An old dog with new tricks: An automated,dry‐deposition Tauber trap

Establishing a modern pollen analogue for remote, high‐deposition environments (e.g. ice caps) presents a unique problem that is difficult to address with current technology. Collecting modern pollen with traditional Tauber traps in these locations (at sub‐annual resolution) is nearly impossible due to the time and costs involved in frequent, long‐distance or remote travel. Presented in this paper is an automated, dry‐deposition Tauber trap with the ability to open and close on a timer, which allows for pollen collection at programmable intervals. This new trap (along with three traditional Tauber traps) was field tested in the summer of 2005 at the University of Colorado's Niwot Ridge Long‐Term Ecological Research Station (LTER) located in the Front Range of the Colorado Rockies. During the research, one of the traditional traps became damaged and was subsequently discarded from the study. Significant variability in pollen concentrations and percentages was found in the remaining traps. Statistical tests revealed that the pollen assemblage collected in the automated trap was statistically no different to the pollen collected in the traditional Tauber traps. Field testing in a cold, high‐wind environment also revealed the weaknesses of acrylic as a trap material, and identified several improvements that could be made to the overall design. Further testing aside, this modified, automated Tauber trap now permits modern pollen rain studies at higher resolutions in more remote locations.     

Pollen input to, and incorporation in, two crater lakes in tropical northeast Australia

Pollen input to the water surfaces of maar crater lakes Barrine and Eacham (1km(2) and 0.5km(2) respectively, ca. 720m a.s.l.), surrounded by rainforest in northeastern Australia, were measured in floating Tauber traps for a variety of periods spanning the years 1978 to 1985. The mean weekly total pollen catch is 75% of that estimated for the surrounding region of varied vegetation. Regardless of their sources, the influxes of pollen taxa are unevenly distributed over the lakes' surfaces. There is similar variation through time, with some indication that this might be smoothed over periods of 5years or more. There are no inflow streams and pollen input down surrounding slopes is negligible. Mean total pollen influx to seston traps close to the lakes' bottoms (1979 to 1988) is <5% of that to the Tauber traps, a discrepancy attributed to trap design. In contrast, mean annual influx measured by the Tauber traps is similar to that estimated from dated sediment samples younger than 1966 AD at Lake Barrine. The proportions of different pollen taxa are less affected by trap position or period of exposure than are their influxes; their mean percentages for Tauber traps, seston traps and sediment samples are all rather similar.The similarity between the mean contribution of exclusively rainforest pollen to the lakes' surfaces (56%) and to Oldfield traps in rainforest interiors (51%) emphasizes the importance of the rainforests, which clothe the crater walls, as sources of pollen to the lakes. The impact of pollen from other vegetation in the region, although present, is much smaller than at interfaces between rainforest and other vegetation types. All this pollen is mixed within and above the crater and delivered to the lakes' surfaces by gravity and frequent rainfall. Limnological processes redistribute it in the water body before it is incorporated into the deep-lake sediments.The value and limitations of current pollen transport and accumulation theory are noted in relation to sites with morphologies similar to these two crater lakes and to the irregular flowering and floristic inhomogeneity of tropical rainforest. The potential for the use of modern pollen input data in the interpretation of pollen analyses from the sediments of such sites is explored.     

Pollen transfer and periodicity in a rain-forest situation

Initial results, from pollen traps positioned on a small lake situated near to the margin of rain-forest in northeastern Queensland, are presented. These are compared with results derived by Tauber from a lake within an area of temperate mixed deciduous forest. It appears that, although pollen deposition from rain-forest vegetation is very low, it is of regional significance and dominated by pollen of top canopy species. Seasonal variations in the taxonomic composition of pollen deposition are evident with deposition being greatest at the end of the dry season.     

Comparative study of different methods for capturing airborne pollen,and effects of vegetation and meteorological variables

The atmosphere of Mar del Plata city (Argentina) was monitored using three different pollen traps—Burkard, Rotorod, and Tauber—during a flowering season (mid-winter to springtime) in order to compare the diversity and amounts of pollen grains collected in each trap. Sixty three percent of taxa diversity was simultaneously recorded by all three apparatuses. The five most abundant types of pollen in the three traps were Platanus, Ulmus, Quercus, Poaceae, and Fraxinus. The Tauber trap contained the most pollen from taxa with the largest grains, and exclusively trapped ten pollen types with entomophilous characteristics. The amount of pollen in each trap and local/extra-local plant abundance were compared to elucidate the effect of the method used on the pollen–vegetation relationship. The correlation coefficients for total pollen were positive and significant between all pairs of traps. The maximum peak was observed first in the Burkard trap, in agreement with an increase in temperature, but the general pattern in the three traps was similar, with a maximum in early spring. Opposite deviations from the mean value were observed for the Burkard and Tauber data; these deviations were associated negatively with wind speed and relative humidity, respectively. This paper discusses whether in some cases the pollen records could be used in an equivalent manner, although with some limitations.     

