Patella ferruginea is the most threatened macroinvertebrate in the western Mediterranean, where it is at serious risk of extinction. There is little information on the status of the various populations and most data were published more than 25 years ago. This study provides updated information on the global status of this species, and implications for management and conservation, and tests the hypothesis that population structure can be influenced by collection by people and by the type of substrate. Fifty-five localities were surveyed in Corsica, Sardinia, Tuscany and Sicily, on the islands of Egadi and Pantelleria, and on the Zembra archipelago and Tunisian coasts. The species is extinct on mainland Italy and Sicily but isolated individuals can be found on Egadi and Pantelleria. Populations on Corsica and Sardinia have declined dramatically during the last 25 years. The population in the Zembra archipelago is well preserved, although more widely on Tunisian coasts the species is highly threatened. The information provided here, combined with information from the literature, indicates a strong decline and/or extinction of many populations throughout the western Mediterranean and the presence of healthy populations only in some locations along the north African coast. The species exhibits an increase in density and mean size in areas free of human pressure but the type of substrate (natural or artificial) has no strong influence.

Taxonomic diversity and temporal patterns in abundance of periphytic ciliate communities across taxonomic levels were studied to monitor water quality in Korean coastal waters during April 2007. Specifically we compared two methods based on an artificial substrate (glass slide): the polyurethane foam enveloped slide (PFES) and the conventional slide (CS) systems. The results demonstrated that: (1) the colonization patterns of the ciliate communities at all taxonomic levels showed a lower variability in the PFES system than those of the CS system; (2) The taxonomic diversity (Δ) and taxonomic distinctness (Δ*) were significantly higher in the PFES system than those in the CS system; and (3) all four taxonomic diversity/distinctness indices represented lower variability in the PFES system than those of the CS samples. These findings suggest that the PFES system is more effective than the CS system for measuring the colonization patterns and taxonomic distinctness parameters that are increasingly used as potential indicators of water quality. This conclusion supports our previous suggestion that the PFES system is a better tool than the CS system for monitoring water quality in the marine ecosystem, using periphytic ciliates.

Structural parameters of periphytic ciliate communities on a modified substrate were studied in Korean coastal waters during the period August–November 2007. In order to reduce the strong disturbances from tidal current and circulation in marine ecosystems, a modified slide method, named the polyurethane foam enveloped slide (PFES) system, was used to host ciliate communities. A total of 37 ciliate species, about half of which belong to the orders Hypotrichida and Cyrtophorida, were identified using living observation and silver impregnation method with this system. The sessile ciliates belonged to the orders Peritrichida and Suctorida, while the motile forms were represented primarily by the species of the orders Hypotrichida, Cyrtophorida and Pleurostomatida. The species diversity and evenness were significantly higher in the PFES system than those on the conventional slides (paired t-test: t = 2.384, 2.415; P < 0.05). Multivariate analysis revealed that the ciliate communities from both sampling systems had similar species composition, but represented significant differences in species distribution and temporal dynamics mainly due to the most dominant peritrich Zoothaminium duplicatum, which overly colonized the conventional slides. Results suggest that the PFES system is more effective than the conventional slide method for periphytic ciliate colonization with high species diversity, evenness and sensitive temporal dynamics mainly due to the reduction of disturbances from tidal current and circulation in marine ecosystems.