Poaceae Pollen Research Articles

Anthropic pollen indicators: poaceae pollen of non-native species in Southern Brazil

Anthropic pollen indicators: poaceae pollen of non-native species in Southern Brazil

How to prepare a pollen calendar for forecasting daily pollen concentrations of Ambrosia, Betula and Poaceae?

Forecasting daily airborne pollen concentrations is of great importance for management of seasonal allergies. This paper explores the performance of the pollen calendar as the most basic observation-oriented model for predicting daily concentrations of airborne Ambrosia, Betula and Poaceae pollen. Pollen calendars were calculated as the mean or median value of pollen concentrations on the same date in previous years of the available historic dataset, as well as the mean or median value of pollen concentrations of the smoothed dataset, pre-processed using moving mean and moving median. The performance of the models was evaluated by comparing forecasted to measured pollen concentrations at both daily and 10-day-average resolutions. This research demonstrates that the interpolation of missing data and pre-processing of the calibration dataset yields lower prediction errors. The increase in the number of calibration years corresponds to an improvement in the performance of the calendars in predicting daily pollen concentrations. However, the most significant improvement was obtained using four calibration years. The calendar models correspond well to the shape of the pollen curve. It was also found that daily resolution instead of 10-day averages adds to their value by emphasising variability in pollen exposure, which is important for personal assessment of dose-response for pollen-sensitive individuals.

ИЗМЕНЕНИЕ ЛАНДШАФТНО-КЛИМАТИЧЕСКИХ УСЛОВИЙ ПРИАЗОВЬЯ В СРЕДНЕМ И ПОЗДНЕМ ГОЛОЦЕНЕ, "Известия Российской академии наук. Серия географическая"

The article presents the results of the pollen analysis of the marine sediments of the Azov Sea. Conducted research of subrecent pollen spectra of surface sediment layer is allowed to form an idea of the character of vegetation cover of the coast. The composition and ratio of the main spectrum components agree well with the structure of the surrounding steppe communities, which indicates the prospectivity of the method for regional paleoreconstructions. According to the obtained radiocarbon data, the studied marine sediments were formed during the last 6500 calendar years BP. In the pollen spectra of most columns, there is a high content of pollen of herbaceous plants (80% on average). The group of grasses is dominated by pollen of Chenopodiaceae, Artemisia and Poaceae, in addition, there is a permanent presence of pollen grains of indicative species of dry steppe communities (Ephedra, Plumbaginaceae). However, vegetation cover and climate did not remain constant. A set of phases had been revealed for the last 6500 calendar years BP, namely, 6200–5700, 5500–4000, 3200–2500, 1800–1500, and 650–150 calendar years ago BP, characterized by a significant increase in the amount of pollen of tree species (up to 40%). During these phases, probably, there was the expansion of the area occupied by the forest vegetation in valleys of large rivers under more humid climatic conditions.

The allergenic pollen in the atmosphere of El-Hadjar city (Annaba, Algeria)

The aeropalynogical study of the atmosphere of El-Hadjar town was carried out during one year, from June 1, 2012 to May 31, 2013. The collected pollen during the sampling period yielded 2729 pollen grains/cm2 belonging to 50 taxa, distributed on 20 families (Apiaceae, Arecaceae, Asteraceae, Boraginaceae, Brassicaceae, Caryophyllaceae, Chenopodiaceae/Amaranthaceae, Cupressaceae, Cyperaceae, Ericaceae, Fabaceae, Lamiaceae, Mimosaceae, Pinaceae, Poaceae, Rosaceae, Scrophulariaceae, Ulmaceae, Urticaceae and Vitaceae.); 24 genera (Alnus, Artemisia, Betula, Borago, Carya, Casuarina, Echium, Ephedra, Eucalyptus, Fraxinus, Juglans, Juncus, Ligustrum, Mercurialis, Melia, Pistacia, Plantago, Platanus, Populus, Quercus, Rumex, Salix, Tilia and Trifolium.) and, 6 species (Castanea sativa, Corylus avellana, Olea europaea, Quercus ilex, Ricinus communis and Typha angustifolia). The pollen peak concentration was recorded in April with 715 GP/cm2 and the minimum value in October with 36.08 GP/cm2. The pollen spectrum has a percentage of 52.31% of pollen tree. The Cupressaceae family contributed with 12.84%, Olea europaea with 6.95%, Eucalyptus and Casuarina with 5.85 and 5.71%. The highest percentage of this type of pollen occurs in November with 90.51%, dominated by Casuarina pollen with 86.31%. The highest concentrations of tree taxa are: Eucalyptus (35.03%) and Ligustrum (16.21%) in June. Fraxinus with 64.64% in December, Ericaceae 17.42% in March; Olea europaea and Quercus in April with 18.86% and 6.79% respectively. The pollens of the herbs present 44.89%. They are characterized by the major presence of Poaceae and Mercurialis pollen with the following percentages: 21.49% and 11.75%. It seems that the months of July (86.33%) and August (80.14%) mark the highest percentages of non-tree pollen

