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Seagrass ecosystems status between the sliding baseline syndrome and the need for reference conditions

Marine coastal ecosystems are facing compositional and functional changes due to the increasing h... more Marine coastal ecosystems are facing compositional and functional changes due to the increasing human footprint worldwide, and the assessment of their long-term changes becomes particularly challenging in this new "Anthropocene Epoch". Measures of change can be done by comparing the present ecosystem status to a defined baseline representing the reference condition. The "syndrome" of the sliding (or shifting) baselines, which describes the incremental lowering of ecological standards, has become a major concern when long-term changes have to be assessed because an already degraded environment status could be accepted as reference. The challenge of delineating ecosystems change in the context of sliding baselines is particularly relevant along highly anthropized coasts, as the case of the Liguria (NW Mediterranean Sea), where pristine coastal areas could not be expected anymore. The Marine Strategy Framework Directive (MSFD, 2008/56/EEC) suggests three approaches ...

Abrupt Change in a Subtidal Rocky Reef Community Coincided with a Rapid Acceleration of Sea Water Warming

Diversity, 2019

Seawater warming is impacting marine ecosystems, but proper evaluation of change requires the ava... more Seawater warming is impacting marine ecosystems, but proper evaluation of change requires the availability of long-term biological data series. Mesco Reef (Ligurian Sea, Italy) offers one of the longest Mediterranean data series on sessile epibenthic communities, based on underwater photographic surveys. Photographs taken in four stations between 20 m and 40 m depth allowed calculating the percent cover of conspicuous species in 1961, 1990, 1996, 2008, and 2017. Multivariate analysis evidenced an abrupt compositional change between 1990 and 1996. A parallel change was observed in Ligurian Sea temperatures. Two invasive macroalgae (Caulerpa cylindracea and Womersleyella setacea) became dominant after 1996. Community diversity was low in 1961 to 1996, rapidly increased between 1996 and 2008, and exhibited distinctly higher values in 2008–2017. A novel community emerged from the climate shift of the 1990s, with many once characteristic species lost, reduced complexity, biotic homogeniz...

Thirty year ecosystem trajectories in a submerged marine cave under changing pressure regime

Marine environmental research, 2018

Marine caves are unique and vulnerable habitats exhibiting high biodiversity and heterogeneity, b... more Marine caves are unique and vulnerable habitats exhibiting high biodiversity and heterogeneity, but threatened by multiple global and local disturbances. Marine caves, although widely distributed along the Mediterranean coast, suffer for the lack of quantitative data on their structure and function, which hinder their conservation status assessment. Thanks to the availability of a nearly 30-year-long series of data (1986-2013), we evaluated ecosystem change in the Bergeggi marine cave (Ligurian Sea, NW Mediterranean), a cave with a complex shape and high habitat heterogeneity. Non-taxonomic descriptors were adopted, namely growth forms (GF) and trophic guilds (TG), which are informative about ecosystem structure and functioning, respectively. The cave experienced a general trend of change during the last three decades, mainly due to the decline in the cover of sessile organisms (especially 3-dimensional forms) matched by an increase of turf and sediment, thus causing the structural ...

Integración de el índice ESCA por medio de los macro-invertebrados sésiles

Scientia Marina, 2017

The ESCA (Ecological Status of Coralligenous Assemblages) index was developed to assess the ecolo... more The ESCA (Ecological Status of Coralligenous Assemblages) index was developed to assess the ecological quality of coralligenous habitat using macroalgae as a biological indicator. The aim of this study was to evaluate the response to human-induced pressures of macroalgae and sessile macro-invertebrates shaping the coralligenous habitat and to integrate their sensitivity into the ESCA index. Coralligenous assemblages were sampled at 15 locations of the NW Mediterranean Sea classified into three groups: i) marine protected areas; ii) low urbanized locations; and iii) highly urbanized locations. A sensitivity level value was assigned to each taxon/group on the basis of its abundance in each environmental condition, the data available in the literature and the results of an expert judgement survey. The index that includes the totality of the assemblages (named ESCA-TA), calculated using both macroalgae and sessile macro-invertebrates, detected the levels of human pressure more precisely...

The two facets of species sensitivity: Stress and disturbance on coralligenous assemblages in space and time

Marine pollution bulletin, Jan 6, 2017

Marine coastal ecosystems are affected by a vast array of human-induced disturbances and stresses... more Marine coastal ecosystems are affected by a vast array of human-induced disturbances and stresses, which are often capable of overwhelming the effects of natural changes. Despite the conceptual and practical difficulty in differentiating between disturbance and stress, which are often used interchangeably, the two terms bear different ecological meanings. Both are external agents, but the former causes mortality or physical damage (subtraction of biomass), whereas the latter causes physiological alteration (reduction in productivity). Sensitivity of marine organisms may thus have a dual connotation, being influenced in different ways by disturbance and by stress following major environmental change. Coralligenous assemblages, which shape unique biogenic formations in the Mediterranean Sea, are considered highly sensitive to change. In this paper, we propose a method to differentiate between disturbance and stress to assess the ecological status of the coralligenous assemblages. Dist...

Impact of a harbour construction on the benthic community of two shallow marine caves

Marine Pollution Bulletin, 2017

Marine caves are unique and vulnerable habitats, threatened by multiple global and local disturba... more Marine caves are unique and vulnerable habitats, threatened by multiple global and local disturbances. While the effects of climate change on marine caves have already been investigated, no information exists about the effects of local human impacts, such as coastal development, on these habitats. This study investigated the impact of the construction of a touristic harbour on two shallow underwater marine caves in the Ligurian Sea (NW Mediterranean). As a standard methodology for monitoring marine caves does not exist yet, changes over time on the benthic community were assessed adopting two different nontaxonomic descriptors: trophic guilds and growth forms. Harbour construction caused an increase of sediment load within the caves, with a consequent decline of filter feeder organisms. Abundance of small organisms, such as encrusting and flattened sponges, was greatly reduced in comparison to organisms with larger and erect growth forms, such as domed mounds and pedunculated sponges. Our study indicated that growth forms and trophic guilds are effective descriptors for evaluating changes over time in marine caves that could be easily standardised and applied in monitoring plans. In addition, as the harbour construction impacted differently according to the cave topography, the use of a systematic sampling in different zones of an underwater cave is recommended.

