Long-distance Pollen Transport Research Articles

The Full-Glacial Forests of Central and Southeastern Europe

The presence of trees in central and southern Europe during the last full-glaciation has long been a matter of debate. A low but persistent presence of fossil tree pollen in central and southern European full-glacial paleoecological sequences has been interpreted either as representing long-distance pollen transport from southerly refuges or as representing in situ refugial populations. Here we present macroscopic charcoal results from 31 sequences located throughout Hungary that provide unequivocal evidence for the presence of at least seven different tree types between approximately 32,500 and 16,500 14C yr B.P. This evidence is presented in conjunction with molluscan and pollen analyses to indicate that during the last full-glaciation, trees grew as far north as Hungary, probably in microenvironmentally favorable sites. These areas provided an important cold-stage refugium for the European flora and fauna.

Long-distance transport of pollen into the Arctic

Airborne particulates can be carried over long distances, but for significant quantities of particulates larger than a few micrometres in diameter to be transported more than a few kilometres usually requires a means of injecting the material high into the atmosphere, such as a volcanic eruption, forest fire or desert windstorm. But an unusual event occurred in the Canadian Arctic last year, in which significant amounts of pine and spruce pollen (30-55 μm long) were transported roughly 3,000 km.

Evidence of long-distance transport of mountain cedar pollen into Tulsa, Oklahoma

&p.1: Previous study of Cupressaceae pollen in the Tulsa atmosphere during December and January suggested that the source of this pollen is the Juniperus ashei (mountain cedar) populations that occur mainly in southern Oklahoma and central Texas. The present investigation examined the evidence of long-distance transport of pollen from these populations during the 1996/1997 season at three sites in Oklahoma using Burkard traps. Two of the pollen-monitoring stations were operated in conjunction with Mesonet meteorological stations. It was found that the December and January Cupressaceae pollen occurs outside of the local season at Tulsa. Pollen concentrations are intermittent and correspond to days of peak concentrations at sites nearer the mountain cedar populations. Peak concentrations are associated with winds coming from the south over the mountain cedar areas. Diurnal rhythms show night-time peaks with a delay in timing at the northern-most site. These results are all consistent with the hypothesis that pollen is being transported over long distances from the mountain cedar populations to Tulsa, Oklahoma. These findings are important as they represent one of the few incidences of long-distance transport of pollen in significant concentrations to an area where the source vegetation is not present. Pollen-monitoring sites located in conjunction with Mesonet meteorological stations provide a unique opportunity to further examine atmospheric conditions during long-distance transport events. This will aid future studies of the spatial modeling of long-distance dispersal of pollen.

Diurnal Variation of Airborne Birch Pollen at Some Sites in Sweden

Abstract A study of the diurnal variations of airborne birch pollen in Sweden showed that the effect of rainfall on pollen counts is more complex than was previously thought. Most of the pollen counting sites in Sweden showed the same pattern of diurnal variations as described by other observers, i. e. lower concentrations during the early morning and a maximum in the middle of the day or early in the evening. Especially in one pollen counting site, viz, in Östersund, near the geographical centre of Sweden, we noted many occasions when the concentration of birch pollen increased concurrently with the beginning of heavy showers of rain. A few hours later the number of pollen grains decreased, when the pollen was washed out of the air. We noted great differences in the occurrence of such pollen peaks between different parts of the country. The phenomenon was more frequent in Östersund than in Stockholm, maybe due to the differing topography. Heavy rains seem to be more influential if large amounts of pollen have previously been brought high up into the air, e.g. by warm air or by long-distance transport of pollen, and this should be considered when making pollen forecasts.

Implications of recent long-distance pollen transport events for the interpretation of fossil pollen records in Fennoscandia

Under favourable conditions, a considerable amount of long-distance transported pollen can be deposited far from its place of origin. In Fennoscandia, in most cases, such situations occur when there is a strong southerly air circulation from South-Europe and/or North-Africa. Soil particles and pollen grains associated with the top soil or the present vegetation, can be lifted up by strong surface winds and brought up to higher levels, where further transportation takes place. During the last few years several of these events have been reported.The pollen analysis of three events with coloured precipitation from different parts of Fennoscandia provides information about such exotic pollen rain and its extent. The quantity of exotic pollen in the snow samples analysed is high, generally in the range of 500–2000 pollen grains cm−2 per episode. However, the amount of transported pollen can even be as great as that deposited during local anthesis in the same year, and influx values can exceed 30, 000 pollen grains cm−2 per few hours of snowfall. The results are analysed in relation to trajectory calculations, the actual phenological data, and pollen concentrations monitored by volumetric sampling from the air. Since the long-distance transport of pollen grains depends mainly on climatological factors, the hypothesis that exotic pollen deposition was common throughout the whole of the Holocene in Fennoscandia is presented. Long-distance transport of pollen grains can, therefore, be regarded as a potential source of error in the interpretation of Holocene pollen diagrams from Fennoscandia.