Comparative palynology of Macrotermes sp. mounds and Vespula vulgaris nests on the University of Lagos campus, Akoka: preliminary study

AbstractIn order to assess the environmental indicator potential of wasp nests and termite mounds, the palynomorph content of three randomly selectedMacrotermessp. mounds (termitaria) and twoVespula vulgarisnests collected on the University of Lagos campus were examined. Palynological analysis showed the presence of 298 well-preserved palynomorphs showing characteristic morphological features. The recovered palynomorphs included pollen, pteridophyte spores and fungal spores, along with insect parts (106), diatoms (7) and a protist (1). The pollen assemblage of termite mounds comprised 78 pollen and pteridophyte spores, with Poaceae and Arecaceae pollen as dominants. In the wasp nest the pollen assemblage comprised 28 pollen and spore taxa, with Poaceae and Arecaceae pollen also dominant. Both mounds and nests had, besides diatoms, six pollen and spore taxa: Poaceae, Amaranthaceae, Pteridophyte spores, Arecaceae,Raffiasp. andRhizophorasp. Vegetational grouping of the recovered pollen and spores indicated five phytoecological groups: secondary forest, mangrove swamp forest, freshwater, open vegetation and Poaceae. In statistical analyses, termite mounds had a higher species richness value (2.08 as compared to 1.99 from the wasp nests), while the wasp nests had a higher species diversity value (0.997 as compared to 0.845 from the termite mounds). Pollen analyses of the termite mounds and wasp nests suggest that both could be useful tools in environmental studies. This is the first attempt to evaluate the potential of termite mounds and wasps nest as natural pollen accumulators in Nigeria. The results suggest new possibilities for the use of the pollen records preserved in termite mounds and wasp nests for environmental studies.

Access of Dynamics Vegetation during Holocene by Poaceae Pollen Grains

Access of Dynamics Vegetation during Holocene by Poaceae Pollen Grains

Last millennial environmental dynamics in the western Peruvian Andes inferred from the development of a cushion-plant peat hillock

For the first time, an isolated cushion-plant peat hillock was investigated, a so far neglected feature of high-Andean spring ecosystems. These small hillocks typically cluster around springs within the upper catchment areas of larger cushion-plant peatlands at altitudes ranging from 4000 m to 5000 m a.s.l.The size of the investigated peat hillock, located within the Río Viscas catchment area (Lucanas province, District of Ayacucho) at 4250 m a.s.l., is relatively small (about 10 m in diameter). Due to its dome-shaped and densely green habitus, it overlooks the surrounding vegetation by about 1–2 m and stands out by its color. Terrestrial laser scanning (TLS) techniques are used in order to provide insights into the spatial extension of the Distichia muscoides-dominated vegetation stand.For the reconstruction of environmental dynamics during the past millennium, plant micro-/macrofossil analyses and total carbon/total nitrogen measurements were applied. Based on radiocarbon dating, the peat archive provides a chronology for the past 1050 years. We interpret phases of relatively high abundances of Poaceae pollen in our record as an expansion of Andean grasslands during humid phases. Drier conditions are indicated by a decrease of Poaceae pollen and higher abundances of Asteraceae pollen. The results reflect significant climate oscillations and provide evidence for a sustained dry phase between AD 900 and AD 1100. A more humid and cooler phase prevailed from around AD 1300 to AD 1825, during the Little Ice Age.Our data provide evidence that such a spatially defined peat-accumulating ecosystem, as represented by the studied peat hillock, is capable to survive pronounced climatic oscillations as long as it does not lose its protective cushion-plant surface. As peat hillocks are heavily affected by grazing, multitemporal studies should be carried out to document changes and to provide new insights into adaption strategies of vegetation to changing environmental conditions.

