185 research outputs found

    A Palm fossil closely related to <i>Chamaerops humilis</i> L. from the Lower Miocene of Sardinia

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    This paper deals with the anatomical and histological study of a silicified specimen of a palm consisting of a part of the trunk surrounded by roots. The sample comes from the Lower Miocene of North West Sardinia. The comparison with fossil species and existing species leads to the conclusion that the specimen belongs to a new fossil species closely related to Chamaerops humilis L., widespread throughout the Mediterranean area. Paleo-environmental considerations confirm the presence in Sardinia, in the epoch in question, of formations of Mediterranean forest corresponding in part to forest existing in North Africa today. Viene presentato lo studio anatomo-istologico di un reperto silicizzato di palma costituito da una parte di fusto con un rivestimento esterno di radici. Il campione proviene da formazioni attribuite al Miocene basale della Sardegna Nord-Occidentale. Il confronto con specie fossili e attuali ha permesso di accertare che si tratta di una nuova specie fossile che presenta notevole affinità con Chamaerops humilis L. e che viene perciò indicata come Palmoxylon homeochamaerops. Le considerazioni di ordine paleoambientale confermano la presenza all'epoca di formazioni di foresta mediterranea corrispondenti in parte a quelle che attualmente si rinvengono nell'Africa settentrionale ed in particolare nel Sud del Marocco

    Cartography and diachronic analysis of the vegetation of S'Ena Arrubia Lagoon (Centre-Western Sardinia)

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    The vegetation map of S'Ena Arrubia Lagoon in centre-western Sardinia (1: 2,500 scale) is presented and some diachronic remarks are made by referring to historical data available. The main object of this cartography, after a research on the biotope vegetation, is to allow the biomonitoring of an extremely important site for the biodiversity conservation (Protected Area: S.I.C., Z.P.S., I.B.A.), which is to use for an ecologically aware management

    The Vegetation of S'Ena Arrubia lagoon (centre-western Sardinia)

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    This study describes the vegetation of S'Ena Arrubia lagoon, in the Gulf of Oristano, in the centre-western coast of Sardinia. This lagoon is classified as: Special Protection Zone (S.P.Z.) according to EEC Directive 79/409, community importance site according to EEC Directive 92/43, I.B.A. (Important Birds Area) site and fixed oasis of fauna protection and natural reserve. Throughout the years it was subject to several alterations. The most important ones were carried out in the Seventies and allowed the marine water upwelling and the fast removal of freshwater coming from the watershed. Before the fulfilment of these interventions, lagoon waters had a low salinity, as demonstrated by previous vegetation studies that showed the presence of freshwater communities and, only to a smaller extent, of halo-tolerant and halophile ones. This phytosociologic study led to the identification of several associations that are showed in the groups of merely halophile vegetation, in the freshwater and subhalophile lagoon vegetation and in the merely anthropogen vegetation typologies. The location of the considered typologies is represented with distributive patterns, which synthesise the current state of vegetation referring to the salinity. Two new associations, the Inulo crithmoidis-Paspaletum vaginati and the Astero tripolii-Bolboschoenetum maritimi, are here described. The first is dominated by the presence of Paspalum vaginatum Swartz, recorded for the second time in Italy and for the first time in Sardinia. It is recorded near the inlet, where it forms mosaics together with Salicornietum emerci association and it is also present, as bolboschoenetosum maritimi subassociation, in more inland and less salty zones. The latter new association includes the subhalophile reedswamps that are present in the areas floodcd by salty waters for a long time, where it replaces the Scirpetum compacto-littoralis, a less halophile association present in several siles of the Mediterranean and also in Sardinia. In addition, it is necessary to point out the recovery of Salicornietum venetae association, characterised by the presence of Salicornia veneta Pign. et Lausi, which was believed endemic in the North Adriatic lagoons. Finally, the significance of environmental changes fulfilled in the basin, which are the reason for some vegetation modifications and are detected by comparison between current associations and those at the beginning of the Seventies, is pointed out

