Airborne pollen of Ambrosia in Burgundy (France) 1996–1997

Pollen counts in Burgundy were monitored by means of four Hirst volumetric traps. Their analysis revealed a sharp rise of Ambrosia from 1996 to 1997. The minimum amount of ragweed pollen likely to provoke allergies (13 grains m–3) was reached or exceeded several days every year, but without leading to clinical symptoms. The circadian variation of Ambrosia pollen showed two peaks: the first one in the morning was suggested to coincide with local pollination, although the second one, in the afternoon, seemed to result from a long range transport which was confirmed by the study of wind roses.     

Airborne pollen and spores of León (Spain)

A qualitative and quantitative analysis of airborne pollen and spores was carried out over 2 years (from September 1987 to August 1989) in the city of León. Slides were prepared daily using a volumetric pollen trap, which was placed on the Faculty of Veterinary Science building (University of León) 12m above ground-level. Fifty-one pollen types were observed; the most important of these were: Cupressaceae during the winter,Pinus andQuercus in spring, and Poaceae, Leguminosae and Chenopodiaceae in the summer. The results also showed the existence of a rich mould spore assemblage in the atmosphere. The group of Amerospores (Penicillium, Aspergillus andCladosporium) as well as Dictyospores (Alternaria) were the most abundant;Puccinia was common in the air in August. Fluctuations in the total pollen and spores m³ of air were compared with meteorological parameters (temperature, relative humidity and rainfall). From the daily sampling of the atmosphere of León, considering the maximum and minimum temperature and duration of rainfall, the start of the pollen grain season was observed generally to coincide with a rise in temperature in the absence of rain.     

Airborne pollen concentrations,solid particle content in the air and allergy symptoms in Córdoba (Spain)

During 1991 and 1992, hourly measurements were taken of solid particulates (size, 22–25 μm).Olea and grass pollen and spores. The results were then compared with symptoms recorded in patients consulting the Allergy Unit during the period of highest pollen concentrations (April–June). The spore-trap slides were studied by spectrophotometry in order to analyse the total solid particulates content in the air as a possible synergic agent of the pollen. This allowed the volume of material present in the air to be determined and expressed as a percentage of total optical density (OD). Allergy symptom data were obtained from the study of subjective clinical records completed by patients, who were required to note down the severity of a selected series of symptoms every 4 h using a scale from 0–3. The results showed a clear link during the season between hourly peaks and pollen concentrations, and the different patterns of response associated with the dominant pollen types. An attempt has been made to determine whether a relationship exists between the increment of the optical density and the symptomatic response. The positive relationship encountered seems to indicate that a synergic agent takes an active part in the effects produced by pollen in the patients.     

Anther cultures of tetraploid Solanum genotypes—the influence of gelling agents and correlations between incubation temperature and pollen germination temperature

Four tetraploid potato genotypes (194.10, 199.13, 201.5, 201.12) were examined in anther culture. The androgenic responses were in general high. Cv. 199.13 contributed with the best response, varying between 0.38 and 0.55 embryoids per anther. Gellan gum or potato starch were used as gelling agents in a double-layer medium. Anthers incubated on potato starch gave a higher embryo yield in the beginning of the culture period, compared to anthers cultivated on gellan gum. The number of embryoids per anther, however, was higher on gellan gum at the end of the culture period. Anther cultures of potato were incubated in two different temperatures (20 °C and 25 °C), and the highest embryo yield was obtained in 25 °C except for genotype 201.12 where no difference was found between the two temperatures. Experiments with pollen germination in various temperatures (10 °C and 20 °C) were correlated to anther culture experiments. Also in case of pollen germination, genotype 201.12 was temperature-independent, while germination was stimulated by higher temperatures in the other genotypes.     

