The dynamics of the Corylus, Alnus, and Betula pollen seasons in the context of climate change (SW Poland).

The changes in the main features of early spring tree or shrub pollen seasons are important due to the significant impact on the occurrence of pollen-related allergy symptoms. This study shows the results of pollen monitoring for a period of eleven years (2003-2013) using a Burkard volumetric spore trap. The main characteristics of the hazel, alder, and birch pollination season were studied in Wroclaw (SW Poland). The statistical analyses do not show a significant trend of annual total pollen count or shift in timing of the pollen season in the period of analysis. The research confirms a great impact (at the statistically significant level of 0.05) of the heat resources on pollination season (the value of the correlation coefficient ranges from -0.63 up to -0.87). Meteorological variables (e.g. sum of temperature for selected period) were compiled to 5-year running means to examine trends. Changes in the pollination period features due to climate change including both timing and intensity of pollen productivity, would have important consequences for allergy sufferers.

Migration patterns of subgenus Alnus in Europe since the last glacial maximum: a systematic review.

BACKGROUND/AIMS: Recently, new palaeoecological records supported by molecular analyses and palaeodistributional modelling have provided more comprehensive insights into plant behaviour during the last Quaternary cycle. We reviewed the migration history of species of subgenus Alnus during the last 50,000 years in Europe with a focus on (1) a general revision of Alnus history since the Last Glacial Maximum (LGM), (2) evidence of northern refugia of Alnus populations during the LGM and (3) the specific history of Alnus in particular European regions. METHODOLOGY: We determined changes in Alnus distribution on the basis of 811 and 68 radiocarbon-dated pollen and macrofossil sites, respectively. We compiled data from the European Pollen Database, the Czech Quaternary Palynological Database, the Eurasian Macrofossil Database and additional literature. Pollen percentage thresholds indicating expansions or retreats were used to describe patterns of past Alnus occurrence. PRINCIPAL FINDINGS: An expansion of Alnus during the Late Glacial and early Holocene periods supports the presence of alders during the LGM in southern peninsulas and northerly areas in western Europe, the foothills of the Alps, the Carpathians and northeastern Europe. After glaciers withdrew, the ice-free area of Europe was likely colonized from several regional refugia; the deglaciated area of Scandinavia was likely colonized from a single refugium in northeastern Europe. In the more northerly parts of Europe, we found a scale-dependent pattern of Alnus expansion characterised by a synchronous increase of Alnus within individual regions, though with regional differences in the times of the expansion. In southern peninsulas, the Alps and the Carpathians, by contrast, it seems that Alnus expanded differently at individual sites rather than synchronously in whole regions. CONCLUSIONS: Our synthesis supports the idea that northern LGM populations were important sources of postglacial Alnus expansion. The delayed Alnus expansion apparent in some regions was likely a result of environmental limitations.

Ecotoxicological effects evoked in hydrophytes by leachates of invasive Acer negundo and autochthonous Alnus glutinosa fallen off leaves during their microbial decomposition.

Throughout 90-day biodegradation under microaerobic conditions, invasive to Lithuania species boxelder maple (Acer negundo) leaves lost 1.5-fold more biomass than that of autochthonous black alder (Alnus glutinosa), releasing higher contents of N(tot), ammonium and generating higher BOD(7). Boxelder maple leaf leachates were characterized by higher total bacterial numbers and colony numbers of heterotrophic and cellulose-decomposing bacteria than those of black alder. The higher toxicity of A. negundo aqueous extracts and leachates to charophyte cell (Nitellopsis obtusa), the inhabitant of clean lakes, were manifested at mortality and membrane depolarization levels, while the effect on H(+)-ATPase activity in membrane preparations from the same algae was stronger in case of A. glutinosa. Duckweed (Lemna minor), a bioindicator of eutrophic waters, was more sensitive to leaf leachates of A. glutinosa. Fallen leaves and leaf litter leachates from invasive and native species of trees, which enter water body, affect differently microbial biodestruction and aquatic vegetation in freshwater systems.

