Altitudinal and horizontal shifts of the upper boundaries of open and closed forests in the Polar Urals in the 20th century

In the Polar Urals (the Rai-Iz massif and Mounts Tchernaya and Malaya Tchernaya), altitudinal and horizontal shifts of the upper boundary of open and closed larch forests in the 20th century have been studied. Spatiotemporal parameters of these shifts have been assessed with the aid of the ARC/INFO geographic information system (ESRI Inc., United States), using our original large-scale geobotanical maps showing the distribution of different types of forest-tundra communities in the early 1910s and 2000s. The results show that tree vegetation has been actively expanding to higher elevations over the past 90 years. On average, the upper boundaries of open and closed forests have ascended 26 and 35 m and shifted horizontally 290 and 520 m, respectively. These shifts have been conditioned by climate warming and increasing humidity observed since the 1920s.     

Mass spectrometric isotope dilution analysis for accurate determination of elements in environmental samples†

The application of mass spectrometric isotope dilution analysis in environmental analytical chemistry is described. Different ionization methods used in mass spectrometry for isotope dilution analysis and the advantage of isotope dilution analysis owing to its accuracy are discussed. The principle of the isotope dilution technique is explained using thallium analysis as an example. Possible methods of sample decomposition for organic and inorganic matrices and of element separation are given. Using lead, cadmium and thallium analyses as examples the application of mass spectrometric isotope dilution analysis for determination of toxic metals in environmental samples is shown. The determination of chloride and bromide traces in snow is given as an example of non‐metal analysis. The possibility of determining pure elements by the isotope dilution technique using a long‐lived radioactive isotope as a spike is discussed.     

Soil particle-size composition and coastal erosion and accretion study in Soc Trang mangrove forests

Coastal erosion results in loss of land, which impacts the economy, coastal residents and settlement plans, especially in the context of rising sea levels caused by climate change. Studying soil particle-size fractions in mangrove forests will help provide a better understanding of the relationship between soil proportions and coastal processes as well as the role of mangrove forests to support coastal planning and management. Soil samples were collected at 26 sampling plots at depths of 10 cm and 40 cm in the Cu Lao Dung (CLD), Long Phu (LP) and Vinh Chau (VC) mangrove forests in Viet Nam’s Soc Trang Province. The soil proportions based on six different particle-sizes (<0.074 mm, 0.074–0.1 mm, 0.1–0.25 mm, 0.25–0.5 mm, 0.5–1.0 mm, and >1.0 mm) were measured using a dry sieving method. Analysis showed that soil particle-sizes ranging between 0.074 and 0.5 mm made up 75–95 % of the soil sample weight at both depths. The high standard deviation values of soil proportions of each given particle-size among sampling plots indicated the soil proportions by particle-size varied widely across the sampling plots. Cluster analysis found similar pattern of soil particle-size proportions for samples collected in CLD and VC, and different pattern of soil particle-size proportions in samples collected at LP, which is more impacted by the Mekong River flow and has a thin mangrove forest belt.?Non-metric dimension scaling (NMDS) analysis showed that sampling plots across the landward sites of the three mangrove forest areas were distributed in the nearby locations (Stress?=?0.11). This indicated that soil proportions of particle-sizes of samples collected from areas of the natural forest composed of different species were more similar. Such similarities were not found, however, in samples collected from middle and seaward plots dominated by single-species plantations.     

Long-term monitoring of environmental change in German towns through the use of lichens as biological indicators: comparison between the surveys of 1970, 1980, 1985, 1995, 2005 and 2010 in Wetzlar and Giessen

Background

In the years 1970, 1980, 1985, 1995, 2005 and 2010, lichen mapping in the towns of Wetzlar and Giessen in Hesse was performed. The aim was to show the effects of immission load. Despite the application of modified test methods during the study period, the results can still be compared directly because they could be adapted to the requirements of the guidelines of the Association of German Engineers. Even the earlier study results could be interpreted partly within the scope of the guidelines. Parallel to the lichen mapping, comparative examinations of pH on tree bark were carried out.

Results

In both towns, the pH of the tree bark has been increasing continuously, presently almost reaching pre-industrial values. The increase was stronger in Wetzlar than in Giessen. In 1970, the lichen vegetation showed a complete depletion. Since then the number of species has risen significantly. This development happened faster and more intensely in Wetzlar. The comparison of the lichen vegetation between 1970 and 2010 also shows an increased existence of species that are favored by hypertrophic air contaminants. In the 2010 survey, some species considered as being promoted by global warming were found for the first time.

Conclusions

The increase of the bark pH can be explained by the decreasing acid pollution, primarily SO₂. This is also assumed to be the main cause for the increasing number of lichen species. An explanation for Wetzlar's advantage is that the acid pollutants had been neutralized by a local industrial emittent of lime dust. With the reduction of dust emissions in Wetzlar due to the installation of filters, the bark pH in both towns steadily converged in the reference period. An examination of pre-industrial lichen studies shows that in both towns the original state of lichen vegetation has not been restored yet.     

