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Margherita Sirna Terranova Sabrina Lo Brutto Marco Arculeo Jeffry B. Mitton 《Marine Biology》2006,150(1):89-101
Brachidontes pharaonis (Fisher P, 1870) is an Indo-Pacific mussel that has colonized the Mediterranean Sea via the Suez Canal. Mussels may have migrated by natural dispersal of pelagic larvae, or they may have been transported on the hulls of ships, or in ballast water, or by some combination of these. Mitochondrial COI sequences (618 bp) from 101 mussels from six localities in the central and eastern Mediterranean Sea and from one site in the Red Sea were used to describe population structure. Analysis of molecular variance indicated that frequencies differed among populations, and that 92% of the variation resided within populations. The majority of haplotypes were private alleles. No simple pattern of longitudinal variation was detected for haplotype frequencies, haplotype diversity, or nucleotide diversity. A variety of tree-building algorithms (NJ, MP, ME) gave consistent results, showing two sister groups. One clade had a leucine (L-form) and the other one a methionine (M-form) at the 30th amino acid. These sympatric forms were detected within all localities and they had similar frequencies in males and females. The M- and L-form were separated by a 7.3% sequence divergence, indicating that this is an ancient polymorphism. Closely related species of mussels had exclusively the L-form, so we infer that the M-form evolved from the L-form lineage of B. pharaonis, probably in the northern portion of the Red Sea. Neutrality tests detected an excess of rare mutations, a pattern of variation expected in expanding populations. Patterns of variation detected by Tajima’s D suggest that some form of balancing selection has maintained this polymorphism. 相似文献
165.
Groundwater management by watershed agencies: an evaluation of the capacity of Ontario's conservation authorities 总被引:4,自引:0,他引:4
Watershed-based resource management organizations around the world are becoming more involved in groundwater management. This reflects, among other considerations, growing awareness of the critical role that these local agencies can and should play in the management of groundwater resources. Ontario's conservation authorities (CAs) are an important example. CAs are taking on new responsibilities for groundwater data collection, monitoring and planning. Unfortunately, not all local organizations are equally capable of participating effectively in groundwater management. This certainly is the case among Ontario's 38 CAs, which have highly variable levels of financial and staff resources. Local capacity for water management can be explored from the perspective of the institutional environment, the watershed community, and the financial, technical and staff resources of the organizations. This paper presents an evaluation of the groundwater management capacity of Ontario's conservation authorities, drawing on two detailed case studies (the Upper Thames River CA and the Ganaraska Region CA), and additional data gathered from all 38 CAs. Institutional issues, such as the clarity of management roles and senior government commitment to local management, as well as resourcing concerns, local working relationships, and public support, largely determine the capacity of CAs to expand their involvement in groundwater management. Strengthening the capacity of watershed-based agencies to participate in groundwater management is an important challenge in all jurisdictions, as these agencies are well placed to reinforce municipal groundwater management by identifying local needs and trends, facilitating communication and cooperation, and promoting best management practices. 相似文献
166.
Preferences for dealing with environmental problems: an empirical study of managers in three mainland Chinese cities 总被引:1,自引:0,他引:1
This study examines managerial preferences for various policy mechanisms commonly used to address environmental problems using a sample of 653 Chinese managers from firms in Beijing, Dalian and Guangzhou. Overall, these managers appeared to favor regulatory instruments, placing somewhat less faith in market and communicative instruments. However, all measures appear to have ample support within each subgroup. In addition, the influence of two situational factors on these preferences was investigated--the immediacy of environmental impact and diffusion of responsibility. The results of the study indicate that these two factors interact in explaining managerial preferences, but only for the use of market mechanisms. 相似文献
167.