Atmospheric transport of freshwater algae Pediastrum in the American Southwest

A single colony of the freshwater green algae Pediastrum boryanum boryanum was observed in a 1994 Tauber trap north of Santa Fe, New Mexico, USA. The rate of deposition for the colony is low, 0.8 per square centimeter per year. The likely source of the freshwater algae is Cochiti Lake reservoir 42 km southwest of the Tauber pollen collector. The ability of Pediastrum to be dispersed in the atmosphere and to survive desiccation gives the freshwater algae a unique biogeographic capability of rapid dispersal and colonization independent of streams and aquatic birds.     

The start of the birch pollen season in Finnish Lapland: separating non‐local from local birch pollen and the implication for allergy sufferers

Determining the start of the birch pollen season requires the reliable separation of non‐local from locally produced birch pollen. The research was undertaken close to the latitudinal birch tree line at the Kevo Subarctic Research Institute (69°45′N 27°01′E) in northern Finland. By comparing phenological and aerobiological observations, the proportion of birch pollen present in the air before local anthesis commences can be delimited. We coupled this with data of pollen deposition monitored by means of a modified Tauber trap. The dominant birch species at Kevo is the mountain birch Betula pubescens ssp. czerepanovii, whereas B. pubescens ssp. pubescens is very rare, hence we consider the proportion of the southerly B. pubescens‐type pollen deposited in the pollen trap to be non‐local in origin.

We did not observe any trend towards an earlier start of the phenologically observed mountain birch anthesis at Kevo as predicted from work elsewhere. Moreover, the fixed 2.5% threshold method for determining the birch pollen season proved not to be applicable since in many years this threshold was reached before the end of continuous snow cover. The results indicate that in some years non‐local birch pollen contributes considerably to the allergen load in Lapland with up to 57% of the total birch pollen sum being recorded before the day on which local anthesis commenced, and up to 70% of the annual birch pollen deposited being of the southerly birch type.     

阴山山脉东段花粉通量及其与表土花粉比较研究

阴山山脉东段蛮汉山和大青山山顶草甸、桦木林、虎榛子灌丛、人工油松林及杂草草原5个植被类型花粉通量与表土花粉对比研究发现,不同植被类型及同一植被类型不同样点花粉通量和花粉浓度差异明显,捕捉器样品花粉源区面积小于表土样品,能较好地反映样品点周围植被组成,但受虫媒植物和局地植物花粉影响,与表土样品花粉组合差异明显;表土样品中松属、桦属、蒿属及藜科花粉含量多高于捕捉器样品,表明这些花粉不仅易于传播,而且在表土中具有较强的保存能力;禾本科花粉具低代表性,花粉保存能力较低.地层花粉分析中应引起注意.     

Comparison of pollen sampling with a Burkard Spore Trap and a Tauber Trap in a warm temperate climate

Aerobiological data have been widely used by many scientists, including those that study modern flora as well as those wishing to reconstruct past vegetational associations. Burkard (Hirst-type) volumetric spore traps are widely used instruments for studying airborne pollen, while Tauber traps are typically used to analyze pollen deposition. The present study compared the pollen collected by these two methods in Tulsa, Oklahoma a warm temperate area with year-round pollen. There was a strong correlation between the pollen influx from the Tauber traps and cumulative sum of average daily airborne pollen concentrations recorded with the Burkard spore trap over the course of 12 months from 1 Feb 1997 through 1 Feb 1998. The correlation coefficient between all taxa over the 12 months was 0.914; while the correlation coefficient for the monthly totals was 0.972. The data showed that both methods reflected local anemophilous vegetation although variations occurred in the prevalence recorded by both samplers.     