    O nekim biljnim zajednicama s vrstom Euphorbia dendroides L. u Grčkoj

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    The article is a study of vegetation in some maquises of Euphorbia dendroides and Olea sylvestris the authors have found in continental Greece at Monastiraki (the Corinth Canal) and on the island of Crete (at Kissomos and Sauda). Such vegetation belongs to the association Oleo-Euphorbie- tum dendroidis Trinajstic (1973) 1984 described for some places along the coast of Yugoslavia. Among the relevés shown, the ones coming from Monastiraki are the most corresponding to the association, while the others taken on the Island Crete belong to a really nitrophilous variant of the same association.Prikazana je vegetacija nekih sastojina s vrstama Euphorbia den- droides i Olea sylvestris, koje su autori pronašli u kontinentalnoj Grčkoj kraj Monastirakija (Korintski kanal) i na otoku Kreti (u Kissomosu i Saudi). Ta je vegetacija označena kao asocijacija Oleo-Euphorbietum dendroidis Trinajstić (1973) 1984 opisana ranije iz nekih područja jugoslavenske obale. Među prikazanim sastojinama najviše odgovaraju asocijaciji one iz okolice Monastirakija, dok ostale, snimljene na otoku Kreti, pripadaju nitrofilnoj varijanti te asocijacije. Iznesena su napokon neka razmatranja o rasprostranjenosti te zajednice u Sredozemlju. Autori smatraju da je as. Oleo-Euphorbietum dendroidis prisutna samo na Balkanskom poluotoku gdje se javlja u obliku dviju geografskih rasa, od kojih je jedna rasprostranjena pretežno uz Jadran s mezofilnim karakteristikama, i druga uz Egejsko more termofilnoga karaktera. Sastojine s vrstom Ephorbia dendroides, dominantnom u središnjem i zapadnom Mediteranu, pripadale bi, međutim, drugim zajednicama koje će moći biti opisane kasnije nakon podrobnijih istraživanja

    Halophilous vegetation of Olbia pond system (NE-Sardinia)

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    Authors report some results about a phytosociological study concerning the wetlands to the south of Olbia (Gallura, north-eastern Sardinia). Vegetation analysis allowed to detect 21 associations, among them two are new and denominated Halimionio portulacoidis-Limoniastretum monopetali ass. nova and Ephedro fragilis-Pistacietum lentisci ass. nova. Among them, the association Halimiono portulacoidis-Limoniastretum monopetali shows a particular phytogeographical interest, because it sets the Limoniastrum monopetalum vegetation in the only Sardinian station of this shrubby Plumbaginacea. From a syntaxonomic point of view, described syntaxa are included in 9 vegetation classes. Plant landscape of the area was reconstructed by the study of chain contacts among different communities, placed in space according to humidity and salinity gradients, determined by substratum texture and micromorphology. On the basis of phytocoenotic diversity stressed by this research, this study area is believed to be deserving of protection aiming at conserving and managing its populations and plant communities

    A Phytosociological study of the deciduous oak woods of Sardinia (Italy)

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    We present here the results from a phytosociological and synchorological study of the deciduous oak woods of Sardinia. This vegetation analysis has allowed the individuation of three new associations: Lonicero implexae-Quercetum virgilianae, Ornithogalo pyrenaici-Quercetum ichnusae and Glechomo sardoae-Quercetum congestae. The Lonicero implexae-Quercetum virgilianae association includes the woods on calcareous substrata spread throughout Northern Sardinia, which can occasionally be found in southern areas; the first of these are rich in mesophilous species and are attributed to the subassociation cyclaminetosum repandi, while the others are referred to quercetosum virgilianae. The Ornithogalo pyrenaici-Quercetum ichnusae association, more widely distributed in Central-Northern Sardinia, includes the climatophilous deciduous woods that are found on lithological substrata of a non-carbonatic nature, and in particular, on andesites, trachytes and metarenites. The typical aspect is referred to the subassociation cytisetosum villosi, while the subassociation ilicetosum aquifolii includes the more mesophilous woods on basaltic substrata. The Glechomo sardoae- Quercetum congestae association always includes the woods found on the non-carbonatic substrata in the higher altitude areas with an oceanic pluviseasonal temperate bioclimate. Of this, the subassociation quercetosum congestae, on the granite areas, and oenanthetosum pimpinelloidis, on those metamorphic and of basalt, are proposed. At the higher hierarchical levels, the association Lonicero implexae-Quercetum virgilianae is referred to the endemic Sardinian-Corsican suballiance Clematido cirrhosae-Quercenion ilicis, of the alliance Fraxino orni-Quercion ilicis, while for the other associations the new suballiance Paeonio morisii-Quercenion ichnusae, (holotypus: Glechoma sardoae-Quercetum congestae ass. nova) particular to the Sardinian biogeographic subprovince, is proposed, of the alliance Pino calabricae-Quercion congestae, the order Quercetalia pubescentipetraeae, and the class Querco roboris-Fagetea sylvatica