Annual Records of Airborne Pollen of Poaceae in Five Areas in Lagos, Nigeria

Poaceae pollen grains are known to be highly allergenic and they are potential causes of allergic respiratory diseases. In order to investigate the incidence of airborne Poaceae, and contribute to current trends in the development of aeropalynology/allergy studies in Nigeria, five highly populated locations in Central Lagos State, Surulere, Ebute-Metta, University of Lagos, Bariga and Gbagada, were sampled. Gravimetric aerosamples were collected monthly from January 2013 to December 2014. The lowest count in 2013 was recorded in the Ebute-Metta area (179), while the highest in 2013 was recorded in Gbagada (564). In 2014, the Surulere area (282) had the lowest count while Bariga (671) had the highest. The locations have similar monthly pollen distribution pattern but different peak months. Generally, Poaceae pollen counts were lowest in the months of June and July. These are therefore the safest months for Poaceae pollen hypersensitive individuals in the study areas. Relative humidity was the most important meteorological parameter with significant correlations in Ebute-Metta and Bariga locations. Results from this work will form the basis for a forecast service required to inform and educate the general public and allergy sufferers about Poaceae pollen distribution in Lagos State.

Pollen morphology of the Poaceae: implications of the palynological and paleoecological records of the southeastern Amazon in Brazil

ABSTRACTA detailed assessment of Poaceae pollen morphology was performed using light and scanning electron microscopy (LM and SEM, respectively), digital image processing and multivariate data analysis of species from the montane savanna (canga vegetation) of the Serra dos Carajas region in the southeastern Amazon to discriminate the lower taxonomic levels and, accordingly, the habitat types of Poaceae. Poaceae pollen are generally stenopalynous monoporate grains with annulate and operculate pores, and distinguishing species by ornamentation using LM is impossible. Under SEM, Poaceae have mainly areolate microechinate/granulose ornamentation, except for Eragrostis maypurensis (rugulate-microechinate), Andropogon bicornis, Trichanthecium parvifolium and T. polycomum (rugulate granulose), and Rhytachne gonzalezii (microechinate). Digital image processing of ornamentation under SEM coupled with multivariate data analysis allowed for differentiation between the E. maypurensis, R. gonzalezii, A. capillaris, Otachyrium versicolor, Paspalum carinatum and T. polycomum. Distinguishing species of the wet savanna, such as Isachne polygonoides, R. gonzalezii, O. versicolor, P. virgatum, and T. polycomum, from species of the dry savanna can improve paleoecological and paleoclimatic interpretations.

Poaceae pollen in the atmosphere of Tetouan (NW Morocco): effect of meteorological parameters and forecast of daily pollen concentration

The Poaceae pollen season has been characterized in Tetouan during a 7-year period, and the effect of weather conditions on daily concentrations was examined. The forecast models were produced using a stepwise multiple regression analyses. Firstly, three models were constructed to predict daily Poaceae pollen concentrations during the main pollen season, as well as the pre-peak and post-peak periods with data from 2008 to 2012 and tested on data from 2013 and 2014. Secondly, the regression models using leave-one-out cross-validation were produced with data obtained during 2008–2014 taking into account meteorological parameters and mean pollen concentrations of the same day in other years. The duration of the season ranged from 70 days in 2009 to 158 days in 2012. The highest amount of Poaceae pollen was detected in spring and the first fortnight of July. The annual sum of airborne Poaceae pollen concentrations varied between 2100 and 6251. The peak of anthesis was recorded in May in six of the other years studied. The regression models accounted for 36.3–85.7% of variance in daily Poaceae pollen concentrations. The models fitted best when the mean pollen concentration of the same day in other years was added to meteorological variables, and explained 78.4–85.7% of variance of the daily pollen changes. When the year 2014 was used for validating the models, the lowest root-mean-square errors values were found between the observed and estimated data (around 13). The reasonable predictor variables were the mean pollen concentration of the same day in other years, mean temperature, precipitations, and maximum relative humidity.

