• Title/Summary/Keyword: age diversity

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Actual Vegetation Potential Natural Vegetation of Pukhansan National Park, Mid-western Korea (북한산국립공원의 현존식생과 잠재자연식생)

  • 이은복
    • The Korean Journal of Ecology
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    • v.20 no.6
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    • pp.439-450
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    • 1997
  • The potential natural vegtation of the Pukhansan National Park area, mid-western Korea, was inferred from the actual vegetation. With the phytosociological classification and field surveys, the actual vegetation map of the park area was made on a scale of 1:25, 000, including fourteen communities. By the analyses of the species diversity, the age structure, the human interferences and various informations on vegetation changes, two pathways of late stage succession from Pinus densiflora forests to the climatic climax were suggested. One is from Quercus serrata forests to Q. mongolica forests throughout the mountain and the other, from Q. variabilis or Q. acutissima forests to Carpinus laxiflora forests in lower parts. Considering the vegetation changes, the potential natural vegetation of the park area mainly composed of Q. mongolica, C. laxiflora, P. densiflora and Zelkova serrata forest as the climatic and/or edaphic climax was inferred.

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Forest Patch Characteristics and Their Contribution to Forest-Bird Diversity - Focus on Chungcheong Province Area - (산림패치의 특성이 조류 종 다양성에 미치는 영향분석 - 충청지역을 중심으로 -)

  • Lee, Dong-Kun;Park, Chan;Oh, Kyu-Sik
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.13 no.5
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    • pp.146-153
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    • 2010
  • Urban development typically results in many species being confined to small, isolated and degraded habitat fragments. Fragment size and isolation underpin many studies of modified landscape to prevent biodiversity loss. However, habitat characteristics such as vegetation structure and edge effects are less frequently incorporated in planning. The relative influence of biogeographic (e.g. size, isolation) and vegetation parameters on assemblages is poorly understood, but critical for conservation management. In this study, the relative importance of biogeographic and vegetation parameters in explaining the diversity of forest-interior dwelling birds in forest fragments in Chungcheong Province Area. Fragment size and vegetation characteristics were consistently important predictors of bird diversity. Forestinterior bird richness was influenced by fragment size (0.437), wood age (0.332), wood diameter (0.068), and patch shape (-0.079). To preserve bird diversity of Chungcheong Province Area, it is important to consider differing responses of bird diversity to landscape change, move beyond a focus primarily on spatial attributes (size, isolation) to recognize that landscape change also has profound effects on habitat composition and quality. The result is very useful for long-term aspect of biodiversity conservation plan in regional scale.

Molecular Diversity of Rhizobacteria in Ginseng Soil and Their Plant Benefiting Attributes (인삼토양 내 근권세균의 다양성 및 식물에의 유용 특성)

  • Hong, Eun Hye;Lee, Sun Hee;Vendan, Regupathy Thamizh;Rhee, Young Ha
    • Korean Journal of Microbiology
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    • v.48 no.4
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    • pp.246-253
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    • 2012
  • The purpose of this study was to investigate the molecular diversity of rhizobacteria associated with ginseng of varying age levels and their plant benefiting attributes. A total of 143 different isolates belonging to 15 different bacterial genera were recovered. Although variation was found in the rhizobacterial community due to age of the plant, majority of bacteria belong to Firmicutes (58%). In which, Bacillus was found to be the predominant genus irrespective of age of the ginseng. To assess the plant benefiting attributes, 30 representative isolates were selected. The results indicated that some of the isolates could exhibit multiple plant growth promoting traits like secretion of cell wall degrading enzymes, production of indole-3-acetic acid, synthesis of siderophores, solubilization of phosphates and soil pathogens inhibition. It can be suggested that strains of B. subtilis, B. amyloliquefaciens, B. velezensis, and B. licheniformis were positive for all the above traits, which have potential to be used as plant growth promoting inoculants to improve ginseng crop in the future.

