The effects of air pollutants on the epicuticular wax structure of conifer needles and the ecophysiological consequences of the injuries are reviewed on the basis of published literature and the authors' recent investigations. Degradation of the epicuticular waxes, which appears as a fusion of wax tubes in the epistomatal chambers and finally results in an amorphous appearance of the waxes, is the most common micromorphological injury type observed in studies on the genera Abies, Larix, Picea, and Pinus. The rate of erosion correlates well with the level of air pollution, but clear evidence for the specificity of the symptoms for different air pollutants has not been observed. It is concluded that the erosion of the epicuticular waxes, a phenomenon with a large geographic distribution, is a relevant factor of the multiple forest decline syndrome. Erosion of the waxes can change needle wettability and rain retention. Increased needle wettability and permeability of the cuticles can result in enhanced leaching of nutrients and uptake of pollutants. Increased or decreased stomatal and cuticular diffusion resistance of the needles leads to altered transpiration rates. Due to the changed chemical microenvironment of the needles, the conifers are predisposed to various biotic and abiotic stresses. Because the epicuticular waxes are one of the first targets of a variety of air pollutants, they can widely be used as an early indicator of air pollution effects.
ABSTRACT. This study focuses on the resonance strategies of Sámi reindeer herders in four reindeer-herding cooperatives in northernmost Finland in climatically extreme years, specifically those occurring during the period 1970 -2007. "Resonance" is an instinctive and indwelling reaction of a herder to a specific change (in contrast to coping, which is a more general response). The study is based on interviews with herders, field experiences, reindeer population statistics, and weather data. Before the 1960s, herders were able to deal with changing weather conditions by using intensive herding techniques and semi-tame reindeer. After the 1960s, reindeer became wilder because of the use of snowmobiles and more extensive herding techniques. The herders of the fell and forest cooperatives did not have sufficient means to prevent the serious reindeer losses in 1972 -74, which resulted from two years of hard snow and ice cover, hot summers, and the free ranging of loose herds. In each of the four cooperatives studied, most of the old siida herds were combined, and one solution to handling large, loose herds was to build fences between cooperatives. Since the 1990s, all four cooperatives have used diverse herding and pasture rotation strategies to cope with the critical winter months. The herding techniques and the human-reindeer relationship in the fell cooperatives have differed from those in the forest cooperatives mainly because of differences in pasture types, topography, and microclimate. The contrast can be seen particularly in snow and ice conditions, as open fell regions have a thin and compact snow cover, whereas forest regions typically have deep, soft snow. This research shows that the resonance strategies of Sámi reindeer herders are both heterogeneous and dynamic: herders change them constantly, drawing on both old and new techniques to deal with the variable weather.
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