Poaceae pollen as the leading aeroallergen worldwide: A review.

The Poaceae family comprises over 12 000 wind-pollinated species, which release large amounts of pollen into the atmosphere. Poaceae pollen is currently regarded as the leading airborne biological pollutant and the chief cause of pollen allergy worldwide. Sensitization rates vary by country, and those variations are reviewed here. Grass pollen allergens are grouped according to their protein structure and function. In Poaceae, although species belonging to different subfamilies are characterized by distinct allergen subsets, there is a considerable degree of cross-reactivity between many species. Cross-reactivity between grass pollen protein and fresh fruit pan-allergens is associated with the appearance of food allergies. The additional influence of urban pollution may prompt a more severe immunological response. The timing and the intensity of the pollen season are governed by species genetics, but plant phenology is also influenced by climate; as a result, climate changes may affect airborne pollen concentrations. This article reviews the findings of worldwide research which has highlighted the major impact of climate change on plant phenology and also on the prevalence and severity of allergic disease.

Estimating the abundance of airborne pollen and fungal spores at variable elevations using an aircraft: how high can they fly?

Airborne pollen and fungal spores are monitored mainly in highly populated, urban environments, for allergy prevention purposes. However, their sources can frequently be located outside cities’ fringes with more vegetation. So as to shed light to this paradox, we investigated the diversity and abundance of airborne pollen and fungal spores at various environmental regimes. We monitored pollen and spores using an aircraft and a car, at elevations from sea level to 2,000 m above ground, in the region of Thesssaloniki, Greece. We found a total of 24 pollen types and more than 15 spore types. Pollen and spores were detected throughout the elevational transect. Lower elevations exhibited higher pollen concentrations in only half of plant taxa and higher fungal spore concentrations in only Ustilago. Pinaceae and Quercus pollen were the most abundant recorded by airplane (>54% of the total). Poaceae pollen were the most abundant via car measurements (>77% of the total). Cladosporium and Alternaria spores were the most abundant in all cases (aircraft: >69% and >17%, car: >45% and >27%, respectively). We conclude that pollen and fungal spores can be diverse and abundant even outside the main source area, evidently because of long-distance transport incidents.

Poaceae Pollen from Southern Brazil: Distinguishing Grasslands (Campos) from Forests by Analyzing a Diverse Range of Poaceae Species.

This aim of this study was to distinguish grasslands from forests in southern Brazil by analyzing Poaceae pollen grains. Through light microscopy analysis, we measured the size of the pollen grain, pore, and annulus from 68 species of Rio Grande do Sul. Measurements were recorded of 10 forest species and 58 grassland species, representing all tribes of the Poaceae in Rio Grande do Sul. We measured the polar, equatorial, pore, and annulus diameter. Results of statistical tests showed that arboreous forest species have larger pollen grain sizes than grassland and herbaceous forest species, and in particular there are strongly significant differences between arboreous and grassland species. Discriminant analysis identified three distinct groups representing each vegetation type. Through the pollen measurements we established three pollen types: larger grains (>46 μm), from the Bambuseae pollen type, medium-sized grains (46–22 μm), from herbaceous pollen type, and small grains (<22 μm), from grassland pollen type. The results of our compiled Poaceae pollen dataset may be applied to the fossil pollen of Quaternary sediments.

Chemotaxonomy as a tool for interpreting the cryptic diversity of Poaceae pollen

The uniform morphology of different species of Poaceae (grass) pollen means that identification to below family level using light microscopy is extremely challenging. Poor taxonomic resolution reduces recoverable information from the grass pollen record, for example, species diversity and environmental preferences cannot be extracted. Recent research suggests Fourier Transform Infra-red Spectroscopy (FTIR) can be used to identify pollen grains based on their chemical composition. Here, we present a study of twelve species from eight subfamilies of Poaceae, selected from across the phylogeny but from a relatively constrained geographical area (tropical West Africa) to assess the feasibility of using this chemical method for identification within the Poaceae family. We assess several spectral processing methods and use K-nearest neighbour (k-nn) analyses, with a leave-one-out cross-validation, to generate identification success rates at different taxonomic levels. We demonstrate we can identify grass pollen grains to subfamily level with an 80% success rate. Our success in identifying Poaceae to subfamily level using FTIR provides an opportunity to generate high taxonomic resolution datasets in research areas such as palaeoecology, forensics, and melissopalynology quickly and at a relatively low cost.