Quantifying social synergy in insect and human societies

What are the benefits of society? What are the adaptive advantages of social behavior? The fact that societies exist suggest that society favors synergies in the interactions between individuals. One such synergy or adaptive advantage might be the increased efficiency in the use of scarce resources. This has been postulated to occur in the “metabolic scaling law”, where larger organisms with more cells consume less energy per unit mass than smaller organisms. Here, I develop a similar scale-free index for social synergy applicable to energy consumption, and apply it to social insect colonies and human cities. The results show that all societies studied increase the efficiency of energy consumption with increased sizes. This study shows that social synergy is reliably quantifiable and that its increase with size is much larger in social insects than that observed with the metabolic scaling law in organisms. This allows for the first time to compare quantitatively very different societies, permitting novel studies in social dynamics, for example, the study shows that termite colonies achieve much higher social synergy than ant and honey bee colonies and that Brazilian cities achieve more social synergy than Danish or North American ones, posing new intriguing questions.     

Production of food-associated calls in wild male chimpanzees is dependent on the composition of the audience

Chimpanzees produce acoustically distinct calls when encountering food. Previous research on a number of species has indicated that food-associated calls are relatively widespread in animal communication, and the production of these calls can be influenced by both ecological and social factors. Here, we investigate the factors influencing the production of food-associated calls in wild chimpanzees and examine whether male chimpanzees produce food-associated calls selectively in the presence of important social partners. Male chimpanzees form stable long-term social relationships with each other, and these social bonds are vital in enabling a range of cooperative activities, such as group hunting and territory defence. Our data show that males were significantly more likely to produce food-associated calls if an important social partner was nearby, regardless of the size of the audience or the presence of oestrus females. Call production was also mediated by the size of the food patch and by whether or not the food could be monopolised. The presence of important social partners explained most of the variation in male calling behaviour, indicating that food-associated calls are socially directed and serve a bonding function.     

Dynamic response to danger in a parasitoid wasp

Despite the multitude of work on patch time allocation and the huge number of studies on patch choice in the face of danger, the patch leaving response of foragers perceiving cues of danger has received relatively little attention. We investigated the response of parasitoid insects to cues of danger both theoretically and experimentally. Using stochastic dynamic theory, we demonstrate that patch-leaving responses in response to the detection of danger should be seen as a dynamic decision that depends upon reproductive options on the current host patch and on alternative patches that might be found after leaving the current patch. Our theory predicts a sigmoidal response curve of parasitoids, where they should accept the danger and stay on the patch when patch quality is high and should increasingly avoid the risk and emigrate from the patch with decreasing patch quality and decreasing costs of traveling to an alternative host patch. Experiments with females of the drosophilid parasitoid Asobara tabida that were exposed to a puff of formic acid (a danger cue) at different times through their patch exploitation confirmed the theoretical predictions (i.e., a sigmoid response curve); however, the predicted curve was significantly steeper than observed. We discuss the impact of dynamic patch-exit decisions of individual foragers on population and community dynamics.     

Long-term reactions of plants and macroinvertebrates to extreme floods in floodplain grasslands

Extreme summertime flood events are expected to become more frequent in European rivers due to climate change. In temperate areas, where winter floods are common, extreme floods occurring in summer, a period of high physiological activity, may seriously impact floodplain ecosystems. Here we report on the effects of the 2002 extreme summer flood on flora and fauna of the riverine grasslands of the Middle Elbe (Germany), comparing pre- and post-flooding data collected by identical methods. Plants, mollusks, and carabid beetles differed considerably in their response in terms of abundance and diversity. Plants and mollusks, displaying morphological and behavioral adaptations to flooding, showed higher survival rates than the carabid beetles, the adaptation strategies of which were mainly linked to life history. Our results illustrate the complexity of responses of floodplain organisms to extreme flood events. They demonstrate that the efficiency of resistance and resilience strategies is widely dependent on the mode of adaptation.     

Anther-mimicking floral guides exploit a conflict between innate preference and learning in bumblebees (<Emphasis Type="Italic">Bombus terrestris</Emphasis>)

Bee-pollinated plants are frequently dichogamous: e.g. each flower has a discernable male and female phase, with only the male phase offering a pollen reward. Pollen-collecting bees should therefore discriminate against female-phase flowers to maximise their rate of pollen harvest, but this behaviour would reduce plant fitness due to inferior pollination. Here, we test the hypothesis that flowers use pollen-mimicking floral guides to prevent flower-phase discrimination. Such floral guides resemble pollen in spectral reflection properties and are widespread among angiosperm flowers. In an array of artificial flowers, bumblebees learned less well to discriminate between flower variants simulating different flowering phases when both flower variants carried an additional pollen-yellow guide mark. This effect depended crucially on the pollen-yellow colour of the guide mark and on its spatial position within the artificial flower. We suggest that floral guides evolved to inhibit flower-phase learning in bees by exploiting the innate colour preferences of their pollinators.