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This research focuses on the recent pollen image of several vegetation types in NW Italy. In 201 arboreal, shrubby, and herbaceous plant populations, pollen samples were taken from moss polsters, and the corresponding vegetation was recorded using the phytosociological method. Since studies on recent pollen rain in the Mediterranean mountains and coast are rare, this research aims to provide new data and tools to better interpret fossil pollen spectra. Pollen analysis provided data for the comparison between surface spectra and vegetation. Davis indices, fidelity, dispersion, and the relation with vegetation data were calculated for each taxon, and PCA was carried out. Most vegetation types are identifiable through the taxa dominating the pollen spectra, as frequently happens in woodlands (e.g., beech woods, chestnut woods, etc.). Characterizing shrubland and certain tree-dominated vegetation types (e.g., Larix forests) through pollen data is more complex. In this regard, Davis indices are particularly useful for identifying pollen/plant association, over- and underrepresentation of pollen, and taxa indicating vegetation types. Pollen threshold values were calculated which allow the assessment of the local presence of a plant. Overall, the achieved results partially confirm those of previous research carried out in the region, greatly expanding the comparisons between several different plant communities and the database in view of future sharing through the EMPD. [ABSTRACT FROM AUTHOR]

Cupressaceae is one of the most widespread families in the Mediterranean region, widely used as ornamental trees both in cities and extra urban areas. The family is also known to produce a considerable amount of pollen grains. Nevertheless, Cupressaceae pollen is generally scarce in sediments and it is attested to be one of the most underrepresented pollen in ancient spectra. Cupressaceae pollen diffusion was detected by means of two sampling methods: moss cushions, which are able to accumulate pollen grains for several successive years, and volumetric sampler, which records the airborne pollen day by day. The study was conducted in the city of Florence (Italy), repeating moss samplings at the same sites for three times. The comparison between the two sampling methods revealed the low preservation of this pollen type and suggested that even low quantities of this pollen may indicate the local presence of the source plants. In order to test the contribution of the local pollen sources to the background of the airborne pollen, the pollen content of moss cushions was also related to the number of Cupressaceae plants surroundings each sampling site. The results indicate a noticeable influence of the plants growing in a short-range distance. [ABSTRACT FROM AUTHOR]

In Italy, aerobiological monitoring is usually carried out by the regional agencies for environmental protection (ARPA [Agenzia Regionale per la Protezione Ambientale]) using volumetric samplers. Another widespread method for the study of airborne pollen is the analysis of moss cushions, generally used to relate pollen rain to flora and vegetation. In this study, we compare the data coming from these two pollen monitoring methods: volumetric samplers and moss cushions. The study was carried out in the city of Florence (Italy) and took into consideration two different spans of time. The two pollen monitoring methods show quantitative and qualitative differences. The main discrepancy seems to be the direct consequence of the different preservation time of the grains in the moss cushions depending on the features of the pollen grains. The study also provides an estimate of the period of pollen accumulation and preservation in moss cushions, which turned out to be more than five years. The two sampling methods furnish complementary information; volumetric samplers especially suited for aerobiological studies and moss cushions for environmental and palaeobotanical research. [ABSTRACT FROM AUTHOR]

• Gravimetric trap networks at ground level are useful for studying pollen diffusion in urban contexts. • Ornamental trees strongly affect the pollen concentrations inside the urban area. • Pollen surveys at ground level provide information for improving future urban green planning. Urban green areas can improve people's quality of life, although airborne pollen may provoke allergic disease. The record of the pollen rain in different sites within a city can be useful to understand the distance reached by the pollen of different plants and its amount. Moss cushions are natural gravimetric pollen traps and represent a useful and economic tool for this kind of survey. Moss samples were collected from 16 sites in Florence at the distance of a decade. To test the effects of urban green areas on pollen records, the land cover was analyzed in buffers drawn around each sampling site. Pollen frequencies were correlated with the extension of the green spaces and with the number of trees inside the buffers. Pollen concentration maps were drawn to plot the pollen deposition at the different sites of the city center. The pollen records at ground level displayed an uneven concentration across the city and a strong prevalence of arboreal pollen. The greatest statistical correlation between pollen frequencies and arboreal land cover was shown for the larger buffers. The influence of Cupressaceae and Quercus was noteworthy at great distances. Some of the common ornamental trees growing along the main roads, such as Celtis and Tilia , showed a strictly local influence on pollen rain. The results of the study highlight the utility of a network of records inside cities for evaluating the actual contributions of the plants to pollen accumulation at the height where people walk. They may provide a useful indication for the planning of urban green areas in order to reduce health risks for citizens. [ABSTRACT FROM AUTHOR]