A tale of two invaders: divergent spreading kinetics of the alien green algae Caulerpa taxifolia and Caulerpa cylindracea

Biological Invasions, 2015

The two alien green algae Caulerpa taxifolia and Caulerpa cylindracea (formerly Caulerpa racemosa... more The two alien green algae Caulerpa taxifolia and Caulerpa cylindracea (formerly Caulerpa racemosa var. cylindracea) are among the most notorious and threatening invasive species in the Mediterranean Sea. From the beginning of their introduction, C. taxifolia aroused a great concern due to its initial exponential spread and impacts on native ecosystems, whilst C. cylindracea received lower attention. In this paper, the distribution of the two aliens over the last 30 years in the Italian side of the Ligurian Sea (NW Mediterranean Sea) is reviewed and the kinetics of their spreading is compared. We combined available data on habitat occupancy with data on substratum cover obtained during underwater surveys to compute the average annual spreading rates for both aliens. C. taxifolia had an impressive expansion phase from 1984 to 2000 but then, its dispersal rate showed lower than that predicted and the species did not persist in areas formerly colonized. Today, abundance of this species is strongly declined as it disappeared from most of the attained areas. On the contrary, C. cylindracea exhibited an impressive and constant expansion from the beginning of its first appearance in the Ligurian Sea and, today, it is still increasing its range and habitat occupancy. Its abundance results 1.5-times greater than that reached by C. taxifolia during the period of its maximum expansion. The divergent kinetics of spreading of the two aliens prevents any possibility of generalization of the future behaviour of invasive species in the Mediterranean Sea, and continuous and periodic surveys are thus mandatory to understand the kinetics of expansion and to define species-specific models.

The Challenge of Managing Marine Biodiversity: A Practical Toolkit for a Cartographic, Territorial Approach

Diversity, 2012

An approach to the management of marine biodiversity was developed based on two levels of environ... more An approach to the management of marine biodiversity was developed based on two levels of environmental diagnostics: (1) the characterization (to identify types), and (2) the evaluation (to define status and values). Both levels involve the production of maps, namely: (i) morphobathymetry and sedimentology; (ii) habitats; (iii) natural emergencies; (iv) degradation and risk; (v) weighted vulnerability; (vi) environmental quality; and, (vii) susceptibility to use. A general methodological aspect that must be stated first is the need of dividing the mapped area in territorial units corresponding to submultiples of the UTM grid and having different sizes according to the scale adopted. Territorial units (grid cells) are assigned to one of five classes of evaluation, ranging from high necessity of conservation or protection to non-problematic, unimportant or already compromised (according to the specific map) situations. Depending on the scale, these maps are suited

Ecological change, sliding baselines and the importance of historical data: lessons from combing observational and quantitative data on a temperate reef over 70 years

PloS one, 2015

Understanding the effects of environmental change on ecosystems requires the identification of ba... more Understanding the effects of environmental change on ecosystems requires the identification of baselines that may act as reference conditions. However, the continuous change of these references challenges our ability to define the true natural status of ecosystems. The so-called sliding baseline syndrome can be overcome through the analysis of quantitative time series, which are, however, extremely rare. Here we show how combining historical quantitative data with descriptive 'naturalistic' information arranged in a chronological chain allows highlighting long-term trends and can be used to inform present conservation schemes. We analysed the long-term change of a coralligenous reef, a marine habitat endemic to the Mediterranean Sea. The coralligenous assemblages of Mesco Reef (Ligurian Sea, NW Mediterranean) have been studied, although discontinuously, since 1937 thus making available both detailed descriptive information and scanty quantitative data: while the former was u...

An Ecosystem-Based Approach to Assess the Status of a Mediterranean Ecosystem, the Posidonia oceanica Seagrass Meadow

PLoS ONE, 2014

Biotic indices, which reflect the quality of the environment, are widely used in the marine realm... more Biotic indices, which reflect the quality of the environment, are widely used in the marine realm. Sometimes, key species or ecosystem engineers are selected for this purpose. This is the case of the Mediterranean seagrass Posidonia oceanica, widely used as a biological quality element in the context of the European Union Water Framework Directive (WFD). The good quality of a water body and the apparent health of a species, whether or not an ecosystem engineer such as P. oceanica, is not always indicative of the good structure and functioning of the whole ecosystem. A key point of the recent Marine Strategy Framework Directive (MSFD) is the ecosystem-based approach. Here, on the basis of a simplified conceptual model of the P. oceanica ecosystem, we have proposed an ecosystem-based index of the quality of its functioning, compliant with the MSFD requirements. This index (EBQI) is based upon a set of representative functional compartments, the weighting of these compartments and the assessment of the quality of each compartment by comparison of a supposed baseline. The index well discriminated 17 sites in the northwestern Mediterranean (French Riviera, Provence, Corsica, Catalonia and Balearic Islands) covering a wide range of human pressure levels. The strong points of the EBQI are that it is easy to implement, non-destructive, relatively robust, according to the selection of the compartments and to their weighting, and associated with confidence indices that indicate possible weakness and biases and therefore the need for further field data acquisition.

