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Over the last years, world cities have emerged as multiple and complex habitats hosting numerous and varied urban refugia for biodiversity. Therefore, the published literature was systematically reviewed to investigate the increasingly acknowledged role of many urban habitats to function as refugia for species. Many plants and animals were reported to colonize a variety of urban environments: Urban forest/grassland (natural/seminatural), City park, Historical park (villa garden, botanical gardens, cemeteries, etc.), Green spaces (abandoned areas, railways, line of trees, etc.), Water body, and Built area. Refugia were found in over a hundred world cities, especially in medium- to very big-size cities. The number of papers focusing on animals (n = 66) were higher than those regarding plants and mushrooms (n = 19 and n = 1, respectively); however, the number of species recorded within refugia were the highest for plants. Plants exhibited the highest frequency (7 out of 19 papers) in Historical park, while animals in Urban forest/grassland (20 out of 66 papers). In most studies (25.9%), urban refugia were linked to Urban forest/grassland that is terrestrial natural and seminatural sites widespread within or around cities. The 22.3% of studies referred to generic Green spaces of several types interspersed within cities, both public and private. The 14.1% of refugia were found in Built area (artificial). About the 33% of studies reported the presence of species worthy of conservation (rare, endemic, endangered, or protected) for a total of 365 species. The 20% of investigated papers reported the presence of alien species for a total of 879 species. Invasive alien species recorded within refugium areas should be subjected to control measures to prevent degradation to refugia. Overall, the capability for urban areas to host a huge amount of biodiversity needs to be acknowledged by city planners so that management practices that maintain and support such diversity can be pu

Diesel contamination of farming soils is of great concern because hydrocarbons are toxic to all forms of life and can potentially enter the food web through crops or plants used for remediation. Data on plant ability to uptake, translocate and accumulate diesel-derived compounds are controversial not only due to the probable diverse attitude of plant species but also because of the lack of a reliable method with which to distinguish petrogenic from biogenic compounds in plant tissues. The purpose of this study was to set up a GC-MS-based protocol enabling the determination of diesel-derived hydrocarbons in plants grown in contaminated soil for assessing human and ecological risks, predicting phytoremediation effectiveness and biomass disposal. To this end, two plant species, Vicia sativa L. and Secale cereale L., belonging to two diverse vascular plant families, were used as plant models. They were grown in soil spiked with increasing concentrations of diesel fuel, and the produced biomass was used to set up the hydrocarbon extraction and GC-MSD analysis. The developed protocol was also applied to the analysis of Typha latifolia L. plants, belonging to a different botanical family and grown in a long-time and highly contaminated natural soil. Results showed the possibility of distinguishing diesel-derived compounds from biogenic hydrocarbons in most terrestrial vascular plants, just considering the total diesel compounds in the n-alkanes carbon range C10–C26, where the interference of biogenic compounds is negligible. Diesel hydrocarbons quantification in plant tissues was strongly correlated (0.92 < r2 < 0.99) to the concentration of diesel in spiked soils, suggesting a general ability of the considered plant species to adsorb and translocate relatively low amounts of diesel hydrocarbons and the reliability of the developed protocol.

Harmful algal blooms (HABs) have increased in frequency, but despite an extreme increase in research on this topic, general knowledge on HABs is still scarce. Mucilaginous algal blooms, in particular, are ever more present and can heavily affect marine ecosystems. Gorgonians appear significantly affected, as their branches are easily entangled (pelagic aggregates) and overgrown (benthic aggregates) by mucilage. Moreover, their proximity to the bottom makes them susceptible to benthic anoxia. In the present study, we investigated the mucilaginous bloom that affected the gorgonian forests of Tavolara Punta Coda Cavallo Marine Protected Area (MPA) (NE coast of Sardinia) in summer 2020. We focused mainly on the characterization of dominant benthic microalgae, identifying those responsible for the bloom. Sampling was performed considering the colonies of Paramuricea clavata present on hard substrata along 2 transects near the Secca del Papa, in the B Zone of the MPA. The characterization of the microalgal community and the count of the most abundant species (>10 cells ml−1) were carried out using the Utermöhl sedimentation method. The community was mainly composed of diatoms (Bacillariophyta) belonging to the genera Pseudo-nitzschia, Nitzschia and Cylindrotheca. C. closterium appeared to be the most abundant species. These results confirm the importance of diatoms during Tyrrhenian mucilaginous blooms, which could be particularly harmful to gorgonians.

