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Biosystematic researches on Allium cupani group (Amaryllidaceae) in the Mediterranean area.
2015
Allium cupani Raf. is a species complex of the subgenus Allium L., which is taxonomically quite critical mainly for its marked karyological and morphological variability. In the present study, karyo-taxonomic characterization of some peculiar populations of this group from Italian, N African, Balcan and Aegean territories has been performed, using both living plants collected in the field and herbarium material. As a result, ten new species have been recognized and described within the A. cupani complex. They are A. panormitanum from N Sicily, A. samniticum from C Italy, A. mauritanicum from N Morocco and NW Algeria, A. balcanicum from mountains of Balkan Peninsula, A. tzanoudakisanum from …
Trophic structure of vermetid reef community: High trophic diversity at small spatial scales
2013
Stable isotopes were used to investigate contributions of autochthonous (i.e. benthic: epilithon and macroalgae) and allochthonous (i.e. pelagic: phytoplankton) organic matter sources to the diet of suspension-feeders, grazers and predators associated to small reef-pools (cuvettes) created by the reef-building species Dendropoma petraeum in the north-western coast of Sicily (Italy). Contributions of potential food sources were calculated using Bayesian mixing-models and integrated to a multivariate approach to highlight the diversity of C and N pathways within Dendropoma cuvettes. Both pelagic and benthic organic matter sources were exploited by benthic consumers, although clear differences…
Stable isotope analysis of trophic niche in two co-occurring native and invasive terrapins, Emys orbicularis and Trachemys scripta elegans
2016
A trophic niche overlap in native and alien turtle species can lead to competitive interactions whereby allochthonous turtles may outcompete autochthonous individuals and eventually affect viability of natural populations. The European pond turtle (Emys orbicularis) is an autochthonous species threatened by habitat encroachment and competition with the red-eared slider (Trachemys scripta elegans). The latter is an invasive species introduced in Europe from midwestern United States as a pet and now widespread in the natural habitats of E. orbicularis. The extent of trophic competition between E. orbicularis and T. s. elegans in northern Italy was assessed by nitrogen and carbon stable isotop…
Macroalgae transplant to detect the occurrence of anthropogenic nutrients in seawater of highly tourist beaches in Mediterranean islands
2020
In the Mediterranean region, islands are among the most important tourist destinations, being sites of considerable naturalistic, historical and cultural importance. This is highly beneficial for local economies, but may also represent a threat for the environment, especially during the peak season (i.e. summer). Indeed, the sharp demographic increase concentrated in a relatively short period may negatively affect the quality of coastal marine systems and the provision of ecosystem services, producing in turn negative feedbacks on tourism industry. Nevertheless, the assessment of the environmental impact of tourism on coastal seawater has been seldom addressed. Here, we show the results of …
Beyond the mean: A comparison of trace- and macroelement correlation profiles of two lacustrine populations of the crayfish Procambarus clarkii
2018
In invertebrate biomonitors of chemical pollution, emphasis has been generally given to mean accumulation patterns and how they reflect varying environmental levels of contamination. Intra-population variability, and how it relates with individual phenotypic traits, has received less attention. Here, a set of analytes including trace elements (B, Ba, Cd, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sr, V, and Zn), macroelements (C, Ca, K, Mg, N, Na), and carbon and nitrogen stable isotopes (δ13C and δ15N) was measured in two populations of the crayfish Procambarus clarkii from Lake Trasimeno and Lake Bolsena (Central Italy). The influence of location, sex, body size, and condition factor was assessed; in ad…
Sizing up the role of predators on Mullus barbatus populations in Mediterranean trawl and no-trawl areas
2019
Abstract Fishing leads to drastic changes in ecosystems with a net loss of predatory biomass. This issue has been evidenced from historical ecological studies and from the evaluation of the effects of effective and large marine protected areas. In two fishery reserves off the northern Sicily coast the red mullet Mullus barbatus underwent an impressive biomass increment and a few piscivores fish species recovered after a trawl ban. The red mullet, more than 20% of all demersal fish in the untrawled areas, represented a huge food resource to its potential predators. By contrasting two trawled and two untrawled gulfs we figured out predator - prey relationships through the use of a combined ap…
Stable carbon and nitrogen ratios in the sand smelt from a Mediterranean coastal area: Feeding habits and effect of season and size
2002
Enriched (δ13C values (annual average - 11·2%) suggest that in the study site (Stagnone di Marsala, Italy) the sand smelt Atherina boyeri exploited benthic prey throughout the year. In particular, Mysidacea and Isopoda seemed to dominate the diet. Stomach content data from the literature was in partial agreement with the present isotopic analysis suggesting that, while Mysidacea and Isopoda are exploited by A. boyeri, Copepoda Harpacticoida and Amphipoda are the dominant food items of the sand smelt diet. Several hypotheses are proposed to explain such partially different results from the two techniques. Both season and size influenced the δ13C and δ15N values of A. boyeri. Although through…
Leaf vs. epiphyte nitrogen uptake in a nutrient enriched Mediterranean seagrass (Posidonia oceanica) meadow
2012
Abstract In situ nitrogen uptake by leaves and epiphytes was studied in a Mediterranean seagrass (Posidonia oceanica) meadow impacted from a fish farm and a pristine meadow, using 15NH4 and 15NO3 as tracers. In the impacted meadow both leaves and epiphytes yielded higher N concentrations and showed higher specific N uptake, suggesting a linkage between N uptake and its accumulation. Epiphytes took up N faster than leaves in relation to their corresponding biomass, but when assessed per unit area, N uptake was higher in leaves. Leaf N uptake was negatively correlated with epiphyte N uptake. With increasing epiphyte load on leaves, N leaf uptake decreased while N epiphyte uptake increased, in…