Temperate Zone Of Europe Research Articles

Post-marital residence patterns in LBK: Comparison of different models

Many ideas about post-marital residence rules in the society of the first farmers in the European temperate zone (Linear Pottery Culture, ca. 5500–4900 cal BC) have been proposed. The prevailing hypothesis is patrilocality and community exogamy, based on strontium isotope, modern DNA, ancient DNA, linguistic and anthropological evidence. However, presenting several different anthropological models and comparing them with strontium isotope results from two LBK cemeteries (Vedrovice and Nitra), we argue that other post-marital residence rules such as ambilocality, avunculocality, shifting residence or predominant matrilocality were also possible. Arguments set in contradiction to one-sided interpretation of strontium isotope results include a possible practice of polygyny, abduction of young women and non-inhumation burials. A hypothetical model combining patrilocality and matrilocality on different social and geographical levels is proposed.

Population and community‐level compositional patterns shape the realized niche of the rare arctic‐alpine species Carex lachenalii Schkuhr

The ability for vegetative growth and development of generative organs often reflects an adaptation to the environment and may be a suitable proxy for understanding population dynamics of rare relict species. An example of such a plant is Carex lachenalii Schkuhr, an arctic‐alpine species, in the temperate zone of Europe only occurring in isolated localities of high‐elevation mountain ranges. We aimed to assess whether there were relationships between flower production and clonal growth of C. lachenalii, both at the tuft and plot level, and how co‐occurring vegetation could modify this relationship. In the study we focused on population‐level traits of C. lachenalii, vegetation traits and components of functional diversity. At the tuft level we found that the proportion of flowering ramets of C. lachenalii decreased with increasing diameter of the tuft. At the plot level, in snowbed vegetation C. lachenalii produced more flowering ramets. We suggest this is due to higher environmental stress, expressed by high importance of habitat filtering (low functional dispersion) in shaping species composition of co‐occurring vegetation. In granite grasslands and milder environment (expressed by higher functional dispersion), C. lachenalii produced more vegetative ramets, which we suggest is a result of a more competitive environment. While in snowbeds investment in flowering ramets could promote successful persistence of C. lachenalii, survival of subpopulations occurring in the highly competitive conditions of granite grasslands may be uncertain due to potentially weak adaptation to competition with graminoids and dwarf shrubs.

Tick-Borne Encephalitis Virus Infection Alters the Sialome of Ixodes ricinus Ticks During the Earliest Stages of Feeding.

Ticks are hematophagous arthropods that transmit a number of pathogens while feeding. Among these is tick-borne encephalitis virus (TBEV), a flavivirus transmitted by Ixodes ricinus ticks in the temperate zone of Europe. The infection results in febrile illness progressing to encephalitis and meningitis with a possibility of fatality or long-term neurological sequelae. The composition of tick saliva plays an essential role in the initial virus transmission during tick feeding. Ticks secrete a diverse range of salivary proteins to modulate the host response, such as lipocalins to control the itch and inflammatory response, and both proteases and protease inhibitors to prevent blood coagulation. Here, the effect of viral infection of adult females of Ixodes ricinus was studied with the goal of determining how the virus alters the tick sialome to modulate host tissue response at the site of infection. Uninfected ticks or those infected with TBEV were fed on mice and removed and dissected one- and 3-h post-attachment. RNA from the salivary glands of these ticks, as well as from unfed ticks, was extracted and subjected to next-generation sequencing to determine the expression of key secreted proteins at each timepoint. Genes showing statistically significant up- or down-regulation between infected and control ticks were selected and compared to published literature to ascertain their function. From this, the effect of tick viral infection on the modulation of the tick-host interface was determined. Infected ticks were found to differentially express a number of uncategorized genes, proteases, Kunitz-type serine protease inhibitors, cytotoxins, and lipocalins at different timepoints. These virus-induced changes to the tick sialome may play a significant role in facilitating virus transmission during the early stages of tick feeding.

