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This study reported the mass mortality events (MMEs) of Pinna nobilis based on diving surveys in Turkey. Data were collected across 12 sites in the Aegean Sea, and one site in the Sea of Marmara, within the period of June-September 2019. The results showed that a low mortality rate of 10% was found in the Sea of Marmara, and a MME was not detected for this area. In contrast, 97% mortality was recorded for the P. nobilis population distributed in the Turkish Aegean Sea. This discrepancy might be related to the seawater temperature and salinity values of these two seas. The waters of the Sea of Marmara were colder and less salty than the Aegean Sea. The findings highlighted the importance of protecting the healthy population of critically endangered fan mussels in the Sea of Marmara. It was recommended that sound management plans comprising of monitoring, enforcement and public awareness activities could be implemented in order to achieve this. 相似文献
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Zusammenfassung In mitteldevonischen crinoidenreichen Sandsteinen des Gebietes um Lindlar und Gummersbach (Bergisches Land) wurden die durch die variszische Faltung deformierten Gelenkflächen von Crinoidenstielgliedern vermessen und die Abhängigkeit der Verformung von Packungsdichte, Gesteinsmaterial, Klüftung, Schieferung, Teilbarkeit, Faltung und regionalen Faktoren untersucht. 相似文献
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Understanding uncertainty and reducing vulnerability: lessons from resilience thinking 总被引：3，自引：4，他引：3
Fikret Berkes 《Natural Hazards》2007,41(2):283-295
Vulnerability is registered not by exposure to hazards alone; it also resides in the resilience of the system experiencing
the hazard. Resilience (the capacity of a system to absorb recurrent disturbances, such as natural disasters, so as to retain
essential structures, processes and feedbacks) is important for the discussion of vulnerability for three reasons: (1) it
helps evaluate hazards holistically in coupled human–environment systems, (2) it puts the emphasis on the ability of a system
to deal with a hazard, absorbing the disturbance or adapting to it, and (3) it is forward-looking and helps explore policy
options for dealing with uncertainty and future change. Building resilience into human–environment systems is an effective
way to cope with change characterized by surprises and unknowable risks. There seem to be four clusters of factors relevant
to building resilience: (1) learning to live with change and uncertainty, (2) nurturing various types of ecological, social
and political diversity for increasing options and reducing risks, (3) increasing the range of knowledge for learning and
problem-solving, and (4) creating opportunities for␣self-organization, including strengthening of local institutions and building
cross-scale linkages and problem-solving networks. 相似文献
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Z. Berkes 《Theoretical and Applied Climatology》1960,10(4):433-444
Zusammenfassung Unter Verwendung der vonKöppen eingeführten relativen Temperaturen wird die Form der Jahresgänge der Temperatur in Europa untersucht. Für diesen Zweck werden die Änderungen der 30jährigen Normalwerte der Temperatur von Monat zu Monat in Prozenten der Jahresamplitude ausgedrückt.Es wird festgestellt, daß die Frühjahrserwärmung im Mitteleuropa zwischen Januar und April von Südwesten gegen Nordosten fortschreitet und im Siebenbürger Becken verhältnismäßig am stärksten ausgeprägt ist. Die relative sommerliche Erwärmung im Juni ist in der westlichen Ukraine am schwächsten. Das Zentrum der stärksten Abkühlung schreitet von Nordeuropa stufenweise gegen Südwesten fort. Für die Entwicklung der Erwärmungs-und Abkühlungszentren sind außer der Einstrahlung auch advektive und besonders monsunale Einflüsse von Bedeutung.
Mit 6 Textabbildungen. 相似文献
Summary Using the relative temperature introduced byKöppen the shape of the annual variations of temperature in Europe is investigated. To do this, the variations from month to month of the 30-year normal values are expressed in percents of the annual amplitude.It is found that in Central Europe the warming between January and April proceeds from southwest to northeast, and is most pronounced in the Basin of Transylvania (Roumania). Relative heating in June has a minimum in the western Ukraine. The center of cooling proceeds from Northern Europe towards southwest. The development of warming and cooling centers is determined by insolation, advection, and particularly by monsoon effects.
Résumé Etude de la marche annuelle de la température en Europe en utilisant la température relative introduite parKöppen. On exprime dans ce but les variations de mois en mois des moyennes trentenaires en pourcent de l'amplitude annuelle.On constate qu'en Europe centrale le réchauffement printanier, entre janvier et avril, se propage du Sud-Ouest au Nord-Est et se manifeste plus nettement qu'ailleurs sur le Plateau de Transylvanie. Le réchauffement relatif d'été, en juin, est le plus faible en Ukraine occidentale. Le centre du refroidissement maximum se déplace progressivement du Nord de l'Europe vers le Sud-Ouest. Le développement des centres de réchauffement et de refroidissement dépend du rayonnement, mais aussi des processus advectifs, en particulier de ceux qui relèvent de la mousson.
