Abstract In Europe, the recently reported plant pathogen Xylella fastidiosa subsp. multiplex affects several wild, ornamental, and cultivated trees causing scorch diseases. In 2018, the sequence type ...87 was reported in Tuscany on Mediterranean shrubs and trees. Although spittlebugs (Hemiptera: Aphrophoridae) were already identified as main vectors of this bacterium in Europe, their role in the transmission of this subspecies has not been ascertained yet. In this study the ability of Philaenus spumarius and Neophilaenus campestris to acquire and transmit Xylella fastidiosa subsp. multiplex sequence type 87 from and to Rhamnus alaternus was evaluated in two-year semi-field experiments. To acquire the bacterium, insects were confined on wild, naturally infected R. alaternus shrubs for 120 h. Then, they were transferred to healthy plants and maintained in cages for 96 h. To follow the infection, plant samples were collected every two months for three times. Tested plants were destroyed at the end of experiments and roots, twigs and leaves were analysed. Philaenus spumarius showed a significantly higher survival rate than N. campestris . The infection status of both insects and plants was assessed through molecular analysis. P. spumarius and N. campestris were able to infect healthy plants although the acquisition rate and the estimated probability of transmission appeared to be low. These findings provide new accounts on the role of two polyphagous insect vectors in spreading a quarantine organism, which is lethal to a huge number of plant species. However, further studies are needed to disclose more specific interactions within this complex pathosystem.
The investigations of modern pollen and vegetation relationships have long been recognised as an important approach for the convenient interpretation of fossil pollen records. Despite several studies ...on fossil pollen records applied to the Rif landscape, investigations focused on modern pollen and vegetation relationship are still rare. This study aims to provide new data on the modern pollen rain in Bouhachem and Alem landscape and analyse the relationships between modern pollen, vegetation, and various environmental and land-use variables in Bouhachem and Alem mountains (Western Rif mountains). A total of 34 modern surface samples (moss polster) were collected from different vegetation patterns in the Bouhachem Alem landscape and a vegetation survey was conducted at each sampling site. Cluster analysis and Canonical correspondence analysis are used to characterise the vegetation and pollen of the Bouhachem ana Alem mountains. The results show that wooded communities of cedar (Cedrus atlantica), deciduous oak (Quercus pyrenaica, Quercus canariensis), cork oak (Quercus suber), and pine (Pinus pinaster), can be discriminated from low and high matorrals in the Bouhacehm-Alem landscape through the modern pollen assemblages; matorral and open areas have less distinctive pollen signatures of surrounded vegetation because of regional pollens. The altitude, annual precipitation, and tree cover distinguish the high-mountain communities. The land use and anthropogenic variables contribute to differentiate the degraded and grazed communities. Poaceae, Cannabis, Plantago, Asteraceae, and Urtica pollen types are related to anthropogenic activities and should be interpreted carefully. The relationships between the modern pollen of Bouhachem and Alem mountains and broad variables can support the interpretation of paleoenvironmental records from the Rif landscape.
•Pollen–vegetation relation in Rif mountains along ecological gradients and land-use.•The vegetation of the Rif mountains can be discriminated through modern pollen rain.•Several taxa are good indicators of anthropogenic activities in the Rif mountains.•Modern pollen data from the Rif are valuable data for palaeoecological studies.
Airborne particulate matter can represent a serious issue for human health, especially in densely populated urban areas. Moreover, the inhalation of particulate can be more harmful with decreasing ...particles diameter. Vegetation can provide many ecosystem services to the citizens, including the removal of many different pollutants in the air, but while the effect on many gaseous compounds has already been widely proved, the capability of particulate matter (PM) sequestration driven by vegetation and its resulting benefit on air quality has not been deeply investigated yet at larger spatial scale, especially in Mediterranean environment. This study was conducted in the Real Bosco di Capodimonte, a green area of about 125 ha located inside the urban area of Naples (Italy) containing different species typical of the Mediterranean forest ecosystem. To better understand the interaction between PM and the park area, we measured fluxes of PM10, PM2.5 and PM1 with a fast acquisition analyser, according to the Eddy Covariance technique. We found that the particle deposition was higher during the central hours of the day and it was more evident for smaller size particles. Furthermore, the daily PM fluxes found accorded with evapotranspiration and carbon sequestration operated by plants, suggesting a possible active role of vegetation on the particulate deposition.
Display omitted
•We measured particulate matter concentrations within a large green area of Naples.•PM and CO2 fluxes were calculated by mean of eddy covariance technique.•Downward fluxes of particulate were detected during the middle of the day.•Correlations between PM deposition, carbon uptake and evapotranspiration were shown.•Data presented are crucial to understand the role of green areas in PM removal.
We showed the downward flux of particulate and the consequent reduction of its concentration over a green area inside a city, although further investigation is needed to better understand vegetation activity role on particulate deposition and formation.
Summary
Automated pollen analysis is not yet efficient on environmental samples containing many pollen taxa and debris, which are typical in most pollen‐based studies. Contrary to classification, ...detection remains overlooked although it is the first step from which errors can propagate. Here, we investigated a simple but efficient method to automate pollen detection for environmental samples, optimizing workload and performance.