Pollen marqueur de transports à longue distance dans l'atmosphère du sud de l'Ontario (Canada)

An analysis of weekly air samples at four sites in southern Ontario (London, Toronto, Peterborough, Sudbury) provides conclusive evidence for the long-distance transport of pollen of the exotic taxa Entada (Mimosaceae), Dodonaea (Sapindaceae), and Ephedra (Ephedraceae), originating far to the south (at least 1000 km) of the recording stations. The nearest source area for the first two taxa is in the West Indies and Mexico, while Ephedra, previously noted in Late Quaternary sediments from the Great Lakes region, grows commonly in the southwestern region of the United States. Long-distance transport is corroborated by air-mass trajectory analysis and surface-wind patterns at time of exotic occurrences. Key words: aeropalynology, Ontario, airstreams, pollen transport.

Allergic symptoms caused by long-distance transported birch pollen

Abstract Birch pollen allergy is very common in northern Sweden, and the local flowering season never starts before the middle part of May. In the last week of April 1989 patients with birch pollen allergy developed typical symptoms requiring treatment. This pattern was confirmed in a group of patients who registered their symptoms in diaries, while contemporaneous pollen measurements demonstrated high amounts of birch pollen in the air. At that time in the northern part of Sweden, however, no birches were flowering. Meteorological data indicated that strong winds from the south-east during the period transported birch pollen from the Baltic states. Similar weather conditions in 1982, 1984 and in 1990 have also resulted in high amounts of birch pollen in the air long before the local flowering season. It is concluded that long distance transport of pollen may result in clinically significant allergy problems before, and even after the normal local season.

Long-distance pollen transport over the southern Tasman Sea: evidence from Macquarie Island

Abstract Numerous exotic pollen and spore types occur in Holocene lake deposits on Macquarie Island. Most are con~idered to be derived from sources in the south-east Australian region. Myrtaceae pollen, which probably includes both Eucalyptus and Metrosideros, accounts for over 40% of the total exotic counts for 2 cores. Podocarpaceae, Phyllocladus, Casuarina, and Pomaderris are also present in significant proportions. Single records for Dacrydium cupressinum and Ascarina lucida, and the absence of Nothofagus “fusca” suggest that New Zealand pollen sources are relatively poorly represented. This find emphasises the need for caution when assessing the nature of the exotic pollen rain at sites on mainland New Zealand and surrounding islands.

Distribution of airborne pollen and spores and their long distance transport

The atmosphere near the ground contains a mixed population of pollen and spores in the 1 to 90 μm diameter range. Continuous sampling at Rothamsted Experimental Station at 2 m above ground level indicated concentrations averaging 12,000 m−3 over 5 summer months, but 1 million m−3 can occur for short periods. Concentrations change rapidly with locality, season, time of day or night and weather. Normally concentration in the troposphere decreases logarithmically with height. The occurrence of long distance transport of pollen and spores by wind is demonstrated by sampling from aircraft, and supported by much circumstantial evidence. Possible effects of this air spora on the atmosphere may be sought in alterations to: opacity, ionization, condensation nuclei, and sinks for minor gases.

Possible long-distance transport of pollen to New Zealand

(1969). Possible long-distance transport of pollen to New Zealand. New Zealand Journal of Botany: Vol. 7, No. 4, pp. 424-426.

Pollen Analysis of Prehistoric Human Feces: A New Approach to Ethnobotany

AbstractPrehistoric human and nonhuman feces from alcoves in the Glen Canyon region of southern Utah are a rich source of pollen and spores. The dominant pollen types (determined in a 200-grain pollen count) vary greatly from sample to sample, making stratigraphic and climatic interpretation very difficult. The record of economic plant pollen appears to reflect the prehistoric Pueblo diet.Cleome, Zea, Cucurbita, andOpuntiaare the most abundant economic pollen types. Long-distance transport of pollen from distant montane forests will account for the presence of occasional pollen grains of spruce, fir, and alder in certain samples. The salvage and study of ancient human feces promises to reveal new information about the environment and diet of prehistoric man in the Southwest, a development of interest to both the ecologist and the ethnobotanist.