Mit 6 Textabbildungen. 相似文献
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Hydrochemical and water-quality (except biological) data obtained through a two-year sampling and analysis program indicate that the highest concentrations of groundwater pollution occur in the central and eastern parts of Eski?ehir city. Groundwater quality degradation outside the urban area results from agricultural activities. The most serious pollution of groundwater in the Eski?ehir plain is from nitrogen compounds (ammonia, nitrite, and nitrate). The concentrations of ammonia, nitrite, and nitrate of the 51 surveyed water wells range from 0.01–1.65 mg/L, 0.01–1.80 mg/L, and 1.1–257.0 mg/L, respectively. Orthophosphate concentrations in groundwater range from 0.01–1.25 mg/L. Considerable seasonal fluctuation in the groundwater quality was observed. In general, the groundwater quality in wet seasons was better than the quality in dry seasons. 相似文献
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This paper reports on a project to engage researchers and fishers together in adapting social science approaches to the purposes and the constraints of community-based fisher organizations. The work was carried out in the Scotia–Fundy Region of Atlantic Canada (the Bay of Fundy and Scotian Shelf). Its rationale reflects arguments that (1) effective community-based management requires that managers are able to pose and address social science questions, (2) participatory research, involving true cooperation in all stages, can support this process, and (3) there is a need to overcome practical and methodological barriers faced in developing participatory research protocols, to serve the needs of community-based management while not demanding excessive transaction costs. In this paper, we report on work with fisher organizations, both aboriginal and non-aboriginal, in which social science priorities were set by each organization, and small-scale research projects designed and carried out to meet these needs. This work identified interests among fishers in research on three different levels of meaning: (1) practical livelihood concerns, including what, when and where to fish, and with what intensity of effort, (2) social, economic and political issues (e.g., on institutional structures, politics of access and allocation, overlap and conflict between regulatory regimes), and (3) values and ethics that implicitly or explicitly guide policy development and implementation. Several research themes proved crucial, including those of power sharing, defining boundaries of a community-based group, access and equity, designing effective management plans, enforcement, and scaling up for effective regional and ecosystem-wide management. The research results demonstrate the effectiveness of extending participatory methods to challenge traditional scientific notions of the research process. 相似文献
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The compression index (Cc) is a necessary parameter for the settlement calculation of clays. However, determination of the compression index from oedometer tests takes a relatively long time and leads to a very demanding experimental working program in the laboratory. Therefore, geotechnical engineering literature involves many studies based on indirect methods such as multiple regression analysis (MLR) and soft computing methods to determine the compression index. This study is aimed to predict the compression index by using extreme learning machine (ELM), Bayesian regularization neural network (BRNN), and support vector machine (SVM) methods. The selected variables for each method are the natural water content (wn), initial void ratio (e0), liquid limit (LL), and plasticity index (PI) of clay samples. Many trials were carried out in order to get the best prediction performance with each model. The application results obtained from the models were also compared based on the correlation coefficient (R), coefficient of efficiency (E), and mean squared error (MSE). The results indicate that the BRNN method has better success on estimation of the compression index compared to the ELM and SVM methods. 相似文献
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Multi-level, networked participation is a vital component in building social–ecological resilience and the capacity to adapt to environmental change. This paper outlines the ways in which multi-level participation contributes to adaptive capacity and, in so doing, takes a step toward articulating a theory of participation based on resilience thinking. We use a case study of Gabra pastoralist communities of northern Kenya to illustrate how multi-level participation may lead to increasing adaptive capacity, above and beyond existing pastoralist adaptations. The findings suggest that adaptive capacity is systemic—that is to say, it is a property of the social–ecological system, including especially the network of institutional linkages that characterizes that system, as much as it is a property of particular actors within the system. We argue that there are three key elements of meaningful multi-level participation: an institutional environment in which the various levels of institutions are linked, inclusivity in decision-making at these various levels, and deliberation. These three features can work together to create meaningful multi-level participation, to facilitate the co-production of knowledge and to build adaptive capacity. 相似文献
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Forest transition theory describes a reversal in land-use trends for a given area, from a period of net forest area loss, to a period of net forest area gain. Some assume that such forest gain necessarily equates with biodiversity conservation. We question this assumption, based on research conducted in Oaxaca, Mexico. In Oaxaca's northern highlands, low intensity forest use and rotational (milpa) agriculture have led to pronounced spatial heterogeneity in forest structure and composition, and created a high-biodiversity forest-agriculture mosaic. In the Zapotec community of San Juan Evangelista Analco and the Chinantec community of Santiago Comaltepec, as across much of Oaxaca, fewer people are farming; farmers are cultivating less land, working closer to settlements, and growing fewer crop varieties. Widespread agricultural abandonment has initiated unprecedented changes in ecological succession, patch size, and edge effects, which we speculate will be having an impact on the biodiversity of the landscape mosaic. Our work suggests that the decline of land use activity may result in a gradual loss of the forest-agriculture mosaic, leading to localised declines in biodiversity, despite (or because of) extensive forest resurgence. These findings support the view that indigenous cultures in Oaxaca and Mexico should not be seen as an environmental constraint but rather as an agent of landscape renewal that allows for both cultural and biological diversity to flourish, a reality that national and international conservation bodies need to more fully recognise and incorporate into policy. 相似文献