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81.
Alexandra Volokitina Mark Sofronov Tatiana Sofronova 《Mitigation and Adaptation Strategies for Global Change》2008,13(7):661-674
Problem of wildfires has not been resolved anywhere in the world. Mere increase of technical power does not lead to desirable
results. Forests of developed countries burn as actively as those in Africa or in Russia. The main reasons of wildfire problem
are as follows: (1) Constant wandering of dry seasons over the planet causing outbreaks of wildfires. (2) Unpredicted self-development
of ordinary wildfires into awful fire disasters. (3) Difficulties in delivery and use of heavy machines on hardly accessible
territories. (4) Absence of a perfect technique for economic evaluation of how effectively the wildfire control system works.
(5) Absence of the system of payments encouraging wildfire fighters. To solve the problem of wildfires in Russia it is necessary
to: (1) Create the Russian wildfire behaviour and fire effects prediction system on the basis of the developed classification
of vegetation fuels and methods of their mapping as well as maximum utilization of forest inventory information and Geographic
Information System (GIS). (2) Elaborate a technique of proper wildfire monitoring including estimation of vegetation damage.
(3) Improve daily rating of regional fire danger. (4) Improve fire-preventive arrangement of the territory covered by vegetation,
the main goal being creation of favourable conditions for active fire management. (5) Choose the main direction in elaboration
of fire-fighting means and methods taking into account their universality, simplicity, reliability, etc. (6) Elaborate an
improved technique for estimation of economic effectiveness of the wildfire control system. (7) Develop international cooperation
of scientists and professionals in fire management. 相似文献
82.
<Emphasis Type="Italic">Eubacterium rangiferina</Emphasis>, a novel usnic acid-resistant bacterium from the reindeer rumen 总被引:1,自引:0,他引:1
Reindeer are able to eat and utilize lichens as an important source of energy and nutrients. In the current study, the activities of antibiotic secondary metabolites including usnic, antranoric, fumarprotocetraric, and lobaric acid commonly found in lichens were tested against a collection of 26 anaerobic rumen bacterial isolates from reindeer (Rangifer tarandus tarandus) using the agar diffusion method. The isolates were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequences. Usnic acid had a potent antimicrobial effect against 25 of the isolates, belonging to Clostridiales, Enterococci, and Streptococci. Isolates of Clostridia and Streptococci were also susceptible to atranoric and lobaric acid. However, one isolate (R3_91_1) was found to be resistant to usnic, antranoric, fumarprotocetraric, and lobaric acid. R3_91_1 was also seen invading and adhering to lichen particles when grown in a liquid anaerobic culture as demonstrated by transmission electron microscopy. This was a Gram-negative, nonmotile rod (0.2-0.7 x 2.0-3.5 microm) with a deoxyribonucleic acid G + C content of 47.0 mol% and main cellular fatty acids including 15:0 anteiso-dimethyl acetal (DMA), 16:0 iso-fatty acid methyl ester (FAME), 13:0 iso-3OH FAME, and 17:0 anteiso-FAME, not matching any of the presently known profiles in the MIDI database. Combined, the phenotypic and genotypic traits including the 16S rRNA gene sequence show that R3_91_1 is a novel species inside the order Clostridiales within the family Lachnospiraceae, for which we propose the name Eubacterium rangiferina. This is the first record of a rumen bacterium able to tolerate and grow in the presence of usnic acid, indicating that the rumen microorganisms in these animals have adapted mechanisms to deal with lichen secondary metabolites, well known for their antimicrobial and toxic effects. 相似文献
83.
