Northwestern Sardinia Research Articles

An improved digital soil mapping approach to predict total N by combining machine learning algorithms and open environmental data

Digital Soil Mapping (DSM) is fundamental for soil monitoring, as it is limited and strategic for human activities. The availability of high temporal and spatial resolution data and robust algorithms is essential to map and predict soil properties and characteristics with adequate accuracy, especially at a time when the scientific community, legislators and land managers are increasingly interested in the protection and rational management of soil.Proximity and remote sensing, efficient data sampling and open public environmental data allow the use of innovative tools to create spatial databases and digital soil maps with high spatial and temporal accuracy. Applying machine learning (ML) to soil data prediction can improve the accuracy of maps, especially at scales where geostatistics may be inefficient. The aim of this research was to map the nitrogen (N) levels in the soils of the Nurra sub-region (north-western Sardinia, Italy), testing the performance of the Ranger, Random Forest Regression (RFR) and Support Vector Regression (SVR) models, using only open source and open access data. According to the literature, the models include soil chemical-physical characteristics, environmental and topographic parameters as independent variables. Our results showed that predictive models are reliable tools for mapping N in soils, with an accuracy in line with the literature. The average accuracy of the models is high (R2 = 0.76) and the highest accuracy in predicting N content in surface horizons was obtained with RFR (R2 = 0.79; RMSE = 0.32; MAE = 0.18). Among the predictors, SOM has the highest importance. Our results show that predictive models are reliable tools in mapping N in soils, with an accuracy in line with the literature. The results obtained could encourage the integration of this type of approach in the policy and decision-making process carried out at regional scale for land management.

Healthy assemblages of Isidella elongata unintentionally protected from trawling offshore of Asinara Island (northwestern Sardinia, NW Mediterranean Sea)

Deep-sea coral assemblages are marine biodiversity hot spots. Because of their life history traits, deep-sea corals are highly vulnerable to the impacts of human activities such as fishing. The critically endangered “bamboo coral” Isidella elongata is a key structuring species of deep muddy bottoms that is susceptible to habitat destruction, particularly from trawling. A shallow population of this species was recently discovered by a multibeam and ROV survey offshore of the Asinara Island marine protected area (MPA) (northwestern Sardinia, NW Mediterranean Sea). This vulnerable marine assemblage has been found under healthy conditions at depths ranging from 110 to 298 m. Isidella elongata occurs on a muddy seafloor locally characterised by boulders associated with black coral species (Parantipathes larix and Antipathes dichotoma). The lush colonies of I. elongata seem to be related to natural protection from bottom trawling activity; nevertheless, the presence of lost fishing artisanal nets has been observed in the study area. These structuring species are indicators of vulnerable marine ecosystems, and their conservation is essential for preserving marine biodiversity. Therefore, enlarging the perimeter of the Asinara Island MPA into its deeper western waters is suggested to ensure the protection of these valuable and vulnerable marine ecosystems.

Movements of translocated Griffon Vultures (<i>Gyps fulvus</i>) from Sardinia to Corsica call for the transboundary management of an expanding vulture population

The conservation of Griffon Vulture (Gyps fulvus), the most abundant and widespread vulture in Europe, has been the focus of two LIFE project in Sardinia, that foresaw, among other actions, the release of individuals to increase population size. Within the project LIFE Under Griffon Wings (2015-2020), out of 76 Griffon Vultures that have been released in North Western Sardinia, 43 have been fitted with GPS/GSM tags. On the 3rd of April 2023, one of these Griffon Vultures, named “Caniga”, crossed the Strait of Bonifacio and reached Corsica. It stayed on the island for 20 days, before returning to Sardinia on the 23rd of April. Despite Griffon Vultures have been occasionally reported in Corsica in the last decades, this was the first time that one of the individuals released within the LIFE “Under Griffon Wings” project was recorded there. This observation provides evidence that expanding Griffon Vultures in Sardinia could also include Corsica in their movements and calls for the transboundary management of vulture populations between the two islands, including both monitoring and conservation actions minimizing anthropogenic mortality.

Epidemiology of seropositive myasthenia gravis in Sardinia: A population-based study in the district of Sassari.

