共查询到20条相似文献,搜索用时 31 毫秒
1.
Pilvi Siljamo Mikhail Sofiev Elena Severova Hanna Ranta Jaakko Kukkonen Svetlana Polevova Eero Kubin Alexander Minin 《Aerobiologia》2008,24(4):211-230
The paper presents an assessment of birch pollen seasons in Finland and Russia. The re-analysis covered the period from 1994
to 2005 and was focused on suspected long-range transport events that were recorded both in Moscow and at several Finnish
sites. In order to trace the origin of airborne pollen before the onset of local pollination, we used both aerobiological
and phenological observations combined with forward and adjoint (inverse) dispersion model simulations. It is shown that,
although the Moscow region is surrounded by extensive birch forests, it still receives substantial amounts of foreign pollen
before local pollination. In the Moscow region, the sources of long-range-transported pollen are in the south and south-west,
sometimes even in the east. In Finland, there are frequently cases, before the local flowering season, in which Finnish territory
receives Russian pollen; however in the opposite direction, from Finland to the Moscow region, no transport episodes were
unequivocally registered. Analysis of the end of the seasons was more problematic, due to contributions to pollen observations
from local sources; this results in difficulties in the reliable identification of the long-range transport episodes. Apart
from its short-term effects on the pollen seasons, long-range transport can have substantial impacts on the exchange of genetic
material within Europe. A quick atmospheric pathway for gene transport can be important for adaptation of plants to a changing
climate. 相似文献
2.
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. 相似文献
3.
Stein Rune Karlsen Hallvard Ramfjord Kjell Arild Høgda Bernt Johansen Fiona Susan Danks Trond Einar Brobakk 《Aerobiologia》2009,25(1):15-25
Birch (Betula pubescens L.) is by far the most common deciduous tree in Norway and birch forests define the forest line both northwards and upwards.
Because of its mountainous topography, long fjords, and long length from north to south, Norway is climatically and ecologically
very diverse. Therefore, developing pollen forecasts in Norway is a challenging task. In this study we use MODIS-NDVI (normalized
difference vegetation index) satellite data with 250 m spatial resolution and 16-days time resolution for the period 2000–2007,
and birch pollen counts from ten Burkad traps distributed throughout Norway, to characterize the onset of birch flowering
in Norway. Four of the seven trap stations with long-term series show significant values at the 5% level or better between
the MODIS-NDVI defined onset and the date when the annual accumulated birch pollen sum reaches 2.5% of the annual total. A
map of Norway that shows the eight-year mean (2000–2007) onset of birch flowering was produced. It reveals large differences
in the timing of the onset of birch flowering along the north–south and altitude gradients. The map provides useful general
information that can be utilized by the Norwegian pollen forecast service. This study shows that remote sensing is a useful
tool for not only characterizing the onset of the birch pollen season but also revealing regional differences not easily detected
by pollen stations alone. 相似文献
4.
Hanna Ranta Eero Kubin Pilvi Siljamo Mikhail Sofiev Tapio Linkosalo Annukka Oksanen 《Grana》2013,52(4):297-304
The male flowering and leaf bud burst of birch take place almost simultaneously, suggesting that the observations of leaf bud burst could be used to determine the timing of birch pollen release. However, long‐distance transport of birch pollen before the onset of local flowering may complicate the utilization of phenological observations in pollen forecasting. We compared the timing of leaf bud burst of silver birch with the timing of the stages of birch pollen season during an eight year period (1997–2004) at five sites in Finland. The stages of the birch pollen season were defined using four different thresholds: 1) the first date of the earliest three‐day period with airborne birch pollen counts exceeding 10 grains m?3 air; and the dates when the accumulated pollen sum reaches 2) 5%; 3) 50% and 4) 95% of the annual total. Atmospheric modelling was used to determine the source areas for the observed long‐distance transported pollen, and the exploitability of phenological observations in pollen forecasting was evaluated. Pair‐wise comparisons of means indicate that the timing of leaf bud burst fell closest to the date when the accumulated pollen sum reached 5% of the annual total, and did not differ significantly from it at any site (p<0.05; Student‐Newman‐Keuls test). It was found that the timing of leaf bud burst of silver birch overlaps with the first half of the main birch pollen season. However, phenological observations alone do not suffice to determine the timing of the main birch pollen season because of long‐distance transport of birch pollen. 相似文献
5.
