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The importance of robust systems for classifying biogeographical patterns has been emphasized for its usefulness in designing conservation strategies. For such purposes, the distribution patterns of the endemic flora have often been used. Several studies have identified phytogeographical units within Sardinia (western Mediterranean); however, the main part of the island remains unstudied. Thus, the aim of this study is to lay out a comprehensive biogeographical scheme for Sardinia based on endemic vascular plant distributions, together with geological and geomorphological units. We georeferenced, in a 1-km2grid cell, the presence of 290 vascular endemic taxa from the literature, herbarium specimens and field investigators’ research. Sardinia was subdivided into 31 homogeneous units through the integration of geological and geomorphological maps and, subsequently, a presence–absence matrix of endemic taxa in each unit was built. Hierarchical cluster analysis was performed to define two levels of biogeographical units (i.e. sectors and subsectors). For each unit the exclusive and differential endemic taxa were identified. For sectors, indicator species were explored by the Indicator Value (Ind Val) analysis and relationships were analysed by quantitative interaction web. A total of six sectors and 22 subsectors were identified. The highest endemic plant richness was found in the Campidanese-Turritano, Sulcitano-Iglesiente and Supramontano sectors, and in the Gennargenteo, Barbaricino, Iglesiente and Sulcitano subsectors. All sectors were characterized by the presence of exclusive, differential and indicator taxa. The interaction analysis showed the highest uniqueness in endemic flora in the Supramontano and Sulcitano-Iglesiente sectors, which hosted a high number of exclusive endemic species. Mostly mountainous sectors/subsectors had higher endemic-species richness compared with lowland ones. The study showed the relevance of geology and geomorphology, together with accurate data on endemic distribution, to define consistent phytogeographical units. Furthermore, the biogeographical scheme presented here helps to define area-based conservation strategies in Sardinia. [ABSTRACT FROM AUTHOR]

A consistent vegetation classification is an essential tool for conservation and monitoring purposes, also for semi-natural habitats such as pastures and hay meadows that are linked to traditional land use and generally considered crucial to maintain biodiversity within agricultural systems. Indeed, these habitats can be strongly affected by land abandonment or agriculture intensification. Despite their importance in the framework of the EU Habitats Directive (43/92/EEC), information on distribution, species composition, and conservation status is still lacking for many regions. To fill these gaps, we investigated from a phytosociological point of view the sheep pastures of the North-Western Sardinian trachy-basaltic sector. Three main communities were described as new: (i) perennial montane (meso-supratemperate) cattle and sheep pastures (Loto alpini-Festucetum morisianae); (ii) mixed (annual and perennial) Mediterranean (lower Thermomediterranean to lower supratemperate) sheep pastures (Ornithogalo corsici-Poetum bulbosae); and (iii) annual ploughed subnitrophilous Mediterranean and Temperate pastures (Cynosuro polybracteati-Vulpietum ligusticae). As the first two host numerous endemictaxaand show a peculiar floristic composition, we assign them a higher conservation value, testified also by their classification in two newsyntaxa:Danthonio decumbentis-Caricenion insularis(Molinio-Arrhenatheretea) andOrnithogalo corsici-Trifolienion subterranei(Poetea bulbosae), respectively. [ABSTRACT FROM PUBLISHER]

Coastal dune environments are selective ecosystems characterized by a close interaction between abiotic and biotic factors in a dynamic balance. The present study focused on the psammophilous geosigmetum, the most affected by the interactions between physical processes and biological and anthropic processes. The main purpose was to study the relationships between the abiotic properties of the dune and the presence of the various plant communities, combining morpho-sedimentological, geopedological, and geobotanical data. The study was carried out on the well-preserved dune system of Is Arenas (CW Sardinia) which is one of the most important in the Mediterranean area. The analyses revealed differences at the morphodynamic, sedimentological, and geopedological levels. The micro-topography of the dunes affects the values of the main abiotic variables, and determines the presence of various microhabitats of great heterogeneity. This work shows that thedata on the geomorphological dynamics and the chemical–physical processes, correlated with the geobotanical analyses, might make it possible to identify the ecosystemic processes, and thereby plan adequate management and conservation strategies for this coastal dune system. [ABSTRACT FROM PUBLISHER]