The global incidence and prevalence of myasthenia gravis (MG) range between 6-31/million and 10-37/100,000, respectively. Sardinia is a high-risk region for different immune-mediated disorders, but the epidemiology of MG remains unclear. We determined the epidemiology of MG with acetylcholine receptor (AChR)-immunoglobulin G (IgG) and muscle-specific tyrosine kinase (MuSK)-IgG in the district of Sassari (North-Western Sardinia; population, 325,288). From the laboratory of the University Hospital of Sassari (reference for AChR/MuSK-IgG testing in Sardinia since 1998) and the main neurology units in Sardinia, we retrospectively identified MG patients with (1) AChR-IgG and/or MuSK-IgG positivity by radioimmunoprecipitation assay; and (2) residency in the district of Sassari. Incidence (January 2010-December 2019) and prevalence (December 31, 2019) were calculated. A total of 202 patients were included (incident, 107; prevalent, 180). Antibody specificities were AChR (n = 187 [93%]) and MuSK (n = 15 [7%]). The crude MG incidence (95% confidence interval) was 32.6 (26.8-39.2)/million, while prevalence was 55.3 (47.7-63.9)/100,000. After age-standardization to the world population, incidence decreased to 18.4 (14.3-22.5)/million, while prevalence decreased to 31.6 (26.1-37.0)/100,000. Among incident cases, age strata (years) at MG onset were: <18 (2%), 18-49 (14%), 50-64 (21%), and ≥65 (63%). Sardinia is a high-risk region for MG, with a prevalence that exceeds the European threshold for rare disease. Identification of the environmental and genetic determinants of this risk may improve our understanding of disease pathophysiology.

Checklist of the marine malacofauna of Culuccia Peninsula (NW Sardinia, Italy), with notes on relevant species.

Culuccia is a small peninsula of about 3 km2 placed in north-western Sardinia (Italy) at the margin of the Maddalena Archipelago. The marine area surrounding this Peninsula is a Special Area of Conservation, included in the European Natura 2000 Ecological Network of protected areas, but until now, no information on biodiversity of this area is available. In 2021, a research project to study both terrestrial and marine biodiversity of Culuccia has started in order to fill this gap of knowledge. This work provides the first inventory of the marine malacofauna of the coast of Culuccia. Fifteen sites were sampled seasonally for one-year by using different sampling methods and the present study shows the results from approximately 50 scientific SCUBA and free dive surveys, carried out in all main marine habitats of the studied area. In total, 259 species of molluscs were recorded along the coasts of the Culuccia Peninsula (0-25 m depth), belonging to the classes Bivalvia, Gastropoda, Polyplacophora and Scaphopoda. Amongst the four classes recorded, gastropods were the most represented (66.90%; 173 species), followed by bivalves (28.10%; 73 species), polyplacophorans (4.60%; 12 species) and scapophods (0.40%; 1 species). Notes about distribution, conservation status and ecology for some valuable species are provided, together with images of representative species, consisting mainly of in situ photographs. Additionally, the present investigation recorded the presence of four alien species, whose Mediterranean distribution was extended to north-western Sardinia.

A circle that closes. First report of Echinolittorina punctata (Gmelin, 1791) (Gastropoda; Littorinidae) for the coasts of Sardinia

Echinolittorina punctata (Gmelin, 1791), a thermophilic supralittoral species, was historically distributed along the Atlantic coasts from southern Spain to Senegal, and in the southern and eastern sectors of the Mediterranean. In the latter sea it has spread its range northwards only in recent years, moving up the Tyrrhenian coasts of Italy up to Tuscany, the Adriatic ones up to Croatia, and the southern coasts of Western Europe up to France. Sardinia, in an intermediate position between the Italian Tyrrhenian coasts and the southern Spanish and French ones, both recently colonized by E. punctata, presented itself as a foreseeable new settlement area. The discovery of some populations of this species in north-western Sardinia, along the coasts of the municipality of Porto Torres, represents the first report for Sardinia. It fills the last missing range gap for this species to be defined as widely distributed in the Mediterranean. The expansion of this species further northward in the Mediterranean seems linked to the general increase in sea water temperatures resulting from climate change.

Areas of spatial overlap between common bottlenose dolphin, recreational boating, and small-scale fishery: management insights from modelling exercises.

