Whereas most work to understand impacts of humans on biodiversity on coastal areas has focused on large, conspicuous organisms, we highlight effects of tourist access on the diversity of microscopic marine animals (meiofauna). We used a DNA metabarcoding approach with an iterative and phylogeny-based approach for the taxonomic assignment of meiofauna and relate diversity patterns to the numbers of tourists accessing sandy beaches on an otherwise un-impacted island National Park. Tourist frequentation, independently of differences in sediment granulometry, beach length, and other potential confounding factors, affected meiofaunal diversity in the shallow "swash" zone right at the mean water mark; the impacts declined with water depth (up to 2 m). The indicated negative effect on meiofauna may have a consequence on all the biota including the higher trophic levels. Thus, we claim that it is important to consider restricting access to beaches in touristic areas, in order to preserve biodiversity.

The great ecological and economic value of the biocenoses of Marine Protected Area 'Capo Caccia-Isola Piana' (MPA) requires a constant monitoring. For this reason, a continuous study of the area producing overlapping maps useful to control in real time the evolution of the biocenoses is necessary. The integrated use of several methodologies, such as Side Scan Sonar, Remote Operating Vehicle and Drone, has allowed us to realize a very detailed map. This paper presents the marine benthic map of the MPA and compares the present situation with that recorded in 2008.

A number of policy measures have been adopted to cope with ongoing ocean degradation. Marine protected areas (MPAs) are among them. MPAs and their coverage have increased worldwide, including in EU waters. Natura 2000 (Nat2000) sites are at the core of the EU biodiversity conservation strategy and have been established to protect habitats and species included in two EU directives. Besides their specific objectives, their potential to contribute to an ecosystem‐wide conservation and their complementarity with other national and supranational initiatives (e.g. nationally established MPA networks, the Marine Strategy Framework Directive, the Convention on Biological Diversity Ecosystem‐Based Approach) have been called into question. Using visual censuses on rocky reefs, the biomass of whole fish assemblages and of a set of ecologically important species (widely used as indicators of coastal marine ecosystem health) have been assessed to evaluate the potential ecosystem‐wide effectiveness of Nat2000 marine sites located along the coasts of Sardinia (Italy). The assessment was performed in six fully protected MPAs, in 12 Nat2000 sites established or extending at sea, and in 18 adjacent unprotected control sites. Results show that the highest fish biomasses are observed in fully protected MPAs. The values observed at Nat2000 sites do not differ or only slightly differ from those observed at control sites. This shows that Nat2000 sites may not presently contribute to effectively protect fish and the related rocky reef ecosystems. These results do not dismiss at all the role of Nat2000 sites relative to the objectives for which they have been established. However, they show that to achieve ecosystem‐wide benefits it is crucial to rethink and broaden the scope of Nat2000 sites and adapt their management to that. By providing sounder and more comprehensive management plans, and implementing more consistent ecosystem‐wide conservation measures, Nat2000 marine sites could become an extraordinary tool at the EU scale, capable of delivering wider ecological benefits.

Ecosystem Services (ESs) are assuming a constantly increasing importance in management practices due to their key role in ensuring a sustainable future to fauna and flora on Earth. In addition, ES degradation and quality loss jeopardize current human activities. For this reason, it is essential to develop methodologies and practices able to efficiently assess environmental and socio-economic impacts in terms of ES deterioration, especially within protected areas. Norms and regulations have to be able to identify habitat and species categories to be preserved, and to determine the cost of their destruction and decline, according to a holistic vision, which includes social and economic impacts, besides the environmental ones. The paper illustrates the case study of the “Isola dell’Asinara” Marine Protected Area (MPA) in Sardinia, where an experimental methodology was developed with the aim to draw new regulations that integrate conservation measures of Natura 2000 sites included in its territory, provisions determined by the integrated coastal zone management (ICZM) protocol and the Standardized Actions for Effective Management of MPAs (ISEA) project. Subsequently, in order to assess the status of ESs and impacts on ESs located within the MPA territory, an ecosystem-based approach was implemented and applied to the actions defined for the new regulation proposal. Results show that regulations are in this way valuably enriched by environmental aspects of the MPA that would otherwise be overlooked.

