Elena Gottardini

In un contesto di cambiamenti climatici numerosi studi evidenziano effetti sugli ecosistemi descrivendo un trend di anticipo generale negli eventi fenologici, sia per le specie vegetali sia per quelle animali (Parmesan and Yohe, 2003), con anomalie soprattutto nella fenofase primaverile (Walther, 2002). Il polline aerodisperso, considerato un indicatore attendibile della fioritura di piante anemofile, può essere utilizzato come proxy dei cambiamenti climatici. Il presente lavoro mostra i risultati di analisi svolte su dati di concentrazione pollinica giornalieri raccolti presso il centro di monitoraggio aerobiologico della Fondazione Edmund Mach (FEM) a San Michele all’Adige (Trento). Il centro si trova in una posizione privilegiata per descrivere il complesso mosaico di ecosistemi dell’arco alpino: aree coltivate a vigneti e meleti si alternano a zone ruderali, contesti urbani con vegetazione antropica di parchi e giardini, boschi misti decidui (pino, carpino nero, frassino, quercia) e boschi di conifere. Il monitoraggio pollinico viene svolto a San Michele a/A dal 1989, adottando procedure standard (UNI CEN/TS 16868:2015), impiegando personale ben addestrato ed utilizzando materiale iconografico ed una palinoteca di riferimento per le fasi di identificazione dei pollini, allo scopo di assicurare la qualità dei dati raccolti. In questo studio esplorativo sono stati considerati i taxa prevalenti che compongono lo spettro pollinico e che sono stati monitorati presso il centro aerobiologico di San Michele a/A per un intervallo temporale di 26 anni (1989-2014). Utilizzando diverse variabili che descrivono l’andamento stagionale dei pollini (data di inizio, picco e fine pollinazione; indice pollinico), i dati sono stati analizzati allo scopo di verificare l’esistenza di trend temporali relativi sia alla tempistica di comparsa dei pollini in atmosfera sia ai quantitativi. I dati pollinici sono stati inoltre messi in relazione con dati meteorologici ed indici climatici da essi derivati, al fine di comprendere se eventuali cambiamenti possano essere connessi a cambiamenti climatici. I risultati mostrano in sintesi come vi sia una tendenza all’anticipo della data di inizio pollinazione per circa la metà dei taxa considerati, ma con un trend significativo solo per 5 di essi (p<0.05). I quantitativi di polline presentano una tendenza all’aumento per la quasi totalità dei taxa considerati, significativo per la metà di essi. Le correlazioni con i parametri climatici evidenziano come la temperatura sia il fattore maggiormente influente per la data di inizio pollinazione, in particolare per le piante arboree. Correlazioni tra parametri climatici e quantitativi pollinici non risultano invece essere altrettanto marcate. Capire come cambiano i pollini in aria, sia nei quantitativi sia nella tempistica e durata della stagione pollinica, e se ciò sia in relazione con i cambiamenti climatici in atto, è di particolare interesse in collegamento alle patologie allergiche respiratorie. E’ facilmente intuibile infatti come stagioni polliniche prolungate, anticipi nella fioritura nonché quantitativi maggiori di polline in aria possano avere ripercussioni importanti su chi soffre di pollinosi

Forests deliver many ecosystem services, from provisioning to regulating and cultural services. We aimed at demonstrating microclimatic regulation and pollutant removal as especially relevant ecosystem services when considering the tourism vocation of the Alpine regions. A study was realized along an altitudinal gradient (900–1600 m a.s.l.) in Trentino, northern Italy, an area with high touristic presence (ca. 9.3 million overnight stays in summer 2021). Nitrogen dioxide (NO2, µg m−3), ozone (O3, µg m−3) concentrations, air temperature (T, °C), and relative humidity (RH, %) were simultaneously measured in three open-field sites (OF) and below-canopy Norway spruce forest stands (FO) during the period 23 May–7 August 2013. The temperature–humidity index (THI) was calculated. We found a distinct mitigating effect of forest on T, with lower maximum (−30.6%) and higher minimum values (+6.3%) in FO than in OF. THI supported a higher comfort sensation in FO than in OF, especially in the ce...

Tropospheric ozone (O3) concentrations from passive samplers have been monitored according to harmonized methodologies on ICP Forests intensive monitoring (Level II) sites, starting in the year 2000. The objective of measuring the concentrations of ozone is to contribute to a better understanding of the actual exposure of European forest ecosystems to air pollutants. In particular, we aim to (i) quantify ozone concentrations over the course of the vegetation period (April–September), (ii) estimate the related ozone exposures of forest ecosystems, and (iii) detect temporal and spatial trends across Europe.

