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.     

Forecasting the start of the pollen season of Poaceæ: evaluation of some methods based on meteorological factors

The pollen of anemogamous plants is responsible for half the allergic diseases, that is to say a prevalence of 10% in the French population. Poaceæ produce the first allergenic pollen almost everywhere. The work described in this article aimed to validate forecast methods for the use of physicians and allergic people who need accurate and early information on the first appearance of pollen in the air. The methods were based on meteorological parameters, mainly temperature. Four volumetric Hirst traps were used from 1995 to 1998, situated in two departments of Burgundy. Two of the methods tested proved to be of particular interest: the sum of the temperatures and the sum of Q ₁₀ values, an agrometeorological coefficient integrating temperature. A multiple regression, using maximum temperature and rainfall, was also performed but it gave slightly less accurate results. A χ ²-test was then used to compare the accuracy of the three methods. It was found that the date of onset of the pollen season could be predicted early enough to be useful in medical practice. Results were verified in 1999, and the research must be continued to obtain better statistical validity.     

Fisheries impact on the East China Sea Shelf ecosystem for 1969–2000

An ecosystem model representing the continental shelf of the East China Sea was fitted to a time series of data available from 1969 to 2000 using Ecopath with Ecosim. We used a process-oriented model to explore the extent to which changes in marine resources and the ecosystem were driven by trophic interactions and fishing activities. Fishing effort was used to drive the model, and observed catches were compared with the predicted catches in modeling. A reduction in the sum of the squared deviations of the observed and predicted catches was used as a metric for calibrating and assessing the goodness-of-fit of the model. Trophodynamic indicators were used to explore the ecosystem’s structural and functional changes from 1969 to 2000. The model’s predictions were consistent with observed catches for most functional groups. Trophodynamic indicators suggest a degradation pattern over time: both the mean trophic level of community and a modified version of Kempton’s index of biodiversity decreased over the time, while the total flow to detritus and the loss of production due to fishing increased from 1969 to 2000. Additionally, the ratio of demersal/pelagic abundances decreased as a result of an overall decrease in the abundance of demersal species and increase in pelagic fish in the ecosystem.     

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

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

Foraging facilitation among predators and its impact on the stability of predator–prey dynamics

Predator foraging facilitation may strongly influence the dynamics of a predator–prey system. This behavioral pattern is well-observed in real life interactions, but less is known about its possible impacts on the predator–prey dynamics. In this paper we analyze a modified Rosenzweig–MacArthur model, where a predator-dependent family of functions describing predator foraging facilitation is introduced into the Holling type II functional response. As the general assumption of foraging facilitation is that higher predator densities give rise to an increased foraging efficiency, we model predator facilitation with an increasing encounter rate function. Using the tools of bifurcation analysis we describe all the nonlinear phenomena that occur in the system provoked by foraging facilitation, these include the fold, Hopf, transcritial, homoclinic and Bogdanov–Takens bifurcation. We show that foraging facilitation can stabilize the coexistence in the predator–prey system for specific rates, but in most of the cases it can have fatal consequences for the predators themselves.     

Air and surface soil samples – two different pairs of shoes? Comparing the pollen spectrum on different days of the pollen season

The pollen spectra of air and surface soil samples from a rooftop (at 14 m) and from ground level (at 1.6 m) in the suburbs of Vienna (Austria) were compared. Two soil samples and two air samples were taken on four different days to account for possible differences: in winter when no pollination occurred (reference day), in spring during the main flowering of Betula (birch day), in spring/summer during the main flowering of Poaceae (grass day), and in autumn during the main flowering of Ambrosia (ragweed day). Thirty-five different pollen types were used to describe the pollen spectra. Frequencies of certain pollen types reflect a seasonal impact on both the surface soil and air samples and show a similarity between air and soil samples on most of the days. However, the seasonal impact is higher in the air samples and shows a high consistency for ground and rooftop level. Kendall’s tau correlation coefficients further substantiate the similarities of the samples especially for the pollen season days. Exceptions include the winter day when pollination was low and the air samples recorded nearly no pollen at all, and the ragweed day when Ambrosia pollen was abundant in three of four samples but not in the ground surface soil sample. Thus, (1) air and surface pollen samples record similar signals during the pollen season but not during the ragweed and winter season and (2) air and surface pollen samples show the impact of local vegetation also in pollen traps located at different heights.     