Sustainable management requires spatial mapping of both species distribution and human activities to identify potential risk of conflict. The common bottlenose dolphin (Tursiops truncatus) is a priority species of the European Union Habitat Directive, thus, to promote its conservation, the understanding of habitat use and distribution, as well as the identification and spatial trend of the human activities which may directly affect populations traits, is pivotal. A MaxEnt modeling approach was applied to predict the seasonal (from April to September) habitat use of a small population of bottlenose dolphins in the north-western Sardinia (Mediterranean Sea) in relation to environmental variables and the likelihoods of boat and fishing net presence. Then, the overlapping areas between dolphin, fishing net and boat presence were identified to provide insights for the marine spatial management of this area. Three of the main factors influencing the seasonal distribution of bottlenose dolphins in the area are directly (boating and fishing) or indirectly (ocean warming) related to human activities. Furthermore, almost half of the most suitable area for dolphins overlapped with areas used by fishing and boating. Finally, relying on fishing distribution models, we also shed light on the potential impact of fishing on the Posidonia oceanica beds, a protected habitat, which received higher fishing efforts than other habitat types. Modelling the spatial patterns of anthropogenic activities was fundamental to understand the ecological impacts both on cetacean habitat use and protected habitats. A greater research effort is suggested to detect potential changes in dolphin habitat suitability, also in relation to ocean warming, to assess dolphin bycatch and the status of target fish species, and to evaluate sensitive habitats conditions, such as the Posidonia oceanica meadow.

Discarded bottles entrap endemic small mammals species in a large Mediterranean island.

We examined the entrapment effect of discarded bottles on small mammals, along a road network located in North-Western Sardinia (Italy). On 162 bottles, 49 (> 30%) contained at least one animal specimen (invertebrate or vertebrate) and 26 (16%) entrapped 151 small mammals: insectivorous shrews (Soricomorpha) were more frequently recorded. Larger bottles (66cl.) showed a higher number of entrapped mammals, but difference was not significant when compared to smaller bottles (33cl.). Our data highlighted as abandoned bottles represent a threatening factor for small mammals on a large Mediterranean island with over-represented endemic shrews (predators of high trophic level) attracted by insects entrapped in bottles. Correspondence analysis suggest a weak segregation between bottles of different size, related to the abundance of the most entrapped species, the Mediterranean shrew (Crocidura pachyura). This still neglected type of litter, reducing number and biomass of insectivorous mammals of high trophic level and high ecological value may affect the food web in terrestrial insular communities, yet impoverished for biogeographical reasons. However, discarded bottles may represent as low-cost surrogate pitfall traps useful to improve knowledge in poor studied areas. Following the DPSIR (Driving force, Pressure, State, Impact, Response) approach as a framework to select indicator, we suggest as the effectiveness of removal clean-ups could be monitored using both the density of discarded bottles (as indicator of threat pressure) and the abundance of entrapped animals (as indicator of impact on small mammals).

A note on the acoustic assessment of bottlenose dolphin behaviour around fishing gears in the Asinara Island National Park, Italy

Common bottlenose dolphins co-exist with artisanal fisheries in the Asinara Island National Park area (northwestern Sardinia, Italy) and are blamed for damage to some fisheries. To investigate this, two T-POD echolocation loggers were used between July 2003 and October 2004 to monitor the occurrence and behaviour of dolphins in the proximity of three different fishing gear types. With the support of local fishermen, the T-PODs were opportunistically deployed on trammel nets set for striped red mullet or for lobster and on bottom traps set to catch benthic fish species. Inter-click Intervals (ICI) and the Pulse Repetition Frequency (PRF) have been adopted as indicators of dolphins echolocation behaviour in the proximity of fishing gears (Leeney and Tregenza, 2006). PRF values were found to be consistently higher in proximity to trammel nets for striped red mullets compared to the other gears. Moreover, ICI values in the proximity of red mullet trammel nets were found to be statistically lower than those recorded both around trammel nets for lobster (p&lt;0.01) and around traps (p&lt;0.01). These findings suggest that feeding related activities by dolphins could be absent or take place at very low levels in the proximity of traps and, to a lesser extent, in the proximity of trammel nets set for lobster, but may occur more regularly around nets for striped red mullet. The results show that static acoustic monitoring can detect significant differences in dolphin echolocation behaviour around different fishing gears. The findings seem to be consistent with previous evidence of interactions between bottlenose dolphins and fishing gear types in the area.

