Globally, the spread of non-indigenous species in marine ecosystems is a major ecological and socio-economical concern. The need for long-term assessment on a large scale is a pre-requisite for understanding the drivers associated with their establishment and expansion. Here, the patterns of invasions of subtidal soft-bottom assemblages of shelled molluscs have been quantified based on a unique dataset collected between 2005 and 2012 along the coast of Israel (SE Mediterranean Sea), a hotspot of bioinvasion. Overall, the number of non-indigenous species doubled between 2005 and 2012. Significant differences in terms of species richness and relative abundance were observed in space and time in both native and non-indigenous species. A combination of enduring disturbance regimes related to human activities and site-specific environmental conditions seem to have a critical role in promoting the observed patterns. Our results emphasize the value of long term broad-scale systematic surveys to the development of effective environmental policies for the control of bioinvasions.

In the last decade, the 'Cumulative Pressure and Impact Assessment' (CPIA) approach emerged as a tool to map expected impacts on marine ecosystems. However, CPIA assumes a linear response of ecosystems to increasing level of cumulative pressure weighting sensitivity to different anthropogenic pressures through expert judgement. We applied CPIA to Mediterranean coralligenous outcrops over 1000 km of the Italian coastline. Extensive field surveys were conducted to assess the actual condition of coralligenous assemblages at varying levels of human pressure. As pressure increased, a clear shift from bioconstructors to turf-dominated assemblages was found. The linear model originally assumed for CPIA did not fit the actual relationship between expected cumulative impact versus assemblage degradation. A log-log model, instead, best fitted the data and predicted a different map of cumulative impact in the study area able to appreciate the whole range of impact scenarios. Hence, the relative importance of different drivers in explaining the observed pattern of degradation was not aligned with weights from the expert opinion. Such findings stress the need for more incisive efforts to collect empirical evidence on ecosystem-specific responses to human pressure in order to refine CPIA predictions.

Abstract This volume contains the main results of the EC FP7 “The Ocean of Tomorrow” Project CoCoNet, divided in two sections: 1) a set of guidelines to design networks of Marine Protected Areas in the Mediterranean and the Black Seas; 2) a smart wind chart that will allow evaluating the possibility of installing Offshore Wind Farms in both seas. The concept of Cells of Ecosystem Functioning, based on connectivity, is introduced to define natural units of management and conservation. The definition of Good Environmental Status, as defined in the Marine Strategy Framework Directive, is fully embraced to set the objectives of the project, by adopting a holistic approach that integrates a full set of disciplines, ranging from physics to bio-ecology, economics, engineering and many sub-disciplines. The CoCoNet Consortium involved scientist sfrom 22 states, based in Africa, Asia, and Europe, contributing to build a coherent scientific community.

Human activities determine dramatic changes in natural systems, especially in marine coastal areas. This is especially true when economic development is fast and scarcely regulated, representing a serious threat to biodiversity. Besides the obvious prediction of impairment of natural systems, forecasting the effects of human activities can be particularly challenging since they affect species and assemblages, the patterns of distribution and extent of which are often totally unknown. In Vlora Bay, we show through an interdisciplinary project that 15 y of coastal development can result in a loss of over 50% of seagrass cover and a decline in macroalgae cover such as Cystoseira spp., which are structurally and functionally crucial habitats that provide essential goods and services for local human communities and recreation. Furthermore, illegal fishery practices (date mussel fishery, trawling, and use of explosives) contribute to depict a scenario of fragmentation and loss of shallow species-rich assemblages. Large-scale changes in sedimentation patterns have been recognised as one of the main drivers of those changes. This model of development, associated with nearly irreversible environmental consequences, as observed in Albania, can serve as an example for many other Mediterranean areas, showing a combination of high biodiversity and low protection regime. We discuss the urgent need for ecosystem-based management to ensure sustainable development while conserving and managing natural biodiversity and resources.

Ecological connectivity is important for effective marine planning and biodiversity conservation. Our aim was to identify factors important in influencing variation in benthic community structure on shallow rocky reefs in 2 regions of the Mediterranean Sea with contrasting oceanographic regimes. We assessed beta (β) diversity at 146 sites in the littoral and shallow sublittoral from the Adriatic/Ionian Seas (eastern region) and Ligurian/Tyrrhenian Seas (western region) using a null modelling approach to account for variation in species richness. The distance decay relationship between species turnover within each region and geographic distance by sea was determined using generalised linear models. Mantel tests were used to examine correlations between β diversity and connectivity by ocean currents, estimated from Lagrangian dispersal simulations. Variation in β diversity between sites was partitioned according to environmental and spatial components using a distance-based redundancy approach. Species turnover along a gradient of geographic distance was greater by a factor of 3 to 5 in the western region than the eastern region, suggesting lower connectivity between sites. β diversity was correlated with connectivity by ocean currents at both depths in the eastern region but not in the western region. The influ- OPEN ACCESS ence of spatial and environmental predictors of β diversity varied considerably between regions, but was similar between depths. Our results highlight the interaction of oceanographic, spatial and environmental processes influencing benthic marine β diversity. Persistent currents in the eastern region may be responsible for lower observed β diversity compared to the western region, where patterns of water circulation are more variable.