    Bioclimates of Italy

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    The Worldwide Bioclimatic Classification System according to Rivas-Martínez (WBCS) is a bioclimatic classification that is widely used in vegetation science, geobotany, and landscape ecology. To date, only one complete WBCS map has been produced for Italy at the national scale. Here, we define two major updates to the WBCS map of Italy: improvements to the surface spatial accuracy for the climate, especially for precipitation; and detailed mapping of the Submediterraneity Index and its levels, which mainly characterize the ecotone area between the Mediterranean and the Temperate macrobioclimates. Finally, all WBCS units (i.e. macrobioclimates, bioclimatic variants, bioclimates, continentality types, bioclimatic belts) and the Submediterraneity Index are mapped on a scale of 1:2,500,000. These maps and the bioclimatic indices and monthly climatic surfaces are available here as raster data-sets (resolution, 900 m) and are useful for accurate bioclimatic diagnosis for the entire Italian territory. They will also support vegetation–environment relationship analysis, ecological modeling, and applied studies of climate change at the national scale

    Su alcune associazioni di vegetazione nitrofila della Sardegna settentrionale

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    This paper deals about some nitrophilous associations of northem Sardinia. These associations are included in the classes: Pegano-Salsoletea Br.-Bl. e O. de Bolòs 1957, Stellarietea mediae R. Tx., Lohm et Preising in R. Tx. 1950 and Artemisietea vulgaris Lobm, Prsg. et Tx. in Tx. 1950. The new associations Camphorosmo monspeliaceae-Halimionetum portulacoidis, Sileno albae-Acanthetum mollis, Smyrnietum rotundifolii, Bryonio marmoratae-Aretum pieti e Dauco maximi-Magydaridetum pastinaceae are here proposed

    Su alcune formazioni ad <i>Artemisia arborescens</i> L. della Sardegna settentrionale

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    The northern Sardinian Artemisia arborescens and Atriplex halimus vegetation is here studied. This type of vegetation is ascribed to the Atriplici halimi-Artemisietum arborescentis Biondi 1988 association. The association shows a good differentiation with different types of development: a pioner aspect with predominence of Atriplex halimus; an other kind, colonizing fallow fields, which is described by the inuletosum viscosae subassociation and a last one that evolves towards scrub formations included in the Oleo-Ceratonion alli ance referred to the anagyridetosum foetidae subassociation

    Il Paesaggio vegetale della Nurra (Sardegna nord-occidentale)