The Characteristics of Odonata Community According to Age and Size of Pond (연못 조성년도와 크기에 따른 잠자리 군집 특성)

  • Kim, Ji-Suk;Pi, Jae-Hwang;Jung, Tae-Jun;Lee, Kyong-Jae
    • Korean Journal of Environment and Ecology
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    • v.28 no.3
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    • pp.293-301
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    • 2014
  • 15 artificial ponds in Seoul have been examined to find out the characteristics of Odonata community according to age and size of pond. We found 6 Families 36 Species of Odonata community, and Libellulidae was the most frequent and 19 Species were observed among Libellulidae. Considering relative importance with frequency of appearance and density, Ischnura asiatica and Orthetrum albistylum was the most frequent. Also, 16 Species including Lestes temporaris, Sympetrum parvulum, and Anax nigrofasciatus were relatively rare. The result of dominant species tells that Ischnura asiatica in 1 ~ 3 year old ponds, Pantala flavescens-Orthetrum albistylum-Crocothemis servilia mariannae in order of mention in 4 ~ 6 year old ponds, Platycnemis phyllopoda-Ischnura asiatica in order of mention in 10 or more year old ponds are the dominant species. Species diversity index regarding age of pond has been researched, and species diversity index in 10 year old pond was higher than that of in 1 ~ 3 year old pond. Having done the analysis of variance for types of spawn, there are many species Endophytic egg-layers and pasting in mud or sand in 10 year old artificial ponds. The wider ponds get, the higher species diversity index gets. And, we suggest that desirable size for making artificial ponds to increase the species diversity index of Odonata is $100{\sim}300m^2$.

Fish assemblage collected by gill net in the coastal shallow water off Shinsudo, Samchonpo (삼중자망에 의한 삼천포 신수도연안 천해어류 군집의 구조)

  • KIM Chong-Kawn;KANG Yong-Joo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.24 no.2
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    • pp.99-110
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    • 1991
  • Species composition, abundance, seasonality and age composition of the fish assemblage were studied in the coastal shallow water off Shinsudo, Samchonpo. The fishes were collected by gill net from February 1984 to January 1985. Of the 32 fish species collected, the common species throughout the year were Agrammus agrammus, Hexagrammos otakii, Sebastes inermis and Lateolabrax japonicus, which comprised $73.9\%$ in numbers and $73.1\%$ in weight. The mean monthly diversity index was 1.85. The diversity was the highest in October(H'=2.25) and the lowest in April(H'=1.34). In age composition of the four species, A. agrammus and S. inermis consisted of 5 age groups from 0 to 4, H otakii consisted of 4 age groups from 0 to 3 and 1. japonicus consisted of 3 age groups from 0 to 2.

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Community Regeneration and Development Traits of Ulmus pumila L. (비술나무(Ulmus pumila L.) 군락의 재정착과 발달 특성)

  • Young-Chul Kim;Hyun-Hee Chae;Bo-Ram Hong
    • Korean Journal of Environment and Ecology
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    • v.37 no.1
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    • pp.13-34
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    • 2023
  • Many ecologists try to understand plant communities and societies' changing processes by interacting with environmental factors. Plant communities formed in the sidings of streams, which are more dynamic than forest vegetation, are closely related to the disturbance regime of streams. U. pumila, which forms communities at the edges of streams, is distributed over the central and northern regions of the Korean Peninsula. In this study, we intended to explain the regeneration of U. pumila communities in the upstream region of the Namhangang River. Heights from the stream surface to the mid-high points of communities increased when the age class of U. pumila communities increased. On the other hand, the height of U. pumila tended to increase and decrease as the age class increased. The richness (S), evenness (J'), diversity (H'), and maximum diversity (H'max) also showed a tendency to increase and then decrease as the age class increased. On the other hand, the number of stems per individual and density (D) decreased as the age class increased. Seedlings of U. pumila failed to regenerate in the communities at the intermediate or higher stage of the age class. Regeneration of seedlings occurred in the spaces formed by the flooding, which occurred periodically in streams. After regeneration, U. pumila communities grew like a single organism. On the other hand, the plant species consisting of U. pumila communities exhibited a process in which the S and H' increased and then decreased as they developed. In other words, we determined that the changes in the species compositions were associated with changes in each species' environment and community. A space where seeds can regenerate seedlings should be provided for the regeneration of U. pumila communities. In the mid/upstream region of the Namhangang River, where the present study focused, newly formed communities were rare because the space required to regenerate U. pumila ceased to exist. Accordingly, we suggest securing an appropriate space for the regeneration of seedlings to maintain the U. pumila communities in the upstream region of the Namhangang River.