Towards an ecological understanding of the killer trait – A reproducible protocol for testing its impact on freshwater ciliates

Paramecium strains with the ability to kill other paramecia often harbour intracellular bacteria belonging to the genera Caedibacter or Caedimonas. Central structures of this killer trait are refractile bodies (R-bodies) produced by the endosymbionts. Once ingested by a sensitive Paramecium, R-bodies presumably act as delivery system for an unidentified toxin which causes the death of endosymbiont-free paramecia while those infected gain resistance from their symbionts. The killer trait is therefore considered as competitive advantage for the hosts of R-body producers. While its effectiveness against paramecia is well documented, the effects on other aquatic ciliates are much less studied.In order to address the broadness of the killer trait, a reproducible killer test assay considering the effects on predatory ciliates (Climacostomum virens and Dileptus jonesi) as well as potential bacterivorous Paramecium competitors (Dexiostoma campyla, Euplotes aediculatus, Euplotes woodruffi, and Spirostomum teres) as possibly susceptible species was established. All used organisms were molecularly characterized to increase traceability and reproducibility. The absence of any lethal effects in both predators and competitors after exposure to killer paramecia strongly suggests a narrow action range for the killer trait. Thus, R-body producing bacteria provide their host with a complex, costly strategy to outcompete symbiont-free congeners only.     

Birch pollen production,transport and deposition for the period 1984–1993 at Kevo,northernmost Finland

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.     

The pollen season dynamics and the relationship among some season parameters (start,end, annual total,season phases) in Kraków,Poland, 1991–2008

The dynamics of 15 taxa pollen seasons in Kraków, in 1991–2008 was monitored using a Burkard volumetric spore trap of the Hirst design. The highest daily pollen concentrations were achieved in the first half of May, and they were caused mainly by Betula and Pinus pollen. The second period of the high concentrations took place from the middle of July to the end of August (mainly Urtica pollen). Tree pollen seasons were shorter (18–24 days) in comparison with the most herbaceous pollen seasons (73–89 days), except at Artemisia and Ambrosia seasons (30 and 24 days, respectively). The season phases (percentyles) of the spring and late-summer taxa were the most variable in the consecutive years. The highest annual sums were noted for Urtica, Poaceae (herbaceous pollen seasons) and for Betula, Pinus, Alnus (tree pollen seasons), and the highest variability of annual totals was stated for Urtica, Populus, Fraxinus and the lowest for Ambrosia, Corylus, Poaceae. For the plants that pollinate in the middle of the pollen season (Quercus, Pinus and Rumex), the date of the season start seems not to be related to the season end, while for late pollen seasons, especially for Ambrosia and Artemisia, the statistically negative correlation between the start and the end season dates was found. Additionally, for the most studied taxa, the increase in annual pollen totals was observed. The presented results could be useful for the allergological practice and general botanical knowledge.     

Evolution of the term “cellular senescence” and its impact on the current cytogerontological research

The term “cellular/cell senescence” was first introduced by Leonard Hayflick to describe the “age-related” changes in normal eukaryotic cells during aging in vitro, i.e., over the exhaustion of their mitotic potential. In the “classic” variant, it was assumed that cells “grow old” with the help of some internal mechanism, which leads to accumulation of various macromolecular defects (DNA damage in the first place). Currently, as a rule, “cellular senescence” means accumulation/appearance of particular “biomarkers of aging” in cells (they are most often transformed cells that do not demonstrate any replicative senescence) under the influence of various external factors (oxidative stress, H₂O₂, mitomycin C, ethanol, ionizing radiation, doxorubicin, etc.) that cause DNA damage. This phenomenon has been called DDR (DNA Damage Response). Among the said biomarkers, there are senescence-associated beta-galactosidase activity, expression of p53 and p21 proteins as well as of proteins involved in the regulation of inflammation, such as IL-6 or IL-8, activation of oncogenes, etc. Thus, “aging/senescence” of cells does not occur simply by itself—it takes place because of the influence of DNA-damaging agents. This approach, in my opinion, despite being very important to define a strategy to fight cancer, distracts us, yet again, from the study of the real mechanisms of aging. It should be emphasized that the “stationary phase aging” model developed in my laboratory also allows registering the occurrence of certain biomarkers of aging in cultured cells, but in this case they arise due to the restriction of their proliferation by contact inhibition, i.e., due to a rather physiological impact, which does not cause any damage to cells by itself (the situation is similar to what we observe in a whole multicellular organism).     

Does site elevation determine the start and intensity of human impact? Pollen evidence from southern Germany

Vegetation History and Archaeobotany - We investigated lake sediments from Großer Ursee, Landkreis Ravensburg, Allgäu, Baden-Württemberg, to explore whether human activity was...     