Mediterranean coastal wave-climate long-term trend in climate change scenarios and effects on the optimal sizing of OWC wave energy converters

This work assesses the effect of long-term changes in the wave climate on the optimal sizing and performances of oscillating water column wave energy converters along the coastline of the Mediterranean basin. Trends are evaluated based on the projections of future wave climate to 2100 delivered by the Climate Data Store of the Copernicus Climate Change Service under representative atmospheric emission scenarios. The capture width of the device under different wave conditions is computed using an empirical model capable of predicting the device performance with acceptable accuracy and limited computational time. The optimal geometry of the device varies significantly across the different geographical locations, with maximum values of the chamber size along the north African coasts and western Sardinia and Corse, and minimum values in the Adriatic and Aegean Seas. The effect of long-term change in the wave energy resource results in moderate modifications of the optimal geometry, with relative variations between present and future scenarios up to 10% of the size. The annual energy production of the device in the future scenario would significantly increase in most geographical locations, potentially contributing to reducing the Levelized Cost of Energy and favouring the economic competitiveness of this technology. • Effects of long-term changes in the wave climate on the performance of OWCs are studied. • Projections of future wave climate under IPCC emission scenarios are considered. • Trends in the wave power are significant in some Mediterranean locations. • The optimal device geometry in the present and future scenarios varies up to 10%. • The annual energy production in the future scenario could increases in most locations.

Spatial Patterns and Intensity of Land Abandonment Drive Wildfire Hazard and Likelihood in Mediterranean Agropastoral Areas

In Mediterranean agropastoral areas, land abandonment is a key driver of wildfire risk as fuel load and continuity increase. To gain insights into the potential impacts of land abandonment on wildfire risk in fire-prone areas, a fire-spread modeling approach to evaluate the variations in wildfire potential induced by different spatial patterns and percentages of land abandonment was applied. The study was carried out in a 1200 km2 agropastoral area located in north-western Sardinia (Italy) mostly covered by herbaceous fuels. We compared nine land abandonment scenarios, which consisted of the control conditions (NA) and eight scenarios obtained by combining four intensity levels (10, 20, 30, 40%) and two spatial patterns of agropastoral land abandonment. The abandonment scenarios hypothesized a variation in dead fuel load and fuel depth within abandoned polygons with respect to the control conditions. For each abandonment scenario, wildfire hazard and likelihood at the landscape scale was assessed by simulating over 17,000 wildfire seasons using the minimum travel time (MTT) fire spread algorithm. Wildfire simulations replicated the weather conditions associated with the largest fires observed in the study area and were run at 40 m resolution, consistent with the input files. Our results highlighted that growing amounts of land abandonment substantially increased burn probability, high flame length probability and fire size at the landscape level. Considering a given percentage of abandonment, the two spatial patterns of abandonment generated spatial variations in wildfire hazard and likelihood, but at the landscape scale the average values were not significantly different. The average annual area burned increased from about 2400 ha of the control conditions to about 3100 ha with 40% land abandonment. The findings of this work demonstrate that a progressive abandonment of agropastoral lands can lead to severe modifications in potential wildfire spread and behavior in Mediterranean areas, thus promoting the likelihood of large and fast-spreading events. Wildfire spread modeling approaches allow us to estimate the potential risks posed by future wildfires to rural communities, ecosystems and anthropic values in the context of land abandonment, and to adopt and optimize smart prevention and planning strategies to mitigate these threats.

Seasonal bird assemblages in Dehesas (substeppic prairies with Quercus suber) of North-Western Sardinia (Italy): A poorly studied landscape of high eco-biogeographic interest

Dehesas (i.e., substeppic prairies with Quercus suber) represent a poorly studied Mediterranean habitat type of high eco-biogeographic interest. Here, we applied a point-transect method along a yearly cycle (from spring to autumn), to focus on seasonal differences in bird assemblages inhabiting a Dehesas landscape in north-western Sardinia (Italy). We confirmed the presence of Mediterranean species with restricted ranges (e.g. Sturnus unicolor, Sylvia sarda). At the community level, seasonal patterns show significant differences among mean abundance, with a maximum in autumn and a minimum in summer. The highest values in autumn may be explained by the aggregations of wintering small passerines. Considering the univariate metrics of diversity, the number of species significantly differs among seasons, with the richest community in spring. Shannon-Wiener diversity and Margalef (normalized richness) were higher in spring and summer compared to autumn. Habitat heterogeneity of these landscape mosaics, driven by historical agro-pastoral practices (fires and pastures), together with the presence of patchy 'key structures', positively affects bird species richness and abundance, improving, respectively, the number of niches and resources. More resource effort should be devoted to study these habitat types recently interested in an increased anthropogenic pressure (urban sprawl and road infrastructures, location of wind power plants, etc.).&nbsp

Gradients of salinity and plant community richness and diversity in two different Mediterranean coastal ecosystems in NW Sardinia.

