Search results for "gras"

Grassland fire effect on soil organic carbon reservoirs in a semiarid environment

2013

Abstract. The aim of this work was to investigate the effect of an experimental fire used for grassland management on soil organic carbon (SOC) stocks. The study was carried out on Hyparrhenia hirta (L.) Stapf (Hh) grassland and Ampelodesmos mauritanicus (Desf.) T. Durand & Schinz (Am) grasslands located in the north of Sicily. Soil samples were collected at 0–5 cm before and after the experimental fire, and SOC was measured. During the grassland fire, soil surface temperature was monitored. Biomass of both grasses was analysed in order to determine dry weight and its chemical composition. The results showed that SOC varied significantly with vegetation type, while it is not affecte…

Il mese di produzione influenza la qualità di formaggi tipici?

2022

Il settore lattiero-caseario mediterraneo rappresenta una delle più importanti attività legate al lavoro delle terre montane e marginali e alla produzione di prodotti tipici e di qualità. Un prodotto “tipico” è il risultato di diversi fattori strettamente legati all’origine geografica e alle tradizioni sociali e culturali dell’area di produzione. Tali prodotti sono da sempre uno strumento per valorizzare la biodiversità, la cultura e l’economia di definite aree mediterranee. L’Unione Europea riconosce ufficialmente questa diversificazione di prodotto attraverso l’attribuzione di marchi di qualità a denominazione di origine protetta (DOP) e a indicazione geografica protetta (IGP). Nella poli…

Milk fatty acids of cows grazing a mountain diversified grassland is highly affected by the maturity stage of the grass.

2009

CAN HALOPHILA STIPULACEA OUTCOMPETE CYMODOCEA NODOSA? A CASE STUDY OF A MEDITERRANEAN SHALLOW WATER HABITAT

2022

The tropical seagrass Halophila stipulacea (Forsskål) Ascherson entered the Mediterranean Sea through the Suez Canal more than 100 years ago. In the coastal-marine ecosystems the spatial niche of H. stipulacea is often overlapped with that of native Mediterranean Sea seagrasses and therefore it might out-compete them. On the basis of previous observations, we monitored for one year a Southern Mediterranean shallow water habitat (North-Western Sicily Island, Italy, Southern Mediterranean Sea), where H. stipulacea co-occurred with the native seagrass Cymodocea nodosa (Ucria) Ascherson. In this paper we compare sites with (impacted sites) and without H. stipulacea (non-impacted sites) to analy…

Competition between algae and seagrasses: a Ruppia cirrhosa (Petagna) Grande bed in western Mediterranean Sea

2007

Spreading of the alien seagrass Halophila stipulacea (Hydrocharitaceae) along the sicilian coast (western Mediterranean Sea)

2009

Halophila stipulacea (Forsskål) Ascherson is a tropical seagrass distributed along the western coasts of the Indian Ocean and in the Red Sea (den Hartog, 1977). This species was previously considered a paleomediterranean element, survived as a relict in the eastern Mediterranean Sea, but later on Por (1971) hypothesized that it was a Lessepsian immigrant entered the Mediterranean Sea after the opening of the Suez Canal (1869). H. stipulacea remained in the eastern Mediterranean for several decades (Lipkin, 1975), and only recently it spreads towards the western basin through Malta and the Ionian coast of Sicily (Lanfranco, 1970; Van der Velte and Den Hartog, 1989; Alongi et al., 1993). The …

Phytosociological and distributional researches on the grasslands of the class Lygeo-Stipetea in western Sicily.

2009

The thermo and meso-xerophilous pseudo-steppic vegetation is widespread in the driest areas of the Mediterranean Region and is primarily referred at the class Lygeo-Stipetea. This sintaxon includes communities dominated by several hemicryptophytes, which are also associated to some geophytes and therophytes. In Sicily this vegetation is distributed from sea level to 1300-1400 m, on different substrates (limestone, gypsum, schists, calcarenites, conglomerates, etc.), within the thermo and mesomediterranean belt dry to subhumid. Principally, are secondary grasslands used for grazing, localized on previously deforested areas, where the periodic burnings play a fundamental role in maintaining t…

On the origin and evolution of the Mediterranean dry grasslands.

2006

A synthesis on the functional types of Mediterranean dry grasslands is outlined. Three different types are outlined: wintergreen perennial dry grasslands, wintergreen ephemeral dry grasslands, summergreen perennial dry grasslands. The first type is the most primitive, including several relict species, often characterized by very disjoint, sometimes anfi-saharian distribution ranges. The second type is resulting from an evolutionary trend towards short-lived life strategy, triggered by climatic and topographic perturbations that affected the Mediterranean region in the Plio- and Pleistocene. The third type, only marginally occurring in the Mediterranean region, is deriving from Holarctic and…

An “Uncertainty Principle” for the Mediterranean annual dry grasslands

2009

Preliminary results of diachronic researches on the spatial arrangement and species richness in Mediterranean annual dry grasslands (Tuberarietea guttatae) demonstrated that the patchiness resulted minimized and the temporal stability maximized at elevations offering the best compromise between the summer drought stress and the winter cold stress. Moreover, the temporal stability of the Mediterranean annul dry grasslands could not necessarily be related with their demographic inertia, meaning that the turnover and rearrangement of species within the community do not necessarily implicate significant changes in the average species composition over time. On the other hand, the survival chance…

Life on the edge: Adaptations of Posidonia oceanica to hypersaline conditions in a Mediterranean lagoon system

2023

Hypersaline stress is a major stressor in semi-enclosed coastal lagoons, affecting the distribution and survival of key foundation species. In this study, we investigated how Posidonia oceanica meadows responded physiologically and morphologically to different salinity concentrations both in-situ, across a natural saline gradient occurring inside the lagoon system, and in a mesocosm experiment. Leaf water relations, organic osmolytes, photosynthesis, respiration, Chlorophyll-a fluorescence, pigments content, and leaf growth were studied in P. oceanica from three different sites within the Stagnone of Marsala lagoon, as well as after exposing P. oceanica to a salinity level of 46 psu in a 30…