• Journal of Ecology and Environment
• /
• 제40권2호
• /
• pp.89-106
• /
• 2016

Many plant species have two modes of reproduction: sexual and asexual. Both modes of reproduction have often been viewed as adaptations to temporally or spatially variable environments. The plant should adjust partitioning to match changes in the estimated success of the two reproductive modes. Perennial plants showed that favorable habitats in soil nutrients or water content tend to promote clonal growth over sexual reproduction. In contrast, under high light-quantity conditions, clonal plants tend to allocate more biomass to sexual reproduction and less to clonal propagation. On the other hand, plants with chasmogamous and cleistogamous flowers provides with a greater tendency of the opportunity to ensure some seed set in any stressful environmental conditions such as low light, low soil nutrients, or low soil moisture. It is considered that vegetative reproduction has high competitive ability and is the major means to expand established population of perennial plants, whereas cleistogamous reproduction is insurance to persist in stressful sites due to being strong. Chasmogamous reproduction mainly enhances established and new population. Therefore, the functions of sexual and asexual propagules of perennial or annual plants differ from each other. These traits of propagule thus determine its success at a particular region of any environmental gradients. Eventually, if environmental resources or stress levels change in either space or time, species composition will probably also change. The reason based on which the plants differ with respect to favored reproduction modes in each environmental condition, may be involved in their specific realized niche.

• Journal of Ecology and Environment
• /
• 제41권8호
• /
• pp.202-212
• /
• 2017

Background: To reveal establishment strategy of Sparganium erectum, we tried to find realized niche of adults through field survey and effects of water level on the establishment process through mesocosm experiments. Results: In the field survey, the height and coverage of community living in deeper water were greater than those of community living in shallow water. There was no statistically significant difference (p > 0.05) in the means of water and soil properties between the two communities. In mesocosm experiments, we found no correlation between water levels and germination rates, but S. erectum seedlings have characteristics of post germination seedling buoyancy when S. erectum seeds germinated in inundation conditions. Shoot height, total leaf length, and survival rates of sinking seedlings in shallow water levels at -5, 0, and 5 cm were higher than those in deeper water levels at 10 and 20 cm. Floating seedlings established in water levels of 3 and 6 cm only. The seedlings could live up to 6 weeks in floating state but died if they were unable to establish. Conclusions: The water level around adult S. erectum communities in the field were different from the water level at which S. erectum seedlings can survive in the mesocosm experiments. The findings provided not only understanding of S. erectum habitat characteristics but also evidence to connect historical links between the early seedlings stage and adult habitat conditions. We suggested the logical establishment strategy of S. erectum based on the data.

• 산업경영시스템학회지
• /
• 제36권4호
• /
• pp.9-17
• /
• 2013

The purpose of this study is to figure out the impacts of technological innovation and cost management on productivity in small shipping industries to come up with developmental implications. To achieve this, a survey was carried out to 150 workers in small shipbuilding industries through April 2 to April 20, 2012. As for findings stated above, technological innovation and cost management in the Korean small shipbuilding industries were key factors that elevate financial and non-financial productivity. In the light of low technological prowess and cost structure of small shipbuilding industries, their productivity can be improved when intensive cost management with production factor technology as know-how is realized through quality management, which product development technology is the top priority as an independent niche strategy. Consequently, the combination of infrastructures in small shipbuilding industries with continuous efforts for cost reduction by the link to the systematized structure can't only secure their independent competitiveness, but raise their productivity.

• 한국콘텐츠학회논문지
• /
• 제17권6호
• /
• pp.39-54
• /
• 2017

본 연구는 그동안의 공동체 미디어 실천연구들이 전통적 방식의 지상파(전파) 방송에 국한되어 온 것에 대한 문제의식에서 출발하였다. 기존연구들에서 소홀하게 다루어진 온라인 기반 위에서 실천되고 있는 지역 공동체 미디어의 특성과 콘텐츠 제작 및 유통의 특성을 규명하고자 대덕밸리라디오의 사례를 분석하여 다음과 같은 연구결과와 시사점을 얻을 수 있었다. 첫째, 온라인 공동체 미디어 활동은 지역 공동체의 가치를 담아내는 시민미디어(civic/citizen media) 활동이다. 둘째, 미디어 콘텐츠 제작과 유통전략에 따라 퍼블릭 액세스(Public Access)를 통하지 않고도 공동체의 지역성을 실현하는 효과적인 매체 활용을 할 수 있다. 셋째, 온라인 미디어의 콘텐츠는 공동체를 연결하며 개인이 연결점(node)이 되어 온라인과 오프라인에서 상호작용한다. 따라서 본 연구를 통해 온라인 기반 공동체 미디어 실천은 시민들의 미디어 활동의 지속 가능성을 높일 수 있는 틈새(니치) 미디어로서 기능할 수 있다는 것을 밝힐 수 있었다.

• Ocean and Polar Research
• /
• 제31권1호
• /
• pp.97-110
• /
• 2009

Two of the most important topics of the 21st century are ensuring harmony between man and his environment and the emerging long-tail economy in which niche markets are becoming increasingly more important. Since the Industrial Revolution in 17th century, human beings have increasingly exploited the world's natural capital, such as the natural environment and its ecosystems. Now the world is facing limits to sustainable economic growth because of limits to this natural capital. Thus, most countries are beginning to adopt a new development paradigm, the so-called"Green Development Paradigm" which pursues environmental conservation in parallel with economic growth. Recently, the Korean government announced an ambitious national policy of Low Carbon & Green Growth for the next six decades. This is an important step that transforms the existing national policy into a new future-oriented one. The fisheries sector in particular has great potential for making a substantial contribution to this national policy initiative. For example, the ocean itself with its sea plants and phytoplankton has an enormous capacity for fixing carbon, and its vast areas of tidal flats have a tremendous potential for cleaning up pollutants from both the sea and the land. Furthermore, the fishing industry has great potential for the development of fuel-saving biodegradable technologies, and a long-tail economy based on digital technologies can do much to promote the production and consumption of green goods and services derived from the oceans and the fisheries. In order for this potential to be realized, the fisheries authority needs to develop a new green-growth strategy that is practical and widely supported by fishing communities and the markets, taking into account the need for greenhouse gas reduction, conservation of the ocean environment and ecosystems, an improved system for seafood safety, the establishment of strengthened MCS (monitoring control surveillance) system, and the development of coastal ecotourism. In addition, fisheries green policies need to be implemented through a well-organized system of government aids, regulations and compensation, and spontaneous (voluntary) orders in fishing communities should be promoted to encourage far more responsible fisheries.