Acid deposition and the element composition of pine tree rings

The element contents of pine tree rings (Pinus sylvestris L.) were analyzed in five areas differing in the level of sulphur deposition. The elements studied and their average content in xylem were as follows:

aluminium 4.2, manganese 65, zinc 8.4, potassium 390, rubidium 2.2, calcium 930, magnesium 131, phosphorus 38, sulphur 56, nitrogen 0.65, boron 4.3 and molybdenum 0.03 mg/kg.

The contents of aluminium, potassium and rubidium were higher in tree rings from the 1950's on, particularly in southern Finland. The increase is probably due to acid deposition in the soil.     

Identification and level estimation of chlorinated neutral aromatic sulfur compounds and their alkylated derivatives in pulp mill effluents and sediments

Seven effluent samples from a modern pulp mill, in which chlorine and chlorine dioxide bleaching is used, and five sediment samples from the recipient watercourse were investigated for polychlorinated dibenzothiophenes (PCDBTs), polychlorinated thianthrenes (PCTAs), polychlorinated diphenylsulfides (PCDPSs) and for alkylated derivatives of these. Mainly di-, tri-, tetra- and pentachlorinated congeners were studied. Particles and filtrates from the effluents were analyzed separately. The concentration levels of the nonalkylated compounds were found to be higher in the filtrates than in the particles. Trichlorinated dibenzothiophenes and thianthrenes were found as the major congeners. Pentachlorinated derivatives were not found. Alkylated di- and trichlorodibenzothiophenes were detected in some samples, while alkylated chlorinated thianthrenes and diphenylsulfides were nondetectable. The estimated concentration levels of the compounds detected were in the range of 40–2700 pg/L in the pulp mill effluents and in the range of 2–40 pg/g dry weight in the sediments. Mixtures of methylated di- and trichlorodibenzothiophenes used as references in analyses were prepared from methylchlorobiphenyls. Some new pure model compounds were obtained by HPLC fractionation of the chlorination mixture of dibenzothiophene. Structures of these were determined by ¹H NMR.     

Public information revealed by pellets in nest sites is more important than ecto-parasite avoidance in the settlement decisions of Eurasian kestrels

Animals constantly need to acquire information about the environment for settlement decisions, either by using a trial-and-error strategy or by using public information by monitoring conspecifics. We studied a nest box population of Eurasian kestrels Falco tinnunculus in western Finland to test if pellets and other prey remains accumulated on the bottom of nest boxes are used as public information during settlement. During 2002–2013, nest boxes were randomly cleaned (treatment) or left un-cleaned (control) in each season. It is possible that kestrels reuse nest boxes which include information of successful nesting (i.e. have not been cleaned) because they indicate previous breeding attempt at the site. At the same time, this decision may entail costs because of blood-sucking ecto-parasites like Carnus hemapterus overwintering in the layer of pellets. First, we found that egg-laying date was significantly earlier in un-cleaned control boxes than in cleaned treatment boxes, indicating the use of public information revealed by pellets in the settlement decision. Second, the ecto-parasite burden of young nestlings (age 6–15 days) was significantly higher in un-cleaned control nest boxes. We found higher ecto-parasite infestation in early and lower infestation in late nests, a seasonal trend that is in disagreement with the ecto-parasite avoidance hypothesis. Contrary, in overall lower-infected cleaned boxes, ecto-parasite prevalence remained equal throughout the season. However, the ecto-parasite burden had no obvious effect on breeding success. We conclude that the use of pellets revealing successful breeding attempt of the previous year as public information appeared to be important in the settlement decision of kestrels.     

波罗的海生物地理特性的消失:自然过程和人为过程的相互作用

波罗的海的生物地理特性是自上一次冰河期起逐步形成的.波罗的海这种海水,半咸水和淡水物种以及前几个时期的残余物种的特征的混合正在受到环境变化的威胁.本文重点讲述外来物种、富营养化和深海海盆中暂时性缺氧,以及波罗的海在不同的时空内的生物地理统一性等问题.当今的航运活动打破了地理障碍,半成水体的生物区系相互联系在一起,导致世界范围内水生动植物物种的交换和进一步的均一化.     