Comparing pollen spectra from modified Tauber traps and moss samples: examples from a selection of woodlands across Europe

This paper compares pollen spectra derived from modified Tauber traps and moss samples from a selection of woodland types from Bulgaria, the Czech Republic, Georgia, Greece, Poland, Switzerland and Wales. The study examines the representation of individual taxa in the two sampling media and aims to ascertain the duration of pollen deposition captured by a moss. The latter aim was pursued through the calculation of dissimilarity indexes to assess how many years of pollen deposited in a pollen trap yield percentage values that are most similar to those obtained from the moss. The results are broadly scattered; the majority of moss samples being most similar to several years of pollen deposition in the adjacent trap. For a selection of samples, a comparison of the pollen accumulation rate in pollen traps with the pollen concentration in the moss per unit surface indicates that the entrapment and/or preservation of individual pollen types in the moss differ from that in the pollen trap. A comparison of the proportion of different taxa in the moss with the pollen spectrum of 2 years of pollen deposition in the trap also revealed large differences. There is a tendency for bisaccate grains such as Pinus and Picea to have a higher representation in moss than in traps but there is considerable regional variation. The results indicate that pollen proportions from moss samples often represent the pollen deposition of one area over several years. However, bisaccate pollen grains tend to be over-represented in moss samples compared to both pollen traps and, potentially, lake sediments.     

Numerical analysis of surface and fossil pollen spectra from northern Fennoscandia

Aim Determination of the main directions of variance in an extensive data base of annual pollen deposition, and the relationship between pollen data from modified Tauber traps and palaeoecological data. Location Northern Finland and Norway. Methods Pollen analysis of annual samples from pollen traps and contiguous high‐resolution samples from a peat sequence. Numerical analysis (principal components analysis) of the resulting data. Results The main direction of variation in the trap data is due to the vegetation region in which each trap is located. A secondary direction of variation is due to the annual variability of pollen production of some of the tree taxa, especially Betula and Pinus. This annual variability is more conspicuous in ‘absolute’ data than it is in percentage data which, at this annual resolution, becomes more random. There are systematic differences, with respect to peat‐forming taxa, between pollen data from traps and pollen data from a peat profile collected over the same period of time. Main conclusions Annual variability in pollen production is rarely visible in fossil pollen samples because these cannot be sampled at precisely a 12‐month resolution. At near‐annual resolution sampling, it results in erratic percentage values which do not reflect changes in vegetation. Profiles sampled at near annual resolution are better analysed in terms of pollen accumulation rates with the realization that even these do not record changes in plant abundance but changes in pollen abundance. However, at the coarser temporal resolution common in most fossil samples it does not mask the origin of the pollen in terms of its vegetation region. Climate change may not be recognizable from pollen assemblages until the change has persisted in the same direction sufficiently long enough to alter the flowering (pollen production) pattern of the dominant trees.     

Six years of observation of airborne and deposited pollen in central European Russia: first results

The aim of the study was to compare the pollen spectra recorded in rural and urban environments in order to examine whether pollen data obtained in the urban environment could also represent the situation in surrounding rural areas and how urban planting affects the regional pollen spectrum. Daily airborne pollen observations were performed with a volumetric Hirst type trap in Moscow (Russia). Modified Tauber traps were located in the Moscow region. The Tauber traps were installed and treated according to Pollen Monitoring Programme (PMP) guidelines. Spearman correlation coefficients were determined between the percentage of total pollen recorded in the Tauber and Hirst type samplers. The data showed that the Tauber spectra are characterised by higher taxonomic variability, mainly due to the greater occurrence of local herbaceous plants. Pollen types registered by Hirst type samplers were predominantly represented by anemophilous arboreal species, used in urban planting. A significant correlation for annual sums was only observed for Betula pollen, the most abundant component in both sampler types. Data obtained in big cities for dominant taxa can be extrapolated to the surrounding rural territories. The simultaneous use of volumetric and gravimetric samplers can be very useful for palaeo-ecological studies to evaluate the presence of local and transported pollen.     

From early pollen trapping experiments to the Pollen Monitoring Programme

Pollen monitoring has become a standard investigation method for researchers in several disciplines; among them are Quaternary palynologists, who conduct experiments in order to gain insights that will help to interpret the content of pollen in sediments. A review of the literature shows how these experiments diversified during the 1920s and 1930s with an array of different research questions, ranging from pollination biology to hay fever studies. Quaternary palynologists gained renewed interest with the possibility of radiocarbon dating late Quaternary sediments and obtaining accumulation rates. Also, the comprehensive model of pollen deposition and the pollen budget studies by H. Tauber encouraged researchers to conduct similar experiments using the same type of pollen trap, which became the main trapping device for Quaternary palynologists. The high precipitation in the tropics inspired the development of alternative designs. The equipment used to assess the pollen content in the air has evolved from simple gravity devices to different types of apparatus using a vacuum pump or revolving rods that collect the pollen on impact. Silicone impregnated filters exposed perpendicularly to the wind can also yield a volumetric assessment and have proven useful in areas with a low content of pollen in the air. The literature review is followed by a brief account of the developments which established the basis for the formation of a group of scientists monitoring the pollen deposition at a network of sites using standard pollen traps, the Pollen Monitoring Programme (PMP). Over the last 15 years the network has collected a large dataset, which is now available to answer a number of research questions. A summary of selected regions and environments, for which pollen monitoring results are available, is provided to serve as a complement to the investigations mentioned above and to provide an overview that may stimulate new research.     

