• Korean journal of applied entomology
• /
• v.47 no.4
• /
• pp.421-428
• /
• 2008

With the comparison of native Orius strigicollis (Poppius) to European O. laevigatus (Fieber), we investigated biological characteristics such as developmental period, fecundity, life span, predation ability, and augmentation after release. Experiments were carried out at five temperature condition, $15^{\circ}C\;20^{\circ}C,\;25^{\circ}C\;30^{\circ}C$, and $35^{\circ}C$. In the case of O. strigicollis, egg period was $3.1{\sim}14.9$ days (hatchability: $46.7{\sim}88.2%$), and developmental period of nymphs was $9.4{\sim}42.8$ days (survival rate: $2.4{\sim}96.5%$). Fecundity at each temperature was 28.1, 107.9, 123.6, 127.3, and 18.1, respectively. Life span of adults was 63.4, 40.1, 22.1, 18.3, and 11.0 days, respectively. In the case of O. laevigatus, egg period was $3.1{\sim}13.5$ days (hatchability: $65.0{\sim}89.9%$), and developmental period of nymphs was $9.3{\sim}42.0$ (survival rate: $4.3{\sim}80.6%$) days. Fecundity at each temperature was 101.8, 218.6, 224.5, 219.5, and 15.7. Life span of adults was 70.6, 66.4, 32.6, 34.5, and 7.3 days, respectively. In long-day condition (16L:8D), fecundity of O. strigicollis and O. laevigatus was 105.8 $(18^{\circ}C){\sim}142.4(25^{\circ}C)$ and 109.5 $(18^{\circ}C){\sim}191.5(25^{\circ}C)$, respectively. In short-day condition (10L:14D), fecundity of them was 1.0 $(18^{\circ}C){\sim}31.8(25^{\circ}C)$ and 63.0 $(18^{\circ}C){\sim}198.8(25^{\circ}C)$, respectively. Daily prey consumption of second instar Frankliniella occidentalis was 14.3 and 10.9, respectively. In greenhouse, density of O. strigicollis begins to increase from mid May and peaked about early July (1.8 individual/flower), while that of O. laevigatus begins to increase from mid March and peaked about early June (6.6 individual/flower).

• Korean Journal of Ecology and Environment
• /
• v.51 no.1
• /
• pp.71-85
• /
• 2018

A recent topic of interest within ecology is ecosystem services that are importantly connected with biodiversity. Biodiversity is a fundamental component of ecological studies and has been the subject of many studies worldwide. However, studies on the diversity and distribution of freshwater fish were not undertaken in earnest until 2000, and the number of internationally available studies is therefore still limited. In this study, we used data from "The Survey and Evaluation of Aquatic Ecosystem Health (hereafter SEAEH)" within the framework of which whole water systems on the Korean peninsula are annually monitored to investigate and determine the current status of the diversity and distribution of freshwater fish, as well as to elucidate major factors impacting freshwater fish. A total of 130 species from 28 families were identified at around 953 sites in the SEAEH investigation of 2014. The species Zacco platypus (relative abundance: 28.2%) and Z. koreanus (19.3%) were identified as the most abundant species on the Korean peninsula, and besides these 20 endangered species, 51 endemic species and 4 exotic species were also collected. Highest (96 species) and lowest (72 species) diversity were identified in the Han River Watershed and the Yeongsan/Seomjin River Watershed, respectively. The mean endemic rate was 32.7%, which is higher than the previous rate determined in 1995. The exotic species Micropterus salmoides, Lepomis macrochirus and Carassius cuvieri were found in the whole river system except north Yeongdong, whereas Oreochromis niloticus occurred only at three sites due to the cold water temperatures in winter. Totally, 28 species were found to be translocated to different water systems not connected with known original habitats, most translocations occurring in the Nakdong River and the Yeongdong region. Among the translocated species, Opsariichthys uncirostris amurensis, and Erythroculter erythropterus were dominantly distributed in the mid- to lower reaches of Nakdong River where they may be harmful to the native fish assemblages due to their strong predation. The construction of weirs in connection with the "4 River Project" generated changes in fish assemblages before, during and after the project, resulting in altered habitat condition. Especially, a decrease in the number of endemic species and an increase in the abundance of lentic species were seen. Human-induced global warming will allow exotic species requiring high water temperatures to adapt to the environmental conditions of the Korean peninsula, which may enhance the diversity of native fishes and create changes in distribution. For the establishment of realistic and efficient management and protection strategies for Korean freshwater fish, SEAEH, which produces fundamental and quantitative data for Korean streams, is an important and necessary tool.