This study aimed to test if differences in soil salinity, plant richness and diversity were significantly affected by habitat, site and distance from the seashore at three sandy and three rocky coastal sites in north-western Sardinia.Each site has been divided into three belts placed at an equal distance of 50 m from the shoreline. We measured soil salinity using a probe and vascular plants richness and diversity using linear transects at all sites. Average soil salinity varied from 0.115 g/l to 0.180 g/l; it was higher in the rocky habitats than in the sandy ones. A total of 21 species were found per transect/site at the rocky sites and 30 species per transect/site at the sandy sites, with an average of Shannon and Weaver's Diversity Index of 1.8 per each belt at each site. These data confirm that, also in the Mediterranean islands, there are coastal gradients of soil salinity from the seashore to inland areas and that also vascular plant richness and diversity are influenced by the distance from the sea. Soil salinity was strongly affected by the type of habitat, being average at the rocky coasts and negligible at the sandy shores. The site effect was not significant for both soil salinity and plant richness and diversity.

How does soil carbon sequestration affect greenhouse gas emissions from a sheep farming system? Results of a life cycle assessment case study

A life cycle assessment (LCA) study of a transition from semiintensive to semi-extensive Mediterranean dairy sheep farm suggests that the latter has a strong potential for offsetting greenhouse gas (GHG) emissions through the soil C sequestration (Cseq) in permanent grasslands. The extensification process shows clear environmental advantage when emission intensity is referred to the area-based functional unit (FU). Several LCA studies reported that extensive livestock systems have greater GHG emissions per mass of product than intensive one, due to their lower productivity. However, these studies did not account for soil Cseq of temporary and permanent grasslands, that have a strong potential to partly mitigate the GHG balance of ruminant production systems. Our LCA study was carried out considering the transition from a semiintensive (SI) towards a semi-extensive (SE) production system, adopted in a dairy sheep farm located in North-Western Sardinia (Italy). Impact scope included enteric methane emissions, feed production, on-farm energy use and transportation, infrastructures as well as the potential C sink from soil Cseq compared to emission intensity. In order to provide a more comprehensive analysis, we used the following FUs: 1 kg of fat and protein corrected milk (FPCM) and 1 ha of utilised agricultural area (UAA). We observed that the extensification of production system determined contrasting environmental effects when using different FUs accounting for soil Cseq. When soil Cseq in emission intensity estimate was included, we observed slightly lower values of GHG emissions per kg of FPCM in the SI production system (from 3.37 to 3.12 kg CO2 equivalents – CO2-eq), whereas a greater variation we observed in the SE one (from 3.54 to 2.90 kg CO2-eq). Considering 1 ha of UAA as FU and including the soil Cseq, the emission intensity in SI moved from 6257 to 5793 kg CO2-eq, whereas values varied from 4020 to 3299 kg CO2-eq in SE. These results indicated that the emission intensity from semi-extensive Mediterranean dairy sheep farms can be considerably reduced through the soil Cseq, although its measurement is influenced by the models used in the estimation. Highlights - Extensification of dairy sheep systems provides an environmental benefit when soil C sequestration is considered. - Extensification of dairy sheep systems determines lower environmental impact per hectare of utilized agricultural area. - Enteric methane emissions are the main source of GHG emissions of the sheep milk life cycle. - Carbon sequestration in permanent grasslands can considerably contribute to climate change mitigation.

