Search results for "mediterranean"
showing 10 items of 3196 documents
Testing alternative vicariance scenarios in Western Mediterranean discoglossid frogs
2004
Dated molecular phylogenies are often used to interpret evolutionary history with respect to paleogeographic events. Where more than one interpretation is possible, it is desirable but difficult to assess the alternatives in an objective manner. The present work demonstrates a formalized method for testing molecular clock calibrations and biogeographic scenarios based on them. We assessed the plausibility of several previously published biogeographic hypotheses, using the frog genera Alytes, Discoglossus, and Bombina as model groups. Our data set comprised ca. 900bp of partial mitochondrial 16S and 12S rRNA gene sequences (both genes evolved in a clock-like manner across genera) from nearly…
A new association of relict maquis with Ptilostemon greuteri (Oleo-Ceratonion, Quercetea ilicis), located in a circumscribed area of north-western Si…
2022
This paper illustrates the results of a survey aimed at deepening available knowledge on the ecology of Ptilostemon greuteri (Asteraceae), a very rare palaeoendemic and relict nano-phanerophyte discovered about 15 years ago on Monte Inici, near Castellammare del Golfo (province of Trapani, north-western Sicily). Two plant communities characterised by P. greuteri are described in detail; they occur in the locus classicus and in a second, recently discovered stand, which is also very localised and threatened by fire. The field investigations revealed that the sites where the species grows are very similar from the ecological point of view; in fact, both of them are located on the steep slopes…
Do small marinas drive habitat specific impacts? A case study from Mediterranean Sea.
2011
Many human activities add new structures to the marine landscape. Despite the fact that human structures cause some inevitable impacts, surprisingly little information exists on the effects of marina on natural marine assemblages. The aim of this paper is to assess habitat-specific response of benthic sessile organisms of rocky shores in relation to the presence of a small marina. Sampling was carried out at three coastal habitats (midshore, lowshore and subtidal) by means of visual censuses adopting an after-control-impact (ACI) experimental design. It appears that the marina affects the structure and composition of benthic communities of both the midshore and the lowshore. Little effect w…
Typification of the name Senecio pygmaeus (Asteraceae), with some additional taxonomic and phytogeographic remarks
2023
A thorough research on the scientific activity of Guglielmo Gasparrini, Giovanni Gussone and Augustin Pyramus De Candolle allowed the authors to adress a research in several European herbaria looking for the type of the name Senecio pygmaeus DC. The original specimen sent by Gussone and mentioned in the protologue by Candolle is still kept at G-DC and is designated as the lectotype, whilst three other herbarium sheets, preserved at NAP-GUSS, PAL and PAV herbaria respectively, in all probability belong to the same gathering, and are considered as isolectotypes. The authors provide an updated description of this taxon in order to better point out its diagnostic characters. However, further bi…
Effects of fish feeding by snorkellers on the density and size distribution of fishes in a Mediterranean marine protected area
2005
Although there is a great deal of evidence to show that supplementary feeding by humans in terrestrial environments causes pronounced changes in the distribution and behaviour of wild animals, at present very little is known about the potential for such effects on marine fish. This study evaluated the consequences of feeding by snorkellers on fish assemblages in the no-take area of the Ustica Island marine protected area (MPA; western Mediterranean) by (1) determining if reef fish assemblage structure is affected in space and time by tourists feeding the fish; (2) assessing the effects of feeding on the abundance of the most common fish species; and (3) assessing the effects of feeding on t…
Response of benthic foraminifera to heavy metal contamination in marine sediments (Sicilian coasts, Mediterranean sea)
2011
To examine the suitability of benthic foraminifera and their test deformations as bioindicators of pollution in coastal marine environments, we studied foraminifera and metal concentrations in 72 marine sediment samples, collected from the inner shelf along the Sicilian coast (Gulfs of Palermo and Termini) and on the south-eastern coast of Lampedusa Island. These areas are characterised by different environmental conditions. On the basis of pollution sources and foraminiferal assemblages, we recognised different zones in the Gulf of Palermo. The most polluted zones showed high metal concentrations, and low diversity of benthic foraminifera with species typical of stressed environments. By c…
Effect of explosive shallow hydrothermal vents on δ13C and growth performance in the seagrass Posidonia oceanica
2010
Summary 1. Explosive volcanic submarine activity is expected to affect seagrass communities due to sudden and dramatic changes in the physical and chemical features of sea water and sediments, with possibly large ecosystem effects. However, seagrass response to the harsh environmental conditions that arise due to explosive volcanism is as yet unexplored as it is not easy to predict when and where an eruption will occur. Here, we investigate the uptake of hydrothermal carbon within the seagrass Posidonia oceanica by the analysis of δ13C and growth rates in tissue laid down before and after an exceptional and massive hydrothermal gas release in the Aeolian Islands (Italy, Mediterranean Sea). …
Isoëtes sabatina (Isoëtaceae, Lycopodiopsida). Taxonomic distinctness and preliminary ecological insights
2021
1) Isoëtes sabatina is the rarest aquatic quillwort in Europe. Although recently found (2013) in Lake Bracciano (central Italy), the species is just one step away from extinction with an estimated population not exceeding 400 individuals and a spatial range of a few hundred square metres. 2) Lake Bracciano is a deep, oligo-mesotrophic Mediterranean volcanic lake that has been subjected to human activities. From January to October 2017, the lake experienced a dramatic water level decrease (up to −1.50 m), which significantly affected the littoral zone and the habitat of I. sabatina. 3) To improve the chances of survival of I. sabatina, the first eco-taxonomic investigation on this species wa…
New Data on Native and Alien Vascular Flora of Sicily (Italy): New Findings and Updates
2023
In this paper, based on fieldwork and herbaria surveys, new data concerning the presence of 32 native and alien vascular species for Sicily (Italy) are provided. Among the native species, the occurrence of the following taxa is reported for the first time or confirmed after many decades of non-observation: Aira multiculmis, Arum maculatum, Carex flacca subsp. flacca, Mentha longifolia, Oxybasis chenopodioides, Najas minor and Xiphion junceum. Furthermore, we document the presence of three native species (Cornus mas, Juncus foliosus and Limonium avei) that, despite being repeatedly observed in Sicily and reported in the literature, are inexplicably omitted by the most recent authoritative ch…
‘Back to the Future’—Oak wood-pasture for wildfire prevention in the Mediterranean
2021
In the summer of 2021, enormous wildfires in the Mediterranean eliminated huge areas of mainly coniferous forest, destroyed adjacent settlements and claimed the lives of many people. The fires indicate effects of climate change and expose consequences of rural demographic changes, deficits in regional and touristic development planning and shortcomings in forest policy. This forum article highlights the dimensions of the problem, calls for a paradigm shift and shows solutions. Land abandonment, woody plant encroachment and non-reflective afforestation are leading to increasing amounts of combustible biomass. To prevent disastrous fires in future, fundamental changes in tree species composit…