ABSTRACT: A 10 yr study was carried out in the Tremiti Archipelago, a multiple-use Marine Protected Area (MPA) several miles off the mainland (South Adriatic, Italy), with a very small and isolated no-take area established in 1989 and characterized by limited enforcement. Patterns of variation in benthic assemblages along the intertidal rocky shores and in the rocky subtidal inside and outside the no-take area were examined between 2001 and 2010. Remarkable changes in the intertidal assemblages were detected within the no-take area, with an increase of Cystoseira canopies and the development of more diversified understory assemblages through time. Signs of regression in Cystoseira were documented in unprotected control areas. Conversely, < 20 yr after the MPA designation, bare rock and patches of crustose coralline algae characterized subtidal assemblages in the no-take area. Increasing spatial heterogeneity of both intertidal and subtidal assemblages, probably representing an early warning of increasing human pressure, was also assessed. Data on primary production showed significantly higher values in the control areas than in the no-take area, with increasing values over time, indicating that the observed patterns are triggered by a combination of different drivers. Our results suggest that: (1) the effects of protection over benthic assemblages greatly depend on the habitats considered, which in turn, respond differently to specific human pressures occurring within and outside the reserve. A careful analysis of the distribution and intensity of all the activities allowed within multiple-use MPAs is critical for improving the effectiveness of conservation actions. (2) Isolation per se does not guarantee exclusion from human activities. In the presence of low enforcement, isolation may play a limited role in mitigating human pressures on benthic assemblages and may impair the connectivity of reserve networks.

The Mediterranean Sea hosts hundreds of offshore gas platforms, whose activity represents a potential threat to marine ecosystems. Evidence from several studies indicates that nematodes can be highly sensitive to changes in the environmental quality. Here, we investigated the response of nematode assemblages to the presence of offshore gas platforms (located in the central Mediterranean Sea) in terms of spatial heterogeneity, structural and functional diversity. Since the effect of the investigated offshore platforms on macrofaunal assemblages were previously assessed by Terlizzi et al. (2008), the study provided also the opportunity to compare the response of different benthic compartments to the same impact related to fossil fuel extraction on marine environments. The platforms had a significant impact on nematode assemblages up to 1000 m distance from the structure. The effects were evident in term of: a) more homogeneous spatial distribution of nematode assemblages, b) increased trophic diversity of deposit feeders and c) changes in life strategies with an increase of opportunistic species in sediments closer to the platforms. Such effects seemed to be related to the dimension of the platform structures, rather than to chemical pollution or changes in food availability. These findings suggest that the platforms exert a physical alteration of the surrounding environment that is reflected by altered structural and functional traits of nematode biodiversity. The use of nematodes for monitoring the effects of the platforms only partially matched with the results obtained using macrofauna, providing further insights on potential outcomes on the functional response of marine assemblages to fossil fuel extraction.

Submarine caves are considered as a top priority for conservation, but the effects of common pressures are poorly known for these habitats. Here, we examined the effect of recreational human visitation on a selection of submarine caves in a Mediterranean Marine Protected Area (403504000N; 81103900E) where diving activities are regulated. Sampling was conducted in visited and not visited caves to assess whether diving activities have a significant effect on cave habitats, what are the components of biodiversity most affected by this disturbance, and its potential effects on spatial heterogeneity of benthic assemblages. Results clearly showed that human visitation could significantly affect spatial patterns of benthic assemblages. Organisms with erect growth forms were significantly more abundant and homogeneously distributed where diving activities are forbidden. An increase in the small-scale heterogeneity of assemblages and a decrease in their threedimensional structure could be the ultimate consequences of human visitation. The interaction between specific stressors and the patterns of distribution of species and assemblages can drive their spatial heterogeneity also in unique habitats like marine caves, representing an early warning for the development of appropriate management measures.