We applied the YOLOv5 algorithm on samples containing debris and c. 40 Mediterranean plant taxa, designed and tested several strategies for annotation, and analyzed variation in detection errors.
About 5% of pollen grains were left undetected, while 5% of debris were falsely detected as pollen. Undetected pollen was mainly in poor‐quality images, or of rare and irregular morphology. Pollen detection remained effective when applied to samples never seen by the algorithm, and was not improved by spending time to provide taxonomic details. Pollen detection of a single model taxon reduced annotation workload, but was only efficient for morphologically differentiated taxa.
We offer guidelines to plant scientists to analyze automatically any pollen sample, providing sound criteria to apply for detection while using common and user‐friendly tools. Our method contributes to enhance the efficiency and replicability of pollen‐based studies.
The COVID-19 pandemic has induced dramatic effects on the population of the industrialized north of Italy, whereas it has not heavily affected inhabitants of the southern regions. This might be ...explained in part by human exposure to high levels of fine particulate matter (PM) in the air of northern Italy, thus exacerbating the mortality. Since trees mitigate air pollution by intercepting PM onto plant surfaces and bolster the human immune system by emitting bioactive volatile organic compounds (VOCs), we hypothesize a protective role of evergreen forested areas in southern Italy. We compared the mortality rate due to COVID-19, the death number, the positivity rate and the forest coverage per capita in various Italian regions. Hectares of forest per capita and prevalence of deciduous versus evergreen forestal species were also estimated. In silico docking studies of potentially protective compounds found in
Laurus nobilis
L., a typical Mediterranean plant, were performed to search for potential antivirals. We found that the pandemic’s severity was generally lower in southern regions, especially those with more than 0.3 hectares of forest per capita. The lowest mortality rates were found in southern Italy, mainly in regions like Molise (0.007%) and Basilicata (0.005%) where the forest per capita ratio is higher than 0.5 Ha/person. Our findings suggest that evergreen Mediterranean forests and shrubland plants could have protected the southern population by emission of immuno-modulating VOCs and provision of dietary sources of bioactive compounds. Moreover, in silico
studies
revealed a potential anti-COVID-19 activity in laurusides, which are unexplored glycosides from bay laurel. Overall, our results highlight the importance of nature conservation and applications to the search for natural antivirals.
The coronavirus disease 2019 (COVID-19) is causing major sanitary and socioeconomic issues, yet some locations are less impacted than others. While densely populated areas are likely to favor viral ...transmission, we hypothesize that other environmental factors could explain lower cases in some areas. We studied COVID-19 impact and population statistics in highly forested Mediterranean Italian regions versus some northern regions where the amount of trees per capita is much lower. We also evaluated the affinity of Mediterranean plant-emitted volatile organic compounds (VOCs) isoprene, α-pinene, linalool and limonene for COVID-19 protein targets by molecular docking modeling. Results show that while mean death number increased about 4 times from 2020 to 2021, the percentage of deaths per population (0.06–0.10%) was lower in the greener Mediterranean regions such as Sardinia, Calabria and Basilica versus northern regions with low forest coverage, such as Lombardy (0.33%) and Emilia Romagna (0.29%). Data also show that the pandemic severity cannot be explained solely by population density. Modeling reveals that plant organic compounds could bind and interfere with the complex formed by the receptor binding domain of the coronavirus spike protein with the human cell receptor. Overall, our findings are likely explained by sea proximity and mild climate, Mediterranean diet and the abundance of non-deciduous Mediterranean plants which emit immunomodulatory and antiviral compounds. Potential implications include ‘forest bathing’ as a therapeutic practice, designing nasal sprays containing plant volatile organic compounds, and preserving and increasing forest coverage.
Background: Canopy phenology, foliar biochemistry, and leaf lifespan vary according to season within and across species. Intrinsically, this variation should also determine changes in the spectral ...properties of foliar tissue. However, whether canopy phenology and leaf spectroscopy co-vary across species has seldom been tested in seasonal drylands. Questions and / or Hypotheses: We tested the covariation between growth rate, foliage phenology, and leaf spectral indices, expecting that species with high growth rates should have large variability in relative leaf number and foliar spectroscopy. Studied species / data description / Mathematical model: We partition the intra and interspecific variation in relative leaf number and spectroscopy within nine perennial chaparral shrub species. Study site and dates: Rancho El Mogor, Valle de Guadalupe, Baja California, during 2017 and 2018. Methods: Foliage phenology was quantified with an index of relative leaf number, foliar spectroscopy with three standard vegetation indices, and resource-use with stem growth and leaf functional traits. Results: Species with higher variability in foliage phenology (more deciduous species) had higher stem growth rates. The three vegetation indices varied significantly across species (ca. 20 % of explained variance), and across seasons within species (ca. 55 % of explained variance). The values of the three vegetation indices were correlated, and only NDVI was correlated with foliage phenology and stem growth. Conclusions: Our results show that variations in relative leaf number and spectroscopy in chaparral species are coupled with functional traits of species involved in resource exploitation strategies in a seasonally arid environment.
