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141.
Advances in pollination ecology from tropical plantation crops 总被引:3,自引:0,他引:3
Although ecologists traditionally focus on natural ecosystems, there is growing awareness that mixed landscapes of managed and unmanaged systems provide a research environment for understanding basic ecological relationships on a large scale. Here, we show how tropical agroforestry systems can be used to develop ideas about the mechanisms that influence species diversity and subsequent biotic interactions at different spatial scales. Our focus is on tropical plantation crops, mainly coffee and cacao, and their pollinators, which are of basic ecological interest as partners in an important mutualistic interaction. We review how insect-mediated pollination services depend on local agroforest and natural habitats in surrounding landscapes. Further, we evaluate the functional significance of pollinator diversity and the explanatory value of species traits, and we provide an intercontinental comparison of pollinator assemblages. We found that optimal pollination success might be best understood as a consequence of niche complementarities among pollinators in landscapes harboring various species. We further show that small cavity-nesting bees and small generalist beetles were especially affected by isolation from forest and that larger-bodied insects in the same landscapes were not similarly affected. We suggest that mixed tropical landscapes with agroforestry systems have great potential for future research on the interactions between plants and pollinators. 相似文献
142.
The debate about the revision of the EU directive 91/414 has often been characterized by unobjective criticism of the existing regulations and of the authorities involved in the regulatory procedure. This made many consumers feel uncertain and left the public with the impression that the current regulatory system for plant protection products in Europe was not safe for consumers and the environment. However, a detailed evaluation of these statements has clearly demonstrated that the current regulatory procedure is safe and recent scientific knowledge is taken into account. The risk potential calculated for aquatic and terrestrial organisms in Germany has continuously decreased since 1987. The effects and the benefits of the new regulations, which have reached a level of complexity as never before, are discussed in this context. From an industry perspective, clear legal regulations and practical implementations are essential to guarantee the transparence of the regulatory process and predictability of the outcome. 相似文献
143.
Towards a Formal Framework of Vulnerability to Climate Change 总被引:7,自引:0,他引:7
Cezar Ionescu Richard J. T. Klein Jochen Hinkel K. S. Kavi Kumar Rupert Klein 《Environmental Modeling and Assessment》2009,14(1):1-16
There is confusion regarding the notion of “vulnerability” in the climate change scientific community. Recent research has
identified a need for formalisation, which would support accurate communication and the elimination of misunderstandings that
result from the use of ambiguous terminology. Moreover, a formal framework of vulnerability is a prerequisite for computational
approaches to its assessment. This paper presents an attempt at developing such a formal framework. We see vulnerability as
a relative concept in the sense that accurate statements about vulnerability are possible only if one clearly specifies (1)
the entity that is vulnerable, (2) the stimulus to which it is vulnerable and (3) the preference criteria to evaluate the
outcome of the interaction between the entity and the stimulus. We relate the resulting framework to the Intergovernmental
Panel on Climate Change conceptualisation of vulnerability and two recent vulnerability studies.
This paper is dedicated to the memory of Gerhard Petschel-Held, whose pioneering work on syndromes of global change has been
a source of inspiration for us and for others across various schools of thought on vulnerability. 相似文献
144.
Evaluation of a respirometric test method to determine the heterotrophic yield coefficient of activated sludge bacteria 总被引:1,自引:0,他引:1
The heterotrophic yield coefficient of activated sludge bacteria is an important parameter in the field of wastewater degradation kinetics and the determination of degradation kinetics of defined chemicals. With the help of easily biodegradable organic compounds like glucose and acetate the respiration kinetics of degrading activated sludge bacteria was studied. The results of the respiration analysis were transformed to examine the degradation and respiration kinetics of municipal wastewaters at different food to microorganism ratios (F/M ratios). It was proved that the heterotrophic yield coefficient of aerobically degrading activated sludge bacteria could reliably be determined and that the heterotrophic yield coefficient was independent of the F/M ratio over a wide range. 相似文献
145.
Yoko Ishigami Author Vitae Raymond M. Klein Author Vitae 《Journal of Safety Research》2009,40(2):157-164
Introduction
Although it is becoming more and more accepted that driving while talking on a cell phone can be hazardous, most jurisdictions are making handheld phone use illegal while allowing hands-free phone use.Methods
The scientific literature exploring the effects of these two types of cell phone use on driving and driving-related performance is reviewed here.Results
Our review shows that talking on the phone, regardless of phone type, has negative impacts on performance especially in detecting and identifying events. Performance while using a hands-free phone was rarely found to be better than when using a handheld phone. Some studies found that drivers compensate for the deleterious effects of cell phone use when using a handheld phone but neglect to do so when using a hands-free phone.Impact on Industry
Current research does not support the decision to allow hands-free phone use while driving. 相似文献146.
