Differences in the growth response of three bryophyte species to nitrogen

The effect of nitrogen on biomass production, shoot elongation and relative density of the mosses Pleurozium schreberi, Hylocomium splendens and Dicranum polysetum was studied in a chamber experiment. Monocultures were exposed to 10 N levels ranging from 0.02 to 7.35 g N m⁻² during a 90-day period. All the growth responses were unimodal, but the species showed differences in the shape parameters of the curves. Hylocomium and Pleurozium achieved optimum biomass production at a lower N level than Dicranum. Pleurozium had the highest biomass production per tissue N concentration. Tolerance to N was the widest in Dicranum, whereas Hylocomium had the narrowest tolerance. Dicranum retained N less efficiently from precipitation than the other two species, which explained its deviating response. All species translocated some N from parent to new shoots. The results emphasize that the individual responses of bryophytes to N should be known when species are used as bioindicators.     

Time-Varying Parameter Analysis of the Baltic Sea Freshwater Runoffs

The Baltic Sea runoff events during 1970–2000 were analysed with non-linear estimation in order to find potential stability and time-varying (non-constancy) properties of time series parameters. In the Baltic Sea area, the wintertime rainfall is expected to increase, especially in the northern parts of the watershed; furthermore, seasonality is expected to decrease, i.e. the runoffs will become more evenly distributed over seasons, mainly by decreasing springtime peaks. We found a general increase in runoffs over the time period studied that consisted of a level shift upwards during the early 1980s. The runoffs considerably resulted from inputs in the months of April to June (which points to the significance of winter precipitation) and are biased to northern parts of the catchment. Our results suggest that this is connected with snow and ice melting in the northern areas of the watershed, especially in the subarctic catchment area of the Neva River (the area includes, for example, three of the four biggest lakes in Europe, Lake Ladoga, Lake Onega and Lake Saimaa, which are annually covered by ice). The yearly variation in runoff is significantly stabilised by large N–S extension of the watersheds of these lakes. The results are generally in accordance with the presented climatic expectations; however, decreasing seasonality was not obvious in the series yet. However, we found potential implications of system change towards decreased seasonality. By better understanding of ongoing processes in the sea, the results can give us an opportunity to better evaluate the system control, predicted areal consequences and ecosystem effects of the climate change. The analysis proved to be a sensitive tool for studying climatic variation in a relatively small area and over a short time span.     

Selection of Islands for Conservation in the Urban Archipelago of Helsinki, Finland

Abstract: The occurrence of vascular plants was surveyed on 207 islands (size range 0.01–390.2 ha, number of plant species 1–449) offshore from the city of Helsinki in the Baltic Sea to examine the conservation value of these islands. We calculated a rarity score for each species (1/number of islands occupied by the species) and a biodiversity score for each island (sum of the rarity scores of each species present on the island). Positive correlations between species number and biodiversity score (r _s = 0.97, p < 0.001) and between biodiversity score and island area (r _s = 0.87, p < 0.001) indicated that these parameters are heavily dependent on island size. With the goal of including at least one occurrence (island) of all plant species, an iterative selection algorithm chose a set of 41 islands whose average size (29.3 ha) was four times the average size of all existing islands (7.0 ha). Strong nestedness ( N < 54) explains the concentration of plant species diversity on large islands. An operational strategy for selection of sites for protection is to complement the set produced by a selection algorithm with target species not yet included (e.g., endangered species with several occurrences). Comprehensive mapping and analysis of a taxonomic group will help integrate conservation biology into land-use planning and increase the quality of the networks of protected areas.     

Silvicultural management in maintaining biodiversity and resistance of forests in Europe-boreal zone: case Finland

The majority of untouched natural boreal forests have been regenerated through large catastrophes, occurring by intervals between 50 and 100 years. Storm and fire will open the landscape, result in a huge amount of dead or dying trees and let the pioneer tree species germinate. These processes are the guideline for Finnish forest management today.The main focus by maintaining the biodiversity in Finnish boreal forest zone is directed to managed forests. Nature-orientated silviculture on stand level is practised. The site type classification, a reflection of the modern concept of biodiversity and developed by Cajander early in 1900s, on the basis of natural vegetation composition of the site, has the central role by choosing tree species, regeneration methods and thinning procedure, and reflects also on the site productivity. The small size of stands, the abundance of natural seedlings in planted stands and the popularity of mixed stands have a positive impact on biodiversity of forests. The protection of small-sized valuable habitats in commercially managed stands, the leaving of retention trees standing and lying in the forest in all phases of the rotation, are activities made for biodiversity. Many insects and fungi are adapted to catastrophes and so they can survive in single stems left on regeneration areas. Maintaining the biodiversity in multifunctional forests is also supported by the new forest legislation and by the criteria of Finnish Forest Certification System.     