Changes in the pollen seasons of the early flowering trees Alnus spp. and Corylus spp. in Worcester, United Kingdom, 1996-2005.

Previous work on Betula spp. (birch) in the UK and at five sites in Europe has shown that pollen seasons for this taxon have tended to become earlier by about 5-10 days per decade in most regions investigated over the last 30 years. This pattern has been linked to the trend to warmer winters and springs in recent years. However, little work has been done to investigate the changes in the pollen seasons for the early flowering trees. Several of these, such as Alnus spp. and Corylus spp., have allergens, which cross-react with those of Betula spp., and so have a priming effect on allergic people. This paper investigates pollen seasons for Alnus spp. and Corylus spp. for the years 1996-2005 at Worcester, in the West Midlands, United Kingdom. Pollen data for daily average counts were collected using a Burkard volumetric trap sited on the exposed roof of a three-story building. The climate is western maritime. Meteorological data for daily temperatures (maximum and minimum) and rainfall were obtained from the local monitoring sites. The local area up to approximately 10 km surrounding the site is mostly level terrain with some undulating hills and valleys. The local vegetation is mixed farmland and deciduous woodland. The pollen seasons for the two taxa investigated are typically late December or early January to late March. Various ways of defining the start and end of the pollen seasons were considered for these taxa, but the most useful was the 1% method whereby the season is deemed to have started when 1% of the total catch is achieved and to have ended when 99% is reached. The cumulative catches (in grains/m(3)) for Alnus spp. varied from 698 (2001) to 3,467 (2004). For Corylus spp., they varied from 65 (2001) to 4,933 (2004). The start dates for Alnus spp. showed 39 days difference in the 10 years (earliest 2000 day 21, latest 1996 day 60). The end dates differed by 26 days and the length of season differed by 15 days. The last 4 years in the set had notably higher cumulative counts than the first 2, but there was no trend towards earlier starts. For Corylus spp. start days also differed by 39 days (earliest 1999 day 5, latest 1996 day 44). The end date differed by 35 days and length of season by 26 days. Cumulative counts and lengths of season showed a distinct pattern of alternative high (long) and low (short) years. There is some evidence of a synchronous pattern for Alnus spp.. These patterns show some significant correlations with temperature and rainfall through the autumn, winter and early spring, and some relationships with growth degree 4s and chill units, but the series is too short to discern trends. The analysis has provided insight to the variation in the seasons for these early flowering trees and will form a basis for future work on building predictive models for these taxa.

Synergistic effect of Glomus intraradices and Frankia spp. on the growth and stress recovery of Alnus glutinosa in an alkaline anthropogenic sediment.

The presence of actinorhizas and arbuscular mycorrhizas may reduce plant stresses caused by adverse soil conditions. A greenhouse experiment was conducted using a sediment with a high pH, resulting from the disposal of waste originated at an acetylene and polyvinylchloride factory, in which Black alder (Alnus glutinosa) seedlings were inoculated either with Glomus intraradices BEG163 (originally isolated from the same sediment), Frankia spp. or both symbionts. After a 6-month growth period, plants inoculated with both symbionts had significantly greater leaf area, shoot height and total biomass when compared with the uninoculated control, the Frankia spp. and the G. intraradices treatments alone. In dual inoculated plants the N and P leaf content was significantly increased. A defoliation experiment was performed to evaluate the stress recovery of A. glutinosa and plants inoculated with both symbionts had a faster leaf regrowth and produced greater numbers of leaves. The dual inoculation resulted in greater numbers of and larger root nodules than when inoculated with Frankia spp. alone. The length and NADH diaphorase activity of the extraradical mycelium of G. intraradices was also significantly greater when dual inoculation was performed. The inoculation with Frankia spp. alone was shown to improve A. glutinosa growth, whereas G. intraradices alone had no positive effect under these environmental conditions. However, when the two symbionts were inoculated together a synergistic effect was observed resulting in a greater benefit for the plants and for both symbionts. The relevance of these findings for the phytorestoration of anthropogenic stressed sediments with high pH is discussed.