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51.
Analysis of variation in morphological characters of Potanin Altai osman, Oreoleuciscus potanini, from two freshwater and one brackish water lakes of Western Mongolia has shown that specimens of different ecological forms—herbivorous and piscivorous—form two integral and, at the level under consideration, internally indivisible units in the system of phenetic diversity of the species O. potanini.  相似文献   
52.
Policy reform can be complex and fraught with contending arguments. Although much research has been conducted into the politics of coalition formation, less attention has been devoted to legitimating logics in policy reform. Drawing on the work of Boltanski and Thévenot, this exploratory study addresses this deficit by examining the influence of justifications deployed in policy debates. The paper analyses the role of shifting reasoning in contentious debates concerning attempts to reform water policy, including the introduction of domestic water charges in Ireland. Employing data from parliamentary deliberations, the paper traces the changing forms of justification used by those favouring and opposing the reforms. This examination suggests the importance of aligning an argument’s content with the shifting context into which it is introduced. The paper highlights the benefits of an investigative approach concerning policy justification for understanding policy reform dynamics at the intersection of politics and environmental communication.  相似文献   
53.
Power-line grids are increasingly expanding worldwide, as well as their negative impacts on avifauna, namely the direct mortality through collision and electrocution, the reduction of breeding performance, and the barrier effect. On the other hand, some bird species can apparently benefit from the presence of power lines, for example perching for hunting purposes or nesting on electricity towers. In this perspective essay, we reviewed the scientific literature on both costs and benefits for avifauna coexisting with power lines. Overall, we detected a generalized lack of studies focusing on these costs or benefits at a population level. We suggest that a switch in research approach to a larger spatio-temporal scale would greatly improve our knowledge about the actual effects of power lines on bird populations. This research approach would facilitate suitable landscape planning encompassing both mitigation of costs and promotion of benefits for bird populations coexisting with power lines. For example, the strategic route planning of electricity infrastructures would limit collision risk or barrier effects for threatened bird populations. Concurrently, this strategic route planning would promote the range expansion of threatened populations of other bird species, by providing nesting structures in treeless but potentially suitable landscapes. We suggest establishing a collaborative dialogue among the scientific community, governments, and electricity companies, with the aim to produce a win–win scenario in which both biodiversity conservation and infrastructure development are integrated in a common strategy.  相似文献   
54.
Continuous in-situ measurements of NMHCs at Mace Head, Ireland during two full annual cycles from January 2005 to January 2007 were used to investigate NMHC emission sources and transport including dilution and photochemical oxidation. The Mace Head research station is ideally located to sample a wide range of air masses including polluted European transport, clean North Atlantic and Arctic air masses and the ultra-clean, Southern Atlantic air masses. The variety in air mass sampling is used to investigate interaction of emissions, transport, dilution and photochemistry. Variability of long-lived hydrocarbon ratios is used to assess and estimate typical transport times from emission source to the Mace Head receptor. Seasonality in the ratios of isomeric alkane pairs (for butane and pentanes) are used to assess the effects of atmospheric transport and photochemical ageing. Finally, the natural logarithms of NMHC ratios are used to assess photochemical oxidation.  相似文献   
55.
There is strong world-wide interest in developing new and improved processes for post-combustion capture of CO2, often using chemical absorption. Developers of new processes make positive claims for their proposals in terms of low energy consumption, but these are usually difficult to validate. This paper demonstrates that rigorous application of thermodynamic analysis and process simulation provides a powerful way to quantitatively estimate the energy requirements of CO2-capture processes by applying the methodology to the analysis and evaluation of the chilled-ammonia process.  相似文献   
56.