The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats

PLoS ONE, 2010

Funding: The authors gratefully acknowledge the support given by the European Census of Marine Li... more Funding: The authors gratefully acknowledge the support given by the European Census of Marine Life, the Total Foundation and the Alfred P. Sloan Foundation. MC was supported financially by the European Commission Marie Curie Postdoctoral Fellowship through the International Outgoing Fellowships (Call FP7-PEOPLE-2007-4-1-IOF) for the ECOFUN project and by Dalhousie University (Halifax, Canada). EB acknowledges financial support from GRACCIE project C5D2007-00067 funded by the Spanish Ministry of Science and Innovation. BG thanks the support of SESAME funded by the European Commission's Sixth Framework Program on Sustainable Development, Global Change and Ecosystems. JISS acknowledges ECOLIFE (CGL2008-05407-C03-03) funds of the Ministry of Science and Innovation of Spain. The present paper is a contribution of JG, DM and XT to the projects 2009SRG665 and 2009SGR484 of the ''Generalitat de Catalunya'', and of DM and XT to project CTM2007-66635 funded by the Ministry of Science and Innovation of Spain. Research by C. N. Bianchi on Mediterranean Sea biodiversity is partly supported by the project ''The impacts of biological invasions and climate change on the biodiversity of the Mediterranean Sea'' (Italy-Israel cooperation) funded by the Italian Ministry of the Environment. The funders had no role in study design, data collection and analysis, decision to published, or preparation of the manuscript.

Seasonal grazing and food preference of herbivores in a Posidonia oceanica meadow

Scientia Marina, 2001

Seasonal grazing of the fish Sarpa salpa (L.), the urchin Paracentrotus lividus Lamarck and the i... more Seasonal grazing of the fish Sarpa salpa (L.), the urchin Paracentrotus lividus Lamarck and the isopods Idotea spp. was compared with the C/N ratio of adult and intermediate leaves and epiphytes of Posidonia oceanica (L.) Delile, collected at three different depths. Despite seasonal differences in grazing, herbivores showed preferences throughout the year for adult leaves with more epiphyte and higher N contents. The maximum grazing on adult and intermediate leaves was observed in September and in June for fish and in March for urchins, whereas it was irregular for isopods. Grazing by the three herbivores was not related to their preference for leaves or epiphytes, notwithstanding the seasonal differences in their C and N contents. We concluded that herbivores show no preference for food type throughout the year and that seasonal consumption of P. oceanica is related mainly to herbivore behaviour.

Conserving Biodiversity in a Human-Dominated World: Degradation of Marine Sessile Communities within a Protected Area with Conflicting Human Uses

PLoS ONE, 2013

Conservation research aims at understanding whether present protection schemes are adequate for t... more Conservation research aims at understanding whether present protection schemes are adequate for the maintenance of ecosystems structure and function across time. We evaluated long-term variation in rocky reef communities by comparing sites surveyed in 1993 and again in 2008. This research took place in Tigullio Gulf, an emblematic case study where various conservation measures, including a marine protected area, have been implemented to manage multiple human uses. Contrary to our prediction that protection should have favored ecosystem stability, we found that communities subjected to conservation measures (especially within the marine protected area) exhibited the greatest variation toward architectural complexity loss. Between 1993 and 2008, chronic anthropogenic pressures (especially organic load) that had already altered unprotected sites in 1993 expanded their influence into protected areas. This expansion of human pressure likely explains our observed changes in the benthic communities. Our results suggest that adaptive ecosystem-based management (EBM), that is management taking into account human interactions, informed by continuous monitoring, is needed in order to attempt reversing the current trend towards less architecturally complex communities. Protected areas are not sufficient to stop ecosystem alteration by pressures coming from outside. Monitoring, and consequent management actions, should therefore extend to cover the relevant scales of those pressures.

Hydrothermal studies in the aegean sea

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere, 2000

The aims of the Aegean Hydrothermal Fluxes and Biological Production project were to estimate the... more The aims of the Aegean Hydrothermal Fluxes and Biological Production project were to estimate the fluxes of fluids, chemicals, heat and bacteria, from hydrothermal vents, establish the controls on venting dynamics, measure the productivity in the region of the vents and establish the effect of the vents on biodiversity of both prokaryotes and eukaryotes. This paper presents an initial synthesis of the project results. Research was done both by land-based SCUBA diving and from several vessels at a number of active sites in the near-shore coastal regions of Milos and Kos, with some additional studies at Methana, Lesbos and Santorini. Vent water composition showed very large variations. This was due to the mixing, of hydrothermal reservoir fluids, vapour condensate and seawater altered by interactions of fluid-sediment-bacteria in different proportions, in the gasohydrothermal vents. The composition ranged from nearly sea water with only slightly reduced pH, to higher or lower salinity fluids with a pH as low as 3 and with large enrichments in heavy and trace metals. Phase separation was a common feature at these shallow vents. The dry gas phase was mainly CO,, but with significant amounts of H,S, CH, and H,. These fluids commonly passed through soft sediments before venting from the seafloor and induced a convection cell of pore-water entrainment from deeper sediment layers into the water column with a consequent Ire-charge' down-flow of seawater into the sediment around the vent outlets. Such complex conditions may well explain the high biodiversity of Bacteria, Archaea and epifaunal species surrounding the vents. As many as 44 % of the archaeal lineages detected were found to represent novel phyla. Epifaunal diversity was particularly high with over 200 species recorded at the shallower Milos vents. These vents may form a 'steppingstone' for warmer water species to colonise the surrounding areas when water temperatures permit.