Global Climate Data Processing and Mapping of Degradation Mechanisms and Degradation Rates of PV Modules

Photovoltaic (PV) systems are the cheapest source of electricity in sunny locations and nearly all European countries. However, the fast deployment of PV systems around the world is bringing uncertainty to the PV community in terms of the reliability and long-term performance of PV modules under different climatic stresses, such as irradiation, temperature changes, and humidity. Methodologies and models to estimate the annual degradation rates of PV modules have been studied in the past, yet, an evaluation of the issue at global scale has not been addressed so far. Hereby, we process the ERA5 climate re-analysis dataset to extract and model the climatic stresses necessary for the calculation of degradation rates. These stresses are then applied to evaluate three degradation mechanisms (hydrolysis-degradation, thermomechanical-degradation, and photo- degradation) and the total degradation rate of PV modules due to the combination of temperature, humidity, and ultraviolet irradiation. Further on, spatial distribution of the degradation rates worldwide is computed and discussed proving direct correlation with the Köppen-Geiger-Photovoltaic climate zones, showing that the typical value considered for the degradation rate on PV design and manufacturer warranties (i.e., 0.5%/a) can vary ± 0.3%/a in the temperate zones of Europe and rise up to 1.5%/a globally. The mapping of degradation mechanisms and total degradation rates is provided for a monocrystalline silicon PV module. Additionally, we analyze the temporal evolution of degradation rates, where a global degradation rate is introduced and its dependence on global ambient temperature demonstrated. Finally, the categorization of degradation rates is made for Europe and worldwide to facilitate the understanding of the climatic stresses.

Divergent fire history trajectories in Central European temperate forests revealed a pronounced influence of broadleaved trees on fire dynamics

Fire occurrence is driven by a complex interplay between vegetation, climatic, landform and human factors making it challenging to separate the individual effect of each variable. Here we present a reconstruction of the Holocene biomass burning history of two regions located in the Central European temperate zone that differ in the timing of the Middle Holocene expansion of broadleaf-dominated forest communities. This allowed us to investigate the effect of biotic changes on past fire activity. Multiple-site charcoal accumulation records were used to estimate regional-scale trends in biomass burning and to compare them with major trajectories of vegetation development. Extensive 14C-dated soil charcoal records collected within both regions were amalgamated using a cumulative probability function to identify a stand-scale proxy of past fire occurrence. Our results suggest that rising vegetation productivity driven by rapid Early Holocene climate amelioration enhanced biomass burning. The increased fire activity during this period was driven by both a drier- and warmer-than-present climate and easily flammable fuels produced by conifer-dominated vegetation. We identified an inhibiting effect of the concomitant Fagus sylvatica expansion on levels of biomass burning that occurred asynchronously between our mountain and mid-elevation sandstone regions 6500 cal yr BP and 4900 cal yr BP, respectively. The amount of compositional change in plant communities was more related to the transformation of major vegetation types than to fluctuations in fire activity levels. The divergent timing of the fire decline in response to the Fagus sylvatica expansion implies biotic control over biomass burning that is independent of a direct climatic influence.

Primary forest distribution and representation in a Central European landscape: Results of a large-scale field-based census