Nicole Riddell Gilles Arsenault Jeff Klein Alan Lough Chris H. Marvin Alan McAlees Robert McCrindle Gordia MacInnis Ed Sverko Sheryl Tittlemier Gregg T. Tomy 《Chemosphere》2009,74(11):1538-1543
1,2,5,6-Tetrabromocyclooctane (TBCO) is a commercial brominated flame retardant that is employed mainly as an additive in textiles, paints and plastics. Very little is known about its presence or behavior in the environment or its analysis. TBCO can exist as two diastereomers, the stereochemistries of which have not been previously reported. We have named the first eluting isomer, under HPLC conditions, as alpha-TBCO (α-TBCO) and the later eluting isomer as beta-TBCO (β-TBCO) when using an Acquity UPLC BEH C18 column with methanol/acetonitrile/water as the mobile phase. The structural elucidation of these two isomers was accomplished by 1H NMR spectroscopy, GC/MS, LC/MS and X-ray structure determinations. α-TBCO is (1R,2R,5S,6S)-1,2,5,6-tetrabromocyclooctane and β-TBCO is rac-(1R,2R,5R,6R)-1,2,5,6-tetrabromocyclooctane. As with some other brominated cycloaliphatic compounds, TBCO is thermally labile and the isomers easily interconvert. A thermal equilibrium mixture of α- and β-TBCO consists of approximately 15% and 85% of these isomers, respectively. Separation of the two diastereomers, with minimal thermal interconversion between them, is achievable by careful selection of GC-capillary column length and injector temperature. LC/MS analyses of TBCO also presents an analytical challenge due to poor resolution of the isomers on chromatographic stationary phases, and weak intensity of molecular ions (or major fragment ions) when using LC-ESI/MS. Only bromide ions were seen in the mass spectra. APCI and APPI also failed to produce the molecular ion with sufficient intensity for identification. 相似文献
147.
Johannes Klein 《Local Environment》2016,21(2):254-271
Calls for more stakeholder participation and cooperation, the acknowledgement of uncertainties as well as for flexible and robust solutions have become frequent in the literature on climate change adaptation. Recent studies show that these calls are taken up only reluctantly in local adaptation compared to sectoral and technical solutions. The aim of this study is to examine to which extent adaptation as an embedded process within the local context allows for stakeholder participation, cooperation and the robustness and flexibility of adaptation measures. It applies an analytical approach, combining an action framework of adaptation and document-based discourse analysis, to assess both the procedural and the substantive viewpoint of an adaptation case in Finland. This twofold approach provides insight into how the adaptation process and content influence and condition each other. The analysis highlights how new approaches to adaptation have to compete with prevailing discourses and institutionalised practices, as public authorities take the dominant role in adaptation, striving for certain and safe solutions. This process has few participatory elements and leaves little leeway to address uncertainty. 相似文献
148.
Thomas Klein Jaakko Kukkonen ?sl?g Dahl Elissavet Bossioli Alexander Baklanov Aasmund Fahre Vik Paul Agnew Kostas D. Karatzas Mikhail Sofiev 《Ambio》2012,41(8):851-864
This article reviews interactions and health impacts of physical, chemical, and biological weather. Interactions and synergistic effects between the three types of weather call for integrated assessment, forecasting, and communication of air quality. Today’s air quality legislation falls short of addressing air quality degradation by biological weather, despite increasing evidence for the feasibility of both mitigation and adaptation policy options. In comparison with the existing capabilities for physical and chemical weather, the monitoring of biological weather is lacking stable operational agreements and resources. Furthermore, integrated effects of physical, chemical, and biological weather suggest a critical review of air quality management practices. Additional research is required to improve the coupled modeling of physical, chemical, and biological weather as well as the assessment and communication of integrated air quality. Findings from several recent COST Actions underline the importance of an increased dialog between scientists from the fields of meteorology, air quality, aerobiology, health, and policy makers. 相似文献
149.
150.
Diversity, ecosystem function, and stability of parasitoid-host interactions across a tropical habitat gradient 总被引:4,自引:0,他引:4
Global biodiversity decline has prompted great interest in the effects of habitat modification and diversity on the functioning and stability of ecosystem processes. However, the applicability of previous modeled or mesocosm community studies to real diverse communities in different habitats remains ambiguous. We exposed standardized nesting resources for naturally occurring communities of cavity-nesting bees and wasps and their parasitoids in coastal Ecuador, to test the effects of host and parasitoid diversity on an ecosystem function (parasitism rates) and temporal variability in this function. In accordance with predictions of complementary host use, parasitism rates increased with increasing diversity, not simply abundance, of parasitoids. In contrast, parasitism decreased with increasing host diversity, possibly due to positive prey interactions or increased probability of selecting unpalatable species. Temporal variability in parasitism was lower in plots with high mean parasitoid diversity and higher in plots with temporally variable host and parasitoid diversity. These effects of diversity on parasitism and temporal stability in parasitism rates were sufficiently strong to be visible across five different habitat types, representing a gradient of increasing anthropogenic modification. Habitat type did not directly affect parasitism rates, but host and parasitoid diversity and abundance were higher in highly modified habitats, and parasitoid diversity was positively correlated with rates of parasitism. The slope of the richness-parasitism relationship did not vary significantly across habitats, although that for Simpson's diversity was significant only in rice and pasture. We also show that pooling data over long time periods, as in previous studies, can blur the effect of diversity on parasitism rates, and the appropriate spatiotemporal scale of study must be considered. 相似文献