VoI. 126, n. 5, 1992 BOCCHIERI M. -The flora of the island Piana (Sardinia, ltaIy) . 651Giorn. Bot. Ital., 126: 651-707, 1992 La flora marina della Sardegna: inventario delle alghe bentoniche Key words: benthic marine aIgae, Sardinia, distribution, flora, check listo INTRODUZIONELo scopo del presente lavoro è quello di presentare le conoscenze esistenti sulla flora bentonica della Sardegna al fine di valutarne la consistenza. Si ritiene infatti che un tale documento possa contribuire allo sviluppo delle ricerche biogeografiche nel Mediterraneo. In particolare il lavoro è inserito in un progetto più ampio, coordinato dai Prof.i T. Gallardo dell'Università di Madrid, M.T. Ribera Siguan e A. Gomez Garreta dell'Università di Barcellona, per la redazione di una check-list delle Alghe del Mediterraneo. MATERIALI E METODIIl solo lavoro che riportava un elenco floristico delle alghe della Sardegna, realizzato da BARBEY (1884), forniva una lista delle alghe fin ad all'ora segnalate in Sardegna da diversi algologi (Piccone; Gennari; Canepa; Marcucci; Grunow; De Notaris; Moris; Gestro; Marcacci). I contributi recenti CHIAPPINI, 1970;DEssì, 1975Molinier, 1955;SOLAZZI, 1968 SOLAZZI, , 1969 SOLAZZI, , 1971 SOLAZZI e TOLOMIO, 1974; Cossu e GAZALE, 1990a; GAZALE e MORUCCI, 1991;Cossu et al., 1990; Cossu et 651 al., 1992;PORCHEDDU et al., 1990); più altri ritrovamenti inediti, hanno indotto alla realizzazione di un nuovo lavoro di sintesi.L'ordinamento sistematico seguito è quello proposto da FELDMANN (1978) con alcuni aggiornamenti. Per la tassonomia della famiglia delle Acrochaetiaceae si è seguito il lavoro di GARBARY (1987), per il genere Peyssonnelia, il lavoro di BOUDOURESQUE et DENIZOT (1975), per il genere Polysiphonia,]. FELDMANN (1981), per il genere Cystoseria, AMICO et al. (1985), per il genere Cladophora, VAN DEN HOEK (1963). Inoltre sono state consultate le recenti monografie, della Corsica (BOUDOURESQUE et PERRET-BoUDOURESQUE, 1987) e della Sicilia (GIAC-CONE et al., 1985).Le abbreviazioni dei nomi degli Autori sono quelle proposte dal Taxonomic Literature (STAFLEU et COWAN, 1977.Per ciascuna specie viene riportato oltre all' attuale epiteto, quello con cui è stato segnalato; viene riportata inoltre la località di ritrovamento, con il relativo riferimento bibliografico e la sua ecologia che deriva sia da osservazioni dirette sia dai dati di letteratura (BOUDORESQUE 1984;GIACCONE et al., 1985).La flora sarda è stata confrontata con undici flore delle seguenti aree mediterranee: Adriatico (GIACCONE, 1978); Spagna (BALLESTEROS, 1990); Pirenei orientali (FELDMANN, 1937(FELDMANN, , 1939BOUDOURESQUE et al .. , 1984); Grecia (GERLOFF e GEISSLER, 1971;GIACCONE, 1968; HARITONIDIS e TSEKOS, 1974, 1975, 1976 NIZAMUDDIN e LEHNBERG, 1970; TSEKOS e HARI-TONIDIS, 1974, 1977; Napoli, che include quelle di Ischia e Cilento (FUNK, 1927(FUNK, , 1955 CI-NELU, 1971; EDWARDS et al., 1975); Tunisia (BEN MAIZ et al., 1987); Baleari (BALLESTEROS, 1984(BALLESTEROS, , 1989 CREMADES, 1989;RULL et al., 1987; RIBERA e GOME...