Given the global intensification of forest management and climate change, protecting and studying forests that develop free of direct human intervention—also known as primary forests—are becoming increasingly important. Yet, most countries still lack data regarding primary forest distribution. Previous studies have tested remote sensing approaches as a promising tool for identifying primary forests. However, their precision is highly dependent on data quality and resolution, which vary considerably. This has led to underestimation of primary forest abundance and distribution in some regions, such as the temperate zone of Europe. Field-based inventories of primary forests and methodologies to conduct these assessments are inconsistent; incomplete or inaccurate mapping increases the vulnerability of primary forest systems to continued loss from clearing and land-use change. We developed a comprehensive methodological approach for identifying primary forests, and tested it within one of Europe’s hotspots of primary forest abundance: the Carpathian Mountains. From 2009 to 2015, we conducted the first national-scale primary forest census covering the entire 49,036 km2 area of the Slovak Republic. We analyzed primary forest distribution patterns and the representativeness of potential vegetation types within primary forest remnants. We further evaluated the conservation status and extent of primary forest loss. Remaining primary forests are small, fragmented, and often do not represent the potential natural vegetation. We identified 261 primary forest localities. However, they represent only 0.47% of the total forested area, which is 0.21% of the country’s land area. The spatial pattern of primary forests was clustered. Primary forests have tended to escape anthropogenic disturbance on sites with higher elevations, steeper slopes, rugged terrain, and greater distances from roads and settlements. Primary forest stands of montane mixed and subalpine spruce forests are more abundant compared to broadleaved forests. Notably, several habitat types are completely missing within primary forests (e.g., floodplain forests). More than 30% of the remaining primary forests are not strictly protected, and harvesting occurred at 32 primary forest localities within the study period. Almost all logging of primary forests was conducted inside of protected areas, underscoring the critical status of primary forest distribution in this part of Europe. Effective conservation strategies are urgently needed to stop the rapid loss and fragmentation of the remaining primary forests. Our approach based on precise, field-based surveys is widely applicable and transferrable to other fragmented forest landscapes.

Adding ecology into phylogeography: ecological niche models and phylogeography in tandem reveals the demographic history of the subalpine warbler complex

ABSTRACTCapsule: This study documents evidence of interglacial refugia during the Last Interglacial for birds in the Mediterranean region, and emphasizes the importance of the Last Interglacial on the geographic distribution and genetic structure of Mediterranean species.Aims: We focused on the historical biogeography of the subalpine warbler complex: Subalpine Warbler Sylvia cantillans and Moltoni’s Warbler Sylvia subalpina; we tested if this Mediterranean bird complex shared a similar demographic fate as the present-day widespread species in the temperate zones of Europe, through the late Quaternary glacial-interglacial cycles.Methods: An ecological niche model was developed to predict the geographic distribution of the subalpine warblers under the past (the Last Interglacial and the Last Glacial Maximum) and the present bioclimatic conditions. Additionally, Bayesian Skyline Plot analysis was used to assess effective population size changes over the history of the subalpine warbler complex.Results: During the Last Glacial Maximum, the subalpine warblers almost reached their current distribution in the Mediterranean region; yet, unlike the widespread temperate bird species, they survived the Last Interglacial in allopatric refugia in the Mediterranean region.Conclusion: A unique biogeographic pattern was revealed, indicating the importance of the Last Interglacial on current distributional patterns and demographic histories of common bird species in the Mediterranean region. This study suggests that Mediterranean biogeography is far more complex than previously assumed, and so deserves further study and more attention.

Key factors affecting the diversity of Sphagnum cover inhabitants with the focus on ground beetle assemblages in Central-Eastern European peat bogs

A key structural component in peat bog formation is Sphagnum spp., which determines very specific associated environmental conditions. The aim of this study was to characterise some of the key factors affecting the diversity, species richness and abundance of sphagnum inhabiting ground beetles and to examine the maintenance of stable populations of cold adapted specialised peat bog species. A total of 52 carabid species were recorded by pitfall traps along six main habitats, such as the lagg zone, pine bog, hollows, hummock open bog and dome. The results are characterised by a low diversity, which vary significantly among habitat types, and include a high abundance of a few carabid species. Among the variables influencing carabid species richness and abundance were plant cover, pH and the conductivity of the Sphagnum mat water. Vascular plant cover was a key factor shaping carabid beetle assemblages in the slope and the dome, while electric conductivity affected carabid beetle assemblage in the lagg. Whereas, the water level was the most important factor for the hollows. At the same time, peat bog specialists showed low sensitivity to the gradient of the analysed variables. Most of the specialised species are protected boreal beetles in the temperate zone of Europe, and therefore Belarusian peat bogs are a significant repository of cold adapted specialised bog species and potentially represent a significant refugia for these species in the context of global warming.

