences. We concluded that the examined fish species can assume a new muscle isotopic signature relatively quickly in response to changes in the isotopic composition of their diet and/or diet shifts
The use of fish communities as a biological quality element to monitor ecological status of transitional waters
No full textFirst records of <I>Rhizopogon rocabrunae</I> and <I>R. pumilionum</I> (<I>Boletales</I>) from Italy
No full textThe effects of anthropogenic organic matter inputs on stable carbon and nitrogen isotopes in organism from different trophic levels in a southern Mediterranean coastal area
No full textStable isotope ratios were used to determine the impact of anthropogenically derived organic matter from onshore and offshore
fish farming and a sewage outfall on organisms at different trophic levels (primary producers and consumers) on the south-east
coast of Sicily (Italy, Mediterranean). Representative macroalgae and consumers were collected in three sampling locations:
“Impact” and two putative “Controls” sited to the north of the impacted location. While δ13C values of both organic matter sources
and consumers varied little between locations, δ15N spatial variability was higher and δ15N was shown to be a good descriptor of
organic enrichment and uptake of anthropogenically derived material within coastal food webs. Isotopic data were analysed using a
multivariate approach. Organic matter sources and benthic components were more sensitive to pollution than nektobenthic species
and revealed that the effects of anthropogenic activities seem to be detectable over a wide area. The study site is characterised by
wide waste dispersal, which brings a reduction in impact in the area directly affected by organic matter inputs and enlarges the area
of moderate impact
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