Human influence on California fire regimes. 总被引:6,自引:0,他引:6
Alexandra D Syphard Volker C Radeloff Jon E Keeley Todd J Hawbaker Murray K Clayton Susan I Stewart Roger B Hammer 《Ecological applications》2007,17(5):1388-1402
Periodic wildfire maintains the integrity and species composition of many ecosystems, including the mediterranean-climate shrublands of California. However, human activities alter natural fire regimes, which can lead to cascading ecological effects. Increased human ignitions at the wildland-urban interface (WUI) have recently gained attention, but fire activity and risk are typically estimated using only biophysical variables. Our goal was to determine how humans influence fire in California and to examine whether this influence was linear, by relating contemporary (2000) and historic (1960-2000) fire data to both human and biophysical variables. Data for the human variables included fine-resolution maps of the WUI produced using housing density and land cover data. Interface WUI, where development abuts wildland vegetation, was differentiated from intermix WUI, where development intermingles with wildland vegetation. Additional explanatory variables included distance to WUI, population density, road density, vegetation type, and ecoregion. All data were summarized at the county level and analyzed using bivariate and multiple regression methods. We found highly significant relationships between humans and fire on the contemporary landscape, and our models explained fire frequency (R2 = 0.72) better than area burned (R2 = 0.50). Population density, intermix WUI, and distance to WUI explained the most variability in fire frequency, suggesting that the spatial pattern of development may be an important variable to consider when estimating fire risk. We found nonlinear effects such that fire frequency and area burned were highest at intermediate levels of human activity, but declined beyond certain thresholds. Human activities also explained change in fire frequency and area burned (1960-2000), but our models had greater explanatory power during the years 1960-1980, when there was more dramatic change in fire frequency. Understanding wildfire as a function of the spatial arrangement of ignitions and fuels on the landscape, in addition to nonlinear relationships, will be important to fire managers and conservation planners because fire risk may be related to specific levels of housing density that can be accounted for in land use planning. With more fires occurring in close proximity to human infrastructure, there may also be devastating ecological impacts if development continues to grow farther into wildland vegetation. 相似文献
84.
Alexandra Schrempf Christine Reber Alberto Tinaut Jürgen Heinze 《Behavioral ecology and sociobiology》2005,57(5):502-510
The ant species Cardiocondyla batesii is unique in that, in contrast to all other ant species, both sexes are flightless. Female sexuals and wingless, ergatoid males mate in the nest in autumn and young queens disperse on foot to found their own colonies in spring. The close genetic relatedness between queens and their mates (rqm=0.76±SE 0.12) and the high inbreeding coefficient (F=0.55; 95%CI 0.45–0.65) suggest that 83% of all matings are between brothers and sisters. As expected from local mate competition theory, sex ratios were extremely female biased, with more than 85% of all sexuals produced being young queens. Despite the common occurrence of inbreeding, we could not detect any adult diploid males. Though the probability of not detecting multiple mating was relatively high, at least one-third of all queens in our sample had mated more than once. Multiple mating to some extent counteracts the effects of inbreeding on worker relatedness (rww=0.68±SE 0.05) and would also be beneficial through decreasing diploid male load, if sex was determined by a single locus complementary system.Communicated by L. Sundström 相似文献
85.
Anastasios I. Stamou Kimon Hadjibiros Andreas Andreadakis Alexandra Katsiri 《Environmental Modeling and Assessment》2007,12(3):157-170
A water quality model (MERES) is applied in the multi-purpose reservoir of Plastiras in Greece. The model was calibrated with
limited field data using the standard trial and error procedure; next, it was applied for four scenarios of reservoir operation,
which correspond to four values of minimum water levels (MWL). Model results were combined with landscape aesthetics to establish
a “safe” MWL in the reservoir. MWL was proposed to be +784 m, a value that ensures a very good water quality by retaining
the reservoir in the status of “a little beyond oligotrophic” and a very good quality of landscape with an acceptable area
of dead zones; it also ensures an annual release of 127.5 hm3 of water within a reliability level of 90%. This quantity can be considered as acceptable from the water supply point of
view. 相似文献
86.
Lanka Thabrew Alexandra Ewing Mark Abkowitz George Hornberger 《Journal of Environmental Planning and Management》2018,61(1):49-63
With the growing importance of environmental sustainability in the corporate sector, businesses are compelled to progress from assessing and benchmarking their environmental impact to making decisions on how to prioritize impact reduction alternatives. Most often, business decisions are driven by financial metrics, but with sustainability improvements becoming a business goal, it is also important to assess metrics from environmental and social spheres; nevertheless, practically and systematically performing such an assessment is challenging. We present an application of a multi-criteria decision analysis (MCDA) method that addresses the aforementioned challenges in a corporate setting. Our case study company – one of the largest inland marine freight carriers in the United States – promotes a business culture focused on financially viable, yet socially and environmentally responsible solutions. Thus, we combine life cycle analysis (LCA), financial calculation methods, and corporate surveys to quantify environmental, economic, and social performance measures, respectively. Multiattribute utility theory is integrated with analytic hierarchy processes (AHPs) and fuzzy analysis to create a carefully designed framework for corporations with diverse groups of stakeholders. With company leadership, implementation is feasible and successful at prioritizing alternatives among diverse stakeholders. The process provides a platform for negotiation and promotes discussions on decision drivers. The use of MCDA methodologies promoted the inclusion of a suite of metrics that aligned with the company's sense of social and environmental responsibility, generating an in-depth analysis of the alternatives that factored in other things besides economics. Return-on-investments (ROI) calculations, the typical approach used in the corporate setting, would have required significantly less time and effort from the company, but the results of our MCDA application indicated that inclusion of triple bottom line metrics delve deeper into stakeholder preferences. Thus, our case study company gained a holistic view of the candidate alternatives, in addition to creating a platform for structured discussions about company goals and priorities. 相似文献
87.