Changing disturbance‐diversity relationships in temperate ecosystems over the past 12000 years

Abstract Disturbances such as fires and grazing have major impacts on biodiversity. While it has been suggested that species richness is highest with intermediate levels of disturbance, currently there is no consensus due to an absence of data covering large temporal and spatial scales. We developed a new method to examine disturbance‐diversity relationships (DDR) using sedimentary pollen data linked with species’ disturbance ecology. We reconstructed disturbance and diversity dynamics in the region of the European temperate zone over the last 12,000 years and calculated DDR for 900‐year sequential temporal windows. Disturbance frequency was highest in the early and late Holocene, while remaining low in the mid‐Holocene. Diversity increased continuously from the start of the Holocene. Our results demonstrate that over the past 12,000 years DDR changed from hump‐shaped into monotonic increasing pattern. While both highly disturbed and undisturbed sites were strongly impoverished in the early Holocene, as species migrated, biodiversity levels have subsequently affected disturbance regimes with highly disturbed sites now being the highest in species richness. Synthesis. Land‐use changes in the last 4,000 years created an increasingly patchy landscape, allowing invasive species adapted to high‐frequency disturbance to migrate across the landscape. The link between high diversity and disturbed areas is relatively recent and may anticipate even greater disturbance frequencies in future. Our findings also support a hypothesis that species migration, and the structure of the species pool critically determines the response of biota to external factors such as disturbance.

Environmental Modelling of Forest Vegetation Zones as A Support Tool for Sustainable Management of Central European Spruce Forests

Abstract The impact of climate change on forest ecosystems may manifest itself by a shift in forest vegetation zones in the landscape northward and into higher elevations. Studies of climate change-induced vegetation zone shifts in forest ecosystems have been relatively rare in the context of European temperate zone (apart from Alpine regions). The presented paper outlines the results of a biogeographic model of climatic conditions in forest vegetation zones applied in the Central European landscape. The objective of the study is a prediction of future silvicultural conditions for the Norway spruce (Picea abies L. Karst.), which is one of the principal tree species within European forests. The model is based on a general environmental dependence of forest vegetation zones on the long-term effect of altitudinal and exposure climates defined by the mean and extreme air temperatures and the amount and distribution of atmospheric precipitation. The climatological data for the model were provided by a validated regional climate database for 2010 – 2090 according to the SRES A1B scenario, bound to specific geo-referenced points in the landscape. The geobiocoenological data in the model were provided by the Biogeography Register database which contains ecological data on the landscape bound to individual cadastres of the entire Czech Republic. The biogeographic model applies special programs (the FORTRAN programming language) in the environment of geographic information systems. The model outputs can be clearly graphically visualized as scenarios of predicted future climatic conditions of landscape vegetation zones. Modelling of the regional scenario of changes in the climatic conditions of forest vegetation zones reveals that in the prediction period of 2070 and beyond, good and very good climatic conditions for the cultivation of forests with dominant Norway spruce will be found only in some parts of its today’s native range in forest vegetation zones 5 – 8. Based on the results provided by the regional scenario, the authors of this paper recommend fundamental reassessment of the national strategy of sustainable forest management in the Czech Republic, stipulating that the current practice of spruce cultivation be reduced only to areas specifically defined by the biogeographic model. The paper shows that biogeographic models based on the concept of vegetation zoning can be applied not only in regional scenarios of climate change in the landscape but also as support tools for the creation of strategies of sustainable forest management.

Wintering range of Pipistrellus nathusii (Chiroptera) in Central Europe: has the species extended to the north-east using urban heat islands?

Abstract Recent climate warming is thought to affect the migratory behavior and geographical range shifts of Pipistrellus nathusii. This bat of the European temperate woodland zone is known to migrate up to 1900 km between its breeding and wintering areas where it uses overground roosts for hibernation. New wintering areas of the species have been recorded lately mainly in the cities of Central Europe, largely extending its winter distribution to the north-east. The growing detection of the winter occurrence of P. nathusii has coincided with an increase in mean winter temperatures and urban warming. Our analysis shows that a winter isotherm of −2.5°C acts as a border for the winter occurrence of P. nathusii, and the species uses urban areas, most likely benefiting from the effect of urban heat islands. Accordingly, the island-like pattern of P. nathusii’s regular wintering habitats distribution in Central Europe seems to reflect the thermal and structural diversity of the environment. The use of diverse anthropogenic roosts suggests that the species is well-adapted to urban habitats, thus demonstrating its ecological plasticity.