Predicting the Poaceae pollen season: six month-ahead forecasting and identification of relevant features.

In this paper, we approach the problem of predicting the concentrations of Poaceae pollen which define the main pollination season in the city of Madrid. A classification-based approach, based on a computational intelligence model (random forests), is applied to forecast the dates in which risk concentration levels are to be observed. Unlike previous works, the proposal extends the range of forecasting horizons up to 6 months ahead. Furthermore, the proposed model allows to determine the most influential factors for each horizon, making no assumptions about the significance of the weather features. The performace of the proposed model proves it as a successful tool for allergy patients in preventing and minimizing the exposure to risky pollen concentrations and for researchers to gain a deeper insight on the factors driving the pollination season.

Modeling pollen time series using seasonal-trend decomposition procedure based on LOESS smoothing.

Analysis of airborne pollen concentrations provides valuable information on plant phenology and is thus a useful tool in agriculture-for predicting harvests in crops such as the olive and for deciding when to apply phytosanitary treatments-as well as in medicine and the environmental sciences. Variations in airborne pollen concentrations, moreover, are indicators of changing plant life cycles. By modeling pollen time series, we can not only identify the variables influencing pollen levels but also predict future pollen concentrations. In this study, airborne pollen time series were modeled using a seasonal-trend decomposition procedure based on LOcally wEighted Scatterplot Smoothing (LOESS) smoothing (STL). The data series-daily Poaceae pollen concentrations over the period 2006-2014-was broken up into seasonal and residual (stochastic) components. The seasonal component was compared with data on Poaceae flowering phenology obtained by field sampling. Residuals were fitted to a model generated from daily temperature and rainfall values, and daily pollen concentrations, using partial least squares regression (PLSR). This method was then applied to predict daily pollen concentrations for 2014 (independent validation data) using results for the seasonal component of the time series and estimates of the residual component for the period 2006-2013. Correlation between predicted and observed values was r=0.79 (correlation coefficient) for the pre-peak period (i.e., the period prior to the peak pollen concentration) and r=0.63 for the post-peak period. Separate analysis of each of the components of the pollen data series enables the sources of variability to be identified more accurately than by analysis of the original non-decomposed data series, and for this reason, this procedure has proved to be a suitable technique for analyzing the main environmental factors influencing airborne pollen concentrations.

THE DISPERSION OF HERBACEOUS PLANT POLLEN IN ITO CITY, SHIZUOKA.

Airborne pollen was examined in Ito City, Shizuoka for the purpose of treatment and prophylaxis pollen allergies because the patients with pollen allergy to herbaceous plants have recently increased. Setting up a Durham's sampler, we measured airborne pollen identified and classified: Poaceae, Polygonaceae, Amaranthaceae, Urticaceae, Cannabaceae, Ambrosia and Artemisia indica.We studied whether each airborne pollen count has something to do with weather condition (2004-2015). Average total airborne Poaceae pollen count and standard deviation from January to June was 19.4±5.5 cells/cm(2), average total airborne Polygonaceae pollen count and standard deviation from April to September was 11.6±13.4 cells/cm(2). Airborne Poaceae, Amaranthaceae, Cannabaceae, Uriticaceae. Ambrosia and Artamisia indica pollen count from July to Deccember in order: 34.0±15.5 cells/cm(2), 1.3±1.1 cells/cm(2), 8.7±6.4cells/cm(2), 4.9±6.4 cells/cm(2), 10.5±7.8 cells/cm(2), and 13.6±16.3 cells/cm(2).Cannabaceae admitted that its airborne pollen count has negative correlation to the rainfall.Artemisia indica admitted that its airborne pollen count has negative correlation to the average temperature. Herbaceous plants pollen doesn't cause allergies because it is much less than tree pollen in ItoCity.It is thought that the diversity of the plants keep the people from having a serious allergy to pollen with awarm weather in this area.