Implications of behavioral change for the resilience of pastoral systems—Lessons from an agent-based model

In many dryland regions, traditional pastoral land use strategies are exposed to various drivers such as demographic or socio-economic change. This may lead to an adjustment of livelihood strategies and behavior of pastoral households, involving a change in attitudes toward livestock, pasture condition and social norms. We use an agent-based model to examine long-term social-ecological consequences and implications for system resilience of such behavioral changes (e.g., giving up a social norm). The model captures feedback between pastures, livestock and household livelihood in a common property grazing system. We systematically compare three stylized household behavioral types (traditional, maximizer and satisficer) that differ in their preferences for livestock, their compliance with social norms on pasture resting and how they are influenced by the behavior of others. Simulation results show that the traditional, norm-abiding household type maintains the pasture condition, provided that overall household numbers do not exceed a critical threshold. In contrast, a switch to a maximizer type that ignores norms may lead to long-term pasture degradation and livestock loss, pushing the system to an undesirable state. A change toward a new satisficing household type that constrains its herd size while diversifying its income sources can lead to improved pasture conditions and higher total livestock numbers, even with increased household numbers. We conclude that changes in household behavior have strong implications for long-term social-ecological system dynamics and have to be considered to assess the resilience of pastoral common property systems.     

Climate change and perishable food hoards of an avian predator: Is the freezer still working?

Changing climate can modify predator–prey interactions and induce declines or local extinctions of species due to reductions in food availability. Species hoarding perishable food for overwinter survival, like predators, are predicted to be particularly susceptible to increasing temperatures. We analysed the influence of autumn and winter weather, and abundance of main prey (voles), on the food‐hoarding behaviour of a generalist predator, the Eurasian pygmy owl (Glaucidium passerinum), across 16 years in Finland. Fewer freeze–thaw events in early autumn delayed the initiation of food hoarding. Pygmy owls consumed more hoarded food with more frequent freeze–thaw events and deeper snow cover in autumn and in winter, and lower precipitation in winter. In autumn, the rotting of food hoards increased with precipitation. Hoards already present in early autumn were much more likely to rot than the ones initiated in late autumn. Rotten food hoards were used more in years of low food abundance than in years of high food abundance. Having rotten food hoards in autumn resulted in a lower future recapture probability of female owls. These results indicate that pygmy owls might be partly able to adapt to climate change by delaying food hoarding, but changes in the snow cover, precipitation and frequency of freeze–thaw events might impair their foraging and ultimately decrease local overwinter survival. Long‐term trends and future predictions, therefore, suggest that impacts of climate change on wintering food‐hoarding species could be substantial, because their ‘freezers’ may no longer work properly. Altered usability and poorer quality of hoarded food may further modify the foraging needs of food‐hoarding predators and thus their overall predation pressure on prey species. This raises concerns about the impacts of climate change on boreal food webs, in which ecological interactions have evolved under cold winter conditions.     

Types of Artemisia pollen season depending on the weather conditions in Wrocław (Poland), 2002–2011

The aim of the study was to characterise Artemisia pollen season types according to weather conditions in Wroc?aw (south-western Poland) in the years 2002–2011. Over the period analysed, the start date of the pollen season (determined by the 95 % method) ranged from 10 July 2002 to 28 July 2010. The start date of the pollen season can be determined by using Crop Heat Units (CHUs). During the period 2002–2011, the Artemisia pollen season started after the cumulative value of CHUs had reached 2,000–2,100 °C. The three distinguished types of Artemisia pollen season are best described by the frequency of weather types defined by the type of circulation, mean daily air temperature, and the occurrence of rain. The variation in these factors affected the dynamics of the pollen season. The noteworthy frequency of days with rain and high seasonal sum of precipitation totals as well as the dominance of cyclonic weather from the westerly direction had an impact on the extension of the pollen season. The meteorological factors that directly affect pollen release and transport primarily include air humidity, expressed as vapour pressure (r > 0.3, p < 0.01), temperature(r from 0.2 to 0.4, p < 0.01). The relationships between averaged meteorological data and daily pollen concentration were stronger (r > 0.5, p < 0.01). Based on the correlation analysis, the meteorological variables were selected and regression equations were established using stepwise backward regression analysis.     