Modern Pollen Rain of Mixed Conifer Forest in Changbai Mt., Northeast China

In order to study pollen rain six funnel-like pollen traps were set up on tree trunks 1.3 m above the ground in a firspruce forest in. Changbai Mt. at 1,150 m a.s.1, for a time interval from June 1985 to August 1986. Pollen influx values were calculated by volumetricat and exotic pollen methods (see Table 1). Pollen representation of each major tree type, e. g. Pinus, Abies, Picea, Betula, Larix and some decideous broad-leaved trees, was deduced front a comparison between the percentage of the tree type in pollen spectrum and that in forest. The pollen spectrum obtained from pollen trap was compared with that extracted from surface; ample taken from the same vegetation zone; the differences and their possible causes are also discussed.     

Vegetational and climatic significance of modern pollen rain in northwestern Tibet

In northwestern Tibet, an atmospheric pollen sampling was performed weekly during one year (August 1989 to August 1990). Moreover, 18 dust flux samples were obtained in the same region which covers three geographical units: the western margin of the Taklimakan desert, the northern Karakorum and the northwestern Kunlun mountains. The atmospheric pollen results show that the annual pollen frequency is dominated by regional components of montane and alpine desert and steppe, such as Artemisia, Chenopodiaceae, Cupressaceae and Poaceae. They also show that pollen taxa derived from much more distant sources such as warm temperate and subtropical humid forest zones are sometimes well represented. It is inferred that the majority of airborne pollen has been carried by wind during the flowering seasons of the plants, and this provides an evaluation of the influence of southerly and southwesterly summer monsoon air movements. The similarity of pollen spectra between dust flux samples and the atmospheric pollen trap from the Kunlun Mountains suggests that the pollen deposition evaluated by the dust flux method is representative of the pollen rain in the studied area. The dust samples from lower altitudes are characterized by high values of Chenopodiaceae and low ratios of Artemisia/Chenopodiaceae which vary clearly with altitude and possibly with moisture level. The Artemisia/Ephedra ratio shows similar variations to A/C. The percentage AP value is generally higher in mountains like Kunlun where the plant cover is extremely low in comparison with semiarid massifs such as Karakorum. Therefore, interpretation of AP pollen in the fossil record must take into account long distance wind transport.     

Pollen in aeolian dust with relation to allergy and asthma in Kuwait

The studying of spatial and temporal distribution of pollen is essential, but rarely tackled in the region including Kuwait. Pollen grains and aeolian dust in the state of Kuwait were seasonally monitored from August 2009 to August 2011 to identify and correlate spatially and temporally pollen data with human health asthma and allergy data. The year 2010–2011 yielded a high in deposited dust and pollen compared to 2009–2010 by 33.2 and 9.9%, respectively. The spring (April–May) and the autumn (October–November) seasons marked the most top pollen distribution for Chenopodiaceae, Gramineae (Poaceae), Cyperaceae, Fabaceae, and Plantaginaceae. The pollen graphs for summer (July–August) and winter (January–February) seasons showed low pollen distribution due to the severe drought, dust storms, winter wind and rainfall. There are no correlations found between pollen deposition and the number of asthma patients. The annual dust deposited rate in Kuwait during 2010/2011 was 373 t km^?2 which represented a 33.2% increase compared with 2009/2010. The study has concluded that pollen of Malvaceae, Compositae and Chenopodiaceae is the most common triggers of allergy in Kuwait. Additionally, a positive correlation between the number of allergy patients and deposited dust was observed during March 2010 and 2011.     

煤粉尘沉降对鄂尔多斯高原优势植物羊柴幼苗生长的影响

随着鄂尔多斯煤矿开采的日益加剧,开采和运输过程中产生的煤粉尘沉降已成为影响当地植物生长的一个重要影响因子。通过近自然生境条件下的控制实验,以鄂尔多斯高原优势植物羊柴(Hedysarum laeve)为研究对象,探究不同梯度煤粉尘沉降量(0—3.5 mg/cm2)对其幼苗的光合生理特性和生长的影响。研究结果表明,随着煤粉尘沉降量的增加,羊柴叶片的气孔导度(Gs)、胞间二氧化碳浓度(Ci)、叶片水分饱和水汽压亏缺(Vpdl)等因子发生了不同程度的改变,导致净光合速率(Pn)和蒸腾速率(Tr)降低,使得幼苗的植株高度、叶片数、地上和地下生物量降低。因而,积累到一定程度的煤粉尘颗粒通过影响叶片气孔的水汽交换过程和降低叶片表面的光照强度,影响了叶片的光合生理过程,从而抑制了羊柴幼苗的生长。     