Urban seagrass: Status of Posidonia oceanica facing the Genoa city waterfront (Italy) and implications for management

Marine Pollution Bulletin, 2007

A system of five adjacent Posidonia oceanica meadows facing the waterfront of Genoa city (Liguria... more A system of five adjacent Posidonia oceanica meadows facing the waterfront of Genoa city (Ligurian Sea, NW Mediterranean) was investigated over different spatial scales (meters-kilometers) using three environmental indices: conservation index (CI), substitution index (SI) and phase-shift index (PSI). CI revealed differences mostly at large spatial scale, distinguishing the poor condition of the meadows closest to Genoa centre and harbour from the comparatively healthy condition of the farthest meadows. SI showed differences mostly at small spatial scale (i.e., within meadows), suggesting the influence of local factors in the re-colonisation of regressed meadows by the seagrass Cymodocea nodosa and/or the invasive alga Caulerpa racemosa. Mapping of PSI showed that the meadows closest to Genoa centre and harbour have undergone a nearly total phase shift and have no real potential for recovery: attempts to re-establish P. oceanica there might be a waste of time and money. On the contrary, the meadows farthest from Genoa centre and harbour showed a comparatively low level of phase shift and could still fully recover given specific management actions.

Effects of climate, invasive species and anthropogenic impacts on the growth of the seagrass Posidonia oceanica (L.) Delile in Liguria (NW Mediterranean Sea)

Marine Pollution Bulletin, 2005

Eight shallow water Posidonia oceanica meadows were sampled in June 1999 along 300 km of the Ligu... more Eight shallow water Posidonia oceanica meadows were sampled in June 1999 along 300 km of the Ligurian coast and were compared through shoot density and lepidochronology. The growth of the seagrass was examined in the light of climate fluctuations and local stresses, colonisation by alien, invasive alga Caulerpa taxifolia, and effects of the oil spill from the tanker ''Haven'', and other anthropogenic impacts. Both shoot density and lepidochronology pointed to a generalised state of regression of all the meadows. The analysis of long-term growth curves of the rhizomes showed a positive trend parallel to the increase of air temperature. Two main groups of meadows were individuated on the basis of growth curve similarity. The first included four meadows, namely Ventimiglia, Imperia, Noli and Prelo, that were characterised by average values of rhizome growth of 8-9.1 mm year À1 and shoot density greater than 200 shoots m À2. Although the Imperia meadow was the only one where the alien invasive alga C. taxifolia was found, it did not show differences for rhizome growth in comparison to the other meadows. The second group was formed by meadows that had suffered past anthropogenic impacts: Arenzano and Monterosso al Mare. They showed higher rhizome growth rates (9.4-10.6 mm year À1) and shoot densities between 200 and 100 shoots m À2. At Arenzano, where ''Haven'' oil was stranded in April 1991, no rhizome older than 8 years was found, thus confirming the shoot mortality induced by the oil spill event. The two last meadows exhibited growth curves very different from all the others: Portovenere, is a shallow meadow where P. oceanica merely survives in an extremely degraded situation with highest rhizome growth rate (12 mm year À1), the other, Riva Trigoso, is the only meadow implanted on rock and had the lowest growth rates (7.1 mm year À1).

Bio-mineralogy as a structuring factor for marine epibenthic communities

Marine Ecology Progress Series, 2000

The m e r a l o g i c a l features of the substrate were generally cons~dered a rmnor factor m st... more The m e r a l o g i c a l features of the substrate were generally cons~dered a rmnor factor m structunng manne benthic communities The alm of t h~s work 1s to venfy whether the presence of quartz nunerals in rock may exphcate dlfferences, usually explamed m terms of substrate roughness or other factors In epibenthic cornrnun~hes Laboratory tests on the hydroid Eudendnum glomeratum showed that ~t s planulae settle preferentially on carbonat~c, rather than quartzltic substrates To test the Influence of quartz on established communities, we analysed the specles composition and quanti-tat~ve structure of subhttoral sesslle assemblages on Wferent rocks In several locahhes of the L~gurian and Tyrrhenian seas The observed dlfferences appeared to be related to the presence of quartz in the substrate rock The ~nteractions between organisms and minerals (bio-mmeralogy) mlght play a slgnlficant role on benthic communities affechng not only the inihal colonlsahon but also later assemblages This potential role has been largely neglected to date and further studies are needed to prove ~t s Impor tance KEY WORDS: Substrate colonisation. Mineral composition. Marine benthos distnbution. Hard substrates. Bio-mineralogy 0 Inter-Research 2000 Resale of full article not permitted

Living on the rocks: substrate mineralogy and the structure of subtidal rocky substrate communities in the Mediterranean Sea

Marine Ecology Progress Series, 2004

tion due to changes in abiotic factors (e.g. wave action, water temperature, salinity, habitat co... more

Geo-environmental cartography of the Marine Protected Area “Isola di Bergeggi” (Liguria, NW Mediterranean Sea)

Journal of Maps, 2010

Marine Protected Areas (MPAs) are considered one of the main tools for conservation, valorisation... more Marine Protected Areas (MPAs) are considered one of the main tools for conservation, valorisation and management of coastal marine environments, and are defined by Italian Law (derived from European directives) as territories with "physical, geological, geomorphological and biological features having relevant naturalistic and environmental value". While the bionomic mapping of MPAs has received large attention by researchers, MPA geological or geomorphological cartographies have been seldom realized. In this study we present a geomorphological cartography, comprising also environmental themes having a geomorphological significance, realized in the MPA "Isola di Bergeggi".

Tissue necrosis and mortality of the temperate coralCladocora Caespitosa

Italian Journal of Zoology, 2005

Abstract Mass‐mortality events of the temperate coral Cladocora caespitosa were recorded in the G... more Abstract Mass‐mortality events of the temperate coral Cladocora caespitosa were recorded in the Gulf of La Spezia (NW Mediterranean) in the summers of 1997, 1998 and 1999. At the end of the summer 1999, 60% of the colonies found in 1997 were damaged and more than 50% of the damaged colonies were completely dead. Complete death of the largest colonies caused a modal shift of colony size‐frequency distribution towards the smallest size classes. In order to verify experimentally the hypothesis that mass‐mortality was primarily induced ...