Common Bottlenose Dolphin Protection and Sustainable Boating: Species Distribution Modeling for Effective Coastal Planning

Indicators for preserving marine biodiversity include knowledge of how the spatial distribution and critical habitats of species overlap with human activities and impacts. Such indicators are key tools for marine spatial planning, a process that identifies and resolves conflicts between human uses and the conservation of marine environments. The common bottlenose dolphin in the Mediterranean Sea is considered a vulnerable species by the IUCN Red List and a priority species of the EU Habitat Directive. Here, we estimated spatio-temporal patterns of the species occurrence in the area around one Marine Protected Area (MPA) and two Sites of Community Importance (SCI) of the North western Sardinia, with the aim to predict the species distribution and the main links with the environmental factors and boat traffic. To evaluate whether dolphin groups with calves showed any habitat preference different from groups without calves, separate models for both type of groups were done. The most important contributing variables to the dolphin habitat suitability models were the likelihood of boat presence, habitat type and mean sea surface temperature. Different model outputs were obtained depending on dolphin group composition. The area of high likelihood of dolphin presence ranged between 30 and 60 km2 and was smaller for groups with calves. Further, the area of highest dolphin habitat suitability overlaps with the area of high boat traffic, suggesting that boating in the study site is a potential relevant anthropogenic threat to dolphins. Particularly, boating is concentrated inside and around the MPA/SCIs, indicating the need for stronger restriction measures. We propose updated SCI boundaries for effective protection of common bottlenose dolphins. These areas and the suggestions of regulation are specifically aimed at reducing the impact of boating on dolphins, especially for groups with calves. Synthesis and applications. Management measures should be designed based on the data here provided, and then implemented and enforced to decrease dolphin-boat interactions, especially for mother-calf pairs. The creation of new coastal SCIs should be considered especially where boat traffic overlaps with areas most suitable for dolphins. In these SCIs, boating should be managed to limit disturbance, avoidance or alterations of dolphin vital behaviour.

Tetrapod tracks from the Middle Triassic of NW Sardinia (Nurra region, Italy)

We report here on the first tetrapod tracks from the Triassic of the Nurra region (north-western Sardinia, Italy). The specimens were found on sandstone blocks used to build a fence limiting a seasonal camping, in the coastal area north of Capo Caccia promontory. Lithologic and petrographic features allowed an assignment of the track-bearing blocks to the middle-upper portion of the Anisian (Middle Triassic) Arenarie di Cala Viola (Buntsandstein). Footprints are attributed to the ichnotaxa Rhynchosauroides and Rotodactylus, two common ichnotaxa of late Early Triassic and Middle Triassic ichnofaunas of Europe and United States, commonly referred in the literature to neodiapsid and archosaur producers, respectively.

Amphibole growth from a primitive alkaline basalt at 0.8 GPa: Time-dependent compositional evolution, growth rate and competition with clinopyroxene

Amphibole growth rates were experimentally determined at hydrous (3.3–4.2 wt% H2O), isobaric (0.8 GPa) conditions, variable temperature (1030 and 1080 °C) and dwell time (0.25, 3, 6, and 9 h), using as starting material a primitive alkaline basalt from Procida island (Campi Flegrei Volcanic District, south Italy). Amphibole growth rates decrease from 1.5·10−7 to 2.9·10−8 cm s−1 as the duration of the experiments increase from 0.25 to 9 h. Moreover, increasing both temperature and water content leads to similar growth rate increase at constant dwell time. The comparison between amphibole and clinopyroxene growth rates determined at the same experimental conditions reveals for amphibole a faster growth relatively to the coexisting clinopyroxene, regardless of the dwell time. Furthermore, the experimental time appears to be a critical parameter for the composition of synthetic amphiboles; specifically, edenite is the dominant composition in short experiments (≤3 h), particularly, at low temperature (1030 °C), whereas the magnesiohastingsitic amphibole becomes progressively more important shifting towards longer duration and higher temperature run conditions. The magnesiohastingsite, on the basis of the amphibole-liquid Fe-Mg exchange coefficient values, results to be the compositional term representative of amphibole-melt equilibrium at the investigated P-T-H2O conditions. Finally, experimental growth rates from this study have been used to investigate the crystallization time of natural amphiboles and clinopyroxenes from the Oligo-Miocene cumulates of north-western Sardinia (i.e. Capo Marargiu Volcanic District, Italy), yielding crystallization times of 1.46–3.12 yr.

