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1.
Ambient ultraviolet-B (UVB) radiation impacts plant-dwelling arthropods including herbivorous and predatory mites. However, the effects of UVB on prey?Cpredator systems, such as that between the herbivorous spider mite and predatory phytoseiid mite, are poorly understood. A comparative study was conducted to determine the vulnerability and behavioral responses of these mites to ultraviolet (UV) radiation. First, we analyzed dose?Cresponse (cumulative irradiance-mortality) curves for the eggs of phytoseiid mites (Neoseiulus californicus, Neoseiulus womersleyi, and Phytoseiulus persimilis) and the spider mite (Tetranychus urticae) to UVB radiation from a UV lamp. This indicated that the phytoseiid mites were more vulnerable than the spider mite, although P. persimilis was slightly more tolerant than the other two phytoseiid mites. Second, we compared the avoidance behavior of adult female N. californicus and two spider mite species (T. urticae, a lower leaf surface user; Panonychus citri, an upper leaf surface user) in response to solar UV and visible light. N. californicus actively avoided both types of radiation, whereas P. citri showed only minimal avoidance behavior. T. urticae actively avoided UV as well as N. californicus but exhibited a slow response to visible light as well as P. citri. Such variation in vulnerability and avoidance behavior accounts for differences in the species adaptations to solar UVB radiation. This may be the primary factor determining habitat use among these mites on host plant leaves, subsequently affecting accessibility by predators and also intraguild competition.  相似文献   

2.
In this paper, the new systematical theory and methodology have been applied to the research on the structure, development and coordination of man-environment system in Jiaozuo City. It has been proved that the application of self-organization theory of synergism is successful. Furthermore, on the basis of self-organization theory, a series of mathematical models have been established. The prediction of the status of man-environment system in Jiaozuo City by the year 2010, was made, and the trend of population growth, industrial development, environmental pollution were given. Finally, suggestions for the future development of Jiaozuo City were mentioned.  相似文献   

3.
The acceptance of forestry-based project activities to mitigate greenhouse gases emissions has been subjected to a number of methodological questions to be answered, of which the most challenging are baseline establishment and identification of and measuring leakage. Here we pose hypotheses for and quantify leakage of the Scolel Té project in Chiapas, Mexico. In this project small-scale farmers are implementing forestry, agroforestry, and forest conservation activities, with carbon sequestration as one of the goals. The main leakage monitoring domain is defined as the area owned by the participating farmers or communities outside the area where the specific project activities take place. The null-hypothesis (no leakage) is that non-project land owned by the farmer or community will experience the same carbon stock changes as predicted by the regional baseline, specifically developed for the project. First we assessed the most likely causes and sources of leakage that may occur in the project. From this analysis, one type of leakage seems to be important, i.e., activity shifting. Second we estimated the leakage of a sample of participating farmers and communities. Actual land use was then compared with expected land use derived from the baseline. The Plan Vivo of each participant, complemented with readily available tools to identify the main sources and drivers of leakage are used to develop simple leakage assessment procedures, as demonstrated in this paper. Negative leakage was estimated to be negligible in this study. Incorporating these procedures already in the project planning stage will reduce the uncertainties related to the actual carbon mitigation potential of any forestry project.
B. H. J. De JongEmail:
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4.
Mitigation and Adaptation Strategies for Global Change - This paper was published on March 2017, Volume 22, Issue 3, 469–483pp, titled “Identification of structural breaks in the forest...  相似文献   

5.
HaveacorrectunderstandingoftheattributeofgeologicenvironmentgivefullplaytotheroleofgeoscienceinenvironmentalprotectionHaCheng...  相似文献   

6.
A comprehensive investigation of heavy metal pollutants in Xiangjiang river was accomplished to evaluate their chemical stability through three different ways: (1) Chemical speciation by direct measurements; (2) Chemical equilibrium model simulation; (3) Sediment extraction experiments. All the results demonstrated that the directly bioavailable fraction was in a very limited amount. The metal bound to organic ligands, adsorbed particles and precipitated species presented a buffer for solution species. The majority of metals occured in the residues as solid particulates. It was inferred that the heavy metal pollutants in this aquatic system exhibited a high chemical stability. The critical limits of discharging load and pH values were suggested.  相似文献   

7.
The queens of many eusocial insect species are polyandrous. The evolution of polyandry from ancestral monoandry is intriguing because polyandry undermines the kin-selected benefits of high intracolonial relatedness that are understood to have been central to the evolution of eusociality. An accumulating body of evidence suggests that polyandry evolved from monoandry in part because genetically diverse colonies better resist infection by pathogens. However, a core assumption of the “parasite–pathogen hypothesis”, that there is variation in virulence among strains of pathogens, remains largely untested in vivo. Here, we demonstrate variation in virulence among isolates of Ascosphaera apis, the causative organism of chalkbrood disease in its honey bee (Apis mellifera) host. More importantly, we show a pathogen–host genotypic interaction for resistance and pathogenicity. Our findings therefore support the parasite-parasite hypothesis as a factor in the evolution of polyandry among eusocial insects.  相似文献   