Patterns in the Distribution of Cladocerans (Crustacea: Branchiopoda) in Lakes Across a North–south Transect in Alaska, USA

The remains of cladocerans were examined from the surface sediments of 51 freshwater sites along a north–south transect spanning Alaska. We identified 27 cladoceran taxa from the sediments, consisting primarily of littoral chydorid species. Variations in cladoceran assemblages were related to measured physical and chemical variables using multivariate techniques. Redundancy analysis (RDA) indicated that lake depth, total phosphorus (TP), and altitude all had a significant influence in determining the composition of cladoceran assemblages. Cladoceran communities in tundra and forest-tundra lakes, which were relatively shallow and nutrient-poor, had relatively low abundances of pelagic Cladocera, and were primarily composed of several littoral chydorid species. Among pelagic cladoceran species, there was a distinct shift in dominance from the Bosminidae in lakes in the southern boreal forest region to Daphniidae in lakes in the northern boreal forest. Daphnia dominated lakes had significantly higher total phosphorus, specific conductivity, and calcium concentrations than lakes dominated by Eubosmina. Overall, the relative importance of physical and chemical factors in structuring cladocerans is similar to other previously studied regions, and suggests the Cladocera may be useful as ecological and paleoenvironmental indicators in this region.     

Airborne pollen of entomophilous plants and spores of pteridophytes in Rzeszów and its environs (SE Poland)

Airborne pollen of entomophilous plants occurred in low or very low concentrations, and constituted 4 of the total pollen sum. In 1997–2002, between 18 and 26 taxa were identified. Out of this large group the following taxa were represented in larger concentrations every year– Salix, Acer, Morus, Cichorioideae, Asterioideae, Plantago major/media, Sambucus nigra and Tilia. Microscopic examination revealed that pollen grains of the above mentioned species were often glued together, which is a typical adaptation to this kind of pollination. Club moss (Lycopodium spp.) and horsetail (Equisetum spp.) spores were recorded sporadically. Fern spores were found frequently but in very low numbers. In 2002 the occurrence of the airborne pollen of entomophilous plants in the city and in the countryside was compared. A higher percentage value of pollen was found in the atmosphere of the city rather than in the countryside, due to the high concentration of Acer pollen, which is a partly entomophilous species and common in municipal plantings. In the countryside air there was a higher concentration of pollen from purely entomophilous species, such as Viburnum and Asteroideae.     

Integration of flowering dates in phenology and pollen counts in aerobiology: analysis of their spatial and temporal coherence in Germany (1992–1999)

We studied the possibility of integrating flowering dates in phenology and pollen counts in aerobiology in Germany. Data were analyzed for three pollen types (Betula, Poaceae, Artemisia) at 51 stations with pollen traps, and corresponding phenological flowering dates for 400 adjacent stations (< 25 km) for the years 1992–1993 and 1997–1999. The spatial and temporal coherence of these data sets was investigated by comparing start and peak of the pollen season with local minima and means of plant flowering. Our study revealed that start of birch pollen season occurred on average 5.7 days earlier than local birch flowering. For mugwort and grass, the pollen season started on average after local flowering was observed; mugwort pollen was found 4.8 days later and grass pollen season started almost on the same day (0.6 days later) as local flowering. Whereas the peak of the birch pollen season coincided with the mean flowering dates (0.4 days later), the pollen peaks of the other two species took place much later. On average, the peak of mugwort pollen occurred 15.4 days later than mean local flowering, the peak of grass pollen catches followed 22.6 days after local flowering. The study revealed a great temporal divergence between pollen and flowering dates with an irregular spatial pattern across Germany. Not all pollen catches could be explained by local vegetation flowering. Possible reasons include long-distance transport, pollen contributions of other than phenologically observed species and methodological constraints. The results suggest that further research is needed before using flowering dates in phenology to extrapolate pollen counts.     

Pollen–pistil relationships and pollen size-number trade-off in species of the tribe Lycieae (Solanaceae)

Pollen volume may be involved in different associations with other floral traits. Particularly, the literature indicates that pollen volume can be implicated in a functional relationship with pistil length, and that it may be affected by a trade-off with pollen number because of the subdivision of limited resources. To assess these associations, pollen volume was subjected to correlation analyses with pollen number and pistil length in 20 Argentinean and Chilean taxa of the monophyletic tribe Lycieae. Depending on the mechanisms operating on pollen size and number, the variability of these traits may be different. Therefore, their coefficients of variation were compared. Pistil length and pollen volume showed a strong positive correlation. In contrast, pollen grain size and number were significantly correlated at neither inter- nor intraspecific levels. Results suggest that pollen size and pistil length may co-evolve. The central role of this interaction is discussed. The lack of a correlated variation in pollen size and number may be related to the similar constraints experienced by the species and/or because constraints are operating at the plant level and not at the species level. Lower variance in pollen size compared with pollen number denotes that pollen size may be the main trait subjected to natural selection. Electronic Publication     