Laura Veriankaitė Pilvi Siljamo Mikhail Sofiev Ingrida Šaulienė Jaakko Kukkonen 《Aerobiologia》2010,26(1):47-62
This study analyses the spatial and temporal distribution of regional and long-range transported birch (Betula L.) pollen in Lithuania and the neighbouring countries. The potential long-range transport cases of birch pollen in Lithuania
were analysed for the whole period of available observations, 2004–2007. The birch pollen was recorded at three measurement
stations in Lithuania by using Hirst-type volumetric spore traps. The phenological observations in Lithuania were also used
for the detection of potential long-range transport-induced episodes. Two variants of the regional and continental scale atmospheric
dispersion model SILAM (Lagrangian and Eulerian) in an adjoint mode (used for inverse dispersion modelling and data assimilation),
and the trajectory model HYSPLIT were employed to evaluate the source origins of the observed pollen. During four seasons
in 2004–2007, we found in total 24 cases, during which remarkable pollen concentrations were recorded before the local flowering
season. According to modelling, most of these were originated from the sources outside Lithuania: Latvia, southern Sweden,
Denmark, Belarus, Ukraine and Moldova, possibly, also coastal regions of Germany and Poland. Two episodes were attributed
to local early-flowering birch trees. The spatial and temporal patterns of the long-range transport of early pollen to Lithuania
were found out to be highly variable; the predicted source regions for the cases considered were similar only for some dates
in 2004 and 2006. During the analysed period, we found both cases, in which the predictions of the SILAM model variants and
those of the HYSPLIT model were similar, and cases, in which there were substantial differences. In general, for complicated
atmospheric circulation patterns the model predictions can be drastically different, with a tendency of trajectory model to
fail reproducing the key episode features. 相似文献
6.
Mervi Hjelmroos 《Aerobiologia》1992,8(2):231-236
Summary An example of the potential importance of air masses as carriers of aero-allergens from distant source areas is provided. Considerable amount ofBetula pollen is relatively often transported to Fennoscandia before the local birch flowering period, mainly by southeastern air masses from eastern part of central Europe. Although the distance and the transport time in some cases can be extensive, the pollen grains seem to cause allergic reactions among sensitive persons.A comparison between the clinical results andBetula pollen counts from the time before the local flowering season in Stockholm in 1989 is presented. 相似文献
7.
C. A. Skjøth M. Smith J. Brandt J. Emberlin 《International journal of biometeorology》2009,53(1):75-86
Birch pollen is highly allergenic. Knowledge of daily variations, atmospheric transport and source areas of birch pollen is
important for exposure studies and for warnings to the public, especially for large cities such as London. Our results show
that broad-leaved forests with high birch tree densities are located to the south and west of London. Bi-hourly Betula pollen concentrations for all the days included in the study, and for all available days with high birch pollen counts (daily
average birch pollen counts >80 grains/m3), show that, on average, there is a peak between 1400 hours and 1600 hours. Back-trajectory analysis showed that, on days
with high birch pollen counts (n = 60), 80% of air masses arriving at the time of peak diurnal birch pollen count approached North London from the south in
a 180 degree arc from due east to due west. Detailed investigations of three Betula pollen episodes, with distinctly different diurnal patterns compared to the mean daily cycle, were used to illustrate how
night-time maxima (2200–0400 hours) in Betula pollen counts could be the result of transport from distant sources or long transport times caused by slow moving air masses.
We conclude that the Betula pollen recorded in North London could originate from sources found to the west and south of the city and not just trees within
London itself. Possible sources outside the city include Continental Europe and the Betula trees within the broad-leaved forests of Southern England. 相似文献
8.
