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11.
The impacts of the tsunami in 2004 on the reefs in Surin Marine National Park, Thailand, varied with the location and exposure of the reefs. Channel areas between islands were severely damaged. Areas with steep reef slopes were damaged by sand slides or coral collapse more than areas with low slopes. Massive, sub-massive, and encrusting corals were more resistant and resilient to the direct impact of the tsunami than branching, tabulate, and foliose life forms whereas the latter were more tolerant of temporary coverage by sand. Sub-massive corals were the most tolerant overall and survived sand coverage, breakage, and overturning. Live coral cover measured three months after the tsunami was significantly greater than immediately post-tsunami as broken, moved, or sand-covered corals, recorded as impacted in the initial survey, had survived and were regenerating. Low turbidity, lack of pollution, and mild currents possibly contributed to rapid recovery and limited long-term effects of the tsunami. Impact assessment shortly after a major disturbance may give an initial measure of damage but subsequent surveys must be undertaken to identify long-term effects. Understanding patterns of reef damage can help to formulate reef zoning and protection strategies in response to catastrophic events, but also in advance of such events to improve likely resilience of the marine park to disturbance.  相似文献   
12.
The scleractinian coral Montipora digitata (Acroporidae) is a common reef flat species that thrives under high levels of light and water turbulence, and propagates successfully by natural fragmentation. It was used for transplantation experiments in an attempt to restore a degraded lagoon environment in the northwestern Philippines. Branches about 5 cm high from a natural population in the lagoon were transplanted to dead coral outcrops or knolls in two locations (Binlab and Malilnep-Ac) with different environmental characteristics. Growth and survival were significantly better at Malilnep Ac, which resembled the natural habitat of the species more closely. Environmental conditions at this site also favored the establishment of a greater diversity of species around the coral transplants. There was no difference in performance between transplants on vertical and horizontal surfaces, and the transplants showed limited differences due to density within the experimental range. Significant survival of detached, transplanted colonies or fragments thereof around the bases of the experimental bommies at the more successful site was an additional positive outcome. Water motion showed significant effects on survival and growth, possibly enhancing the suitability of the more successful site for transplantation. These results demonstrate the potential of coral transplantation to initiate the establishment of natural communities in degraded reef areas, a concern for coastal managers in developing countries.  相似文献   
13.
Complex policy frameworks guide the management of the Great Barrier Reef (GBR) at multiple decision-making levels. Mounting pressure on its outstanding universal value suggests that further improvements in governance are required. There has been little examination of the role of policy actors in addressing complex governance challenges in large scale marine protected areas (LSMPAs) involving multi-layered governance conflicts across diverse contexts. Framed by street level bureaucracy, pragmatic planning theory, and lessons from MPA governance, this paper examines how policy actors improvised and collaborated to advance outcomes in the GBR LSMPA. We assessed practice-focused oral histories with experienced policy actors who negotiated agreements and achieved policy outcomes in the GBR between 1985 and 2016. These policy actors were skilled improvisers, alternating between roles as democratisers, mediators, and negotiators. They used collaboration and facilitative leadership to advance policy in the face of governance problems. This enabled them to adapt policy across multi-level decision systems, address power and information imbalances, and generally deal with conflict and uncertainty. A deeper understanding of improvisation will assist governments and others to address complex challenges in LSMPAs.  相似文献   
14.
A recent metaanalysis identified certain management attributes that are associated with successful management of threshold-based systems. However, high variance among case studies indicates that these attributes do not guarantee good conservation outcomes, suggesting that additional factors may be at play. To better understand these additional factors, we compiled a list of effective governance attributes from the literature, and developed guidance for systematically evaluating their presence, absence, and the extent to which each attribute is actually manifested in a given case study. We also examine the distribution of rights and responsibilities within a system, and the resulting impacts on stewardship incentives. Here we present the results of this analysis as applied to Kāneohe Bay, Hawai‘i. Our results confirm that absent or incomplete effective governance attributes can negatively impact conservation outcomes. In Kāneohe Bay, a public-private partnership temporarily compensated for gaps and weaknesses in the governance system, thereby creating conditions conducive to successfully reducing populations of invasive algae. However, this partnership has since dissolved and current capacity to address this and other issues in this system is again lacking. Failure to fix governance weaknesses may compromise the continued health and functioning of the Kāne'ohe Bay system.  相似文献   
15.
在三峡水库消落期和汛期河道恢复至天然状态时,五台梁礁石突出碍航,制约航道发展,亟需实施清礁整治。考虑近期航道建设和远期扩能提升需求,拟定了一次性整体切除清礁方案,并采用数值模拟方法对方案整治效果进行预测分析。结果显示:1)工程实施后,清礁区水深增大,过流能力增加。2)局部水流流态明显改善,水流趋于平顺,航道侧横流减至0.25 m s以下。3)4.5 m水深航道宽度在300 m以上,达到了预期整治目标,证明方案合理、整治效果符合预期。  相似文献   
16.
涪陵—丰都河段内的佛面滩碍航礁石伸出江心,汛期产生强烈的横流,流态紊乱,船舶须过河上行,与下行航路交叉,威胁船舶航行安全。针对上述问题,拟通过炸除佛面滩部分礁石改善通航流态,实现船舶"各自靠右,分边航行"。建立佛面滩河段二维水流数学模型,通过模拟多级流量的流场,确定航行条件最差的最汹流量为2. 45万m~3/s;模拟计算最汹流量下8个炸深方案流场,通过比较各个炸深方案的流速、横向流速、流速横纵比、航行推阻比、单位炸深效比和流态,认为8 m炸深方案最优。  相似文献   
17.
浅谈苏丹港区工程地质特征   总被引:1,自引:0,他引:1  
罗新华 《水运工程》2004,(3):49-50,75
简单介绍苏丹港区珊瑚礁灰岩的地质特征及不均匀风化现象,以及该层的地基承载力。  相似文献   
18.
曹竞梅 《水运工程》2005,(7):74-76,79
介绍西江下游航道整治C1合同段蟠龙石炸礁工程施工方法,可为类似工程提供借鉴。  相似文献   
19.
Effective management of highly biodiverse and threatened reefs requires the identification of human activities driving declines on the particular reef to be managed. The island nation of the Comoros is a model setting to investigate effects of human activities on diverse and threatened coral reefs, with abundant and diverse marine life, local dependence on reef resources, and a variety of anthropogenic pressures on reefs rendering the nation vulnerable to coral reef degradation. Using data from 21 sites throughout the Comoros, we evaluated the relative influence of human activities and other natural and anthropogenic factors on benthic cover and fish richness, abundance, and biomass with the goal of providing prioritized management targets. Human activities including fishing, beach sand extraction, and beachfront housing and development had the strongest relationship with degraded reefs but with some seasonal fluctuation, while geographic patterns most consistently predicted reef degradation across seasons. Comparing analyses conducted with and without human activities as predictors, the inclusion of human activities greatly improved explanatory power. Baseline data on reef biotic composition and localized anthropogenic impacts, monitoring over time, and controlled experiments can facilitate an adaptive management approach for protecting fragile reef ecosystems in the Comoros and elsewhere.  相似文献   
20.
介绍了南海海域的自然条件、南海环礁岛礁地形地貌特点和地质特征等,分析了南海环礁岛礁建港条件,总结 了建设原则,并给出了方案实例。  相似文献   
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