Discovering neglected vegetation in Sardinia: from knowledge to conservation

The "Habitats Directive" (92/43/EEC) was the first EU policy document to provide a list of habitats of conservation concern (Annex I). The habitat types of community interest fall into at least one of these criteria: are in danger of disappearance in their natural range; have a small natural range following their regression or because of their intrinsically restricted area; present outstanding examples of typical characteristics of one or more of the nine European biogeographical regions. However, methodological criteria adopted for their identification have mainly remained unclear, and many relevant vegetation types surprisingly out. The leading causes of this gap could be knowledge lack due to the difficulty of access to the places of presence, the seasonality of the blooms or their small range. This research aims to present a preliminary list of valuable vegetation types occurring in Sardinia, currently not included in the Annex I, to bring them to the attention of the scientific community and managers to promote actions for their conservation. We highlighted the plant communities that can be considered of potential conservation interest basing on expert knowledge, supported by phytosociological relevés already published or unpublished. So far, we have identified more than 30 types of vegetation with different ecological and physiognomic-structural characteristics, as summarized below. Halophytic habitats: glasswort swards with dwarf plants, hosting rare endemics such as Nananthea perpusilla and Filago tyrrhenica, depending on a delicate soil balance of humidity and salinity; alonitrophilous vegetation with Malva lusitanica subsp. lusitanica. Psammophilous habitats: semi-natural vegetation with Echium arenarium and E. sabulicola hosting rare species such as Anchusa sardoa; Ephedra distachya mantles. Watercourses: communities of the endemic alliance Caricion microcarpae hosting rare species such as Carex panormitana. Garrigues: mountain garrigues with Euphorbia spinosa and other endemic Lamiaceae such as Nepeta foliosa; coastal garrigues with localized species such as Helianthemum caput-felis or Viola arborescens, often hosting other relevant species such as Polygala sinisica, P. rupestris and Coris monspeliensis. Scrubs: Pruno-Rubion communities with endemic species such as Ribes sardoum and R. sandalioticum; Bupleurum fruticosum maquis; hygrophilous formations with Myrtus communis and Oenanthe pimpinelloides surrounding Mediterranean temporary ponds. Grasslands: hygrophilous communities with Orchis laxiflora; submediterranean grasslands with the endemic Festuca morisiana; localized formations with Stipa offneri (= S. juncea), Astragalus verrucosus or Sesleria gr. insularis; wooded grasslands with deciduous Quercus spp., with high botanical and faunistic value. Calaminarian habitats: chamaephytic vegetation of the alliance Ptilostemo-Euphorbion cupanii, hosting several endemic species such as Limonium merxmuelleri and Iberis integerrima. Bushes: edapho-hygrophilous vegetation with Rhamnus persicifolia. Woods: Quercus calliprinos woodlands; Ostrya carpinifolia Mediterranean forests. As expected, given the high number of endemic species that characterize Sardinian flora, most neglected vegetation types have a small natural range due to the intrinsically restricted area of the characteristic species. These narrow ranges often provide buffered conditions that can be compromised by changes in land use or environmental conditions, including climate change, so they need appropriate attention to ensure conservation. During the research, several issues emerged that deserve further investigation to obtain a list of plant communities in Sardinia as complete as possible.