This review presents an update on the sources and molecular basis of aeroallergens of plants, derived from pollen, seeds,
leaf and stem detritus and their protein molecules. These aeroallergens are a natural component of the atmosphere, either
because of their natural function or human activity. Pollen is a source of allergens within the 10–200 μm size range, and
while most allergenic pollen types account for only 20–30% of total annual pollen catch, during their flowering season, they
are usually the dominant type. Tree pollen commences the season in winter, with birch pollen counts in Scandinavia being the
highest daily pollen counts yet reported and a major allergen, a 14-kDa protein, which is similar to pathogenesis-related
proteins. Grass pollen follows in spring, and is unique as its two immunodominant allergens, a 35-kDa glycoprotein and 28–32-kDa
protein, are in different cellular sites: the cytosol and surface of pollen grains; and in intracellular starch granules.
The allergens at the pollen surface are not inhalable and can interact only with the eyes, nasal and oral cavities. Starch
granules are released to the atmospheric aerosol when grains rupture in rainwater. These are a major source of allergen-containing
micronic particles, which are important because they are inhalable. At the same time, allergen molecules are present in the
aerosol, and these can bind to soot particles, and so be respired deep into the airways. The major Japanese cedar pollen allergen
has been detected both within the pollen and in orbicules; particles less than 1 μm that line the anther cavity and can be
released into the air when dehiscence occurs. Ragweed is the major cause of late summer hayfever in eastern North America,
where its pollen accounts for up to 41% of the annual pollen catch. It is a major source of aeroallergens in both respirable
and non-respirable size ranges. As a result of human activity, dusts derived from seeds and cereal grains during transport,
storage and milling provide a source of micronic particles, containing potent allergens that can trigger allergic disease. 相似文献
9.
Summary
Betula pollen production and flowering, pollen transport and pollen deposition are considered for the mountain birch region of northern
Finland for the ten-year period 1984–1993. The most abundant flowering year was 1989 and, after that, 1985. In these years
the highest values were also recorded for pollen in the air. There is a significant correlation between the amount of pollen
released and the thermal sum of the previous year. In terms of pollen deposition the peak years were 1989 and 1986. The correlation
between the amount of pollen in the air and that being deposited on the ground is also statisticaly significant. It is evident
that some birch pollen is already present in the air before local flowering begins and that, in some years, this non-local
pollen can account for more than 20% of the yearly total. This preflowering proportion was highest in 1985 and 1993, the latter
being a prolific flowering year in the south of the country. There is a clear relationship between the proportion of the non-local
pollen in the air and the proportion ofBetula pubescens/pendula type pollen deposited on the ground and, conversely, there is a significant correlation between the amount of local pollen
in the air and the amount ofBetula tortuosa plusB. nana type pollen being deposited on the ground. The questions both of the viability of this long-distance pollen and of its ability
to cause allergic reactions are considered. An assessment is also made of the degree to which fossil birch pollen assemblages
can be realistically interpreted in terms of local vegetation if a varying proportion of the same pollen type is non-local. 相似文献
10.
M. Sofiev 《Aerobiologia》2017,33(1):167-179
This discussion paper reveals the contribution of pollen transport conditions to the inter-annual variability of the seasonal pollen index (SPI). This contribution is quantified as a sensitivity of the pollen model predictions to meteorological variability and is shown to be a noticeable addition to the SPI variability caused by plant reproduction cycles. A specially designed SILAM model re-analysis of pollen seasons 1980–2014 was performed, resulting in the 35 years of the SPI predictions over Europe, which was used to compute the SPI inter-annual variability. The current paper presents the results for birch and grass. Throughout the re-analysis, the source term formulations and habitation maps were kept constant, which allowed attributing the obtained variability exclusively to the pollen release and transport conditions during the flowering seasons. It is shown that the effect is substantial: it amounts to 10–20% (grass) and 20–40% (birch) of the observed SPI year-to-year changes reported in the literature. The phenomenon has well-pronounced spatial- and species-specific patterns. The findings were compared with observation-based statistical models for the SPI prediction, showing that such models highlight the same processes as the analysis with the SILAM model. 相似文献
11.
