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.

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

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.

Can we preserve and restore overlooked macroalgal forests?

Habitat degradation and loss are severely affecting macroalgal forests worldwide, and their successful mitigation depends on the identification of the drivers of loss and the implementation of effective conservation and restoration actions. We made an extensive literature review 1- to document the historical (1789-1999) and recent (2000-2020) occurrence of the genus Cystoseira, Ericaria and Gongolaria reported in the literature along the 8000 km of the coasts of Italy, 2- to assess their decline and patterns of extinction, 3- to ascertain the drivers responsible for these changes, 4- to highlight the existence of success stories in their conservation and natural recovery. In the last twenty years, overall information on the distribution of Cystoseira s.l. exponentially increased, although research focused almost exclusively on intertidal reefs. Despite the lack of systematic monitoring programs, the local extinction of 371 populations of 19 different species of Cystoseira s.l. was documented across several regions, since 2000. Coastal engineering and poor quality of waters due to urban, agricultural or industrial activities were often documented as leading causes of habitat loss. However, the drivers of extinction were actually unknown for the majority of the populations and cause-effects relationships are scarcely documented. Although the proportion of protected populations increased to 77.8%, Marine Protected Areas are unlikely to guarantee adequate conservation efficacy, possibly also for the widespread lack of management and monitoring plans dealing specifically with Cystoseira s.l. species, and few evidences of natural recovery were observed. Our review shows the dramatic lack of baseline information for macroalgal forests, highlighting the urgent need for the monitoring of less accessible habitats, the collection of long-term data to unveil drivers of loss, and an updated reporting about the conservation status of the species of interest to plan future interventions.

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 post-industrial 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.

Home advantage? Decomposition across the freshwater-estuarine transition zone varies with litter origin and local salinity.

Expected increases in the frequency and intensity of storm surges and river flooding may greatly affect the relative salinity of estuarine environments over the coming decades. In this experiment we used detritus from three contrasting environments (marine Fucus vesiculosus; estuarine Spartina anglica; terrestrial Quercus robur) to test the prediction that the decomposition of the different types of litter would be highest in the environment with which they are associated. Patterns of decomposition broadly fitted our prediction: Quercus detritus decomposed more rapidly in freshwater compared with saline conditions while Fucus showed the opposite trend; Spartina showed an intermediate response. Variation in macro-invertebrate assemblages was detected along the salinity gradient but with different patterns between estuaries, suggesting that breakdown rates may be linked in part to local invertebrate assemblages. Nonetheless, our results suggest that perturbation of salinity gradients through climate change could affect the process of litter decomposition and thus alter nutrient cycling in estuarine transition zones. Understanding the vulnerability of estuaries to changes in local abiotic conditions is important given the need to better integrate coastal proceses into a wider management framework at a time when coastlines are increasingly threatened by human activities.

Do small marinas drive habitat specific impacts? A case study from Mediterranean Sea.

Many human activities add new structures to the marine landscape. Despite the fact that human structures cause some inevitable impacts, surprisingly little information exists on the effects of marina on natural marine assemblages. The aim of this paper is to assess habitat-specific response of benthic sessile organisms of rocky shores in relation to the presence of a small marina. Sampling was carried out at three coastal habitats (midshore, lowshore and subtidal) by means of visual censuses adopting an after-control-impact (ACI) experimental design. It appears that the marina affects the structure and composition of benthic communities of both the midshore and the lowshore. Little effect was evident on shallow subtidal assemblage structure. The results of the present study clearly show habitat-specific responses of coastal benthic assemblages to the presence of infrastructure.