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