Pollen Deposition on and under the Water Surface

In the summers of 1974 and 1975 pollen deposition was studied in two bays of the Baltic Sea near Stockholm with roofed and unroofed samplers mounted on rafts and with samplers submerged to levels of 30 and 60 cm over the bottom. The unroofed traps show larger totals of pollen grains than the roofed samplers. Sufficient data could not be obtained to establish that the totals of pollen grains in the submerged samplers at level 30 cm were larger than the totals at level 60 cm. The differences in pollen rain in the two seasons can be attributed mainly to the meteorological conditions, viz, to the particularly dry and warm summer of 1975. In the raft samplers the percentages of redeposited arboreal pollen are lower than in the submerged ones. Transport by currents and redeposition influence the pollen spectra in the submerged samplers. The pollen spectra in samplers over and under the water surface depend mainly on the specific composition of the surrounding vegetation. Pollen transport over short distances is therefore of great importance. No evidence was found of long-distance pollen transport.     

Holocene tree‐line fluctuations and climate in central troms,Northern Norway

Based mainly on pollen influx data, an attempt is made at reconstructing Holocene tree‐line fluctuations and palaeotemperatures in central Troms, North Norway. Both past and present‐day (Tauber trap) pollen influx data suggest that influx rates exceeding 250–300 pollen/cm²/year for each of the major arboreal taxa (Betula pubescens and Pinus sylvestris) are only found at sites with corresponding forest types in the immediate surroundings. High influx rates, raised tree‐lines and favourable climatic periods are recorded at 7500–4500 and 3000–2600 B.P. Betula and Pinus woodlands may have reached more than 200 m above their present altitude limits, suggesting a July mean temperature 2°C higher than at present during the Holocene optimum.     

Problems of Pollen Zone Correlation in Southeastern Canada

A brief account is given documenting the development of aerobiological research in the Antarctic. The results of the British Antarctic Survey's contribution to an international programme on long-distance dispersal of aeroplankton over the Southern Ocean are presented. This was achieved by collecting airspora deposited in Tauber traps and in surface snow at sites on South Georgia (sub-Antarctic) and Signy Island (maritime Antarctic). Although only a small number of the samples were analysed, the results provided ample evidence of a continuous immigration of exotic sporomorpha of southern South American provenance. The cause of this rain of biological material is attributed to the not infrequent easterly tracking storm events generated over the south-east Pacific Ocean. As they gain momentum over southern South America they become seeded with pollen and spores, and possibly by larger organelles such as invertebrates and seeds. These high winds may be deflected southwards by a blocking anticyclone over the South Atlantic Ocean, allowing a proportion of the sporomorpha to be deposited over land far to the south. The occurrence of such exotic sporomorpha in these remote and environmentally hostile regions is used here as evidence to support the hypothesis that there is a continuous input into the Antarctic biome of viable propagules from more northerly landmasses. While no exotic bryophyte or lichen spores have yet been detected in trapping experiments, the extremely rare occurrence of certain bryophytes associated only with geothermal sites in the Antarctic and in laboratory-cultured soils from barren ice-free terrain indicates that a pool of viable but dormant propagules is probably widespread in Antarctic soils and ice. However, germination and development in situ are possible only under exceptional environmental circumstances. An international programme is being planned to detect the main trajectories of long-distance transport of propagules into the Antarctic and to test their viability.     

Comparisons of moss polster and pollen trap data: a pilot study

Modern pollen-vegetation relationships have been explored in recent years through analysis of either pollen trap (= absolute results) or moss polster contents (= relative results). In the past few attempts were made to compare data from these two sources. It was the aim of the present study to achieve this comparison through more exact sampling of moss polsters. A pilot study was carried at Morton Lochs, Fife, Scotland where pollen traps have been sampled continuously for ten years. Moss samples were collected from cushions adjacent to two of the pollen traps during May 1985, 1986 and 1987. Moss polsters were sampled usingan equivalent surface cross-section area to that of the traps. In comparing the pollen results from the two sources some similarities can be identified, but in general there are more inconsistencies. These may be traced to difficulties in the precision of moss sampling, variable rates of moss growth and local deposition factors. It is considered that further study, in which these difficulties are minimised, would be justified. Ultimately it is hoped that precise sampling of mosses will produce sufficiently reliable modern pollen rain results to enable pollen-vegetation studies to move away from relative (percentage) values without requiring long-term artificial pollen trapping techniques.