Crossing the Blood-Brain Barrier by Neuroinvasive Pathogens

Abstract The penetration of the blood-brain barrier (BBB) and invasion of the central nervous system (CNS) are important steps for all neuroinvasive pathogens. All of the ways of pathogens passing through the BBB are still unclear. Among known pathways, pathogen traversal can occur paracellularly, transcellularly or using a “Trojan horse” mechanism. The first step of translocation across the BBB is the interactions of the pathogen’s ligands with the receptors of the host brain cells. Lyme disease, the most common vector-borne disease in the temperate zones of Europe and North America, are caused by Borreliella species (former Borrelia burgdorferi sensu lato) that affects the peripheral and the CNS. In this review, we have presented various pathogen interactions with endothelial cells, which allow the disruption of the BBB so that the pathogens can pass across the BBB.

Evaluating the influence of integrative forest management on old-growth habitat structures in a temperate forest region

Integrative forest management attempts to simultaneously fulfill both wood production and biodiversity conservation in a given forest region, and presumably supplants the need for unmanaged forest reserves. This is the dominant management paradigm in the temperate zone of Europe, yet few studies have examined the validity of this approach. We used Slovenia as a test bed to examine how the long-term practice of integrative forest management has influenced two structural components of mature forest conditions, namely coarse woody debris (CWD) and large living trees, as well as the distribution of the White-backed Woodpecker, a species dependent on such conditions. Data were compiled from national inventory plots, coupled with separate surveys in 51 forest reserves. The mean volume of CWD and density of large beech trees across managed forests in Slovenia was 15m3ha−1 and 6ha−1, respectively; these mean values were significantly higher (165m3ha−1 and 55ha−1) in old-growth reserves. CWD was primarily comprised of small diameter pieces in managed forest, whereas large diameter pieces in multiple stages of decay represented most of the volume in reserves. These results, coupled with the limited distribution of the woodpecker across the country, suggest that integrative management practiced over a large scale may be insufficient for maintaining biodiversity dependent on mature forest conditions at current levels of wood extraction.

Joining of the historical research and future prediction as a support tool for the assessment of management strategy for European beech-dominated forests in protected areas

European beech-dominated forests are crucial for maintaining biodiversity in forested mountain landscapes of the European temperate zone. This paper presents the results of research and assessment of management strategy for mountain beech-dominated forests in the Jeseníky Mountains (Czech Republic). Our approach is based on combining research on historical development of the forest ecosystem, assessment of its current state, and predictions of future dynamics using a forest growth simulation model. Using such a method makes it possible to understand the current state of the mountain beech-dominated forest ecosystem and predict its future development as a response to specific management strategies. The application of this method is therefore appropriate for assessing the suitability of selected management strategies in mountain protected areas. Our results show that a non-intervention management for mountain beech forest in the next 80 years complies with the Natura 2000 requirement to maintain the existing character of the forest habitat. Thus, the current management plan for the beech-dominated forests in the Jeseníky Mountains does not require significant corrections in the context of its conservation targets (i.e. maintaining biodiversity and current character of the forest ecosystem dominated by beech). The results of this study suggest that combining the knowledge on historical development with forest growth simulation can be used as a suitable support tool to assess management strategies for forest habitats in protected areas.