Because of the complex geoclimatic dynamics of the Mediterranean basin, resulting from a combination of Tertiary geological processes and Quaternary climatic oscillations, the current species composition of the main continental islands is a mosaic resulting from relative contribution of vicariance, geodispersal and long-distance dispersal by seed. To help distinguish among the contributions of these different dispersal modes to the orchid species richness on the island of Sardinia, we investigated the genetic structure and phylogeographic relationship of the only Platanthera bifolia var . kuenkelei population on the island. By using plastid DNA sequence variation, we show that this recently discovered population is more closely related to the Tunisian P. bifolia var . kuenkelei than to the geographically closer P. bifolia populations from peninsular Italy. Results from haplotype network construction support the hypothesis that the current distribution of P. bifolia var . kuenkelei (Sardinia and Tunisia) is most likely explained by over-sea dispersal. However, haplotype diversity and mismatch analysis of this unique Sardinian population suggest that, if a long-distance dispersal event did occur, it was not recent. More likely, temporarily favourable climatic conditions generated a suitable habitat on the island (also in terms of suitable mycorrhizas and pollinators) and thus a transient opportunity for seedling growth and population establishment of P. bifolia var . kuenkelei from North Africa. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167, 466-475. [ABSTRACT FROM AUTHOR]

Fire is a basic ecological factor that contributes to determine vegetation diversity and dynamics in time and space. Fuel characteristics play an essential role in fire ignition and propagation; at the landscape scale fuel availability and flammability are closely related to the vegetation phenology that directly affects wildfire pattern in time and space. In this view, the annual normalized difference vegetation index (NDVI) profiles derived from high temporal resolution satellites, like SPOT Vegetation, represent an effective tool for monitoring the coarse-scale vegetation seasonal timing. The objective of this study thus consists in quantifying the explanatory power of multitemporal NDVI profiles on the fire regime characteristics of the potential natural vegetation (PNV) types of Sardinia (Italy) over a 5-year period (2000–2004). The results obtained show a good association between the NDVI temporal dynamics of the PNV of Sardinia and the corresponding fire regime characteristics, emphasizing the role of the bioclimatic timing of the vegetation in controlling the coarse-scale wildfire spatio-temporal distribution of Sardinia. By providing a sound phytogeographical framework for describing different wildfire regimes, PNV maps can thus be considered helpful cartographic documents for fire management strategies at the landscape scale. [Copyright &y& Elsevier]

Presents a list articles about bryology. "Bryogeographic Patterns in the Small Islands Surrounding the Italian Peninsula, Sicily and Sardinia," by M. Aleffi, Pedrotti C. Cortini and D. Gafra, published in the 2003 issue of the journal "Bocconea"; "Additions to the Bryoflora of Hawk Mountain Sanctuary, Berks County, Pennsylvania," by S. Bartholomew-Began, published in the 1999 issue of the "Journal of the Pennsylvania Academy of Science"; "The Biodiversity of the Granitic Islands of Seychelles," by J. Gerlach, published in the 2003 issue of the journal "Phalsumia."

The Permian section outcropping at Guardia Pisano (Sulcis area, SW Sardinia), comprises two successions, separated by an unconformity. The lower succession is composed of grey–black sandy shales, rich in plant remains and in sporomorphs, deposited in a fluvial-lacustrine to palustrine environment; followed by layers of rhyolithic lavas and volcanoclastites with silicified plant trunks. Most of the analysed samples yielded a profusion of pollen and spores in a very good state of preservation. Three associations were distinguished. The first one comprises mostly radial and bilateral monosaccate pollen grains and very few spores. This association is characterized by the presence of pollen grains of the genera Crucisaccites, Luberisaccites, Gondwanopollis and Lueckisporites, together with very abundant Potonieisporites and subordinate Florinites. The second association comprises mostly pollen grains of the genus Potonieisporites, represented by many species, together with Limitisporites, Costapollenites, Vittatina and others. Spores mainly represented by azonate trilete and monolete types are more frequent than in the previous association. These first two palynological associations reflect assemblages of meso-xerophilous plants growing in dryer environments, belonging to tropical and subtropical phytogeographic biomas. The third association, mainly composed of Sphenophyte spores, is autochthonous and corresponds to a swampy hygrophilous flora settled after the filling up of the basin. The age inferred by means of sporomorphs is early Asselian which is in good agreement with the mean radiometric age of the volcanic rocks obtained by the ‘SHRIMP’ and the lead-zircon evaporation methods (297 ± 5 Ma). The upper succession, is composed of grey to red sandstones and thin pelites deposited on an alluvial plain under very hot and humid climate; its Permian, post–Asselian age cannot be better constrained because of the scarcity of the fossil content. [Copyright &y& Elsevier]