The impact of meteorological conditions on the concentration of alder pollen in Sosnowiec (Poland) in the years 1997–2017

The aim of the work was to compare the alder pollen seasons in the years 1997–2017 in Sosnowiec. The measurements of pollen concentration were taken with the volumetric method using Burkard’s apparatus. The impact of atmospheric conditions on the daily alder pollen grain concentration, the annual totals, and the duration of pollen seasons were studied. The dependency between each meteorological condition and different features of the alder pollen season was determined by using Pearson’s correlation coefficients, variance analysis with multiple comparison tests, and the linear regression model using backward elimination. It was proven that the temperatures directly preceding the pollination, i.e. the January and February temperatures as well as those from the period from 210 to 180 days preceding the beginning of the season, have the greatest impact on the beginning of the alder pollen season. The value of the daily alder pollen concentration in Sosnowiec showed a positive statistically significant correlation with the air temperature and sunshine duration and a negative correlation with the thickness of the snow cover and air relative humidity. The daily concentration also depended on the type of the weather front, direction of air mass inflow, and the type of the inflowing air mass. The season temperatures and the thermal conditions which were present in the summer of the preceding year impacted the annual totals (SPI) of the alder pollen grains.     

Hindcasting of nutrient loadings from its catchment on a highly valuable coastal lagoon: the example of the Fleet, Dorset, UK, 1866–2004

Background

Nutrient loadings from its catchment upon The Fleet, a highly valuable coastal lagoon in Southern England, were hindcast for the period AD 1866–2004, using a catchment model, export coefficients, and historical data on land use changes, livestock numbers, and human population. Agriculture was the main nutrient source throughout, other inputs representing minor contributions. Permanent pasture was historically the main land use, with temporary grassland and cereals increasing during the mid-20th century. Sheep, the main 19th century livestock, were replaced by cattle during the 1930s.

Results

Total nitrogen loadings rose from ca 41 t yr-1 during the late 19th century to 49–54 t yr-1 for the mid-20th, increasing to 98 t yr-1 by 1986. Current values are ca 77 t yr-1. Total phosphorus loads increased from ca 0.75 t yr-1 for the late 19th century to ca 1.6 t yr-1 for the mid-20th, reached ca 2.2 t yr-1 in 1986, and are now ca 1.5 t yr-1. Loadings rose most rapidly between 1946 and 1988, owing to increased use of inorganic fertilisers, and rising sheep and cattle numbers. Livestock were the main nutrient source throughout, but inputs from inorganic fertilisers increased after 1946, peaking in 1986. Sewage treatment works and other sources contribute little nitrogen, but ca 35% of total phosphorus. Abbotsbury Swannery, an ancient Mute Swan community, provides ca 0.5% of total nitrogen, and ca 5% of total phosphorus inputs.

Conclusion

The Fleet has been grossly overloaded with nitrogen since 1866, climaxing during the 1980s. Total phosphorus inputs lay below 'permissible' limits until the 1980s, exceeding them in inner, less tidal parts of the lagoon, during the 1940s. Loadings on Abbotsbury Bay exceeded 'permissible' limits by the 1860s, becoming 'dangerous' during the mid-20th century. Phosphorus stripping at point sources will not significantly reduce loadings to all parts of the lagoon. Installation of 5 m buffer strips throughout the catchment and shoreline will marginally affect nitrogen loadings, but will reduce phosphorus inputs to the West Fleet below 'permissible' limits. Only a combination of measures will significantly affect Abbotsbury Bay, where, without effluent diversion, loadings will remain beyond 'permissible'.     

Singlet oxygen affects the activity of the thylakoid ATP synthase and has a strong impact on its γ subunit

Singlet oxygen is reported to have the most potent damaging effect upon the photosynthetic machinery. Usually this reactive oxygen molecule acts in concert with other ROS types under stressful conditions. To understand the specific role of singlet oxygen we took advantage of the conditional flu mutant of Arabidopsis thaliana. In flu, the negative feedback loop is abolished, which blocks chlorophyll biosynthesis in the dark. Therefore high amounts of free protochlorophyllide accumulate during darkness. If flu gets subsequently illuminated, free protochlorophyllide acts as a photosensitiser leading almost exclusively to high amounts of ¹O₂. Analysing the thylakoid protein pattern by using 2D PAGE and subsequent MALDI-TOF analysis, we could show, in addition to previous described effects on photosystem II, that singlet oxygen has a massive impact on the thylakoid ATP synthase, especially on its γ subunit. Additionally, it could be shown that the activity of the ATP synthase is reduced upon singlet oxygen exposure and that the rate of non-photochemical quenching is affected in flu mutants exposed to ¹O₂.