Seagrass ecosystems status between the sliding baseline syndrome and the need for reference conditions

Marine coastal ecosystems are facing compositional and functional changes due to the increasing h... more Marine coastal ecosystems are facing compositional and functional changes due to the increasing human footprint worldwide, and the assessment of their long-term changes becomes particularly challenging in this new "Anthropocene Epoch". Measures of change can be done by comparing the present ecosystem status to a defined baseline representing the reference condition. The "syndrome" of the sliding (or shifting) baselines, which describes the incremental lowering of ecological standards, has become a major concern when long-term changes have to be assessed because an already degraded environment status could be accepted as reference. The challenge of delineating ecosystems change in the context of sliding baselines is particularly relevant along highly anthropized coasts, as the case of the Liguria (NW Mediterranean Sea), where pristine coastal areas could not be expected anymore. The Marine Strategy Framework Directive (MSFD, 2008/56/EEC) suggests three approaches ...

Abrupt Change in a Subtidal Rocky Reef Community Coincided with a Rapid Acceleration of Sea Water Warming

Diversity, 2019

Seawater warming is impacting marine ecosystems, but proper evaluation of change requires the ava... more Seawater warming is impacting marine ecosystems, but proper evaluation of change requires the availability of long-term biological data series. Mesco Reef (Ligurian Sea, Italy) offers one of the longest Mediterranean data series on sessile epibenthic communities, based on underwater photographic surveys. Photographs taken in four stations between 20 m and 40 m depth allowed calculating the percent cover of conspicuous species in 1961, 1990, 1996, 2008, and 2017. Multivariate analysis evidenced an abrupt compositional change between 1990 and 1996. A parallel change was observed in Ligurian Sea temperatures. Two invasive macroalgae (Caulerpa cylindracea and Womersleyella setacea) became dominant after 1996. Community diversity was low in 1961 to 1996, rapidly increased between 1996 and 2008, and exhibited distinctly higher values in 2008–2017. A novel community emerged from the climate shift of the 1990s, with many once characteristic species lost, reduced complexity, biotic homogeniz...

Thirty year ecosystem trajectories in a submerged marine cave under changing pressure regime

Marine environmental research, 2018

Marine caves are unique and vulnerable habitats exhibiting high biodiversity and heterogeneity, b... more Marine caves are unique and vulnerable habitats exhibiting high biodiversity and heterogeneity, but threatened by multiple global and local disturbances. Marine caves, although widely distributed along the Mediterranean coast, suffer for the lack of quantitative data on their structure and function, which hinder their conservation status assessment. Thanks to the availability of a nearly 30-year-long series of data (1986-2013), we evaluated ecosystem change in the Bergeggi marine cave (Ligurian Sea, NW Mediterranean), a cave with a complex shape and high habitat heterogeneity. Non-taxonomic descriptors were adopted, namely growth forms (GF) and trophic guilds (TG), which are informative about ecosystem structure and functioning, respectively. The cave experienced a general trend of change during the last three decades, mainly due to the decline in the cover of sessile organisms (especially 3-dimensional forms) matched by an increase of turf and sediment, thus causing the structural ...

Integración de el índice ESCA por medio de los macro-invertebrados sésiles

Scientia Marina, 2017

The ESCA (Ecological Status of Coralligenous Assemblages) index was developed to assess the ecolo... more The ESCA (Ecological Status of Coralligenous Assemblages) index was developed to assess the ecological quality of coralligenous habitat using macroalgae as a biological indicator. The aim of this study was to evaluate the response to human-induced pressures of macroalgae and sessile macro-invertebrates shaping the coralligenous habitat and to integrate their sensitivity into the ESCA index. Coralligenous assemblages were sampled at 15 locations of the NW Mediterranean Sea classified into three groups: i) marine protected areas; ii) low urbanized locations; and iii) highly urbanized locations. A sensitivity level value was assigned to each taxon/group on the basis of its abundance in each environmental condition, the data available in the literature and the results of an expert judgement survey. The index that includes the totality of the assemblages (named ESCA-TA), calculated using both macroalgae and sessile macro-invertebrates, detected the levels of human pressure more precisely...

The two facets of species sensitivity: Stress and disturbance on coralligenous assemblages in space and time

Marine pollution bulletin, Jan 6, 2017

Marine coastal ecosystems are affected by a vast array of human-induced disturbances and stresses... more Marine coastal ecosystems are affected by a vast array of human-induced disturbances and stresses, which are often capable of overwhelming the effects of natural changes. Despite the conceptual and practical difficulty in differentiating between disturbance and stress, which are often used interchangeably, the two terms bear different ecological meanings. Both are external agents, but the former causes mortality or physical damage (subtraction of biomass), whereas the latter causes physiological alteration (reduction in productivity). Sensitivity of marine organisms may thus have a dual connotation, being influenced in different ways by disturbance and by stress following major environmental change. Coralligenous assemblages, which shape unique biogenic formations in the Mediterranean Sea, are considered highly sensitive to change. In this paper, we propose a method to differentiate between disturbance and stress to assess the ecological status of the coralligenous assemblages. Dist...

Impact of a harbour construction on the benthic community of two shallow marine caves

Marine Pollution Bulletin, 2017

Marine caves are unique and vulnerable habitats, threatened by multiple global and local disturba... more Marine caves are unique and vulnerable habitats, threatened by multiple global and local disturbances. While the effects of climate change on marine caves have already been investigated, no information exists about the effects of local human impacts, such as coastal development, on these habitats. This study investigated the impact of the construction of a touristic harbour on two shallow underwater marine caves in the Ligurian Sea (NW Mediterranean). As a standard methodology for monitoring marine caves does not exist yet, changes over time on the benthic community were assessed adopting two different nontaxonomic descriptors: trophic guilds and growth forms. Harbour construction caused an increase of sediment load within the caves, with a consequent decline of filter feeder organisms. Abundance of small organisms, such as encrusting and flattened sponges, was greatly reduced in comparison to organisms with larger and erect growth forms, such as domed mounds and pedunculated sponges. Our study indicated that growth forms and trophic guilds are effective descriptors for evaluating changes over time in marine caves that could be easily standardised and applied in monitoring plans. In addition, as the harbour construction impacted differently according to the cave topography, the use of a systematic sampling in different zones of an underwater cave is recommended.