Mediterranean rhodolith beds are priority marine benthic habitats for the European Com-munity, because of their relevance as biodiversity hotspots and their role in the carbonate budget. Presently, Mediterranean rhodolith beds typically occur within the range of 30–75 m of water depth, generally located around islands and capes, on flat or gently sloping areas. In the framework of a collaboration between the University of Milano-Bicocca and the Marine Protected Area “Capo Carbonara” (Sardinia, Italy), video explorations and sampling collections in three selected sites revealed the occurrence of a well developed and heterogeneous rhodolith bed. This bed covers an area >41 km2 around the cape, with live coverage ranging between 6.50 and 55.25%. Rhodoliths showed interesting morphostructural differences. They are small compact pralines at the Serpentara Island, associated with gravelly sand, or bigger boxwork at the Santa Caterina shoal associated with sand, whereas branches are reported mostly in the Is Piscadeddus shoal, associated with muddy sand. Both in the Santa Caterina shoal and the Serpentara Island, rhodoliths generally show a spheroidal shape, associated with a mean value of currents of 4.3 and 7.3 cm/s, respectively, up to a maximum of 17.7 cm/s at Serpentara, whereas in the Is Piscadeddus shoal rhodolith shape is variable and current velocity is significantly lower. The different hydrodynamic regime, with a constant current directed SW, which deviates around the cape towards E, is responsible for such morphostructural heterogeneity, with the site of the Serpentara Island being the most exposed to a constant unidirec-tional and strong current. We can associate current velocity with specific rhodolith morphotypes. The morphostructural definition of the heterogeneity of rhodoliths across large beds must be considered for appropriate management policies.

Experimental evidence on the bio-ecological effects of microplastics on terrestrial plants is still lacking. In this study, we hypothesized that soil polluted with polyvinyl chloride (PVC) microparticles can negatively influence plant traits, photosynthetic efficiency and phenology of two weeds but with different strength in relation to the species’ life traits. Therefore, we conducted an experiment in a common garden growing the wild species Senecio inaequidens and Centaurea cyanus for about 60 days. The possible toxic effects of soil microplastics (1% of PVC in 100 g of soil medium) were investigated, coupling an analyses on plant traits with an evaluation of the microplastic-induced changes in terms of phenology and photosynthetic efficiency. Overall, results showed that plants in control pots were higher and larger than those in treated ones (C. cyanus plant width: p < 0.05; S. inaequidens—plant height: p < 0.05; plant width: p < 0.05). Moreover, for C. cyanus, photosynthetic efficiency (index Fv/Fm) was significantly lower in the treatment than that in control (p < 0.05). About phenology, the second leaf of S. inaequidens emerged earlier in control than that in treatments (day 12.2 ± 0.25 and 14.3 ± 0.3, respectively; p < 0.001). The obtained results highlight that PVC microparticles may have had negative effects on soil–plant system reducing the performance of plants. Since, up to now, research on the interaction between soil microplastics and terrestrial plants has mainly focused on agricultural plants, this work fills a gap of knowledge regarding wild species (weeds), highlighting the possible future impact of microplastics on biodiversity.

Invasive alien plants may profoundly transform ecosystems over wide areas. The study aimed to assess how the invader Reynoutria bohemica could transform ecosystem components of a native riparian forest in Northern Italy, after about 20 years of invasion. We selected 20 forest sites where we set up two 1 x 1 m plots, one in an invaded and one in a non-invaded patch. Subsequently, we surveyed the properties of litter and mineral soil, soil biological quality (QBS-ar), diversity of plant and microarthropod communities and light intensity at the ground level. To determine if the invader affected the quality of herb layer, we selected the native herb Allium ursinum as the indicator species of good quality forest stand and measured its traits in the paired plots. Following the application of linear mixed effects models, the invaded and non-invaded plots showed differences in soil characteristics and plant community: the thickness of the organic horizon, soil C:N and available P were higher in invaded plots, whereas diversity, light intensity, Allium ursinum abundance and its vegetative vigour were found to be lower. Microarthropod communities and QBS-ar were modestly influenced by R. bohemica. Redundancy analysis of plant community composition indicated that soil C:N and plant richness were the variables most linked to species invasion. This study highlights the ability of R. bohemica to transform certain ecosystem components in native riparian forests, after just a few decades since its first invasion, thereby underlining the need to implement measures to control its spread.

Alien species are among the five drivers of environmental change with the largest relative global impacts. In particular, horticulture is a major introduction pathway of alien plants, but, together with intentional introductions, plants can also be introduced and spread via human-mediated involuntary pathways as contaminants and stowaways. Recurring accidental introductions of alien plants to new areas can be the prelude to invasion on a large scale. Agriculture represents a sector that is severely impacted by invasive alien species and, at the same time, it is likely to be one of the main factors responsible of biological invasions. So, the present review highlights risks related to accidental introduction though human-mediated agricultural pathways of a politically relevant group of alien plants, invasive alien plants of Union concern (IAPUC), that are species whose prevention and management is mandatory in the European Union according to Regulation (EU) n. 1143/2014. Even if most IAPUCs have been primarily introduced as economic plants, several accidental pathways related to agriculture can be identified for each one of them. The implementation of technologies and the sharing of good practices, at a wide scale and at different levels of the society, would help in overcoming several problematic issues related to the accidental transport of IAPUCs.