First aerobiological study in Mediterranean part of Croatia (Dalmatia): pollen spectrum and seasonal dynamics in the air of Split

The aim of this study was to investigate aerobiological dynamics of pollen in the Mediterranean part of Croatia in the air of the city of Split. Pollen monitoring during the period from 2005 to 2013 was performed using a Hirst volumetric trap. Among the identified pollen of 50 taxa, 21 were allergenic. The average annual pollen index was 33,513. Three pollination seasons were established: early winter season dominated by tree pollen, spring–summer season dominated by herbaceous plants and summer–autumn season with lower amounts of Parietaria and Cupressaceae pollen. According to the abundance, the main taxa were: Cupressaceae, Parietaria/Urtica, Pinus, Quercus, Olea, Carpinus/Ostrya, Poaceae, Platanus and Ambrosia. The annual pollen index together with the daily maximum concentrations showed an upward trend for selected taxa during the study period. The highest monthly pollen index and the highest biodiversity were recorded in April and the lowest during the late autumn and winter months. The pollen calendar created for the city of Split confirmed Mediterranean features of the pollen spectrum. The longest pollen seasons were recorded for Cupressaceae, Parietaria/Urtica and Poaceae pollen types. The correlations between pollen concentrations and meteorological parameters were analyzed. The correlations between pollen concentrations and temperature were positive, while the humidity and the precipitation mostly showed negative influence.

Pollen- and charcoal-based evidence for climatic and human impact on vegetation in the northern edge of Wuyi Mountains, China, during the last 8200 years

Pollen and charcoal records derived from the sediment core of Lantianyan (LTY) peat bog, Northern Wuyi Mountain chains, eastern subtropical China, provide valuable information of landscape evolution caused by both climatic variation and anthropogenic activities over the past 8200 years. Our results reveal fluvial and lacustrine deposition between c. 8200 and 5600 cal. yr BP. The high proportion of pollen from evergreen broadleaved forests (e.g. Quercus and Castanopsis) and Alnus trees, a taxon frequently occurring in mountain wetlands, implies a humid interval, which is consistent with the Holocene moisture maximum in eastern China. After 5600 cal. yr BP, the spread of the wooded swamp taxon, Glyptostrobus, suggests shallow water conditions and peat formation caused by gradual drying. The drying trend generally corresponds with the speleothem isotope record from this region, revealing a weakening East Asian summer monsoon (EASM) due to a decrease in Northern Hemisphere summer insolation (and in air temperature). Peaks in the abundance and concentration of Glyptostrobus pollen at c. 4600–4400 cal. yr BP and c. 3300–3000 cal. yr BP suggest two periods of swamp expansions, which coincide with the drought intervals revealed by the speleothem records. The LTY pollen and charcoal record demonstrates that human-induced land cover change was negligible before 3600 cal. yr BP. We consider the first signal of intensive human activity and landscape clearing to be the noticeable increase in charcoal particles at around 3600 cal. yr BP. This anthropogenic impact is followed by a dramatic decrease in arboreal pollen and increase in Poaceae pollen percentages, likely reflecting a transition to rice-paddy agriculture in the study area.

Characterisation of the airborne pollen spectrum in Guadalajara (central Spain) and estimation of the potential allergy risk

Aerobiological research into airborne pollen diversity and seasonal variations in pollen counts has become increasingly important over recent decades due to the growing incidence of asthma, rhinitis and other pollen-related allergic conditions. Airborne pollen in Guadalajara (Castilla-La Mancha, Spain) was studied over a 6-year period (2008-2013) using a Hirst-type volumetric spore trap. The highest pollen concentrations were recorded from February to June, coinciding with the pollen season of the pollen types that most contribute to the local airborne pollen spectrum: Cupressaceae (32.2%), Quercus (15.1%), Platanus (13.2%), Olea (8.3%), Populus (7.8%) and Poaceae (7.2%). These are therefore critical months for allergy sufferers. The pollen calendar was typically Mediterranean and comprised 25 pollen types. Between January and March, Cupressaceae pollen concentrations exceeded allergy risk thresholds on 38 days. Other woody species such as Olea and Platanus have a shorter pollen season, and airborne concentrations exceeded allergy risk thresholds on around 13 days in each case. Poaceae pollen concentrations attained allergy risk levels on 26 days between May and July. Other highly allergenic pollen types included Urticaceae and Chenopodiaceae-Amaranthaceae, though these are less abundant than other pollen types in Guadalajara and did not exceed risk thresholds on more than 3 and 5 days, respectively.