The use of SEM/EDX for studying the distribution of air pollutants in the surroundings of the emission source

A new application of SEM/EDX-methods to study the distribution of air pollutants in the surroundings of an emission source is described. An energy dispersive X-ray microanalyzer (EDX) connected to a scanning electron microscope (SEM) was used to measure the amount of several elements on the surface of Scots pine bark. To test this method, bark samples were collected near a limestone quarry and plant. The results indicated that the pollutant gradient in the surroundings of the emission source was clearest, when this new method was used. The coefficient of determination (R2) for calcium on pine bark was as high as 0.99, whereas in the same study line, measurements of total Ca content of pine needles and soil humus yielded R2 values of 0.46 and 0.74, respectively.     

Infrared thermography reveals effect of working posture on skin temperature in office workers

Introduction. Musculoskeletal symptoms related to using traditional computer workstations are common. Quantitative methods for measuring muscle stress and strain are needed to improve ergonomics of workstations. We hypothesize that infrared thermography (IRT) is suited for this purpose. Methods. This hypothesis was evaluated by estimating muscle activity in upright and traditional working postures with IRT and surface electromyography (sEMG). IRT and sEMG measurements were conducted in 14 female participants with both working postures. First, measurements with the traditional posture were performed. Later, participants had 1?month to adjust to the upright working posture before repeating the measurements. IRT images were acquired before and after a full working day, with sEMG recordings being conducted throughout the measurement days. Participants evaluated their neck pain severity using neck disability index (NDI) questionnaires before the first and after the second measurement day. Results. Spatial variation in upper back temperature was higher (p?=?0.008) when working in traditional posture and the upright working posture reduced (p?p?=?0.003) after working in the upright posture. Conclusion. IRT was found suitable for evaluating muscle activity and upright working posture to reduce the NDI and muscle activity in the upper back.     

Climate Warming and Pikeperch Year-Class Catches in the Baltic Sea

Climate change scenarios concerning the Baltic Sea predict increase in surface water temperatures. Pikeperch (Sander lucioperca (L.)) inhabits the coastal areas of the northern Baltic Sea and is an important fish species for the Finnish fisheries. The year-class strength of pikeperch varies strongly between years and significantly depends on water temperature. We aimed to study the effects of changing temperature conditions on pikeperch fisheries and distribution based on commercial catch data from the period 1980–2008 in the Finnish coastal areas of the Baltic Sea. The results indicated that warmer summers will produce stronger pikeperch year-classes that consequently contribute significantly to the future catches. The average temperature in June–July explained 40% of the variation in the year-class catches in the Gulf of Finland and 73% in July–August in the Archipelago Sea. During the study period, the distribution of pikeperch catches expanded toward north along the coasts of the Bothnian Sea.     

波罗的海未来冰情的数值研究

全球气候变化被认为对波罗的海物理和生态特性有影响.通过全球海气循环模型(AOGCM)的结果统计或动态缩减规模法可以预测未来气候对某一地区的影响.本文用两种不同的波罗的海冰-海耦合模型来模拟现在和未来约100年的冰情.已使用大气气候模型进行了两次以10年为期限的模拟实验,一个实验说明了工业化前的气候状况l检验模拟).另一个是CO2这种温室气体浓度增加150%时的全球气候变暖实验(方案模拟).模型模拟真实地再现了当前气候学冰情和一年里的变化.两个模型模拟的波罗的海每年最大结冰范围是l80～420×10xkm2(检验模拟)和45～270×103km2(方案模拟).检验模拟和方案模拟中每年的最大冰厚分别是32～96cm和11～60cm.对比早期的预测,海冰仍是每年冬天在波的尼亚湾北部和芬兰湾最东部形成总之,两个模型模拟得到的量的变化--像结冰范围和冰厚及其一年里的变化等--相对相似,这是值得注意的.因为这两个冰-海耦合模拟系统是独立研制的.这增加了预测波罗的海未来冰情的可靠性.     

Ecological condition of forests around the eastern part of the Gulf of Finland

The effects of air pollutants on forests around the eastern part of the Gulf of Finland were studied by measurement of the sulphur and calcium content of pine needles and evaluation of the ecological conditions of pine forests. Several parameters for pine trees and their needles were chosen as well as the species composition and condition of epiphytic lichens. Very high pine needle S- and Ca-contents were measured in the vicinity of the Narva and Slantsy plants. In this region both the acid and basic pollutant load is massive, partly neutralizing each other. It is suggested that the total load will, sooner or later, cause unexpected environmental damage. Wide 'lichen desert' areas were detected around Narva and Slantsy. Near the margins of these areas extraordinary epiphytes on pines were observed namely Xanthoria parietina (L.) Th.Fr. and red-coloured green alga Trentepohlia umbrina. They are regarded as indicators of alkaline pollution. The lowest pine needle S- and Ca-contents of the study area were measured in south-eastern Finland. The condition of pine forests and their needles was, however, better on the neighbouring Karelian Isthmus although the species number of epiphytic lichens was very low and the condition of the lichens was poor. It is suggested that these most sensitive indicators of air pollutants are damaged by pollutants from St Petersburg and Narva. Vast virgin forests of the Karelian Isthmus act as pollutant sinks reducing the effect of pollutants on trees. On the Finnish side intensive forest management has been carried on for many decades making forests and trees more sensitive to pollutants.