Niche dynamics represent an important element in predicting potential invasion areas of alien species and their impacts as well as in understanding mechanisms underlying invasion success. Pueraria lobata, commonly named “kudzu”, is an Asian vine and one of the 100 worst invasive species in the world. In Europe, it is a serious pest although its distribution is quite localized. At present, no detailed information about niche dynamics following its introduction to Europe is available, so it is not known whether the plant has shifted its niche or not, as well as whether it has filled the whole available climatic niche. To fill this gap of knowledge, we applied the unified COUE (i.e., centroid shift, overlap, unfilling, and expansion) framework to evaluate the shift in the climatic niche in the invasive with respect to the native range. According to our analysis, kudzu showed climatic niche conservatism following its introduction to Europe: we detected a shift in the position of centroids of native and invasive niche of kudzu, likely due to a difference in climate availability rather than to a colonization of novel climatic conditions. In Europe, kudzu is occupying a subset of the climate of the native range, mainly characterized by colder and drier conditions than those characterizing the Asian Pacific range of the plant. These conditions are marginal and rarely experienced by the plant in its native range. Furthermore, the absence of any niche expansion indicates that a spread to novel climates should be excluded for the European kudzu. The high niche unfilling suggests that kudzu has not yet occupied the majority of suitable climates available in Europe, even if, climatic conditions similar to its native range are not so widespread in Europe. Multivariate environmental similarity surface analysis suggests that it may expand its European range. Thus, it is pivotal that measures of prevention, early detection and monitoring are timely and effectively implemented to avo

Anthropic diesel-derived contamination of Mediterranean coastal waters is of great concern. Nature-based solutions such as phytoremediation are considered promising technologies to remove contaminants from marine environments. The aim of this work was to investigate the tolerance of the Mediterranean autochthonous seaweed Caulerpa prolifera (Forsskal) Lamouroux to diesel fuel and its hydrocarbon degradation potential. Changes in C. prolifera traits, including its associated bacterial community abundance and structure, were determined by fluorescence microscopy and next-generation sequencing techniques. Thalli of C. prolifera artificially exposed to increasing concentration of diesel fuel for 30 days and thalli collected from three natural sites with different levels of seawater diesel-derived hydrocarbons were analysed. Gas chromatography was applied to determine the seaweed hydrocarbon degradation potential. Overall, in controlled conditions the lower concentration of diesel (0.01%) did not affect C. prolifera survival and growth, whereas the higher concentration (1%) resulted in high mortality and blade damages. Similarly, only natural thalli, collected at the most polluted marine site (750 mg L−1), were damaged. A higher abundance of epiphytic bacteria, with a higher relative abundance of Vibrio bacteria, was positively correlated to the health status of the seaweed as well as to its diesel-degradation ability. In conclusion, C. prolifera tolerated and degraded moderate concentrations of seawater diesel-derived compounds, especially changing the abundance and community structure of its bacterial coating. The protection and exploitation of this autochthonous natural seaweed-bacteria symbiosis represents a useful strategy to mitigate the hydrocarbon contamination in moderate polluted Mediterranean costal environments.

Horticulture is a major pathway of introduction of aquatic plants. Among traded aquatic plants, we found two species belonging to the genus Lagarosiphon Harv. (Hydrocharitaceae), native to South and Central Africa, L. major (Ridl.) Moss and L. cordofanus Casp. L. major is the main representative of the genus, having already been introduced via horticulture sale beyond its native range, and often becoming invasive. In contrast, L. cordofanus is a lesser-known congener that could be potentially sold as an alternative to L. major. It is relatively understudied, and has yet to be recorded in the wild outside its native range. Many factors can promote the invasiveness of an alien plant; among them, increased nutrient availability often facilitates opportunistic alien species such as L. major. In a horizon-scanning perspective, a manipulative experiment under controlled conditions was performed to test the response of L. cordofanus to different trophy levels using L. major as the tolerant alternative species. According to our results, the naturalization of L. cordofanus in temperate shallow waters does not seem likely, especially if considered in comparison to L. major.