L. Cecchi T. Torrigiani Malaspina R. Albertini M. Zanca E. Ridolo I. Usberti M. Morabito P. Dall’ Aglio S. Orlandini 《Aerobiologia》2007,23(2):145-151
Ragweed is an allergenic weed of public health concern in several European countries. In Italy ragweed occurs prevalently
in north-north-eastern regions, where sensitization is increasing. Because of the small diameter of pollen grains, ragweed
pollen is often involved in episodes of long-range transport, as already shown in central Italy. The objective of this study
was to evaluate the extent of such transport by comparing pollen and meteorological data for two northern Italian cities (Parma
and Mantova) with data from Pistoia and Florence in central Italy. In 2002 and 2004 peaks in ragweed pollen levels were detected
in these four cities on the same day, and concentrations of the grains were above clinical thresholds. Weather-map analysis
and computation of back-trajectories showed that air masses from eastern Europe might carry ragweed pollen to a wide area
of central and northern Italy. These findings suggest that episodes of long-range transport of ragweed pollen could be clinically
relevant, resulting in sensitization of a large number of people. The results might provide a basis for monitoring and forecasting
periods of long-distance transport with the objective of reducing their effects on allergic patients. 相似文献
12.
Pollen forecasts are a fundamental prerequisite to obtain prophylactic measures for allergic individuals. Mugwort belongs
to the most relevant allergenic pollen types after grasses and birch. An approach to modeling of mugwort pollen concentrations
has not been attempted previously in Germany. A process-oriented mathematical model for the relative local daily average mugwort
airborne pollen concentration was developed on the basis of pollen and weather data measured during a 6-year period. The model
depends on the daily minimum and maximum temperature, amount of precipitation and atmospheric pressure, which have to and
can be supplied by measurement and prediction. The comparison of modeling results and pollen counting for an additional year
confirms the fitness of the model. A computer program was written, which rests upon the model and supplies daily predictions
of mugwort pollen flight during the period of the weather forecast. The latter should allow a pollen forecasting period of
about 5 days, with an accuracy of about 32–63% explained variance, which in view of the low mugwort pollen counts (nine grains/m3 maximum in the validation year) represents a high relative measurement error. The mathematical model may serve to improve
and rationalize of present pollen forecasts. 相似文献
13.
Alexander G. Mahura Ulrik S. Korsholm Alexander A. Baklanov Alix Rasmussen 《Aerobiologia》2007,23(3):171-179
The purpose of this study was to investigate the relationship between possible long-distance transport of birch pollen and
episodes of elevated concentration in Denmark. By analysis of a twenty-six year (1980–2006) time-series of bi-hourly birch
pollen counts from two sites (Copenhagen and Viborg) episodes of elevated counts (more than 100 grains) were identified in
fewer than 2% of cases. Trajectory analysis showed that such episodes are primarily associated with long-distance transport
from Eastern Europe and Scandinavia (43 and 33% of events, respectively); the lowest contribution originated from the British
Isles. Long-term episodes (as in 1993 and 2006) occurred when atmospheric conditions favored long-distance transport from
several source regions in succession. 相似文献
14.
M. Sofiev P. Siljamo H. Ranta T. Linkosalo S. Jaeger A. Rasmussen A. Rantio-Lehtimaki E. Severova J. Kukkonen 《International journal of biometeorology》2013,57(1):45-58
A birch pollen emission model is described and its main features are discussed. The development of the model is based on a double-threshold temperature sum model that describes the propagation of the flowering season and naturally links to the thermal time models to predict the onset and duration of flowering. For the flowering season, the emission model considers ambient humidity and precipitation rate, both of which suppress the pollen release, as well as wind speed and turbulence intensity, which promote it. These dependencies are qualitatively evaluated using the aerobiological observations. Reflecting the probabilistic character of the flowering of an individual tree in a population, the model introduces relaxation functions at the start and end of the season. The physical basis of the suggested birch pollen emission model is compared with another comprehensive emission module reported in literature. The emission model has been implemented in the SILAM dispersion modelling system, the results of which are evaluated in a companion paper. 相似文献
15.