A tale of two invaders: divergent spreading kinetics of the alien green algae Caulerpa taxifolia and Caulerpa cylindracea

Biological Invasions, 2015

The two alien green algae Caulerpa taxifolia and Caulerpa cylindracea (formerly Caulerpa racemosa... more The two alien green algae Caulerpa taxifolia and Caulerpa cylindracea (formerly Caulerpa racemosa var. cylindracea) are among the most notorious and threatening invasive species in the Mediterranean Sea. From the beginning of their introduction, C. taxifolia aroused a great concern due to its initial exponential spread and impacts on native ecosystems, whilst C. cylindracea received lower attention. In this paper, the distribution of the two aliens over the last 30 years in the Italian side of the Ligurian Sea (NW Mediterranean Sea) is reviewed and the kinetics of their spreading is compared. We combined available data on habitat occupancy with data on substratum cover obtained during underwater surveys to compute the average annual spreading rates for both aliens. C. taxifolia had an impressive expansion phase from 1984 to 2000 but then, its dispersal rate showed lower than that predicted and the species did not persist in areas formerly colonized. Today, abundance of this species is strongly declined as it disappeared from most of the attained areas. On the contrary, C. cylindracea exhibited an impressive and constant expansion from the beginning of its first appearance in the Ligurian Sea and, today, it is still increasing its range and habitat occupancy. Its abundance results 1.5-times greater than that reached by C. taxifolia during the period of its maximum expansion. The divergent kinetics of spreading of the two aliens prevents any possibility of generalization of the future behaviour of invasive species in the Mediterranean Sea, and continuous and periodic surveys are thus mandatory to understand the kinetics of expansion and to define species-specific models.

The Challenge of Managing Marine Biodiversity: A Practical Toolkit for a Cartographic, Territorial Approach

Diversity, 2012

An approach to the management of marine biodiversity was developed based on two levels of environ... more An approach to the management of marine biodiversity was developed based on two levels of environmental diagnostics: (1) the characterization (to identify types), and (2) the evaluation (to define status and values). Both levels involve the production of maps, namely: (i) morphobathymetry and sedimentology; (ii) habitats; (iii) natural emergencies; (iv) degradation and risk; (v) weighted vulnerability; (vi) environmental quality; and, (vii) susceptibility to use. A general methodological aspect that must be stated first is the need of dividing the mapped area in territorial units corresponding to submultiples of the UTM grid and having different sizes according to the scale adopted. Territorial units (grid cells) are assigned to one of five classes of evaluation, ranging from high necessity of conservation or protection to non-problematic, unimportant or already compromised (according to the specific map) situations. Depending on the scale, these maps are suited

Ecological change, sliding baselines and the importance of historical data: lessons from combing observational and quantitative data on a temperate reef over 70 years

PloS one, 2015

Understanding the effects of environmental change on ecosystems requires the identification of ba... more Understanding the effects of environmental change on ecosystems requires the identification of baselines that may act as reference conditions. However, the continuous change of these references challenges our ability to define the true natural status of ecosystems. The so-called sliding baseline syndrome can be overcome through the analysis of quantitative time series, which are, however, extremely rare. Here we show how combining historical quantitative data with descriptive 'naturalistic' information arranged in a chronological chain allows highlighting long-term trends and can be used to inform present conservation schemes. We analysed the long-term change of a coralligenous reef, a marine habitat endemic to the Mediterranean Sea. The coralligenous assemblages of Mesco Reef (Ligurian Sea, NW Mediterranean) have been studied, although discontinuously, since 1937 thus making available both detailed descriptive information and scanty quantitative data: while the former was u...

An Ecosystem-Based Approach to Assess the Status of a Mediterranean Ecosystem, the Posidonia oceanica Seagrass Meadow

PLoS ONE, 2014

Biotic indices, which reflect the quality of the environment, are widely used in the marine realm... more Biotic indices, which reflect the quality of the environment, are widely used in the marine realm. Sometimes, key species or ecosystem engineers are selected for this purpose. This is the case of the Mediterranean seagrass Posidonia oceanica, widely used as a biological quality element in the context of the European Union Water Framework Directive (WFD). The good quality of a water body and the apparent health of a species, whether or not an ecosystem engineer such as P. oceanica, is not always indicative of the good structure and functioning of the whole ecosystem. A key point of the recent Marine Strategy Framework Directive (MSFD) is the ecosystem-based approach. Here, on the basis of a simplified conceptual model of the P. oceanica ecosystem, we have proposed an ecosystem-based index of the quality of its functioning, compliant with the MSFD requirements. This index (EBQI) is based upon a set of representative functional compartments, the weighting of these compartments and the assessment of the quality of each compartment by comparison of a supposed baseline. The index well discriminated 17 sites in the northwestern Mediterranean (French Riviera, Provence, Corsica, Catalonia and Balearic Islands) covering a wide range of human pressure levels. The strong points of the EBQI are that it is easy to implement, non-destructive, relatively robust, according to the selection of the compartments and to their weighting, and associated with confidence indices that indicate possible weakness and biases and therefore the need for further field data acquisition.