Ecological indicators likely constitute the mainstream tools in assessing the quality of aquatic ecosystems as they condense composite biological information into single measures, easier to handle for environmental managers and more understandable for non-scientific users. However, sampling settings can influence the performance of most indices, and their use is often constrained to specific habitat types. Average taxonomic distinctness (Delta+) and variation in taxonomic distinctness (Delta+) may represent promising tools in overcoming sampling bias, and potentially applicable to a wide range of environmental contexts. In marine systems, such metrics showed higher sensitivity than classical indices in discriminating among perturbed and unperturbed conditions, though a number of studies found Delta+ and Delta+ also varying along natural gradients, suggesting a lower ability to discern human-driven variations from natural variability than what expected. Here, analyzing existing data sets from previous impact assessment studies, we test the response of Delta+ and Delta+ in detecting the effects of different sources of anthropogenic disturbance on marine mollusks and polychaetes from Mediterranean soft sediments and hard substrates. Our results showed that neither classical univariate analyses on Delta+ and Delta+ values nor their associated statistical framework were able to discern among perturbed and unperturbed sites, highlighting a low sensitiveness of such metrics in detecting assemblage variations related to anthropogenic disturbance. Delta+ and Delta+ are based on presence/absence data, and assume impacts being likely to induce variations in taxonomic structures of assemblages. As a consequence, they could experience reduced discrimination power when impacts mostly affect relative abundances of organisms rather than assemblage composition, or drive species replacement within higher taxa. Our results also showed that habitat type could strongly affect taxonomic relatedness of species within assemblages, and that this effect can vary among different organisms, suggesting that the departures from expectation of Delta+ and Delta+ values might not be always univocally attributable to human perturbations, since possibly depending on habitat effects. Taxonomic distinctness indices can provide useful additional information on taxonomic diversity of assemblages, crucial to better address the wide concept of biological diversity. However, the effectiveness of such measures in disclosing the effects of human disturbance is still unclear, requiring further investigations especially on their potential application in defining the ecological status of coastal rocky systems.

Reproductive cycles of marine invertebrates with complex life histories are considered to be synchronized by water temperature and feeding conditions, which vary with season and latitude. This study analyses seasonal variation in the occurrence of oyster (Crassostrea gigas) and mussel (Mytilus edulis/galloprovincialis) larvae across European coastal waters at a synoptic scale (1000s of km) using standardised methods for sampling and molecular analyses. We tested a series of hypotheses to explain the observed seasonal patterns of occurrence of bivalve larvae at 12 European stations (located between 37 degrees N and 60 degrees N and 27 degrees W and 18 degrees E). These hypotheses included a model that stated that there was no synchronisation in seasonality of larval presence at all between the locations (null hypothesis), a model that assumed that there was one common seasonality pattern for all stations within Europe, and various models that supposed that the variation in seasonality could be grouped according to specific spatial scales (i.e., latitude, large marine ecosystems and ecoregions), taxonomic groups, or several combinations of these factors. For oysters, the best models explaining the presence/absence of larvae in European coastal waters were (1) the model that assumed one common seasonal pattern, and (2) the one that, in addition to this common pattern, assumed an enhanced probability of occurrence from south to north. The third best model for oysters, with less empirical support than the first two, stated that oysters reproduced later in the south than in the north. For mussels, the best models explaining the seasonality in occurrence of larvae were (1) the model that assumed four underlying trends related to large marine ecosystems, and (2) the one that assumed one common seasonal pattern for larvae occurrence throughout Europe. Such synchronies in larval occurrences suggest that environmental conditions relevant to bivalve larval survival are more or less similar at large spatial scales from 100s to 1000s of km. To unravel the underlying mechanisms for this synchronisation is of particular interest in the light of changing environmental conditions as the result of global climate change and the possible consequences for marine food webs and ecosystem services.

Assessing the distribution and intensity of human threats to biodiversity is a prerequisite for effective spatial planning, harmonizing conservation purposes with sustainable development. In the Mediterranean Sea, the management of Marine Protected Areas (MPAs) is rarely based on explicit consideration of the distribution of multiple stressors, with direct assessment of their effects on ecosystems. This gap limits the effectiveness of protection and is conducive to conflicts among stakeholders. Here, a fine scale assessment of the potential effects of different combinations of stressors (both land- and marine-based) on vulnerable rocky habitats (i.e. lower midlittoral and shallow infralittoral) along 40 km of coast in the western Mediterranean (Ionian Sea) has been carried out. The study area is a paradigmatic example of socio-ecological interactions, where several human uses and conservation measures collide. Significant differences in the structure of assemblages according to different combinations of threats were observed, indicating distinct responses of marine habitats to different sets of human pressures. A more complex three-dimensional structure, higher taxon richness and β-diversity characterized assemblages subject to low versus high levels of human pressure, consistently across habitats. In addition, the main drivers of change were: closeness to the harbour, water quality, and the relative extension of beaches. Our findings suggest that, although efforts to assess cumulative impacts at large scale may help in individuating priority areas for conservation purposes, the fact that such evaluations are often based on expert opinions and not on actual studies limits their ability to represent real environmental conditions at local scale. Systematic evaluations of local scale effects of anthropogenic drivers of change on biological communities should complement broad scale management strategies to achieve effective sustainability of human exploitation of marine resources.