abstract Vegetation and plant landscape of the La Maddalena archipelago (North-Eastern Sardinia). We
present here a phytosociological study of the vegetation and plant
landscape of the La Maddalena archipelago, which is situated in the
Bocche di Bonifacio, between north-eastern Sardinia and southern
Corsica. The lithological substratum of the archipelago is mainly made
up of granite from plutonic intrusions, of the Superior Permian
Carboniferous period. The area is part of the Mediterranean
macrobioclimate, pluviseasonal-oceanic bioclimate, upper
thermomediterranean thermotype, low dry ombrotype. On the basis of
published data, the flora of the archipelago includes 986 taxa, of which
51 are endemic. The dominant life form is of therophytes, which
represent around 50% in all.
The plant communities identified through
the phytosociological analyses are presented in groups according to
their ecological and structural characteristics. Moreover, these
communities are presented in an overall syntaxonomic scheme. Twenty new
associations are described: Agrostio stoloniferae-Cyperetum badii, Alismo lanceolatae-Gratioletum officinalis, Allio commutati-Lavateretum arborae, Anthoxanto aristati-Agrostietum salmanticae, Apio crassipi-Isoetetum tigulianae, Arenario balearicae-Menthetum requienii, Baldellio ranunculoidis-Eleocharitetum palustris, Bellio bellidioidis-Arenarietum balearicae, Callitrico stagnalis-Glycerietum spicatae, Catapodio marini-Silenetum beguinotii, Exaculo pusilli-Lythretum portulae, Isoeto istrici-Montietum amporitanae, Junco acuti-Oenanthetum crocatae, Myrto communis-Salicetum atrocinereae, Polypogono subspathacei-Parapholidetum filiformis, Romuleo requienii-Bellidetum bellidiodis, Romuleo requienii-Colchicetum corsicae, Rubo ulmifolii-Myrtetum communis, Salicornio patulae-Crypsidetum aculeatae, Sileno nummicae-Malcomietum ramosissimae.
The
interpretation of the dynamic relationships between the plant
communities has allowed seven vegetation series to be recognised: two
climatophilous (Prasio majoris-Querco ilicis Σ phillyreetosum angustifoliae and Galio scabri-Querco suberis Σ quercetosum suberis), two edaphoxerophilous (Erico arboreae-Junipero turbinatae Σ and Oleo sylvestris-Junipero turbinatae Σ), one edaphohygrophilous (Oleo sylvestris-Junipero turbinatae Σ), one riparian (Populo albi Σ) and one marshy (Myrto communis-Salicio atrocinereae Σ).
The
landscape units (geosigmeta) have been identified through the
integration of the vegetation series with the environmental factors.
Since the territory has geological and bioclimatic characteristics that
are fairly uniform, the resulting vegetal landscape can be included
mainly in the Holm oak series geosigmetum (Prasio majoris-Querco ilicis Σ phyllireetosum angustifoliae), and to a minimal extent in the Cork oak series geosigmetum (Galio scabri-Querco suberis Σ quercetosum suberis).
However,
this uniformity is only apparent, since by passing to a greater level
of detail, the analyses have allowed a high degree of phytocoenotic
biodiversity to be revealed, linked to the micromorphological,
microedaphic and microclimatic variations (microgeosigmeta). Among these
very particular microenvironments there are, for example, those that
can be found inside the tafonies, in the rock fissures, in the temporary
ponds, in the fragile sand ecosystems and in the therophytic
grasslands, where there are communities characterised by endemic species
and with an ecology often defined by intermediate conditions of
microecotonal character.
The problems concerning the management of
the plant landscape are stressed in the conclusions from the point of
view of a management model that guarantees the conservation of the
natural resources in a way that is compatible with the socio-economic
development of the territory and its potential for exploitation.
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