The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats

PLoS ONE, 2010

Funding: The authors gratefully acknowledge the support given by the European Census of Marine Li... more Funding: The authors gratefully acknowledge the support given by the European Census of Marine Life, the Total Foundation and the Alfred P. Sloan Foundation. MC was supported financially by the European Commission Marie Curie Postdoctoral Fellowship through the International Outgoing Fellowships (Call FP7-PEOPLE-2007-4-1-IOF) for the ECOFUN project and by Dalhousie University (Halifax, Canada). EB acknowledges financial support from GRACCIE project C5D2007-00067 funded by the Spanish Ministry of Science and Innovation. BG thanks the support of SESAME funded by the European Commission's Sixth Framework Program on Sustainable Development, Global Change and Ecosystems. JISS acknowledges ECOLIFE (CGL2008-05407-C03-03) funds of the Ministry of Science and Innovation of Spain. The present paper is a contribution of JG, DM and XT to the projects 2009SRG665 and 2009SGR484 of the ''Generalitat de Catalunya'', and of DM and XT to project CTM2007-66635 funded by the Ministry of Science and Innovation of Spain. Research by C. N. Bianchi on Mediterranean Sea biodiversity is partly supported by the project ''The impacts of biological invasions and climate change on the biodiversity of the Mediterranean Sea'' (Italy-Israel cooperation) funded by the Italian Ministry of the Environment. The funders had no role in study design, data collection and analysis, decision to published, or preparation of the manuscript.

Seasonal grazing and food preference of herbivores in a Posidonia oceanica meadow

Scientia Marina, 2001

Seasonal grazing of the fish Sarpa salpa (L.), the urchin Paracentrotus lividus Lamarck and the i... more Seasonal grazing of the fish Sarpa salpa (L.), the urchin Paracentrotus lividus Lamarck and the isopods Idotea spp. was compared with the C/N ratio of adult and intermediate leaves and epiphytes of Posidonia oceanica (L.) Delile, collected at three different depths. Despite seasonal differences in grazing, herbivores showed preferences throughout the year for adult leaves with more epiphyte and higher N contents. The maximum grazing on adult and intermediate leaves was observed in September and in June for fish and in March for urchins, whereas it was irregular for isopods. Grazing by the three herbivores was not related to their preference for leaves or epiphytes, notwithstanding the seasonal differences in their C and N contents. We concluded that herbivores show no preference for food type throughout the year and that seasonal consumption of P. oceanica is related mainly to herbivore behaviour.

Conserving Biodiversity in a Human-Dominated World: Degradation of Marine Sessile Communities within a Protected Area with Conflicting Human Uses

PLoS ONE, 2013

Conservation research aims at understanding whether present protection schemes are adequate for t... more Conservation research aims at understanding whether present protection schemes are adequate for the maintenance of ecosystems structure and function across time. We evaluated long-term variation in rocky reef communities by comparing sites surveyed in 1993 and again in 2008. This research took place in Tigullio Gulf, an emblematic case study where various conservation measures, including a marine protected area, have been implemented to manage multiple human uses. Contrary to our prediction that protection should have favored ecosystem stability, we found that communities subjected to conservation measures (especially within the marine protected area) exhibited the greatest variation toward architectural complexity loss. Between 1993 and 2008, chronic anthropogenic pressures (especially organic load) that had already altered unprotected sites in 1993 expanded their influence into protected areas. This expansion of human pressure likely explains our observed changes in the benthic communities. Our results suggest that adaptive ecosystem-based management (EBM), that is management taking into account human interactions, informed by continuous monitoring, is needed in order to attempt reversing the current trend towards less architecturally complex communities. Protected areas are not sufficient to stop ecosystem alteration by pressures coming from outside. Monitoring, and consequent management actions, should therefore extend to cover the relevant scales of those pressures.

Hydrothermal studies in the aegean sea

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere, 2000

The aims of the Aegean Hydrothermal Fluxes and Biological Production project were to estimate the... more The aims of the Aegean Hydrothermal Fluxes and Biological Production project were to estimate the fluxes of fluids, chemicals, heat and bacteria, from hydrothermal vents, establish the controls on venting dynamics, measure the productivity in the region of the vents and establish the effect of the vents on biodiversity of both prokaryotes and eukaryotes. This paper presents an initial synthesis of the project results. Research was done both by land-based SCUBA diving and from several vessels at a number of active sites in the near-shore coastal regions of Milos and Kos, with some additional studies at Methana, Lesbos and Santorini. Vent water composition showed very large variations. This was due to the mixing, of hydrothermal reservoir fluids, vapour condensate and seawater altered by interactions of fluid-sediment-bacteria in different proportions, in the gasohydrothermal vents. The composition ranged from nearly sea water with only slightly reduced pH, to higher or lower salinity fluids with a pH as low as 3 and with large enrichments in heavy and trace metals. Phase separation was a common feature at these shallow vents. The dry gas phase was mainly CO,, but with significant amounts of H,S, CH, and H,. These fluids commonly passed through soft sediments before venting from the seafloor and induced a convection cell of pore-water entrainment from deeper sediment layers into the water column with a consequent Ire-charge' down-flow of seawater into the sediment around the vent outlets. Such complex conditions may well explain the high biodiversity of Bacteria, Archaea and epifaunal species surrounding the vents. As many as 44 % of the archaeal lineages detected were found to represent novel phyla. Epifaunal diversity was particularly high with over 200 species recorded at the shallower Milos vents. These vents may form a 'steppingstone' for warmer water species to colonise the surrounding areas when water temperatures permit.