• Korean Journal of Environment and Ecology
• /
• v.25 no.3
• /
• pp.358-364
• /
• 2011

To examine the possibility of natural regeneration of six Acer species in broadleaved mixed forest in Korean peninsula, samples of six Acer species' samaras were collected at several seed sources from September to October 2009 and 2010, and seed morphological characteristics and viability were studied using cutting method. Inflorescense type of Acer mandshuricum(AM), A. pseudosieboldianum(APS) and A. palmatum(AP) is corymb, that of A. pictum subsp. mono(APSM) and A. okamotoanum(AO) is flat-topped panicle, and that of A. ukurunduense(AU) is raceme. Number of seed-set per inflorescense proves the highest value 38.5 sets in AU and the lowest value 2.4 sets in APS. Diameter of the seeds proves highest value 13.5mm in AO, and the lowest value 4.7mm in APS. Angles between the wings proves the highest values $130.05^{\circ}$ in APS, and the lowest value $48.60^{\circ}$ in AU. Air dry weight of 20 seed-sets proves highest value 3,900mg, in AO, and the lowest value 404mg in AU. Viable seed ratio of AP proves 50%, and that of AU does 43.2%. Those of other four species ranges 8.6~22.2%. Considering postdispersal seed predators and disturbance of litter, viable seeds of APSM, AO, AM, and APS supplied in the natural forest in Korea might be insufficient for seedling establishment. This study showed that sound viable seed supply might be key factors of natural regeneration of major Acer species in Korea. The openings made by insect pests were observed on the seed-coat of APSM, AM, AU, and APS samara, and Bradybatus sharpi were observed in the samaras of APSM and AO. Further study on the seed insect fauna, pre- and post-dispersal seed viability, and annual variation on these factor should be needed.

• Journal of Oral Medicine and Pain
• /
• v.32 no.2
• /
• pp.137-150
• /
• 2007

Trees emit phytoncide into atmosphere to protect them from predation. Phytoncide from different trees has its own unique fragrance that is referred to as forest bath. Phytoncide, which is essential oil of trees, has microbicidal, insecticidal, acaricidal, and deodorizing effect. The present study was performed to examine the effect of phytoncide on Porphyromonas gingivalis, which is one of the most important causative agents of periodontitis and halitosis. P. gingivalis 2561 was incubated with or without phytoncide extracted from Hinoki (Chamaecyparis obtusa Sieb. et Zucc.; Japanese cypress) and then changes were observed in its cell viability, antibiotic sensitivity, morphology, and biochemical/molecular biological pattern. The results were as follows: 1. The phytoncide appeared to have a strong antibacterial effect on P. gingivalis. MIC of phytoncide for the bacterium was determined to be 0.008%. The antibacterial effect was attributed to bactericidal activity against P. gingivalis. It almost completely suppressed the bacterial cell viability (>99.9%) at the concentration of 0.01%, which is the MBC for the bacterium. 2. The phytoncide failed to enhance the bacterial susceptibility to ampicillin, cefotaxime, penicillin, and tetracycline but did increase the susceptibility to amoxicillin. 3. Numbers of electron dense granules, ghost cell, and vesicles increased with increasing concentration of the phytoncide, 4. RT-PCR analysis revealed that expression of superoxide dismutase was increased in the bacterium incubated with the phytoncide. 5. No distinct difference in protein profile between the bacterium incubated with or without the phytoncide was observed as determined by SDS-PAGE and immunoblot. Overall results suggest that the phytoncide is a strong antibacterial agent that has a bactericidal action against P. gingivalis. The phytoncide does not seem to affect much the profile of the major outer membrane proteins but interferes with antioxidant activity of the bacterium. Along with this, yet unknown mechanism may cause changes in cell morphology and eventually cell death.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.24 no.1
• /
• pp.128-138
• /
• 2019

