Phytosociological study of the shrub and pre-forest communities of the effusive substrata of NW Sardinia

The trachybasalt biogeographic sub-district of the NW Sardinian district, included in the coastal and hilly sub-sector of the Sardinian biogeographic sector, is characterised by two large effusive complexes: that of the rhyolites, andesites and dikes of the Oligo-Miocene alkaline volcanic cycle (14-32 Ma) and alkaline basalts, rhyolites, rhyodacites and dikes of the volcanic cycle with alkaline, transitional and sub-alkaline affinity of the Pliocene-Pleistocene (0.14-5.3 Ma). Between 2000 and 2004, 156 surveys were carried out on shrub communities in order to improve knowledge of their phytosociology. Vegetation analysis led to the identification of 11 associations and 13 subassociations, referring to 3 syntaxonomic classes. Of these, 5 new associations are hereby described for the first time: Clematido vitalbae-Maletum pumilae, Crataego monogynae-Aceretum monspessulani, Lavatero olbiae-Rubetum ulmifolii, Genisto desoleanae-Ericetum arboreae and Telino monspessulanae-Cytisetum villosi

Halophilous vegetation of Olbia pond system (NE-Sardinia)

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

Caratterizzazione fitosociologica dell’habitat prioritario 6220*-“Percorsi substeppici di graminacee e piante annue dei <i>Thero-Brachypodietea</i>”: caso di studio della Sardegna settentrionale

In this paper we aimed at characterizing phytosociologically the priority habitat 6220* in Northern Sardinia. In the study area this habitat is identified on the field by the presence of 18 plant associations, referred to the following syntaxonomic classes: Helianthemetea guttati, Poetea bulbosae, Artemisietea vulgaris and Lygeo-Stipetea. Within the Brachypodio ramosi-Dactyletalia hispanicae order of the Artemisietea vulgaris class, three new associations are here described for the first time: Ophrydo praecocis-Dactyletum hispanicae, Orchido longicorni-Dactyletum hispanicae and Orchido collinae-Dactyletum hispanicae which are all referred to the Leontodo tuberosi-Bellidion sylvestris alliance. The wide structural and functional heterogeneity, that prevent from outlineing common management strategies to all the 4 vegetation classes included in the habitat, suggests the need of a clarification of the Habitats Directive and its revision on the basis of the recent phytosociologic findings

Gli Habitat terrestri costieri e litorali della Sardegna settentrionale: verifica della loro attribuzione sintassonomica ai sensi della Direttiva 43/92/CEE “Habitat”

In this work we talk about coastal and littoral terrestrial habitats and plant communities in Northern Sardinia. We check the right attribution of different plant communities to their habitat type, among those indicated in the Annexe I of the 43/92/EEC Habitat Directive, and the coherence between the Natura 2000 Network and the tested habitat presence in the study area. Finally, some critical examples, regarding either the interpretation or the application of the Habitat Directive, are discussed. In the study area 16 community habitats have been detected, and among them three are priority habitats (1510*, 2250* and 2270*). 15 habitats are confirmed, been mentioned in at least one Natura 2000 formulary, instead, habitat 2220 is here reported for the first time in Northern Sardinia. The presence in the study area of 5 habitats mentioned in Natura 2000 formularies (1310, 2110, 2120, 2240 and 5410) is not confirmed. The percentage of high threatened habitats in the study area (37.5%) is higher than the national one (24%). On the other hand the percentage of low risk habitats in coastal areas of Northern Sardinia (37.5%) is lower than the Italian one (48%). These considerations give priority to the conservation of the coastal and littoral areas in Northern Sardinia. Finally, the discussion of some critical applicative examples bring us to ask for a really needed Habitat Directive Annexe I revision