The green alga Caulerpa cylindracea Sonder (Chlorophyta; Bryopsidales) is one of the most invasive alien macroalgae in the Mediterranean Sea, where it is also spreading on rhodolith beds, an important biogenic assemblage typical of deep substrates. Despite the importance of rhodoliths, data on the competitive interactions with C. cylindracea are still scarce. To deepen the knowledge on the topic, C. cylindracea occurrence on the rhodolith bed of Capo Carbonara Marine Protected Area (Italy) was explored. Quantitative analyses of videoframes obtained from Remote Operated Vehicle records in three different MPA sites, Is Piscadeddus, Santa Caterina, and Serpentara, allow for estimates of both the cover of rhodoliths (considering the main morphotypes) and of C. cylindracea, as well as their competition. All sites showed a well-developed rhodolith bed, although some differences were highlighted in their composition in terms of morphotype, shape, and dimension of rhodoliths, as well as in the C. cylindracea cover. In particular, Santa Caterina appeared to be the site with the highest mean total cover of rhodoliths (68%), and of C. cylindracea (25%). The obtained results suggest that different competitive interactions occur between C. cylindracea and rhodolith beds, in relation to the morphostructural composition of the latter and in response to environmental conditions that affect rhodolith bed composition.

The investigation of plant assemblages growing in urban ecosystems offers the chance to observe new interactions among biodiversity, urban planning and public health, in the context of a changing world with increasing city surfaces and populations. In this context, the aim of this work is the study of floristic, ecological and functional diversity of land use types of Milan, such as a) Built-up areas (urbanized and productive zones), b) Roads (borders and flowerbed of main boulevards and avenues), c) Railways (tracks borders, stations and adjacencies) and d) Green areas (parks, gardens, and orchards). A floristic survey was performed through stratified sampling and a floristic database was built. The following bioecological information was added to each sampling location: species richness, %alien species, úmilies, %life forms, functional diversity, %Grime's CSR strategies, Ellenberg's indicator values (EIVs), urbanity index and functional diversity estimators. Differences among land use types were detected with linear mixed models. In total, about 300 taxa were recorded, and 34 % of the species surveyed were aliens. The Railways were prominent with regard to several traits such as floristic richness, number of insect-pollinated species, mean EIV for light and soil reaction and functional diversity estimators. On the other hand, the urbanity index was the lowest in Railways. In general, Urban areas and Roads had lower trait values, while Green areas had intermediate performances. Our results showed that despite the expected high presence of ruderal and alien species, typical of disturbed environments, the urban landscapes of Milan are diversified in their ecological functions and included areas rich in uncommon species limited to peculiar habitats. The railway landscape of Milan represents a reservoir and refuge for many native species, incorporating microhabitats not present in other city landscapes. Therefore, railway areas should be included in the planning of gr

The aim of this study was to define the simplest and least expensive protocol for total protein extraction for three different macroalgae of the genus Caulerpa (the invasive C. taxifolia and C. cylindracea and the autochthonous C. prolifera). Five multi-step protein extraction procedures, set up for other macroalgal species, were tested. For each of them, different pre-treatment and extraction conditions were simultaneously examined, according to a factorial design, considering the starting material, the solvent-to-biomass ratio, and the incubation temperature. Protein yield in the obtained extracts was estimated with the Bradford method. Further, polyacrylamide gel electrophoresis (SDS-PAGE) was used to resolve proteins, assessing their quality and integrity. Significant differences in protein yield were observed among the extraction protocols and the conditions tested, also in relation to the considered species. Profiles having an acceptable quality were obtained for C. prolifera and C. cylindracea, and from the obtained results, the best method to obtain high yield and quality protein extracts for the two above-mentioned species appears to require the use of a primary TCA/acetone extraction buffer followed by a lysis buffer with NaCl, KCl, urea, Triton, SDS and a protease inhibitor. The best results, in particular, were obtained starting from fresh pulped material with a buffer-to-biomass ratio of 10:1 and an incubation temperature of 4°C. For C. taxifolia, instead, none of the tested protocols produced satisfactory results and further studies will be required.

Background: Although abnormalities in gut microbiota are hypothesized to influence the pathogenesis and clinical phenotype of Parkinson's disease (PD), prospective studies on de novo patients are lacking. Objective: To preliminarily investigate whether gut microbiota in early untreated PD may predict motor and non-motor features progression over a 3-year period. Methods: 16S ribosomal RNA gene amplicons were sequenced on fecal samples of 39 de novo PD patients. Multiple confounders were taken into account, including dietary habits. Motor and non-motor symptoms were assessed using validated scales at baseline and followed-up yearly for 3 years. At last follow-up, a detailed neuropsychological assessment was additionally performed. A general linear model for repeated measurements-adjusted by dopaminergic therapy at followup-was used to investigate the relationship between bacterial taxa abundance at baseline (stratified by the median of distribution at baseline) and outcome variables. Results: Twenty-five patients were included (11 refused, 2 lost at follow-up, 1 died). Lower abundance of Roseburia (Firmicutes phylum) at baseline was associated with worse evolution of motor, non-motor and cognitive functions at 3-year follow-up. Similarly, lower abundance of Ruminococcaceae and Actinobacteria at baseline was associated with faster worsening of global cognitive functions. At follow-up, frontal lobe functions were the features most robustly associated with baseline microbial abnormalities. Conclusion: In the present exploratory study on de novo PD, we found an association between abnormal distribution of specific bacterial taxa and the progression of motor and non-motor features over a 3-year period. This proof-of-principle study supports the design of a larger observational study aiming to determine whether these differences survive multiple-comparison correction and define microbiota-specific subgroups suitable for therapeutic targeting.