Balancing Efficiency and Flexibility in Software Project: The Role of Team Collective Improvisation, behavioral integration, and member diversity

  • Lee, Young-Joo;Lee, Jung-Hoon;Ham, Kyung Sun
    • Journal of Contemporary Eastern Asia
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    • v.16 no.1
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    • pp.22-45
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    • 2017
  • The successful management of software (SW) projects is a continuous concern to managers, which is attributed to the contradictory demands that most projects are facing; meeting user requirements within time and budget limit while flexibly dealing risks during the progress of the projects. The present study asserts project performance and risk mitigation are not tradeoff but to be achieved simultaneously, which is called SW project ambidexterity. Drawing on the literature on organizational behavior, hypotheses are developed speculating the relation among project performance, risk mitigation, team collective improvisation, team behavioral integration, and team diversity. Using empirical data collected from 102 SW project teams of 507 team members in South Korea, empirical analysis indicates team collective improvisation is a significant antecedent to SW project ambidexterity, playing a pivotal role to balance the contradictory demands. Furthermore, team behavioral integration positively influences the degree of team collective improvisation, and the magnitude of the relation is partially contingent on the team members' age and major diversity. The present study advances theory by providing a context specific explanation about the SW project ambidexterity and its precedents.

Do Board Traits Influence Firms' Dividend Payout Policy? Evidence from Malaysia

  • TAHIR, Hussain;RAHMAN, Mahfuzur;MASRI, Ridzuan
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.3
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    • pp.87-99
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    • 2020
  • The study aims to investigate factors that determine dividend payout policy using 336 non-financial firm year observations covering the period 2005 to 2016 in Malaysia. We found a significant positive relationship between corporate board size, board members average age, board tenure and dividend payout policy. We also found a strong negative effect and statistically insignificant relationship of board diversity, board independence, CEO duality and dividend payout policy. Additional, financial leverage has a negative effect on dividend payout policy. It is also noticed that firms with diverse boards are more likely to pay dividends and tend to pay larger dividends than those with non-diverse boards. Our results suggest that board diversity has a significant impact on dividend payout policy. Impact of board diversity on dividend payout policy is particularly conspicuous for firms with potentially greater agency problems. Our findings are consistent with the argument that corporate board traits enhancement positively affect the dividend payout policy which is beneficial for shareholders. This study offers useful insights into the current global debate on board traits and its implications for firms. The dividend payout policy signals good news to investors. Corporate board traits and firm's financial decision are the factors that disrupt the dividend decision.

Rural landscape and biocultural diversity in Shinan-gun, Jeollanam-do, Korea

  • Kim, Jae-Eun
    • Journal of Ecology and Environment
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    • v.38 no.2
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    • pp.249-256
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    • 2015
  • Islands are often habitats to unique species because they have different environmental conditions from the mainland and other islands. Another characteristic of islands is their limited natural resources, which has led island residents to heavily rely on traditional ecological knowledge (TEK) and use resources sustainably. The so-called "Maeul landscape" shows the interrelationship of biological species and people's use of natural resources. Shinan-gun is an administrative district located in the southwestern part of Korea that forms an archipelago with huge tidal flat areas. Since long ago, people's use of these tidal flats shows a high degree of biocultural diversity. Maeul landscapes also show humans' adaptation to the natural environment. For instance, strong winds blowing mainly from the northwest have led people in Shinan-gun to create "Ushil," a windbreak forest with stone blocks to block wind from their villages and agricultural fields. At present, the transfer of TEK to future generations is at stake due to socio-economic changes that cause island populations to shrink and age rapidly. Islands are often regarded as good destinations for tourism, but attention should also be given to sustainable development due to the environmental characteristics of islands. International organizations are making efforts to curb the threats of global environmental problems especially on small islands. Their activities are aimed at seeking solutions that stress the central role of biocultural diversity in establishing the sustainable use of natural resources on islands. Joint efforts oflocal people and government authorities to protect and conserve the Maeul landscape should be encouraged.