Urban seagrass: Status of Posidonia oceanica facing the Genoa city waterfront (Italy) and implications for management

Marine Pollution Bulletin, 2007

A system of five adjacent Posidonia oceanica meadows facing the waterfront of Genoa city (Liguria... more A system of five adjacent Posidonia oceanica meadows facing the waterfront of Genoa city (Ligurian Sea, NW Mediterranean) was investigated over different spatial scales (meters-kilometers) using three environmental indices: conservation index (CI), substitution index (SI) and phase-shift index (PSI). CI revealed differences mostly at large spatial scale, distinguishing the poor condition of the meadows closest to Genoa centre and harbour from the comparatively healthy condition of the farthest meadows. SI showed differences mostly at small spatial scale (i.e., within meadows), suggesting the influence of local factors in the re-colonisation of regressed meadows by the seagrass Cymodocea nodosa and/or the invasive alga Caulerpa racemosa. Mapping of PSI showed that the meadows closest to Genoa centre and harbour have undergone a nearly total phase shift and have no real potential for recovery: attempts to re-establish P. oceanica there might be a waste of time and money. On the contrary, the meadows farthest from Genoa centre and harbour showed a comparatively low level of phase shift and could still fully recover given specific management actions.

Effects of climate, invasive species and anthropogenic impacts on the growth of the seagrass Posidonia oceanica (L.) Delile in Liguria (NW Mediterranean Sea)

Marine Pollution Bulletin, 2005

Eight shallow water Posidonia oceanica meadows were sampled in June 1999 along 300 km of the Ligu... more Eight shallow water Posidonia oceanica meadows were sampled in June 1999 along 300 km of the Ligurian coast and were compared through shoot density and lepidochronology. The growth of the seagrass was examined in the light of climate fluctuations and local stresses, colonisation by alien, invasive alga Caulerpa taxifolia, and effects of the oil spill from the tanker ''Haven'', and other anthropogenic impacts. Both shoot density and lepidochronology pointed to a generalised state of regression of all the meadows. The analysis of long-term growth curves of the rhizomes showed a positive trend parallel to the increase of air temperature. Two main groups of meadows were individuated on the basis of growth curve similarity. The first included four meadows, namely Ventimiglia, Imperia, Noli and Prelo, that were characterised by average values of rhizome growth of 8-9.1 mm year À1 and shoot density greater than 200 shoots m À2. Although the Imperia meadow was the only one where the alien invasive alga C. taxifolia was found, it did not show differences for rhizome growth in comparison to the other meadows. The second group was formed by meadows that had suffered past anthropogenic impacts: Arenzano and Monterosso al Mare. They showed higher rhizome growth rates (9.4-10.6 mm year À1) and shoot densities between 200 and 100 shoots m À2. At Arenzano, where ''Haven'' oil was stranded in April 1991, no rhizome older than 8 years was found, thus confirming the shoot mortality induced by the oil spill event. The two last meadows exhibited growth curves very different from all the others: Portovenere, is a shallow meadow where P. oceanica merely survives in an extremely degraded situation with highest rhizome growth rate (12 mm year À1), the other, Riva Trigoso, is the only meadow implanted on rock and had the lowest growth rates (7.1 mm year À1).

Bio-mineralogy as a structuring factor for marine epibenthic communities

Marine Ecology Progress Series, 2000

The m e r a l o g i c a l features of the substrate were generally cons~dered a rmnor factor m st... more The m e r a l o g i c a l features of the substrate were generally cons~dered a rmnor factor m structunng manne benthic communities The alm of t h~s work 1s to venfy whether the presence of quartz nunerals in rock may exphcate dlfferences, usually explamed m terms of substrate roughness or other factors In epibenthic cornrnun~hes Laboratory tests on the hydroid Eudendnum glomeratum showed that ~t s planulae settle preferentially on carbonat~c, rather than quartzltic substrates To test the Influence of quartz on established communities, we analysed the specles composition and quanti-tat~ve structure of subhttoral sesslle assemblages on Wferent rocks In several locahhes of the L~gurian and Tyrrhenian seas The observed dlfferences appeared to be related to the presence of quartz in the substrate rock The ~nteractions between organisms and minerals (bio-mmeralogy) mlght play a slgnlficant role on benthic communities affechng not only the inihal colonlsahon but also later assemblages This potential role has been largely neglected to date and further studies are needed to prove ~t s Impor tance KEY WORDS: Substrate colonisation. Mineral composition. Marine benthos distnbution. Hard substrates. Bio-mineralogy 0 Inter-Research 2000 Resale of full article not permitted

Living on the rocks: substrate mineralogy and the structure of subtidal rocky substrate communities in the Mediterranean Sea

Marine Ecology Progress Series, 2004

tion due to changes in abiotic factors (e.g. wave action, water temperature, salinity, habitat co... more

Geo-environmental cartography of the Marine Protected Area “Isola di Bergeggi” (Liguria, NW Mediterranean Sea)

Journal of Maps, 2010

Marine Protected Areas (MPAs) are considered one of the main tools for conservation, valorisation... more Marine Protected Areas (MPAs) are considered one of the main tools for conservation, valorisation and management of coastal marine environments, and are defined by Italian Law (derived from European directives) as territories with "physical, geological, geomorphological and biological features having relevant naturalistic and environmental value". While the bionomic mapping of MPAs has received large attention by researchers, MPA geological or geomorphological cartographies have been seldom realized. In this study we present a geomorphological cartography, comprising also environmental themes having a geomorphological significance, realized in the MPA "Isola di Bergeggi".

Tissue necrosis and mortality of the temperate coralCladocora Caespitosa

Italian Journal of Zoology, 2005

Abstract Mass‐mortality events of the temperate coral Cladocora caespitosa were recorded in the G... more Abstract Mass‐mortality events of the temperate coral Cladocora caespitosa were recorded in the Gulf of La Spezia (NW Mediterranean) in the summers of 1997, 1998 and 1999. At the end of the summer 1999, 60% of the colonies found in 1997 were damaged and more than 50% of the damaged colonies were completely dead. Complete death of the largest colonies caused a modal shift of colony size‐frequency distribution towards the smallest size classes. In order to verify experimentally the hypothesis that mass‐mortality was primarily induced ...