Background: The so-called “thunderstorm asthma” (TA) is an uncommon but dramatic outbreak of asthma attacks occurring during a thunderstorm in the pollen and moulds season. Mechanisms which make the pollen able to enter the deeper airways and provoke severe asthma symptoms are still unclear. Objective: To test the hypothesis that sub-pollen particles (SPPs) originated from the rupture by an osmotic shock of pollen associated with TA contain allergens. Methods: After hydration, SPPs released from pollen grains of grass, pellitory, olive, cypress, ragweed and birch were isolated and determined by microscopy. Allergens were determined by in vitro ELISA inhibition tests indirectly using the sera from 10 polyreactive patients. An inhibition <50% was considered as negative, 50%-75% moderate and > 75% complete. Results: The inhibition experiments showed that the SPPs from birch and cypress were unable to inhibit serum IgE reactivity to Bet v 1 and Cup a 1, respectively. Ragweed SPPs inhibited ragweed pollen extract and Amb a 1 by 75.8 ± 0.11% and 81.2 ± 0.15%, respectively. Olive and pellitory SPPs retained almost the whole IgE-binding capability in all cases tested. Grass SPPs inhibited 32 ± 0.06% of Lolium perenne Lol p 1 and 65% of Phleum pratense extracts, but results were highly variable for individual allergens (97.5%-0.03% for Phl p 2, 45.3 ± 0.12% for Phl p 5, 24.7 ± 0.22% for Phl p 6, and 38.3 ± 0.2% for Phl p 1). Conclusions: Inhibition experiments confirm the hypothesis that SSPs obtained after the osmotic shock of pollen involved in TA, namely grass, pellitory and olive tree pollen, contain allergens and therefore they can induce severe asthma attacks during thunderstorms.

Using native seed mixtures to create or recover grassland habitats in rotation to crops or in strips surrounding fields is considered a cost-effective practice to enhance ecosystem resilience and agro-biodiversity. The aim of this research was to assess the effects of native hayseed mixtures on plant and microarthropod communities in an agricultural area of Northern Italy. Three different experimental treatments were set up. The first was a control (C) (i.e., non-seeded plots left to spontaneous vegetation succession after ploughing no deeper than 15 cm). The second, hayseed seeded (Hs) after ploughing no deeper than 15 cm. The third experimental treatment was hayseed overseeded (Ov) on the resident plant community after only a superficial harrowing. Ov plots exhibited the preeminent positive effects on the total productivity and quality of the grassland in terms of total vegetation cover, cover and richness of typical grassland species (i.e., Molinio- Arrhenatheretea species), and cover of legumes, grasses and perennial species. Moreover, Ov sites exhibited the highest abundance of microarthropod taxa and soil biological quality (QBS-ar) but only in spring, when the disturbance of ploughing negatively affected Hs and C plots. On the other hand, Hs sites showed a great reduction of invasive alien (i.e., Ambrosia artemisiifolia and Artemisia verlotiorum) and segetal weed species (i.e., Capsella bursa-pastoris and Spergula arvensis) in terms of cover. This study provides valuable indication on using hayseed mixtures to create grassland habitats as reservoir of native flora and soil biodiversity in agriculture areas.

According to projects and practices that the Italian botanists and ecologists are carrying out for bringing “more nature in the city”, new insights for a factual integration between ecological perspectives and more consolidated aesthetic and agronomic approaches to the sustainable planning and management of urban green areas are provided.

