Genetic confirmation of the first Mediterranean record of Holacanthus africanus Cadenat, 1951

The first Mediterranean record of the pomacanthid Holacanthus africanus, caught within the Maltese waters, was assigned based on morphological and meristic characters. However, molecular and genetic analyses are required to confirm the taxonomic determination and avoid misidentification given the abundance of closely-related Pomacanthidae species and the biogeographic significance of this record for the Mediterranean. At the species level, the analyzed specimens gave a 99.7% identity match with H. africanus. This study represents yet another example of molecular analyses supplementing the conclusions of conventional morphological identification exercises.peer-reviewe

Bridging the knowledge gap on the distribution and typology of vermetid bioconstructions along the Maltese coastline : an updated assessment

In the Maltese Islands, insufficient attention has been paid to vermetid reefs, endemic Mediterranean bioconstructions widely distributed along the southern part of the basin. As a result, this is a largely-overlooked coastal ecosystem despite the multitude of ecosystem services it provides. The perennial urban development in the Maltese Islands calls for the adoption of urgent action to protect coastal habitats, in particular bioconstructions that increase biodiversity and contribute to mitigating the effects of climate change. The objective of our study was to extensively document the presence and typology of the vermetid reef ecosystems along the coast of Malta and Gozo, assessing the occurrence of putative anthropogenic threats on the same ecosystem. Quantitative measurements were additionally taken to morphologically characterize the recorded bioconstructions. Furthermore, we tested the human pressure effect on the density of vermetid individuals and associated biodiversity. “True” trottoirs were only documented along the south-east coast of Malta, where unfortunately land reclamation projects are expected to be implemented. Although no direct relation between a number of assessed human activities and the density of vermetid individuals was reported in the current study, we suggest the conduction of further studies to investigate the influence of specific disturbances on the conservation status of this ecosystem. This study expands the existing knowledge on the status of vermetid reefs in the Maltese Islands and calls for management and conservation actions to preserve this bioconstruction.peer-reviewe

Using local ecological knowledge to search for non-native species in Natura 2000 sites in the central Mediterranean sea : an approach to identify new arrivals and hotspot areas

The management of biological invasions is among the most urgent of global challenges and requires a significant monitoring effort to obtain the information needed to take the appropriate decisions. To complement standard monitoring, citizen science is increasingly being used. Within citizen science, the approach of collecting and investigating Local Ecological Knowledge (LEK) proved to be useful in the monitoring of non-native species. A LEK survey was carried out in 10 Sicilian and Maltese Natura 2000 sites in order to help in the early detection of non-native species. The survey was addressed to local fishers and SCUBA divers in order to investigate the occurrence of 24 selected marine non-native species and to identify potential hotspot areas of invasion through the use of six indicators: the occurrence of newly introduced nonindigenous species, the cumulative impacts of invasive alien species (CIMPAL) and the relative importance of species on the cumulative impacts (D1, D2, D3, and D4). The respondents confirmed the presence of 22 species since the year 2000 and reported 10 new ones registered in the investigated areas. The highest CIMPAL value was observed in two Sicilian Natura 2000 sites (ITA090028 and ITA040014) and the lowest on the western coast of Malta (MT0000101, MT0000102, MT0000103, and MT0000104) The four top-priority species according to indicators D1–D4 were Caulerpa cylindracea, C. taxifolia, Siganus luridus and S. rivulatus. The study produced a valid and useful scientific output to suggest and address management strategies to monitor the establishment of the non-native species.peer-reviewe

The challenge of setting restoration targets for macroalgal forests under climate changes

Este artículo contiene 10 páginas, 5 figuras, 1 tabla.The process of site selection and spatial planning has received scarce attention in the scientific literature dealing with marine restoration, suggesting the need to better address how spatial planning tools could guide restoration interventions. In this study, for the first time, the consequences of adopting different restoration targets and criteria on spatial restoration prioritization have been assessed at a regional scale, including the consideration of climate changes. We applied the decision-support tool Marxan, widely used in systematic conservation planning on Mediterranean macroalgal forests. The loss of this habitat has been largely documented, with limited evidences of natural recovery. Spatial priorities were identified under six planning scenarios, considering three main restoration targets to reflect the objectives of the EU Biodiversity Strategy for 2030. Results show that the number of suitable sites for restoration is very limited at basin scale, and targets are only achieved when the recovery of 10% of regressing and extinct macroalgal forests is planned. Increasing targets translates into including unsuitable areas for restoration in Marxan solutions, amplifying the risk of ineffective interventions. Our analysis supports macroalgal forests restoration and provides guiding principles and criteria to strengthen the effectiveness of restoration actions across habitats. The constraints in finding suitable areas for restoration are discussed, and recommendations to guide planning to support future restoration interventions are also included.This study was funded by the EASME–EMFF (Sustainable Blue Economy) Project AFRIMED (http://afrimed-project.eu/, grant agreement N. 789059), supported by the European Community.Peer reviewe

ClimateFish: A Collaborative Database to Track the Abundance of Selected Coastal Fish Species as Candidate Indicators of Climate Change in the Mediterranean Sea