•The population structure and temporal dynamics of almond natural regeneration differed between habitats.•Almond densities were much higher under pine afforestation.•The naturalization status of the ...almond in Europe and Italy is reviewed.•The first study of almond populations occurring in natural habitats in Europe is reported.
Although Prunus dulcis has been frequently listed in non-native floras all around the world, its naturalization has been rarely studied in the field. Probably, because this species has generally invaded synanthropic habitats. We assessed the density of natural regeneration of almond, biometric parameters (height and basal stem diameter), and the distribution in life stage classes in three different ecological contexts in Sicily (Mediterranean Italy): one natural habitat (maquis), one pine afforestation and two prickly pear orchards. We recorded 236 naturally regenerating almond individuals, with density ranging from 140 individuals per hectare (prickly pear orchard 1) up to 2,400 individuals per hectare (pine afforestation). Despite the higher density, almond individuals presented the lowest height and basal stem diameter under pine afforestation, suggesting a more recent establishment. Reproductive individuals were dominant (67.8%), followed by pre-reproductive (22.1%), and juveniles (10.1%). Although the naturalization of the almond in Mediterranean contexts is not new, in the last two decades there is evidence of an increasing trend. Most importantly, for the first time, we found the almond thriving within a natural habitat in large areas covered by Mediterranean maquis. Since the almond appears to be perfectly integrated within local plant communities, the origin and meaning of this peculiar vegetation aspect deserve to be further deepened.
Questions
Dryland annual plant communities constitute the most species‐rich small‐scale vegetation in the Mediterranean. Nevertheless, the composition and diversity of these units and the factors ...controlling their variation are still insufficiently understood. Therefore, we investigated species composition and richness patterns in relation to important environmental gradients provided by climate and soil.
Location
Central Crete, Greece.
Methods
The study is based on 82 plots of 4 m2 sampled at altitudes between 11 and 1400 m a.s.l. We conducted vegetation relevés and soil analyses. We used generalised additive models to model species richness and community characteristics along the studied gradients. We then performed distance‐based redundancy analysis to determine the main environmental factors influencing species composition. To determine species of diagnostic value for bedrock types, we applied an indicator species analysis. Correlation tests were used to test the performance of the South Aegean Plant Indicator Values on our dataset.
Results
We recorded 347 taxa (species and subspecies) of 43 plant families, and mean species numbers of 47.2 ± 12.5 per plot. While overall species richness varied only slightly along the analysed environmental gradients, significant changes were observed for relative proportions of species from different life forms and families. Soil pH and elevation had the highest influence on the variation in species composition (21.0% explained). We found 22 species indicative of calcareous rock and 24 species indicative of lime‐deficient rock types. The South Aegean Plant Indicator Values were relatively strongly correlated with environmental variables.
Conclusions
Results indicate considerable species turnover both along climatic (elevation) and soil gradients, highlighting the special importance of soil pH. The data provided by our study are expected to supply relevant ecological background information for a pending classification of East Mediterranean annual‐rich vegetation.
This study explores the rich diversity of annual plant communities in drylands of central Crete, Greece, and their response to climate and soil factors. We found significant species turnover along environmental gradients, in particular soil pH, and identified indicator species for different bedrock types. Our findings offer substantial ecological insights for understanding, classifying, and preserving East Mediterranean annual‐rich vegetation.
Urban and peri-urban forests provide a multitude of Ecosystem Services to the citizens. While the capacity of removing carbon dioxide and gaseous compounds from the atmosphere has been tested, their ...capacity to sequestrate particles (PM) has been poorly investigated. Mediterranean forest ecosystems are often located nearby or inside large urban areas. This is the case of the city of Rome, Italy, which hosts several urban parks and is surrounded by forested areas. In particular, the Presidential Estate of Castelporziano is a 6000 ha forested area located between the Tyrrhenian coast and the city (25 km downtown of Rome). Under the hypothesis that forests can ameliorate air quality thanks to particle deposition, we measured fluxes of PM1, 2.5 and 10 with fast optical sensors and eddy covariance technique. We found that PM1 is mainly deposited during the central hours of the day, while negligible fluxes were observed for PM 2.5 and 10. A Hybrid Single–Particle Lagrangian Integrated Trajectory model (HYSPLIT v4) simulated PM emission from traffic areas in the city of Rome and showed that a significant portion of PM is removed by vegetation in the days when the plume trajectory meets the urban forest.
Display omitted
•A peri-urban Mediteranean forest near the city of Rome is exposed to anthropogenic PM.•Bi-directional fluxes of PM were measured in a Holm Oak forest with eddy covariance.•The forest is a sink for PM 1 during the central hours of the day while fluxes of PM 2.5 and PM 10 were negligible.•HYSPLIT model simulations showed a potential to abate up to 23% of PM 1 from ambient air.
Eddy Covariance PM fluxes and a Hybrid Single–Particle Lagrangian Integrated Trajectory model (HYSPLIT) showed that periurban forest can sequestrate PM from the pollution plume transported to the experimental site from the city of Rome.
PDF