Background: Ambrosia artemisiifolia L. is one of the most important sources of allergenic pollen in many regions of the world. Its health impact increased over the last decades and is expected to further increase in consequence of climate change. However little information is available on the specific role played by temperature on allergy rising. The aim of this work was to evaluate the effect of temperature on A. artemisiifolia growth, flowering and pollen allergenicity, the major plant functional traits influencing the prevalence and severity of pollinosis. Results: Plants were grown in controlled conditions at three thermal regimes: "Low" (LT: 18-14 °C light-dark), "Intermediate" (IT: 24-20 °C light-dark) and "High" (HT: 30-26 °C light-dark). During plant development, plant vegetative and reproductive morpho-functional traits were measured and, at the end of plant life-cycle, mature pollen was collected and analyzed for its allergenic properties by slot blot, 1D- and 2D-western blot (by using a pool of sera from ragweed-allergic patients) and liquid chromatography-tandem mass spectrometry. A. artemisiifolia showed a great development plasticity leading to a broad temperature tolerance. Shoot architecture, growth rate, number of male inflorescence and pollen allergenicity were temperature-responsive traits. Pollen allergenicity increased in parallel with temperature and differences were related to allergen synthesis and Amb a 1-IgE-binding. Flavonoids whose concentration in pollen decreased with the increase of temperature, were recognized as the cause of the negligible Amb a 1-IgE binding in LT pollen. Conclusions: Results show that temperature governs plant development and pollen allergenicity influencing the temporal and spatial magnitude of subject exposure to allergens.

This paper focuses on the interactive short and long-term effect of three different stressors on a macroalgal assemblage. Three stressors are considered: herbivory, nutrients and mucilage. The experiment was conducted in Tavolara Punta Coda Cavallo Marine Protected Area (Mediterranean Sea) during a bloom of the benthic mucilage-producing microalga Chrysophaeum taylorii (Pelagophyceae); this microalga is recently spreading in the Mediterranean Sea. On a rocky substratum, 36 plots 20 x 20 cm in size were prepared. Factorial combinations of three experimental treatments were applied in triplicate, including three grazing levels crossed with two nutrient enrichment and two mucilage removal treatments. Significant differences were observed among treatments 8 weeks later, at the end of summer. In particular, dark filamentous algae were more abundant in all enriched plots, especially where mucilage and macroalgae had been removed; a higher percent cover of crustose coralline algae was instead observed where nutrients had been increased and no grazing pressure acted. Furthermore, the abundance of Dictyota spp. and Laurencia spp. was significantly higher in enriched mucilage-free plots where the grazing pressure was null or low. However, the effects of the treatments on the overall assemblage of the macroalgal community were not long persistent (36 weeks later). These results illustrate the capacity of a shallow-water macroalgal community to quickly recover from the simultaneous impacts of herbivory, nutrient enrichment, and mucilage.

Allergen-containing subpollen particles (SPPs) are micrometric or sub-micrometric particles (0.12–5 µm) released from pollen. They are able to reach the lower airways, causing allergenic reactions. SPP release occurs through the pore of intact grains or by rupture of the whole grain. In this paper the results of two laboratory experiments investigating the dynamics of SPP release for three alien species of Ambrosia genus are shown. Rainwater composition and wind speed were considered, by simulating different conditions, in accordance with a fully orthogonal experimental design. The principle response variable was the total percentage of SPPs-releasing pollen grains; also the percentage of intact grains releasing SPPs through the pore and of broken SPPs-releasing grains were considered. Both osmotic and mechanical shock caused the discharge of SPPs but different results were observed. The highest number of releasing grains was recorded in case of acid solution and 20 knots wind speed. Moreover, wind and rainfalls caused SPPs release through different mechanisms. Wind mainly provoked a mechanical shock leading to grain rupture, whereas rainfall caused mainly SPPs release through the pore of intact grains. Comparing species, the effect of wind and at least in some cases also that of rainwater appeared to be less relevant for Ambrosia trifida than for Ambrosia psilostachya and Ambrosia artemisiifolia. The obtained results suggest a species-specific response of Ambrosia species to wind speed and rainwater that lead to a different release of SPPs and then to a species-specific impact on allergy according to the characteristics of their growth environment.

In this study, gamete release by Caulerpa cylindracea was investigated for the first time in the Tyrrhenian Sea (Sardinia, Western Mediterranean), focusing on the main environmental factors triggering gametogenesis and spawning of the species. For this purpose, a combination of field and laboratory experiments was conducted. First, a 2-year mensurative experiment was performed in the field during summer to individuate and quantify the occurrence of C. cylindracea gametogenesis and spawning events, linking them to environmental conditions. Then, based on the results of the field work, a laboratory experiment was performed to directly test, under controlled conditions, the effect on the above-mentioned processes of two abiotic factors that appeared to play a key role in species gamete release processes in the area: sea water temperature and water movement. During the 2 years of field research, several gametogenesis events were recorded in the study area and two spawning events also occurred. Significant differences were observed between the ratio of fertile and total thalli and between releasing thalli (RT) and fertile thalli (FT), among sites with different hydrodynamic conditions and sampling periods with different sea water temperatures. Overall, these results suggest that C. cylindracea sexual reproduction also occurs in the Tyrrhenian Sea, and that, therefore, new genotypes that favor the invasive profile of the species could be produced in the basin, where both its gametogenesis and spawning seem to be mainly regulated by water movement and sea water temperature.