Airborne pollen of Betula,Corylus and Alnus in Zagreb,Croatia. A three‐year record

The aim of this study was to construct a picture of the influence of meteorological conditions on the start and duration of the airborne Betulaceae pollen season and the pollen concentrations in the atmosphere of Zagreb, Croatia. The study during three seasons (2002–2004) used a 7‐day Hirst‐type volumetric pollen and spore trap. Total annual airborne pollen of Alnus, Corylus and Betula greatly varied from year to year. The differences in the dates of onset of airborne pollen presence of Alnus, Corylus and Betula noted in Zagreb in 2002–2004 were controlled by weather conditions, particularly temperature and precipitation. In all years studied, airborne pollen peaks were recorded on days with temperature above 0°C and without or minimal precipitation. The mean number of days with airborne pollen concentrations exceeding levels which provoke symptoms of an allergic reaction was 15, 16 and 29 days for alder, hazel and birch, respectively. The results of the present study may provide useful data for allergologists to reach accurate diagnoses, and timely information on concentrations of airborne pollen types and concentrations for individuals with pollen hypersensitivity.     

Effect of air temperature on forecasting the start of the Betula pollen season at two contrasting sites in the south of Europe (1995–2001)

In order to survive periods of adverse cold climatic conditions, plant requirements are satisfied by means of physiological adaptations to prevent cells from freezing. Thus, the growth of woody plants in temperate regions slows down and they enter into a physiological state called dormancy. In order to identify the chilling and heat requirements to overcome the dormancy period of Betula in the south of Europe, a comparative study was carried out with aerobiological pollen data of a 7-year (1995-2001) period in Vigo (Spain) and Perugia (Italy). To satisfy chilling requirements, base temperatures of 7 degrees C and 5.75 degrees C showed a lower standard variation coefficient: 3.94% and 2.36% in Perugia and Vigo respectively. In the case of heat accumulation, the sum of mean temperatures in Perugia and the sum of maximum temperatures in Vigo were the parameters that showed a minor coefficient of variation (11.13% and 14.51% respectively).     

Seasonal and synoptic climatic drivers of tree growth in the Bighorn Mountains,WY, USA (1654–1983 CE)

In the United States’ (US) Northern Rockies, synoptic pressure systems and atmospheric circulation drive interannual variation in seasonal temperature and precipitation. The radial growth of high-elevation trees in this semi-arid region captures this temperature and precipitation variability and provides long time series to contextualize instrumental-era variability in synoptic-scale climate patterns. Such variability in climate patterns can trigger extreme climate events, such as droughts, floods, and forest fires, which have a damaging impact on human and natural systems. We developed 11 tree-ring width (TRW) chronologies from multiple species and sites to investigate the seasonal climatic drivers of tree growth in the Bighorn Mountains, WY. A principal component analysis of the chronologies identified 54% of shared common variance (1894–2014). Tree growth (expressed by PC1) was driven by multiple seasonal climate variables: previous October and current July temperatures, as well as previous December and current April precipitation, had a positive influence on growth, whereas growth was limited by July precipitation. These seasonal growth-climate relationships corresponded to circulation patterns at higher atmospheric levels over the Bighorn Mountains. Tree growth was enhanced when the winter jet stream was in a northward position, which led to warmer winters, and when the spring jet stream was further south, which led to wetter springs. The second principal component, explaining 19% of the variance, clustered sites by elevation and was strongly related to summer temperature. We leverage this summer temperature signal in our TRW chronologies by combining it with an existing maximum latewood density (MXD) chronology in a nested approach. This allowed us to reconstruct Bighorn Mountains summer (June, July, and August) temperature (BMST) back to 1654, thus extending the instrumental temperature record by 250 years. Our BMST reconstruction explains 39–53% of the variance in regional summer temperature variability. The 1830s were the relatively coolest decade and the 1930s were the warmest decade over the reconstructed period (1654–1983 CE) – which excludes the most recent 3 decades. Our results contextualize recent drivers and trends of climate variability in the US Northern Rockies, which contributes to the information that managers of human and natural systems need in order to prepare for potential future variability.     