The assessment of Visible Foliar Symptoms (VFS) is commonly adopted by forest monitoring programs to evaluate ozone impact on vegetation. The occurrence of ozone VFS may differ among individuals of the same species at the same site, and within leaves of the same individual. The aim of this study was to identify site and plant characteristics as well as functional leaf traits associated with the occurrence and severity of VFS in Viburnum lantana (an ozone-sensitive species) and at the scale of an individual site. V. lantana plants growing at one site of the ViburNeT monitoring network (Trentino, North Italy) experiencing high ozone levels were surveyed in relation to 1) sun exposure, 2) shading effect from neighbor vegetation, 3) plant height and 4) presence and severity of VFS. Leaves from three different sections of each plant were subjected to a phenotypic characterization of leaf area, dry weight, specific leaf area (SLA), chlorophyll content (ChlSPAD), percentage of VFS, and ada...

The effects of pollen on dissolved inorganic nitrogen (DIN) compounds in throughfall water are not completely understood. We conducted a 7-day leaching experiment with pollen from silver birch (including a sterilized control), European beech, sessile oak, Scots pine, Corsican black pine and Norway spruce using an immersion medium containing nitrate (11.295 mg N l-1). Within 2 hours, pollen released substantial amounts of potassium (K+), phosphate (PO3-) and organic compounds. Solute concentrations of ammonium (NH4+) were built up over time. In treatments with pollen from birch, oak and beech, nitrate (NO3-) concentrations started to decrease after 24–48 hours, while simultaneously nitrite (NO2-) emerged, but part of the inorganic nitrogen could no longer be detected in solution. For birch, sterilisation of the pollen made no difference, indicating that microorganisms on the pollen played no substantial role in the observed N transformations. Conditions in the samples were oxic (1.82...

Ozone-induced visible foliar injury has been assessed during 2002-2014 according to ICP Forests standardized methods. This activity provided 29,809 records from 285 woody plant species, 169 plots and 19 countries. Data were evaluated for the entire period 2002-2014 as well as for 2009 only, when spatial coverage was the greatest. First results reveal that 55.0% of the assessed plots were symptomatic, and 26.0% of species developed ozone visible injury. Beech (Fagus sylvatica) was the species with the highest frequency of symptomatic observations (plot and years) in both 2002-2014 (40.1%) and 2009 (42.9%). The frequency of symptom reports occurred without a clear spatial pattern. In case, higher frequency of symptom occurrence seemed more common from northern Italy to NorthWest Germany, and towards East Europe. At country level, temporal trend analysis indicates a downward trend of mean frequency of symptomatic species for five out of six countries. Overall (all plots together), ther...

A stratified random sampling design was adopted to contrast sites with different ozone exposure levels (≤ 18,000 and >18,000 μg m(-3) h) in order to define whether and to what extent a relationship exists between potential risk (estimated by exposure to ozone) and the response of Viburnum lantana L. in terms of foliar symptoms. The study was designed over a meso-scale (6200 km(2)), carried out in 2010 and repeated in 2012 on a subset of sites. No difference was found between the occurrences of symptoms in relation to soil moisture or plant size. Although no direct significant exposure-response function could be identified, when data were aggregated according to ozone exposure levels the symptoms (in terms of number of symptomatic plants and symptomatic leaves per plant) were found to be significantly more frequent at sites with higher exposure (AOT40>18,000 μg m(-3) h), especially at high elevations (>700 ma.s.l.). The 2012 results confirmed the 2010 findings. Although ozon...

Specific visible foliar injuries were demonstrated to occur on plants of Viburnum lantana L. (wayfaring tree) when exposed to ozone in open-top chamber experiments. However, although evidence of visible injury was reported even for native plants, no comprehensive testing has been carried out under real field conditions. Thus, the extent to which V. lantana may match the requirements to be used as an in situ bioindicator is not fully known. To investigate the actual responsiveness of native V. lantana plants to ozone under field condition, two 1 × 1 km quadrates (named "Margone" and "Lasino"), for which the occurrence of different ozone levels was known, were considered. There, a fully randomized design was adopted to ensure within-quadrate replications and to select V. lantana plants. Measurements confirmed different exposure levels (Margone, Accumulated ozone concentrations Over a Threshold of 40 ppb h (AOT40): 31 952 ppb h; Lasino, AOT40: 23 259 ppb h). Ozone visible foliar symptoms (i) matched the known symptomatology, (ii) were easy to be identified, (iii) confirmed by microscopical validation, and (iv) observed at both quadrates. However, higher frequency of symptoms, earlier date of onset and faster development occurred at the quadrate with the highest ozone exposure (Margone), although not always proportionally with the difference in ozone exposure. This may be partly due to inherent covariation of environmental variables (higher ozone exposure occurred at the sites with higher relative humidity and cooler air temperature, a set of conditions that may promote ozone uptake), and partly due to a set of (unmeasured) other factors that may cause additional oxidative stress to plants. Implications for biomonitoring are discussed.