Sequential polyandry by brood desertion increases female fitness in a bird with obligatory bi-parental care

Parental care may be costly to parents because it decreases resources allocated to self-maintenance and may thus reduce survival and future reproductive success. An inter-sexual conflict may exist in animals with obligatory bi-parental care, such as birds of prey, in which females incubate and brood, whereas males provision food for their families. We analysed 29 years of data (1981–2009) from a study population of Tengmalm’s owls Aegolius funereus in western Finland to examine the occurrence and timing of brood desertion and sequential polyandry, and recorded a total of 1,123 monogamous and 12 polyandrous females. These data were supplemented with the 29-year nationwide Finnish ringing data, which included 11,590 monogamous and 20 polyandrous females. The 12 polyandrous females started egg-laying in their two nests at intervals of 54–68 days (mean 60 days), thus deserting their first broods when the age of oldest young averaged 21 days. Thirty-two polyandrous females re-mated and raised a second brood at a median distance of 4.5 km (range 1–196 km). These females produced 79% more eggs, 93% more hatchlings and 73% more fledglings than did females that laid simultaneously but remained monogamous. Our results show that not only males, but also females of altricial species with bi-parental care can increase their fitness by deserting their first brood when it will be cared for by the males. Earlier studies have shown that male owls can increase their lifetime reproductive success by simultaneous polygyny, and we suggest that an inter-sexual “tug-of-war” over bi-parental care exists in Tengmalm’s owls.     

Integrating nature-based tourism and forestry in private lands under heterogeneous visitor preferences for forest attributes

Developing nature-based tourism in private lands calls for new mechanisms to consolidate the interests of the tourism industry, visitors, and landowners. This choice experiment study elaborates on the heterogeneity of visitors’ preferences and willingness to pay (WTP) for enhanced forest amenities and ecosystem services. The survey, targeting domestic and foreign tourists visiting the Ruka-Kuusamo area in Finland, considered four attributes: landscape quality, outdoor routes, forest biodiversity, and carbon sequestration. For observed heterogeneity, the visitors were grouped by their attitudes towards forest management. Unobserved heterogeneity in visitors’ choice behaviour and WTP was examined with the latent class model. While most visitors had environmentally friendly attitudes and were willing to pay, especially for enhanced landscape quality and biodiversity, considerable heterogeneity was revealed in terms of three segments with distinctive attitudes, choice behaviour and WTP. The variation in WTP has important implications for the design of a scheme of payments for environmental management.     

Forest Taxation and Rotation Age under Private Amenity Valuation: New Results

This paper studies the impact of harvesting, property, and profit taxes on private rotation age in an ongoing rotations model, where the private landowner is interested not only in the present value of harvest revenue, but also in the private amenity services provided by the forest stand. The main finding of the paper is that conventional wisdom about the rotation effects of forest taxes, distilled from the Faustmann model, predominantly ceases to hold. This is because forest taxes distort the relative profitability of timber and amenity production in a way that is sensitive to the precise nature of amenity valuation. Therefore, the design of forest tax policy necessitates good knowledge of the landowner's objective function concerning the type of amenity services.     

Contribution of winter to the annual CH4 emission from a eutrophied boreal lake

The springtime methane (CH4) emission from a small, eutrophied boreal lake was assessed during the winter ice-cover by measurement of gas ebullition and CH4 accumulation in the water column in association with the development of oxygen depletion after ice formation. The winter CH4 production was estimated to result in a loss of 3.6-7.9 g CH4 m(-2) from the lake to the atmosphere during the short period of ice melt. This could account for 22-48% of the annual CH4 emission from the pelagic zone of the lake. The contribution of winter to the annual CH4 release can be similar or even higher in seasonally ice-covered northern aquatic ecosystems than in northern terrestrial wetlands, thus winter must be considered in any studies into the aquatic CH4 emissions. The trophic state and wintertime oxygen conditions, linked to the changes in land-use in the catchments and climate, are important factors controlling the springtime lake CH4 emissions.