Modifiers of the temperature–mortality association in Shanghai, China

Various factors can modify the health effects of temperature. Prior findings about modifiers are inconsistent, and such studies have been conducted mostly in developed countries. We conducted a time-series analysis to examine the modifying effect of gender, age and education on the association between temperature and daily mortality in Shanghai, China, using 4 years (2001–2004) of daily data. A natural spline model was used to analyze the data. Elderly subjects were found to be more vulnerable to temperature health effects compared with younger people. We observed no significant modifying effect of gender or education level. These findings may provide useful information for local governments seeking to take steps to protect vulnerable sub-populations.     

Flora and fauna of the sublittoral hard substrata in the Oosterschelde (The Netherlands) — interactions with the North Sea and the influence of a storm surge barrier

Since 1979 the flora and fauna of the artificial rocky shores of the Oosterschelde estuary have been investigated by diving biologists.Spatial and temporal patterns of species diversity and biomass were studied and several groups of species (communities) were distinguished. A west-east gradient in species composition was found. Species distribution proved to be mainly determined by current velocities, silt and plankton concentrations in the water, underwater irradiance, and the nature of the substratum. Some indications of migration between the basin and the North Sea are shown. Biomass of the hard substratum fauna was compared with that of the soft bottom fauna; the ratio appeared to be about 1 : 2, which is surprisingly high considering the small area available for hard substratum fauna.The key to the interactions with the North Sea is found in the water movements and the volume of water passing through the mouth of the basin during each tide. The abiotic and subsequent biotic changes in the basin caused by the building of the storm surge barrier are discussed, and used to illustrate the measure of dependence of the Oosterschelde on the North Sea.     

Annual variation of airborne pollen in the city of Palencia,Spain, 1990–1992

The aim of this work is to present the atmospheric pollen concentrations of Palencia, Spain. Data were collected for three consecutive years (1990–92). An active volumetric pollen trap, type CAP2, was used. During this time, 88 different pollen types were identified, of which 27 occured at more than 0.15% of the total pollen recorded annually. These types formed the main pollen spectrum of this sampling station. Pollen coming from herbs (Poaceae, Chenopodiaceae, Plantago Urticaceae, etc.) was predominant (53.79%); arboreal pollen (Quercus, Populus Cupressaceae, etc.) represented 42.11%, and pollen from shrubs (Ericaceae, Sambucus etc.) only 4.10%.

May and June was the time of the year with maximum pollen emission to the air. This was due to the quantities of pollen coming from Poaceae and Quercus which together represent 47.25% of the pollen recorded over the three‐year sampling period. Herbaceous pollen appeared throughout the year with maximum concentrations recorded in the spring, coinciding with the maximum levels of arboreal pollen in the atmosphere.

An analysis of multiple regression and one‐way anova test between pollen concentrations and selected meteorological parameters show that relative humidity and average temperature are the meteorological factors most correlated with the concentrations of specific pollen types (Plantago, Ligustrum, Sambucus, Carex). In the same way, when the winds are predominantly from the northeast (second quadrant), there are higher pollen concentrations of Sambucus Ericaceae and Mercurialis.     