The benthic mucilage producing microalga Chrysophaeum taylorii Lewis and Bryan (Pelagophyceae) has recently received attention for its rapid spread in the Mediterranean Sea, where its blooms have remarkable detrimental effects. So far no information on C. taylorii response to multiple stressors, especially in terms of mucilage hyperproduction, is available in the literature yet, and a manipulative field experiment in this topic was designed in Tavolara Punta Coda Cavallo Marine Protected Area. The aim of the study was to test the effects of nutrient enrichment (addition of nutrients), mechanical disturbance (partial and total benthic organisms removal) and hydrodynamics (increased water turbulence) on C. taylorii cell density and mucilage abundance. To the purpose, the three above mentioned stressors were simulated and the three treatments were assigned to 20 × 20 cm plots following a full-factorial design (n = 3). Interactive effects of the three stressors affected significantly both benthic C. taylorii cell density and mucilage cover although differently. Mechanical disturbance and high hydrodynamics produced consistent effects on cell density and mucilage production (i.e. the former factor enhancing and the latter decreasing). Nutrient enrichment on the contrary led to contrasting effects, promoting cell abundance and inhibiting mucilage production. Therefore, important mucilage blooms are expected in oligotrophic sheltered coastal locations where barren areas are present.

The role of commercial harbours as sink and source habitats for non-indigenous species (NIS) and the role of recreational boating for their secondary spread were investigated by analysing the fouling community of five Italian harbours and five marinas in the western Mediterranean Sea. It was first hypothesised that NIS assemblages in the recreational marinas were subsets of those occurring in commercial harbours. However, the data did not consistently support this hypothesis: the NIS pools of some marinas significantly diverged from harbours even belonging to the same coastal stretches, including NIS occurring only in marinas. This study confirms harbours as hotspots for marine NIS, but also reveals that numbers of NIS in some marinas is higher than expected, suggesting that recreational vessels effectively facilitate NIS spread. It is recommended that this vector of NIS introduction is taken into account in the future planning of sustainable development of maritime tourism in Europe.

This contribution describes the white patch disease (CWPD) on coralline red algae (Rhodophyta, Corallinophycideae), observed for the first time in a rhodolith bed (aggregates of nodules of unattached growth forms of non-geniculate calcareous red algae) of the Aegadian Islands during the summer of 2016.

Nowadays harmful algal blooms (HABs) represent a serious problem for the conservation of the biodiversity in the Mediterranean Sea. Nevertheless the knowledge on the presence of potentially toxic benthic microalgae in particular habitats, such as tide pools, is still scarce. In order to detect HAB-producing benthic microalgae in tide pools of the rocky intertidal zone, a pilot study was conducted in Tavolara Punta Coda Cavallo Marine Protected Area (MPA) during the late spring of 2016. Three different pools were sampled in two study sites (six pools were sampled in total) and the cell density of toxic species was estimated in each. In all the collected samples, the two potentially toxic dinoflagellates, Prorocentrum lima (Ehrenberg) F. Stein and Coolia monotis Meunier, were recorded and significant differences in their density were observed, in relation to both sites and pools.

Gammarids are one of the most successful invaders in freshwater ecosystems due to both their diet plasticity and high reproductive capability. The Balkanic amphipod, Gammarus roeselii Gervais, 1835, has colonised a small canal in the southern part of the sub-lacustrine Ticino River basin (Northern Italy), where it lives in sympatry and shares the same habitat with the native species Echinogammarus stammeri (Karaman, 1931). We surveyed the populations of the two species over 12 months (from July 2014 to June 2015) to investigate their structure and dynamics. The overall densities of the two populations were similar in the study area, but we observed marked differences in the population structure: G. roeselii was in fact more successful than the native gammarid in achieving the adult stage, and E. stammeri exhibited a rather limited reproductive period, which does not justify the stable occurrence of juvenile individuals. We hypothesise that the population of the native gammarid in this small habitat is supported by a continuous upstream immigration of individuals from the Ticino River, while G. roeselii exhibits a well-structured and self-reproducing population.