Marco Conedera Willy Tinner Sara Crameri Damiano Torriani Anne Herold 《Vegetation History and Archaeobotany》2006,15(4):263-272
The pollen/vegetation relationship in broadleaved forests dominated by Castanea sativa was analysed using an empirical approach. The pollen content of surface sediments of three lake basins of different sizes (6.3, 22.2, and 101.2 ha) in Ticino (southern Switzerland) was used for a comparison with the surrounding vegetation. We surveyed the vegetation around the two small lakes, Lago di Origlio and Lago di Muzzano, and estimated the relative crown coverage of tree species. The regional vegetation outside the lake catchment (ca. >1 km) was determined with the data from the first Swiss National Forest Inventory. For the third large lake, basin of Ponte Tresa, we used only this latter approach for comparison with pollen data. We compare uncorrected and corrected pollen percentages with vegetational data that were processed with distance-weighting functions. To assess the degree of correspondence between pollen and vegetation data we define a ratio pollen/vegetation, which allows a comparison at the taxon level. The best fit between total pollen load and vegetation is reached for a distance from the lake shore of ca. 300 m for Lago di Origlio (150×350 m in size) and of ca. 600 m for Lago di Muzzano (300×750 m in size). Beside these general patterns, our analysis reveals taxon-specific pollen dispersal patterns that are in agreement with results from previous studies in northern Europe. Ratios of species with local (proximal) and long-distance (distal) pollen dispersal provide evidence that pollen dispersal mechanisms can influence the size of the taxon-related pollen source area, from small (100–400 m) to large (>5 km) for the same lake. The proportion of distal species increases with increasing lake size, highlighting the predominance of atmospheric pollen transport. We conclude that the large species-related differences in pollen source areas have to be taken into account when the provenance at a site is estimated and discussed. 相似文献
16.
Climate change and its impact on birch pollen quantities and the start of the pollen season an example from Switzerland for the period 1969–2006 总被引:2,自引:1,他引:1
As published by the Intergovernmental Panel on Climate Change (IPCC) global warming is a reality and its impact is huge like the increase of extreme weather events, glacier recession, sea level rise and also effects on human health. Among them allergies to airborne pollen might increase or change in pattern due to the invasion of new allergic plants or due to different behavior of plants like earlier flowering. In this study we used the longest Swiss airborne pollen data set to examine the influence of the temperature increase on the time of flowering. In the case of Basel, where pollen data for 38 years are available, it was shown that due to a temperature increase the start of flowering in the case of birch occurred about 15 days earlier. Apart from a shift of the start of the flowering there is also a trend towards higher annual birch pollen quantities and an increase of the highest daily mean pollen concentrations. Due to global warming and because symptoms may appear earlier in the year people suffering from a pollen allergy might face a new unaccustomed situation. 相似文献
17.
We present a model for the prediction of the magnitude ofBetula flowering and pollen dispersal which may be used in the management of birch pollinosis and in the planning of clinical trials. The pollen sum during the flowering season is regressed on the temperature sum from May 1st to July 20th during the initiation year, the pollen sum of the initiation year, and the temperature sum during the main pollen season in the flowering year. We suggest that the fluctuating flowering pattern inBetula alba-species is primarily determined by the availability of assimilation products during inflorescence initiation and development during the spring one year before anthesis. When inflorescences, which are initiated during the previous year, elongate in the beginning of anthesis, they act as strong sinks to stored carbohydrates, and thus compete with developing leaves and shoots. The result is an initially reduced photosynthetic capacity in years with intense flowering, and a limited potential for the initiation of new inflorescences for the following year. The ambient temperature during catkin initiation affects assimilation efficiency and is a determinant of about equal importance to flowering intensity as is the magnitude of the flowering in the initiation year. The amount of pollen dispersed is also dependent on the weather during anthesis, which is not possible to predict until about one month in advance. The two other independent variables are available during the previous summer, making it possible to give a sufficiently valid prediction to allergologists about the magnitude of the next birch pollen season, according to its botanical determinants. We suggest that the varying reproductive output inBetula alba should not be described as true masting. A more parsimonious explanation to the flowering pattern is that an individual continually maximizes reproductive effort, according to what is possible, but that reproduction is often constrained by the environment. 相似文献
18.