Effect of forest stand management on species composition, structural diversity, and productivity in the temperate zone of Europe

Forests in Central Europe have been used since centuries and were systematically changed by silvicultural practices since the late 1700s. Focusing on possible biodiversity losses, forest stand management primarily impacts on the biodiversity attributes ‘composition, structure and functioning’ that are interlinked and incorporate different organizational and spatial ecosystem levels. Forest stand management can manipulate tree species diversity, which in turn affects stand structure and finally leads to changes in forest functions and services. We used meta-analyses to review 49 papers with 197 comparisons on compositional and structural diversity between unmanaged and managed forests as well as 53 comparisons of biomass productivity between mixed and monoculture forests throughout the temperate biome of Europe. Besides management impacts, for species and structural comparisons, we took time since abandonment of forest stand management into consideration when dealing with unmanaged forests. For species richness and diversity, we could not detect significant management effects; no significant influences of time since abandonment of management could be identified either. Structural attributes partly revealed considerable responses to forest stand management. Importantly, deadwood quantity, the number of microhabitats, and tree size diversity were reduced by forest stand management, while no effect was found for stand basal area and the number of living trees. Some of these effects become more pronounced with increasing time since abandonment. Forest productivity was significantly enhanced by regular moderate thinning compared with untreated stands and by tree species mixing compared with monospecific stands. Based on these results, we discuss the role of direct and indirect silvicultural effects, interactions between biodiversity components, the problem of defining the unmanaged reference state, and perspectives for forest stand management in practice.

Overstorey dynamics controls plant diversity in age-class temperate forests

Forest management is widely considered to have an impact on the understorey plant diversity, which is essential for sustainable forestry and nature conservation. However, contradictions among previous large-scale studies and meta-analyses raised the need for better-designed research. Such research should identify drivers controlling diversity and species composition, quantify the overstorey-understorey relationships and their dynamics in the temperate forests.Two spatial scales (2.25m2; 314m2) and stratified random sampling design were used to record understorey vegetation and overstorey and environmental properties along the whole lifecycle of managed Norway spruce (108years) and European beech (140years) stands, the most wide-spread mountain forest types in European temperate zone. The dataset also includes primeval fir-beech forests located in the same area.Forest management significantly altered understorey diversity and species composition in both beech and spruce stands. Diversity measures changed considerably over the development of managed stands, exhibiting the rapid decline from species-rich forest clearings to poor stands of 30–40years, later slowly recovering and reaching the average level of old-growth forests at the age of over 100years. The impact of management was stronger at the smaller scale. It is caused by the fine-scale character of overstorey-understorey interactions, and it is weakened due to stand structure heterogeneity in larger scales.Competition of overstorey trees was identified as the most important driver of understorey diversity and its temporal dynamics. It was also reflected in the litter amount, which negatively affected diversity especially in the beech forests. In contrast, the light amount was a more important factor in the spruce stands.We conclude that comparisons between datasets that are heterogeneous regarding overstorey age and proportion of development stages, as well as meta-analyses based on such inconsistent studies, can lead to confusing conclusions and improper applications. As a practical implementation, we recommend using overstorey tree density as the most efficient measure for assessment, prediction and managing understorey plant diversity.

Assessment of Forest Management in Protected Areas Based on Multidisciplinary Research

The remnants of primeval Norway spruce forests in the European temperate zone are crucial for maintaining forest biodiversity in high mountain landscapes. This paper presents results of a multidisciplinary research and evaluation project on the management practices for mountain spruce forests in the Natura 2000 site (National Nature Reserve Serak-Keprnik in the Hruby Jesenik Mountains, the Czech Republic). Results are based on combining research on the historical development of the forest ecosystem and predictions of future dynamics using a forest growth simulation model. The presented results show that a non-intervention management strategy for mountain spruce forest in the next 50 years complies with the Natura 2000 requirement to maintain the existing character of the forest habitat. Thus, the results indicate that the current management plan for the spruce forests does not require significant corrections in the context of its conservation goals (i.e., maintaining biodiversity and current character of the forest ecosystem dominated by Norway spruce). The results of this study suggest that combining the knowledge of historical development with forest inventory data using forest growth simulation represents a suitable support tool for the assessment of management practices for forest habitats in protected areas.