Effects of pre and post-veraison water deficit on Vermentino cluster microclimate and berry composition

The influence of light and thermal microclimate on berry quality of a Vermentino vineyard, managed with deficit irrigation strategies in north-western Sardinia, was analyzed. Two water deficit, pre- (ED) and post-veraison (LD), an irrigation (IC) and a non-irrigation (NC) control treatments were compared during berry development. Grapevine performances were evaluated by analyzing leaf gas exchange, source-sink balance, light and thermal microclimate effects on berry composition. Early and/or late deficit irrigation following a mild to moderate water stress threshold enabled high leaf physiological performances. Though with high stomatal conductance sensitivity to water deficit and anisohydric behavior, this variety exhibited high assimilation rate and quick recovery capacity after enduring moderate and severe water stress. All treatments achieved satisfactory sugar and acidic levels. Berry phenols were higher in LD due to lower canopy coverage and better light conditions compared to IC. Up to mid-ripening, cluster exposure to elevated temperatures negatively influenced phenolic accumulation, mostly in NC and to a lower extent in ED. In the last ripening weeks, total phenols was majorly influenced by light interception.

Foxes provide a direct dispersal service to Phoenician junipers in Mediterranean coastal environments: ecological and evolutionary implications

Background and aims – Exploring the role of mammalian carnivores as seed dispersers in Mediterranean environments is crucial for understanding biotic interactions and preserving mutualistic networks in areas with high biodiversity. We examine the potential role of the Sardinian fox ( Vulpes vulpes subsp. ichnusae ) as a seed-disperser of two juniper species ( Juniperus phoenicea subsp. turbinata and J. oxycedrus subsp. macrocarpa ) in Mediterranean coastal environments.Methods – Observational and manipulative experiments were conducted in five coastal sites in north-western Sardinia (Italy) between 2010 and 2013.Key results – We found that Sardinian fox actively disperses seeds of J. phoenicea subsp. turbinata, whereas no evidence was obtained for the fox dispersing seeds of J. oxycedrus subsp. macrocarpa. Fox scat contained, on average, 73–86 J. phoenicea subsp. turbinata seeds, accounting 16.3–17.8 % of the average dung weight. The role of Sardinian fox as a primary disperser of J. phoenicea subsp. turbinata is by directly dispersing juniper seeds (via defecation) to a specific microhabitat (i.e. 80–90 % of dung was released on dwarf plants, mainly Helichrysum italicum subsp. microphyllum ), which positively affected the survival of emerged seedlings). We quantified that fox dispersed 30 to 100 seeds per day per hectare (3 500–10 500 seeds per hectare in one winter season).Conclusions – We reported that Sardinian fox is a direct disperser of J. phoenicea subsp. turbinata, thus playing a major role in secondary successional dynamics in Mediterranean coastal environments. Evolutionary implications are discussed, in that the positive interaction between Sardinian fox and J. phoenicea subsp. turbinata could be recent, following the introduction of fox to the Tyrrhenian islands during the 7 th –6 th millennium BC.

Effects of vineyard floor cover crops on grapevine vigor, yield, and fruit quality, and the development of the vine mealybug under a Mediterranean climate

The influence of complete cover cropping (inter- and intra-row) on grapevine growth, yield and must quality was evaluated in a three-year field trial in a commercial vineyard in northwestern Sardinia (Italy). Effects on developmental and reproductive parameters of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), were also investigated. The cover crop treatments were: natural covering, legume mixture, grass mixture, and conventional soil tillage, which was included as the reference treatment. Relative to soil tillage, cover crops reduced grape production by modifying yield components in different ways: legume mixture reduced the cluster weight, whereas grass mixture led to a lower number of clusters per vine coupled with a lower cluster weight. Cover crops also altered the must qualities relative to soil tillage. Grass mixture increased the content of sugar, anthocyanins and polyphenols, whereas legume mixture and natural covering reduced total polyphenols and anthocyanin content, respectively. All the P. ficus biological parameters examined were affected by the floor management practices. Mealybugs reared on grapevines subjected to soil tillage and legume covering showed a faster development time and higher survival, fecundity and fertility than those developed on natural covering and grass plots. The vine mealybug showed a higher performance on grapevines with a higher nitrogen content and vigor. Effects of cover crop treatments appear to be mediated through nutrient availability and content in grape plants. Consequently, utilizing competitive cover crops, while reducing yields, would improve must quality and reduce pest development.