This paper aims to calculate the energetic and environmental effects of an integrated solid waste management system in Palermo, Italy. In particular, the thermal treatment of Municipal Solid Waste (MSW) with energy recovery is assessed. The current characterization at the local scale is taken into account. Two different options of collection are taken into account: (1) unselected wastes; and (2) sorted collection, according to the current Italian regulation. Combustion process is analyzed and the following features are calculated: (1) stoichiometric content of air and air excess; and (2) temperature and enthalpy of flue gases. Energy recovery is performed in the hypothesis of Hirn cycle both with steam condensation to produce only power, and with bleeding cycle for the combined production of power and thermal energy. Total electric efficiency is assumed as representative index of the technological level of the assessed plant. Results show that the thermal treatment of selected MSW, associated with a cogenerative recovery of energy, represents a relevant sustainable strategy of waste valorization as an alternative to fossil fuels. 相似文献
168.
Community Capacity for Adaptation to Climate-Induced Water Shortages: Linking Institutional Complexity and Local Actors 总被引:10,自引:3,他引:7
There is growing concern for the capacity of urban and rural communities to manage current water shortages and to prepare for shortages that may accompany predicted changes in climate. In this paper, concepts relating to the notion of climate adaptation and particularly capacity building are used to elucidate several determinants of community-level capacity for water management. These concepts and criteria are then used to interpret empirically derived insights relating to local management of water shortages in Ontario, Canada. General determinants of water-related community capacity relate to upper tier political and institutional arrangements; the characteristics of, and relationships among, pertinent agencies, groups, or individuals involved in water management; and the adequacy of financial, human, information, and technical resources. The case analysis illustrates how general factors play out in local experience. The findings point to geographically specific factors that influence the effectiveness of management. Key factors include collaboration between water managers, clarification of agency roles and responsibilities, integration of water management and land-use planning, and recognition and participation of both urban and rural stakeholders, whose sensitivities to water shortages are spatially and temporally variable. 相似文献
169.
A Generalized Water Quality Index for Taiwan 总被引:3,自引:0,他引:3
By exploring the behavior and limitations of conventional methods for quality evaluation, a better overall index for water quality in Taiwan and its application in Keya River are proposed. The thirteen variables are employed for the quality assessment. Numerical scales relating to the degree of quality are established for each variable to assess variations in quality and to convey findings in a comprehensive manner to others. The employed variables are categorized into three aspects referred to the principal components analysis, which are 'organics', 'particulates' and 'microorganisms'. The overall index consists of the geometric mean for the three defined aspects and multiplying by three coefficients, which reflect quality degrees of temperature, pH and toxicity, respectively. Besides, the arithmetic mean is addressed among the variables associated in the same aspect. Finally, a fresh, mixed aggregation function is developed for ensuring that the index score tells us something useful and does not hide important information. A case study of the Keya River is made to illustrate the application of this new index system. The new proposed index provides comprehensive information for water quality assessment, than the existing index used in Taiwan does. 相似文献
170.
For decades, industry has been the main source of pollution in China. Determined to make changes, the mainland Chinese authorities have decided to promote mechanisms that incorporate environmental concerns into the internal management of enterprises. This is manifested in the rapid adoption of the ISO14000 standards, including a significant increase in ISO14001 registrations in China. Thus, this study examined the environmental policy statements of 106 certified facilities in mainland China against a strict interpretation of the mandatory requirements of the ISO 14001:1996 standard and the nonmandatory ISO14004 requirements in order to shed some light on the implementation of environmental management systems in an emerging economic giant. It was decided to analyze the environmental policy statement because such a statement is a core element in the ISO system of environmental management of each facility and there are relatively clear and specific requirements on what an environmental policy statement shall include. An analysis of the contents of the environmental policy statements shows that conformance to the relevant requirements of both the mandatory ISO14001 standard and the nonmandatory ISO14004 standard is far from impressive and that the facilities in our sample seldom went beyond the minimum requirements. By using ISO14001 and ISO14004 conformance scores as the dependent variables, we found that conformity to ISO14001 and overall conformance to ISO14000 series can be explained to some extent by the degree of top management commitment, the experience with informal environmental management systems, and the form of ownership of the facilities. 相似文献