Chrysophaeum taylorii Lewis & Bryan (Pelagophyceae) is a mucilage-producing benthic microalga that has recently begun to spread in the Mediterranean Sea, where a range expansion is occurring. This paper presents the results of three field experiments that aimed to increase the knowledge on mucilage provision mechanisms for this benthic microalga and to evaluate the importance of mucilage in its range expansion. By means of two correlative field experiments (several years of data were considered to encompass the variability of mucilage cover) we found that, on the sea bottom, mucilage cover does not depend on epilithic cell density and that both its cover and settling are affected by water flow. We also tested the hypothesis that cells embedded in floating mucilage fall on the underlying substratum, where their abundance depends on water flow. To this aim, in the field we manipulated the presence of floating mucilaginous aggregates in cages with different levels of exposure to winds. The abundance of C. taylorii cells on the substratum under cages with mucilage was compared with that of two control treatments: cages without mucilage and mucilage in still water, in the field and lab, respectively. The results suggested that mucilage can represent an excellent strategy for the species to disperse, as C. taylorii cells fall from the floating mucilage and, if the water flow is unimportant, settle on hard substrata just underneath the cage. This study enriches the portfolio of knowledge of the dispersal strategies of microalgae and contributes to the understanding of the spread of invasive species.

Despite the importance of soil reaction for alien plant establishment, few and incomplete studies have included this key factor so far. In this study, we investigated the effects of soil pH on the germination, growth (plant height, width, dry weight, etc.) and reproductive investment (inflorescence size and n° of flowers) of Ambrosia artemisiifolia (common ragweed), an allergenic species that is highly invasive and alien in Europe, through a replicated experiment in controlled conditions. In addition, we determined if soil pH has an effect on the total pollen allergenicity of the species. After preliminary germination tests on agar at different pH (from pH4 to pH8), plants were grown in natural soils with pH values of 5 (acid), 6 (sub-acid) and 7 (neutral) obtained by modifying a natural soil by liming methods (calcium hydroxide solution). Results showed that plants grown at pH7 were shorter and developed leaves at a slower rate than those grown at pH5 and pH6; plants grown at pH7 did not produce flowers and pollen. We also observed that, at pH5 and pH6, larger plants (as assessed by the dry weight of the aerial biomass) had both larger and more numerous inflorescences and emitted pollen earlier. Finally, the IgE-binding signal was higher in pollen samples collected from plants grown at pH5 (Integrated Optical Density, IOD, range: 1.12–1.25) than in those grown at pH6 (IOD range: 0.86 −1.03). Although we acknowledge the limitations of only testing the effects of pH in controlled conditions, this study suggests that soil pH greatly affects the growth and development of A. artemisiifolia and indicates that it may have a role in limiting the distribution and hazardousness of this plant. Future field tests should therefore assess the effectiveness of liming in the management and control of ragweed and other alien species.

Few field studies have investigated how changes at one trophic level can affect the invasibility of other trophic levels. We examined the hypothesis that the spread of an introduced alga in disturbed seagrass beds with degraded canopies depends on the depletion of large consumers. We mimicked the degradation of seagrass canopies by clipping shoot density and reducing leaf length, simulating natural and anthropogenic stressors such as fish overgrazing and water quality. Caulerpa racemosa was transplanted into each plot and large consumers were excluded from half of them using cages. Potential cage artifacts were assessed by measuring irradiance, scouring by leaf movement, water flow, and sedimentation. Algal invasion of the seagrass bed differed based on the size of consumers. The alga had higher cover and size under the cages, where the seagrass was characterized by reduced shoot density and canopy height. Furthermore, canopy height had a significant effect depending on canopy density. The alteration of seagrass canopies increased the spread of C. racemosa only when large consumers were absent. Our results suggest that protecting declining habitats and/or restoring fish populations will limit the expansion of C. racemosa. Because MPAs also enhance the abundance and size of fish consuming seagrass they can indirectly promote algal invasion. The effects of MPAs on invasive species are context dependent and require balancing opposing forces, such as the conservation of seagrass canopy structure and the protection of fish grazing the seagrass.

Chrysophaeum taylorii Lewis and Bryan (Pelagophyceae) is an allochthonous benthic microalga recently recorded in the Mediterranean Sea where it is spreading quickly. Although this species secretes mucilage which is seriously affecting marine communities, it has been scarcely studied and no information on its ecology is available yet. We present the results of a five year study aimed to increase knowledge on substratum and depth preferences of this bloom-forming microalga with special emphasis on its colonisation efficiency.Three separate field experiments established that cell abundances of Chrysophaeum taylorii were significantly lower on macroalgae, mollusc shells and sand than on hard granitic substrata, where the microalga settled efficiently and proliferated immediately independently of the colonisation level of the substratum (bare vs colonised) and the substratum stability (mobility) (cobbles vs rocks). Furthermore, C. taylorii abundance (density) decreased with depth >2m, showing it prefers shallow waters in which it is able to resist to high light intensities.These results offer some important insights into the ecology of this bloom-forming microalga that will contribute to the planning of future research and strategies for management of bloom events.