8.
Impact assessment (IA) is an instrument that is gradually making inroads into European Union policy making. Great ambitions are tied to the introduction of a compulsory system of IA as a way to achieve better regulation but also as a tool to improve legitimacy of government and increase unity in European politics. In order to raise the quality of the assessments, which has been questioned, there is a call for application of more evidence-based methods. As a result, there might be a window of opportunity for greater use of scientific support in impact assessment work.However, the EC's IA system has several overlapping and partly contradictory objectives – to produce estimates about possible future impacts is only one of them. The IA system should be understood as a political instrument shaped by its multiple objectives and the political context of permanent negotiations in which it is situated.The arguments put forward emanate from a close reading of EC documents concerning IA procedures and the ambitions they display paired with assessment practices as revealed in interviews with officials in the main EU institutions, trying to perform IAs and to cope with the political balancing act they are embedded in.  相似文献   

9.
Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 m2 was constructed on an egg duck farm, and water hyacinth (Eichhornia crassipes) was chosen as an aquatic plant for the wetland and used as food for duck production. The objectives of this study were to test the role of water hyacinth in purifying nutrient-rich wastewater and its effects on the ducks’ feed intake, egg laying performance and egg quality. This paper shows that the constructed wetland removed as much as 64.44% of chemical oxygen demand (COD), 21.78% of total nitrogen (TN) and 23.02% of total phosphorus (TP). Both dissolved oxygen (DO) and the transparency of the wastewater were remarkably improved, with its transparency 2.5 times higher than that of the untreated wastewater. After the ducks were fed with water hyacinth, the average daily feed intake and the egg-laying ratio in the test group were 5.86% and 9.79% higher, respectively, than in the control group; the di erences were both significant at the 0.01 probability level. The egg weight in the test group was 2.36% higher than in the control group (P < 0.05), but the feed conversion ratios were almost the same. The eggshell thickness and strength were among the egg qualities significantly increased in ducks fed with water hyacinth.We concluded that a water hyacinth system was e ective for purifying wastewater from an intensive duck farm during the water hyacinth growing season, as harvested water hyacinth had an excellent performance as duck feed. We also discussed the limitations of the experiment.  相似文献   

10.
In this study, we investigated the presence of enteric viruses such as norovirus (NoV), hepatitis A virus (HAV), hepatitis E virus (HEV), and adenovirus (HAdV), in vegetables available on the Italian markets. For this aim, 110 national and international ??ready to eat?? samples were collected and analyzed by biomolecular tests and positive samples were confirmed by sequencing. All samples (100?%) were negative for HAV, HEV, and HAdV, while 13.6?% (15/110) were positive for NoV. Actually there is not a formal surveillance system for NoV infections in Italy but we clearly demonstrated a potential risk associated with the consumption of ??ready to eat?? vegetables. This study confirmed for the first time in Italy the presence of norovirus in semi-dried tomatoes by PCR technique.  相似文献   

11.
Much quantitative research examining the determinants of the ecological footprint has been conducted cross-nationally, where data on cross-boundary flows have been readily available. While local-level studies of the footprint do exist for specific localities, most quantitative research at this scale has examined direct environmental impacts attributed to the internal activities of the locality, for instance, carbon emissions. Our analysis builds on this previous work by exploiting a local-level carbon footprint dataset with coverage for 28,321 zip codes across the United States. Following prior research, we focus on the effect of local affluence, measured in terms of median household income. In spatial regression models, we regress the per capita carbon footprint on local affluence, controlling for a variety of other factors. Consistent with previous work, we find that affluence is positively correlated the carbon footprint and there is no evidence of an environmental Kuznets curve. In the conclusion, we review the results of the study and discuss their implications for policy, specifically in terms of cross-boundary environmental problems.  相似文献   

12.
Forests play a fundamental role in the global carbon cycle and can be managed to mitigate greenhouse gas emissions and conserve or sequester carbon. Global policy and environmental changes can affect regional consumption of forest products, as well as inter-regional trade of forest goods and services. This study analyzes global and regional change impacts on the production, consumption and trade of forest products in two Nordic countries, Finland and Sweden. Annual data on removal and trade (1964–2012) for roundwood and sawnwood is used to identify structural breaks based on Chow tests. According to the analysis, the time period is divided into two periods: t1 (1964–1980) and t2 (1981–2012). In the first period, breaks occurred in 1975 and 1976 in the Finnish model and no break is found in the Swedish model. In the second period, we identify breaks in 1991 and 1992 for the Finnish model and in 2004, 2005 and 2006 for the Swedish model. Although our findings have broad empirical support, we do not identify any specific incident as a direct cause of the changes in the consumption and trade patterns of the two types of wood in these countries. The models and analysis presented here can serve as methodological tools for policymakers to better understand the effects of structural changes in the production of forest goods and services in the Nordic region and globally.  相似文献   

