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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 >2 m, 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Chrysophaeum taylorii (Pelagophyceae) is an allochthonous benthic microalga recently recorded in the Mediterranean Sea. During summer, the occurrence of C. taylorii is usually visible to the naked eye due to the large amount of mucilage this species produces. Information on the spatio-temporal variability of this species and on the predictability of massive mucilage events is still scarce and requires to define ad hoc managing strategies of major bloom events. The aim of this work was to identify the relevant scales of variation in the abundance of C. taylorii abundance and to estimate the relative recurrence of its blooms, testing the hypothesis that mucilage was dependent on the cell density. The first approach was the identification of the most appropriate sampling procedure to estimate benthic cell abundance of C. taylorii. The second one was the estimation of the magnitude of variation in C. taylorii cell abundance attributable to each of several spatial (areas, sites, zones and replicates) and temporal scales (fortnights and years) in the Marine Protected Area of Tavolara Punta Coda Cavallo (Western Mediterranean Sea). The results indicate fortnight and year as the most relevant scales of variability in the cell abundance of C. taylorii and highlight the unimportance of small spatial scales (zone and replicates) to the species variability. The collected data also evidence the absence of a direct relationship between the cell density of C. taylorii and the production of mucilage. In conclusion, these results indicate that patterns in the cell abundance of C. taylorii vary notably depending on the considered scale and that future investigations on processes affecting its performance will need to consider the relevant scales of variation evidenced. [ABSTRACT FROM AUTHOR]

Mediterranean rhodolith beds are priority marine benthic habitats for the European Community, 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 unidirectional 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 × 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 IAPUC 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 IAPUC. [ABSTRACT FROM AUTHOR]

• The success of restoration actions performed at a limestone quarry was assessed. • The restoration success in quarry depends on backfilling material characteristics. • Alpha-diversity and grass cover were dependent on stoniness and soil sand contents. • Grass cover was the only biotic factor dependent on the age of the restored parcels. • Leaf traits (SLA, LNC and LDW) responded to soil sand content in the restored parcels. In limestone quarries, after quarry abandonment, ecological restoration takes place subsequently over several years, often with the use of different procedures and backfilling materials. The success of the different restoration actions performed at a limestone quarry (Colle Pedrino, Lombardy Prealps, Italy) in terms of vegetation cover and biodiversity levels, compared to the surrounding natural areas, was evaluated in this work. Taking into account the soil's chemical-physical characteristics, 24 vegetation plots of 3 × 3 m were set up on seven restored parcels of different ages inside the quarry, of which one was left to spontaneous succession, and one control area outside the quarry was also considered for comparisons. Linear mixed models were employed to assess the effect of the following environmental variables on restoration: age, and several soil factors (stoniness, sand content, CN, K, and organic matter). The restoration success at the different parcels, in terms of total plant cover, grass cover and α- and β-diversity (including Lepidoptera), were thus determined. The variations in plant traits associated with the main environmental factors and floristic composition at the restored parcels were also assessed. The linear models revealed that the grass cover strongly depends on the age of the parcel and some soil factors: sand and potassium contents in the topsoil and organic matter in the subsoil. Moreover, plant and butterfly richness depend on the soil's stoniness and sand content. The species traits also significantly explained the variation in species distribution along the environmental gradients: stronger correlations with sand, potassium contents and stoniness were found. The restoration success in the quarry slopes depended on the backfilling materials used for slope reclamation over time. This factor concurs with the time passed since the restoration/abandonment and has a key background role in shaping the quarry's grass cover and biodiversity gradients. Regarding species assemblages, the key leaf traits of plants linked to resource availability (leaf area, leaf nitrogen and leaf carbon contents) consistently responded to the soil variables within parcels. In conclusion, site-specific studies to evaluate the grain size and the chemical composition of the backfilling materials used in the slope remodelling are recommended to favour a resource-driven plant establishment, spontaneous recolonisation, higher biodiversity and slope stability. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]