RESUMEN
Platanusx hispanica (London plane) is a tree species widely used in urban areas due to the diversity of ecosystem services it provides. However, its functions also have some negative effects or associated disservices, such as the emission of Biogenic Volatile Organic Compounds (BVOCs) and allergens. This work aims to analyze the effect that urban environmental conditions and air pollutants have on pollen emissions of plane tree. The study has been carried out in Granada, in the southeast of the Iberian Peninsula, a city with a Mediterranean climate and one of the most polluted in Spain. Granada is also one of the Mediterranean cities in which the increase in the percentage of the population affected by allergy to Platanus pollen in recent decades has been most significant. The 1992-2019 Platanus pollen data series has been considered to establish the main aerobiological parameters, trends and correlations with meteorological variables and particulate and gaseous atmospheric pollutants, both before and during the flowering period. The average Seasonal Pollen Integral (SPIn) of about 2700 pollen grains has shown a significant increase throughout the series. This increase in allergen emissions could be related to the increase in crown volume associated with tree growth, but also to other environmental factors. Precipitation and minimum temperatures of the winter prior to flowering were the parameters that have shown the most influence with SPIn, while O3 and NOx are the pollutants that have the most effect on the peak value. Due to the good adaptation that London plane has to changing climatic conditions in urban environments, its hegemonic presence as an element of Urban Green infrastructure must be reviewed so that the net balance of ecosystem services is not diminished by the disservices.
Asunto(s)
Contaminantes Atmosféricos/análisis , Árboles , Alérgenos/análisis , Ciudades , Ecosistema , Londres , Polinización , EspañaRESUMEN
The aim of this study was to investigate the main climatic and biological trends related to olive flowering in central-southern Italy compared to those in Andalusia, Spain. Results since 1982 were compared for the two long-series monitoring areas of Cordoba and Perugia, and since 1992-1999 for the short-series areas. The relationship between climatic trends and the biological response of the olive, a widespread culture in the Mediterranean basin, were investigated. An aerobiological method involving capturing pollen released into the atmosphere was utilised as a bioindicator of flowering phenology. The study results confirm the strong relationship between flowering periods and spring temperature trends for the olive. Temperature during March, April and May was the parameter most related to flowering date in the study areas, particularly in Italy. In some cases we found a significant correlation between flowering and past autumn temperatures, probably due to their effect on floral bud dormancy induction, but this phenomenon appeared to be of minor importance in the studied areas. The phenological trend results show the continuous advance of flowering dates to the late 1990s, followed by a relatively stationary time series related to a short-term temperature fluctuation in the Mediterranean area. This latter period probably represents a mesoscale event forced by a macroscale event-the North Atlantic Oscillation. The results reveal that the trend towards increased temperatures, and the consequent flowering advance of some species, indicated some years ago is nowadays not as clear as was expected and should be confirmed over the next few years in the Mediterranean areas under investigation.