We present a model for the prediction of the magnitude ofBetula flowering and pollen dispersal which may be used in the management of birch pollinosis and in the planning of clinical trials.
The pollen sum during the flowering season is regressed on the temperature sum from May 1st to July 20th during the initiation
year, the pollen sum of the initiation year, and the temperature sum during the main pollen season in the flowering year.
We suggest that the fluctuating flowering pattern inBetula alba-species is primarily determined by the availability of assimilation products during inflorescence initiation and development
during the spring one year before anthesis. When inflorescences, which are initiated during the previous year, elongate in
the beginning of anthesis, they act as strong sinks to stored carbohydrates, and thus compete with developing leaves and shoots.
The result is an initially reduced photosynthetic capacity in years with intense flowering, and a limited potential for the
initiation of new inflorescences for the following year. The ambient temperature during catkin initiation affects assimilation
efficiency and is a determinant of about equal importance to flowering intensity as is the magnitude of the flowering in the
initiation year. The amount of pollen dispersed is also dependent on the weather during anthesis, which is not possible to
predict until about one month in advance. The two other independent variables are available during the previous summer, making
it possible to give a sufficiently valid prediction to allergologists about the magnitude of the next birch pollen season,
according to its botanical determinants. We suggest that the varying reproductive output inBetula alba should not be described as true masting. A more parsimonious explanation to the flowering pattern is that an individual continually
maximizes reproductive effort, according to what is possible, but that reproduction is often constrained by the environment. 相似文献
19.
David W Roubik 《Journal of biosciences》1993,18(4):537-552
The bee guild represents direct primary costs of angiosperm reproduction. Tropical flower visitors take an amount comparable
to herbivores, exceeding 3% of net primary production energy. Therefore herbivory and aboveground net primary production have
been underestimated. Comparing pollinators to other herbivores, harvest in mature forest by tropical bees is greater than
leafcutter ants, game animals, frugivores, vertebrate folivores, insect defoliators excluding ants, flower-feeding birds and
bats, but not soil organisms. The ratio of total aboveground net primary production to investment in pollen, nectar and resin
used by pollinators suggests wind pollination is several times more efficient in temperate forests than is animal pollination
in neotropical moist forest. Animal pollination may be favoured by habitat mosaics and an unpredictable or sparse dispersion
of conspecifics — consequences of fluctuating abiotic and biotic environments. Natural selection evidently favours diminished
direct reproductive costs in forests, for example by wind pollination, regardless of latitude and disturbance regime. An example
is “wind pollination by proxy” of dominant trees in seasonal southeast Asian forests. They flower only occasionally and their
pollen is dispersed by tiny winged insects that are primarily carried by the wind — rather than the nectar-hungry bees, bats,
birds and moths used by most tropical flora. Increasing evapotranspiration is associated with greater net primary production;
I show its correlation with species richness of social tropical bees across the isthmus of Panama, which may indicate increasing
forest reproductive effort devoted to flowering, and its monopolization by unspecialized flower visitors in wetter and less
seasonal lowland forests. 相似文献
20.
Skjøth CA Sommer J Brandt J Hvidberg M Geels C Hansen KM Hertel O Frohn LM Christensen JH 《International journal of biometeorology》2008,52(6):453-462
Current aerobiological research applies the hypothesis that the main source of atmospheric birch (Betula) pollen is forest trees. Our results indicate that the measured levels in Copenhagen are not only due to birch trees in Danish forests but that the urban areas also seem to be a significant source of birch pollen. A number of episodes in 2003 with enhanced pollen levels in Copenhagen seem to be associated with parks and gardens inside and just outside the city. Our results also indicate one long-range transport episode from remote sources in Poland and Germany. Finally, our results show that the pollen levels vary considerably over the day and geographically between Copenhagen and the city of Roskilde, 40 km away. We suggest, that these differences in time and space in the pollen levels are mapped using an integrated monitoring strategy. 相似文献