Palynological assessment of the atmosphere in the city of Cherepovets

The article presents the results of the study of aeropalinological spectra of the city of Cherepovets (59 ° 07′59 ″ N, 37 ° 53′59 ″ E), carried out during the growing season 2014-2015. The method of gravimetric sampling was used (Durham’s pollen trap). Data was obtained on 22 taxa and the dynamics of dusting of various palynomorphs; the dominant taxa of palinospectrum were identified, as well as non-pollen palynomorphs in the air. It is shown that Betula pollen grains prevail in the atmosphere of the city. The pollen of woody plants occupies 80% of the total spectrum, and the pollen of herbaceous plants – 20%. Seasonal highs are recorded twice: in May and in late June – early July. This information must be taken into account when accompanying patients with hay fever.

Lidar-Derived Tree Crown Parameters: Are They New Variables Explaining Local Birch (Betula sp.) Pollen Concentrations?

Birch trees are abundant in central and northern Europe and are dominant trees in broadleaved forests. Birches are pioneer trees that produce large quantities of allergenic pollen efficiently dispersed by wind. The pollen load level depends on the sizes and locations of pollen sources, which are important for pollen forecasting models; however, very limited work has been done on this topic in comparison to research on anthropogenic air pollutants. Therefore, we used highly accurate aerial laser scanning (Light Detection and Ranging—LiDAR) data to estimate the size and location of birch pollen sources in 3-dimensional space and to determine their influence on the pollen concentration in Poznań, Poland. LiDAR data were acquired in May 2012. LiDAR point clouds were clipped to birch individuals (mapped in 2012–2014 and in 2019), normalised, filtered, and individual tree crowns higher than 5 m were delineated. Then, the crown surface and volume were calculated and aggregated according to wind direction up to 2 km from the pollen trap. Consistent with LIDAR data, hourly airborne pollen measurements (performed using a Hirst-type, 7-day volumetric trap), wind speed and direction data were obtained in April 2012. We delineated 18,740 birch trees, with an average density of 14.9/0.01 km2, in the study area. The total birch crown surface in the 500–1500 m buffer from the pollen trap was significantly correlated with the pollen concentration aggregated by the wind direction (r = 0.728, p = 0.04). The individual tree crown delineation performed well (r2 ≥ 0.89), but overestimations were observed at high birch densities (> 30 trees/plot). We showed that trees outside forests substantially contribute to the total pollen pool. We suggest that including the vertical dimension and the trees outside the forest in pollen source maps have the potential to improve the quality of pollen forecasting models.

Comparative pollen preferences by africanized honeybees Apis mellifera L. of two colonies in Pará de Minas, Minas Gerais, Brazil

The aim of this study was to investigate the polliniferous floral sources used by Apis mellifera (L.) (africanized) in an apiary situated in Pará de Minas, Minas Gerais state, and evaluate the pollen prefences among the beehives. Two beehives of Langstroth type with frontal pollen trap collectors were used. The harvest was made from September 2007 to March 2008, with three samples of pollen pellets colected per month per beehive. The subsamples of 2 grams each were prepared according to the European standard melissopalynological method. A total of 56 pollen types were observed, identifying 43 genus and 32 families. The families that showed the major richness of pollen types were: Mimosaceae (8), Asteraceae (6), Fabaceae (3), Arecaceae (3), Euphorbiaceae (3), Rubiaceae (3), Caesalpiniaceae (2), Moraceae (2) and Myrtaceae (2). The most frequent pollen types (> 45%) were Mimosa scabrella, Myrcia and Sorocea. The results demonstrated a similarity regarding the preferences of floral sources during the major part of the time. There was a distinct utilization of floral sources among the pollen types of minor frequency. In spite of the strong antropic influence, the region showed a great polliniferous variety, which was an indicative of the potential for monofloral as well as heterofloral pollen production.