Under the effects of global warming, many animals and plants are undergoing rapid distribution shifts. These changes can be particularly rapid in marine fishes, and many species have responded markedly to recent increases in sea temperature. ClimateFish is an open-access database, which collates abundance data for 7 Mediterranean indigenous and 8 non-indigenous fishes, proposed as candidate indicators of climate change. These species have been selected by a network of Mediterranean scientists based on their wide distribution, responsiveness to temperature conditions and easy identification. Data are periodically collected according to a standard visual census protocol in four different depth layers. At present, the database collates data on a total number of 101'771 observed individuals belonging to the 15 target species. Counts were realized along 3142 transects carried out in 7 Mediterranean countries between 2009 and 2021. This database, associated with climate data, offers new opportunities to investigate spatiotemporal effects of climate change and to test the effectiveness of each selected indicator. Data are available at https://doi.org/10.17882/86784.The Mediterranean ClimateFish initiative was initially conceived by the international basin wide monitoring program CIESM Tropical Signals (funded by the Albert II of Monaco Foundation) and subsequently supported by the Interreg Med Programme (Projects: MPA-ADAPT, grant number 1MED15_3.2_M2_337 and MPA Engage, grant number 5MED18_3.2_M23_007), 85% co funded by the European Regional Development Fund

Effects of artificial defences and flooding on coastal habitats and assemblages

Since large stretches of European coasts are already retreating and projected scenarios are worsening, many artificial structures, such as breakwaters and seawalls, are built as tool against coastal erosion. However artificial structures produce widespread changes that alter the coastal zones and affect the biological communities. My doctoral thesis analyses the consequences of different options for coastal protection, namely hard engineering ‘artificial defences’ (i.e. impact of human-made structures) and ‘no-defence’ (i.e. impact of seawater inundation). I investigated two new aspects of the potential impact of coastal defences. The first was the effect of artificial hard substrates on the fish communities structure. In particular I was interested to test if the differences among breakwaters and natural rocky reef would change depending on the nature of the surrounding habitat of the artificial structure (prevalent sandy rather than rocky). The second was the effect on the native natural sandy habitats of the organic detritus derived from hard-bottom species (green algae and mussels) detached from breakwaters. Furthermore, I investigated the ecological implication of the “no-defend” option, which allow the inundation of coastal habitats. The focus of this study was the potential effect of seawater intrusion on the degradation process of marine, salt-marsh and terrestrial detritus, including changes on the breakdown rates and the associated macrofauna. The PhD research was conducted in three areas along European coasts: North Adriatic sea, Sicilian coast and South-West England where different habitats (coastal, estuarine), biological communities (soft-bottom macro-benthos; rocky-coastal fishes; estuarine macro-invertebrates) and processes (organic enrichment; assemblage structure; leaf-litter breakdown) were analyzed. The research was carried out through manipulative and descriptive field-experiments in which specific hypothesis were tested by univariate and multivariate analyses

Recovery ability of lowshore sessile assemblages in a highly contaminated post-industrial area

The inheritance of environmental contamination left by abandoned industrial plants is widespread globally. Here we compared the patterns of recovery of lowshore algal and invertebrate assemblages between the postindustrial site of Bagnoli-Coroglio and four reference sites distributed along the coast in the Gulf of Naples, southern Tyrrhenian Sea. The structure of whole assemblages, richness of taxa and abundance of individual taxa were followed during one year since an event of experimental disturbance consisting in the removal of all erect organisms from the rocky substrate. Our main findings suggest that the examined benthic assemblages recovered effectively and quickly after a pulse disturbance and, contrarily to initial expectations, that this ability was comparable between the post-industrial site and the reference sites. This result is discussed in terms of several plausible processes and mechanisms, including the general capability of intertidal organisms to recover from physical disturbance, the potential high level of environmental stress affecting the reference sites too, the chance that the most intense impacts of contamination remained restricted to the sediments of the post-industrial site without propagating to adjacent rocky habitats, and the large natural variability of reference sites that may have masked weak effects of the historical contamination. Irrespective of the actual causes, we emphasize the need for including natural variability of the examined system in any future restoration interventions, to guarantee representation of the range of variation of target organisms and of their underlying processes, and to avoid confounding the intended post-industrial impact with the effects of other natural and anthropogenic processes

Recruitment patterns in an intertidal species with low dispersal ability: the reef-building Dendropoma cristatum (Biondi, 1859) (Mollusca: Gastropoda)

In the Mediterranean, the gastropod Dendropoma cristatum (sin. D. petraeum (Monterosato, 1884)) is the primary builder of the vermetid reef, an intertidal bioconstruction of exceptional ecological importance. Despite awareness of the need for conservation of this key species, the biology of D. cristatum remains poorly understood. The recruitment of D. cristatum deserves particular attention because the absence of a planktonic larval stage limits its dispersal ability. We examined the temporal pattern of recruitment during the breeding season of D. cristatum from June to September in 2013. Specifically, we compared the two portions of the vermetid reef (i.e. the inner edge and the outer edge) at localities with different exposures to wave motion. The number of recruits peaked in July, when it was significantly higher in the outer than in the inner edge. No differences emerged between localities with different wave exposures; however, the width of the reef was significantly related to the exposure index. Although there are still several gaps in our knowledge of the recruitment dynamics of D. cristatum, this study contributes to characterising recruitment rate variation at small spatial and temporal scales