Regional Environmental Change - In order to combat hunger and feed a growing world population, adapt to climate change and reduce environmental impacts of unsustainable farming practices, the need... 相似文献
88.
As the demand for water in cities increases, the quantity of wastewater being produced is growing at a phenomenal rate. If resources are to be managed effectively, a new paradigm is required for urban wastewater management. This paper reviews the initial findings of a participatory action planning process for managing wastewater for agricultural use. It finds that such processes need considerable facilitation, capacity building and knowledge sharing, but that if a plan can be devised that meets the needs of the stakeholders, even if some compromise is required, then certain stakeholders are likely to take responsibility for specific aspects. This may not meet the entire integrated water resources management (IWRM) vision of the plan but provided the plan is developed in such a way that incremental implementation will be beneficial then this will produce some success and may stimulate further cooperation. 相似文献
89.
Susana Garrido Rui Rosa Radhouan Ben-Hamadou Maria Emilia Cunha Maria Alexandra Chícharo Carl D. van der Lingen 《Marine Biology》2008,154(6):1053-1065
Temporal variation in the fatty acid (FA) composition of stomach contents of Iberian sardines was compared to the relative
contribution to dietary carbon made by different prey types for fish from two areas off Portugal. The effect of the FA content
of the diet on sardine muscle FA composition was also studied, aiming at (1) analysing if FA biomarkers can be used as a complementary
technique for the study of sardine diet and (2) to relate spatial and temporal variations of prey FA content with sardine
condition and reproduction. Significant spatial differences in the FA composition of sardine diet occurred with concentrations
of n-3 polyunsaturated FA, namely eicosapentaenoic acid [EPA, 20:5n-3] and linolenic acid 18:3n-3, being significantly higher
in the diet of sardines from the west coast, whilst the diet of sardines from the south coast was richer in monounsaturated
fatty acids (MUFA), namely the carnivory biomarker oleic acid 18:1n-9. These results are in agreement with the higher contribution
made by diatoms and dinoflagellates to the diet of sardines off the west coast. Spatial variation in sardine dietary FA was
also detected in their muscle composition, specifically for EPA, and the eicosapentaenoic/docosahexaenoic acid and (n-3)/(n-6)
ratios, which were higher in sardines from the west coast. No difference in FA composition was detected between sexes, and
the seasonal variability in sardine total FA concentration was primarily related to the seasonality of spawning. Sardines
accumulate high concentrations of FAs during the resting stage of reproduction when the feeding intensity is similar or lower
to that observed during the spawning season. Additionally, sardines show a high selective retention of MUFA and polyunsaturated
FA (PUFA) throughout the year except at the beginning of the spawning season, when these FAs are largely invested in the formation
of the gonads. Therefore, temporal and regional differences of prey environments are strong enough to be reflected in fish
body composition, namely on the accumulation of essential FAs, which can have a strong impact on reproduction success for
this species. 相似文献
90.
Miguel A. Bedoya-Perez Alexandra J. R. Carthey Valentina S. A. Mella Clare McArthur Peter B. Banks 《Behavioral ecology and sociobiology》2013,67(10):1541-1553
The giving-up density (GUD) framework provides a powerful experimental approach with a strong theoretical underpinning to quantify foraging outcomes in heterogeneous landscapes. Since its inception, the GUD approach has been applied successfully to a vast range of foraging species and foraging scenarios. However, its application is not simple, as anyone who has tried to use it for the first time might attest. Limitations of the technique were noted at its conception, yet only the artificiality of the patches, the appropriateness of the food resource, and the possibility of multiple visiting foragers were identified. Here we show the current uses of GUD and outline the practical benefits as well as the often overlooked limitations of the technique. We define seven major points that need to be addressed when applying this methodology: (1) the curvilinearity between harvest rate and energy, (2) the energetic state of the forager, (3) the effect of group foraging, (4) food quality and substrate properties, (5) the predictability of the patch, (6) behavioral traits of the forager, and (7) nontarget species. We also suggest how GUD experiments can be enhanced by incorporating complementary methods (such as cameras) to better understand the foraging processes involved in the GUD itself. We conclude that the benefits of using GUD outweigh the costs, but that its limitations should not be ignored. Incorporating new methods when using GUD can potentially offer novel and important insights into the study of foraging behavior. 相似文献