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14.
In the 1970s, resource agencies suggested that thermal discharges could affect aquatic life including macrophytes, plankton, and fish. It was suspected that heat and cold shock would affect fish health and behavior, and that thermal plumes might affect migration. From 1978 to 1985, Rochester Gas & Electric Corporation (RG&E) conducted field and laboratory studies on fish to evaluate a power plant’s rapid winter shutdown. Lake Ontario studies included observations of fish in the near-field plume during a shutdown, and resident fish were tagged and used to study immediate and acclimated cold shock. Over 500 fish representing 17 species, captured in and around a power station plume, were used in these cold-shock studies. Five coldwater species accounted for approximately 65% of the tested fish, although clupeids, and coolwater and warmwater fish were evaluated when captured. The internal temperature of many fish was recorded upon capture. Survival for the dominant species was ≃100%, although clupeid survival was ≤10% (n=128). Tagged fish also provided long-term survival, migration, and plume-residence data. To confirm field data, laboratory cold-shock tests were conducted under controlled conditions using hatchery-reared juvenile rainbow trout. The results indicated, for example, that the lower lethal limit for rainbow trout was slightly below 1.0°C, corroborating field data for rainbow trout. These cold-shock studies suggest that previous generic guidelines, such as those provided by the United States Environmental Protection Agency (USEPA), are probably too conservative.  相似文献   

15.
Ecological construction and restoration for sustainable development are now a driving paradigm. It is increasingly recognized that ecological principles, especially landscape ecology theory, are not only necessary but also essential to maintain the long-term sustainability worldwide. Key landscape ecology principles--element,structure and process, dynamics, heterogeneity, hierarchies, connectivity, place and time were reviewed, and use Beijing area as a case study to illustrate how these principles might be applied to ecological construction and restoration, to eventually achieve sustainability. An example to more effectively incorporate the ecological principles in sustainable planning in China was presented.  相似文献   

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18.
The North Frisian Wadden Sea represents one of the best researched natural regions in the world. Since the end of the 1980s, scientific research has been carried out to scientifically study, analyse and assess this intertidal coastal zone under the conceptual umbrella of ecosystem research. The outcome of this assessment materialised in the establishment of the Nationalpark Schleswig-Holsteinisches Wattenmeer. Its implementation caused considerable conflicts between coastal inhabitants, national park authorities and government officials. Arguments in these disputes revolved around the validity and relevance of scientific knowledge generated to assess and legitimately protect the tidelands and areas of the Waddensea. In summary, the whole implementation process was locally perceived as a politically endorsed top-down enforcement strategy only allowing scientific knowledge for decision-making purposes while local concerns and ‘knowledges’ were not included. To learn from these developments and past mistakes, we compare concepts of co-management, boundary work and boundary objects (BO) to theoretically and methodologically explore their potentials to generate shared meanings and instigate communication in the context of future managing purposes. Against this theoretical background, we propose the empirical show-case example of the German concept of ‘Heimat’ as a BO to assess its applicability to study place-based meanings and to illustrate it as a practice-oriented point of entry to initiate productive science-stakeholder interaction (SSI) in managing the North Frisian Wadden Sea.  相似文献   

19.
Now that the sequencing of many genomes has been completed, the basic challenges are finding the genes and predicting their functions. Up until now, a large information gap has existed between the knowledge of genome sequence and our knowledge of protein function. The assessment of gene function may be performed using the tools of reverse genetics, including knock-out mice, antisense oligomers, aptamers, and ribozymes. These approaches have been superseded by RNA interference (RNAi), which exhibits much more potency for the investigation of protein function than the techniques listed above. As already known some years ago, RNAi is based on an ancient anti-viral defense mechanism in lower eukaryotes. It is induced by double-stranded RNA and its processing to 21–23 nt small interfering RNAs (siRNAs), which cause the degradation of homologous endogenous mRNA. The way RNAi works has still to be determined, but it already serves as a first-choice approach to generate loss-of-function phenotypes among a broad variety of eukaryotic species, such as nematodes, flies, plants, fungi and mammals. RNAi also represents an extremely powerful tool, becoming a therapeutic approach to curing infectious diseases originated by viral or parasitic invasion. In this review we present the current view of how RNAi works in different eukaryotic species and its high potential for functional genomics and in rational drug design.  相似文献   

20.
Diapause in arthropods is a physiological state of dormancy that is generally thought to promote survival during harsh seasons and dispersal, but it may also serve to avoid predation in space and time. Here, we show that predation-related odours induce diapause in female adult spider mites. We argue that this response allows them to move into an area where they are free of enemies, yet forced to survive without food. Spider mites are specialised leaf feeders, but—in late summer—they experience severe predation on leaves. Hence, they face a dilemma: to stay on the leaf and risk being eaten or to move away from the leaf and risk death from starvation and thirst. Female two-spotted spider mites solve this dilemma by dramatically changing their physiology when exposed to predation-associated cues. This allows them to disperse away from leaves and to survive in winter refuges in the bark of trees or in the soil. We conclude that the mere presence of predation-associated cues causes some herbivorous mites to seek refuge, thereby retarding the growth rate of the population as a whole: a trait-mediated indirect effect that may have consequences for the stability of predator–prey systems and for ecosystem structure.  相似文献   

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