Links between shoot and plant longevity and plant economics spectrum: Environmental and demographic implications

The tacit assumption of functional ecology is that traits affect plant fitness. However, this link is mediated by demography, e.g. specific leaf area is not affecting changes in abundance directly but through vegetative multiplication or generative reproduction of plants − it means via demographic processes. We propose that in herbaceous perennials, architectural traits that capture shoot development constitute simple morphological surrogates of a number of demographic functions (shoot lifespan, lateral spread, multiplication rate). A shoot is a reiterated basic unit of a plant body in herbs and is easily recognizable as an individual. We propose that potential shoot lifespan (shoot cyclicity) may serve as a simple character relevant to demographic processes of clonal herbs while whole plant longevity plays a similar role for non-clonal herbs. Therefore we examined relationships of shoot and whole-plant lifespans with a key trait of the plant economic spectrum (specific leaf area, SLA) for a large set of Central European temperate zone herbs. We also investigated whether shoot and whole-plant lifespan are non-randomly distributed along environmental gradients, using indicator values and their distribution among plant community types. Finally, we analysed whether shoot cyclicity underlies differences in temporal turnover of plants in species-rich meadows. Our analyses showed that fast-growing species had shorter shoot and/or plant lifespan and preferred more productive environmental conditions, but the relationship was not strong. In addition, the two lifespan measures were independent of each other, indicating that shoot lifespan captures a rather different aspect of plant demography than whole-plant longevity. Turnover of perennial plants with annual shoots in meadow community was much higher than that of plants with long-lived shoots. Whole-plant and shoot lifespan constitute promising proxy variables for a mechanistic link between functional traits and community ecology in the temperate zone and deserves further attention.

Selective Behaviour of Honeybees in Acquiring European Propolis Plant Precursors.

Honey bees harvest resins from various plant species and use them in the hive as propolis. While there have been a number of studies concerning the chemical composition of this antimicrobial product, little is known about selective behavior and bee preference when different potential plant sources of resin are available. The main objective of this paper was to investigate some aspects of behavioral patterns of honeybees in the context of resin acquisition. Samples of propolis originating from temperate zones of Europe and the supposed botanical precursors of the product were analyzed. Taxonomical markers of bud resins of two white birch species, aspen, black poplar, horse-chestnut, black alder, and Scots pine were determined through GC-MS analysis. All these trees have been reported as sources of propolis, but comparisons of the chemical composition of their bud resins with the compositions of propolis samples from seven European countries have demonstrated the presence of taxonomical markers only from black poplar, aspen, and one species of birch. This suggests selective behavior during the collection of bud resins by honeybees. To examine the causes of such selectivity, the antimicrobial properties of bud resins were determined. Horse-chestnut resins had lower antimicrobial activity than the other resins which did not differ significantly.Electronic supplementary materialThe online version of this article (doi:10.1007/s10886-016-0708-9) contains supplementary material, which is available to authorized users.

Hardy exotics species in temperate zone: can "warm water" crayfish invaders establish regardless of low temperatures?

The spreading of new crayfish species poses a serious risk for freshwater ecosystems; because they are omnivores they influence more than one level in the trophic chain and they represent a significant part of the benthic biomass. Both the environmental change through global warming and the expansion of the pet trade increase the possibilities of their spreading. We investigated the potential of four “warm water” highly invasive crayfish species to overwinter in the temperate zone, so as to predict whether these species pose a risk for European freshwaters. We used 15 specimens of each of the following species: the red swamp crayfish (Procambarus clarkii), the marbled crayfish (Procambarus fallax f. virginalis), the yabby (Cherax destructor), and the redclaw (Cherax quadricarinatus). Specimens were acclimatized and kept for 6.5 months at temperatures simulating the winter temperature regime of European temperate zone lentic ecosystems. We conclude that the red swamp crayfish, marbled crayfish and yabby have the ability to withstand low winter temperatures relevant for lentic habitats in the European temperate zone, making them a serious invasive threat to freshwater ecosystems.