Tree-ring-based reconstruction of drought variability (1792–2011) in the middle reaches of the Fen River,North China

We developed a tree-ring chronology based on 52 ring-width series from 25 Pinus tabulaeformis trees at Tianlong Mountain (TLM) using the signal-free method. TLM is located in the middle reaches of the Fen River, North China, and is influenced by the East Asian monsoon system. Tree growth was highly correlated (0.789) with the Palmer Drought Severity Index (PDSI) from May to July and indicated a drought-stress growth pattern. Therefore, we developed a robust May-July PDSI reconstruction for 1792–2011 that explained 62.3% of the instrumental variance for 1951–2005. Severe drought years determined by the reconstruction are consistent with conditions reported in historical documents. The TLM PDSI reconstruction was consistent with other tree-ring-based hydroclimate reconstructions in North China; thus, it may accurately represent dry/wet changes that occur over a large area. Cyclical spectral peaks at 2–8 years in the reconstructed PDSI may indicate ENSO activity, as suggested by the positive correlation with the western Pacific sea-surface temperatures (SSTs) and the negative correlation with the eastern Pacific SSTs on the inter-annual scale.     

Occurrence of the toxigenic fungi (producers of aflatoxins and ochratoxin A) in foodstuffs in the Czech Republic 1999–2000

The occurrence of toxigenic fungi producing aflatoxins and ochratoxin A in foodstuffs was studied in the Czech Republic. Twenty five commodities were collected at twelve collection places in the Czech Republic (300 food samples). The presence of potentially toxigenicAspergillus flavus was observed in 28% of the sampled foods (black pepper, caraway seeds, fruit tea, black tea, oat flakes, fine flour, rolled oat flakes and semolina) in the year 1999, and in 25% of the sampled foods (black pepper, black tea, fine flour) in the year 2000.A tamarii (aflatoxins producer) was found in 3 black pepper samples (25%) in both years. Aflatoxins were detected in black pepper and caraway seed samples in the year 1999 and in sweet red pepper in the year 2000.A parasiticus andA nomius were not isolated. Aspergillus section Nigri (potential producer of ochratoxin A) was detected in some foodstuffs. Ochratoxin A was detected in raisins.Penicillium verrucosum andA ochraceus were not isolated from foodstuffs.     

Response of Betula glandulosa seedlings to simulated increases in nutrient availability,temperature and precipitation in a lichen woodland at the forest–tundra ecotone

Over the last few decades, shrub species have expanded rapidly in open tundra environments due to climate change. Previous experimental studies in this environment have shown that nutrient addition and, to a lesser extent, warming, had positive effects on shrub growth. However, the response of shrub species in open forested ecosystems such as lichen woodland is still largely unknown. The main objective of this study was to evaluate the performance of Betula glandulosa (Michx., dwarf birch) seedlings subjected to direct (warmer temperature, increased precipitation) and indirect (increased nutrient availability) effects of climate change in a lichen woodland (25 % tree cover). The study took place 10 km south of the subarctic treeline in western Québec (Canada). At the end of the second growth season, seedling leaf, woody stem and root biomass along with leaf area had increased significantly in response to nutrient addition. Moreover, seedlings exposed to nutrient addition had greater nitrogen, phosphorus and potassium concentrations in their leaves. Warming treatment also had a significant but weaker impact on leaf and woody stem biomass, while increase in precipitation had only a slight impact on seedling root biomass. Our results indicate that B. glandulosa response to simulated changes in the abiotic environment is similar to that observed in open tundra, suggesting that this species could also become more widespread in the forested ecosystems of the forest–tundra ecotone.     

A three year (1993–1995) calendar of pollen and Alternaria mould in the atmosphere of south western Sydney

The relevance of allergy skin prick testing in the diagnosis and treatment of seasonal allergic rhinitis and pollen asthma can usefully be interpreted in relation to the timing and duration of seasonal symptoms and the presence of pollen and mould spores in the air. This calendar has been constructed from three years continuous observations of pollen and Alternaria mould spore counts between January 1993 and December 1995, using a Burkard 7‐day volumetric spore trap. Of the total airborne pollen, tree pollen comprises 65%, weeds and herbs 11% and grasses 18%. Unidentified pollen, “other”; group, accounts for 6% of the total airborne pollen. The most numerous of the tree pollen is that of the introduced trees cypress (Cupressus spp.) and privet (Ligustrum spp.). Grass pollen is seen in small numbers throughout the winter but shows a rapid increase in spring to peak in mid to late November. Weeds pollinate from early spring through to summer. Alternaria mould, which is a risk factor for childhood asthma, occurs mainly in late spring and summer but is present in small numbers intermittently throughout winter.