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    The description of vegetation typologies that characterise the plant landscape in Nurra - according to phytosociological and sinphytosociological interpretations - is presented. Plant associations found out are here presented from areas closer to the sea towards the inner ones, grouped according to environmental and structural characteristics. The following new associations are described. Crithmo maritimi-Limonietum nymphaei, Evaco pygmaeae-Bellietum bellidioidis, Senecioni leucanthemifolii-Nanantheetum perpusillae, Spergulario salinae-Hordeetum marini, Limonietum laeti-glomerati, Brassico insularis-Seselictum praecocis, Anthyllido vulnerariae-Kundmannietum siculae, Loto cytisoidis-Dactyletum hispanicae, Dactylo hispanicae-Camphorosmetum monspeliacae, Scillo obtusifoliae-Bellidetum sylvestris, Scillo autumnalis-Bellidetum sylvestris, Hypecoo procumbentis-Silenetum nummicae, Bupleuro fontanesii-Scorpiuretum muricati, Rosmarino officinalis-Thymelaeetum tartonrairae, Dorycnio pentaphylli-Cistetum eriocephali, Pyro amygdaliformis-Quercetum ilicis, Euphorbio characiae-Juniperetum turbinatae, Pistacio lentisci-Calicotometum villosae, Crataego monogynae-Pistacietum lentisci. Furthermore, phytosociological and syntaxonomical study of the subnitrophilous hemicryptophyte communities allowed their attribution to the Artemisietea vulgaris c1ass. Within this class the new Brachypodio ramosi-Dactyletalia hispanicae order is described, together with two new alliances, Reichardio maritimae-Dactylion hispanicae and Leontodo tuberosi-Bellidion sylvestris. The order includes the perennial, hemicryptophyte and geophyte, subnitrophilous vegetation of the secondary formations, finding their optimum in the sub-humid and humid mesomediterranean macroclimate, and can also penetrate into the thermomediterranean one for edaphic compensation. Moreover, this study suggests to include in the new Brachypodio ramosi-Dactyletalia hispanicae order, the Bromo-Oryzopsion and the Thero-Brachypodion ramosi alliances. The study of associations and their dynamic relationships also allowed to reconstruct the vegetation series which integration produces the main plant landscape units present in Nurra. The coastal Tyrrhenian, basophilous, calcicole, thermomediterranean and edaphon-xerophilous series of Juniperus turbinata (Chamaeropo humilis-Junipereto turbinatae sigmetum) was reconstructed on Mesozoic limestone. Different plant associations of comophytic and chasmophytic communities integrating the coastallimestone landscape are connected to this pattern by chain relationships. Between the landscape units of the Mesozoic limestone sector and the Paleozoic metamorphic one, the coastal Tyrrhenian, neutroacidophilous, of sandstone, thermomediterranean and edaphon-xerophilous series of Juniperus turbinata with Arbutus unedo (Chamaeropo humilis-Junipereto turbinatae arbutetosum unedonis sigmetum), representing an edaphic variant of the previous one, linked to the violet quartzose sandstone on which a more clayey soil is generated, was reconstructed. The geosigmetum of Mesozoic limestone is completed by the Tyrrhenian, neutroacidophilous, calcicole, thermomediterranean c1imatophilous series of Quercus ilex (Pistacio-Querceto i1icis sigmetum). It is present on the inner hills and, of its series-head, only a few examples of Quercus ilex grove remain, which assume a particular characterisation for the presence of Chamaerops humilis. The Sardinian coastal, neutroacidophilous, of Paleozoic schist, thermomediterranean, climatophilous and edaphon-xerophilous series of Juniperetus turbinata (Euphorbio characiae-Junipereto turbinatae sigmetum) was reconstructed in the metamorphic area. The prevalently chain contact with the subhalophile garigue and the microgeosigmeta of the therophytic and chamaephytic halophile communities occurs in the coastal girdle close to the c1iff. The landscape unit of the coastal metamorphic section is completed by the Tyrrhenian, neutroacidophilous, mesomediterranean, of schist, climatophilous series of Quercus ilex (Erico arboreae-Querceto ilicis sigmetum). In the alluvial plain of Nurra, on strong clayey substrata with a mixed calcicole-silicic matrix, always in thermomediterranean climate but under a marked edaphic compensation, the Sardinian, neutroacidophilous, of plain, edaphon-mesophilous series of Quercus ilex and Quercus suber (Pyro amygdaliformis-Querceto i1icis sigmetum) is found. The geosigmetum of the alluvial plain is completed by the edaphon-hydric series of the alluvial soils in the north-western Sardinia (Allio triquetri-Ulmeto minoris sigmetum). Finally, some indications about land management are given in order to maintain the high biodiversity that currently is still present
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