In subsistence farming systems of the developing world, adoption of resource-conserving practices such as integrated pest management (IPM) is often strikingly low. This has partially been ascribed to researchers’ limited understanding of how technologies develop at the interface of the systems’ social and ecological components. In Honduras (Central America), there exists concern about limited adoption and diffusion of IPM technologies in certain smallholder production systems. In this study, we determine social and ecological drivers of IPM adoption in subsistence maize production in the country’s hillside environment. Honduran small-scale maize production is typified by a key insect pest (the fall armyworm, Spodoptera frugiperda) being partly kept at bay through action of a diverse natural enemy complex, including ants, social wasps, carabid beetles, and spiders. Local agricultural landscapes, primarily shaped through shifting cultivation, provide key resources to maintain this natural enemy diversity. These local ecological conditions and related natural enemy abundance strongly influence farmers’ agroecological knowledge and pest management practices. In the meantime, farmer practices are also affected by local communication networks, which help validate and spread IPM concepts and technologies. Based on our findings, we advocate a holistic approach to improve IPM extension through mapping of agroecological opportunities, visualization of regional patterns in farmer knowledge, and associated priority setting. Local IPM capacity could be built through institutional strengthening and adaptive comanagement, while IPM training should be linked with natural resource management initiatives. These approaches may eventually improve the way IPM is delivered to small-scale farmers who operate in the ecologically diverse environments of the tropics.  相似文献   
57.
The effect of invertebrate predation pressure by the cladoceran Leptodora kindti on the population structure of Daphnia galeata and D. hyalina has been estimated by analyzing the occurrence frequency of the normal and spined morphotypes in Lake Baikal. It is shown that the growth of L. kindti population density leads to an increase in the proportion of the spined morphotype, while that of that of the normal morphotype decreases.  相似文献   
58.
Sex-biased predation is thought to have important implications for sexual selection, sex allocation, and population dynamics (Magnhagen, 1991; Le-Galliard et al., 2005 for an example in lizards). Most studies found that males are subjected to higher predation pressure than females during the reproductive season (Korpimäki, 1985; Lodé et al., 2004; Christe et al., 2006; Costantini et al., 2007). In that period, males are very mobile, emit acoustic signals and exhibit brilliant colourations, which are needed to attract females but may make them more visible to predators. With regard to lizards, a recent study provided the first evidence that males of a lizard species may be preyed on more than females (Costantini et al., 2007). In the present study, we investigated whether there is sex-biased predation on two small lacertid species, the common wall lizard Podarcis muralis (Laurenti, 1768) and the Italian wall lizard Podarcis sicula (Rafinesque-Schmaltz, 1810), by Eurasian kestrels (Falco tinnunculus) during the reproductive season. We also examined whether (1) the rate of predation differed between species and (2) the rate of predation differed across years or among hunting habitats for each species.  相似文献   
59.
On the basis of long-term studies on the ecology of pied flycatcher in Karelia, it has been shown that male nonparticipation in nestling feeding is due to the course of postnuptial molt rather than to the mode of mating relationships, as it was considered previously. This is confirmed by the results of selective capture of birds that have stopped to feed their brood. It is suggested that reduction of parental care is associated with changes in the hormonal balance of molting birds.  相似文献   
60.
Thermal desorption is widely used for remediation of soil contaminated with volatiles, such as solvents and distillates. In this study, a soil contaminated with semivolatile polychlorinated biphenyls (PCBs) was sampled at an interim storage point for waste PCB transformers and heated to temperatures from 300 to 600 °C in a flow of nitrogen to investigate the effect of temperature and particle size on thermal desorption. Two size fractions were tested: coarse soil of 420–841 μm and fine soil with particles <250 μm. A PCB removal efficiency of 98.0 % was attained after 1 h of thermal treatment at 600 °C. The residual amount of PCBs in this soil decreased with rising thermal treatment temperature while the amount transferred to the gas phase increased up to 550 °C; at 600 °C, destruction of PCBs became more obvious. At low temperature, the thermally treated soil still had a similar PCB homologue distribution as raw soil, indicating thermal desorption as a main mechanism in removal. Dechlorination and decomposition increasingly occurred at high temperature, since shifts in average chlorination level were observed, from 3.34 in the raw soil to 2.75 in soil treated at 600 °C. Fine soil particles showed higher removal efficiency and destruction efficiency than coarse particles, suggesting that desorption from coarse particles is influenced by mass transfer.  相似文献   
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