Effects of feeding type and food resource availability on community structure of mollusks inhabiting hard-bottom subtidal areas were investigated. By following guidance from several references, mollusks observed in this study were divided into 5 groups according to feeding type - 1) grazing, 2) filter feeding, 3) deposit feeding, 4) omnivorous and 5) predation. The results showed that both grazing and filter feeders were the most numerous, explaining grazing type in the East Sea accounting for 47.9%, 32.6% in the South Sea and 29.6% for filter feeding, and filter feeding as a dominant feeding type in Yellow Sea accounting for 42.3%. Results of this study showed distinctive difference in community structure depending on mechanism of feeding type and geographical areas where sampling took place. With the results, attempts were made to understand whether community structure could be affected by feeding type or feeding availability and found out that community structure depended heavily on food resource availability. In the East Sea where marine algal density was high, the algal community in the forms of thick-leathery and sheet often occurred in water column with high transparency which provides proper environment for growth. In the South Sea where grazing and filter feeding types were predominated similarly, the algal density was high, but had the relative highest phytoplankton density. Whereas in the Yellow Sea showing the lowest algal biomass compared to the one in the East and the South Sea, and phytoplankton density was similar to those. It might be a adequate environment for filter feeders than grazers. This study concluded that community structure of mollusks showing high abundance was present where food resource availability with types and quantity was high.

• Journal of the Daesoon Academy of Sciences
• /
• v.48
• /
• pp.375-406
• /
• 2024

This study aims to define the meaning of 'Sangsaeng (mutual beneficence)' within the context of 'Sangsaeng ecological theory,' a form of discourse of that has emerged from Daesoon Jinrihoe's perspective on ecology. Sangsaeng ecological theory applies the concept of interdependence to ecology in order to explain how Sangsaeng, which is commonly used as an ethical system for humans, can be applied to the realm of ecology such that it extends its scope of application to include non-human beings. Interdependence, when applied to ecology, is formed via relationships between individuals. Such relationships can be positive, negative, or neutral, and the type of interdependence that emerges can be competitive, predatory, parasitc, and symbiotic. Even if the relationship between individuals ends negatively, it can still exert a positive effect on the ecosystem. Consequently, all of these produce a type of 'dependence'. However, relationships that end negatively can generate grievances, and from the perspective of Sangsaeng ethics, this type of interdependence is to be avoided. Therefore, by way of contrast, ecological Sangsaeng may include both relationships of positive interdependence and relationships of predation, parasitism, and competition in so far as there no grievances. Ecological theory requires a perspective that enables an understand of the relationship between nature and humans in an integrated way that does not separate them. One view of universe, known as Cheonji-saengin-yongin (Heaven and Earth give produce humans make use of them) provides insights into the relationship between the universe and humans and nature and humans from an interdependent perspective. Heaven and Earth take humans as the basis of their existence, and only after humans discover the law of nature and the sacredness behind it can a deep interdependence between Heaven and Earth and humans and nature and humans be established. However, as modern humans emerge, the interdependence between Heaven and Earth and humans collapses as they destroy nature and lower the authority of Shindo (divine order). Haewon Sangsaeng (the resolution of grievances for mutual beneficence) and Boeun Sangsaeng (the reciprocation of favors for mutual beneficence) is the solution to reestablish the interdependence that has been disconnected between Heaven and Earth and humans and nature and humans. The practice of Haewon Sangsaeng through Gongbu rituals is the way to restore interdependence between nature and humans. The process of humans achieving Dotong (mastery of the Dao) through religious practices is the practice of Boeun Sangsaeng, and humans will be reborn into Injon (Human Nobility or 'divine humans') with ecological nature and enjoy an eternal interdependent relationship with nature. In summary, Sangsaeng in the context of Sangsaeng ecological theory is the idea and practice of allowing nature and humans to restore their interdependence and live on eternally.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.12 no.3
• /
• pp.125-132
• /
• 2007

We estimated the distribution of predator-prey interaction strengths for 12 species of herbivores (including amphipods, isopods, gastropods, and sea urchins) and made a regression model that may be applicable to other species. Laboratory experiments were used to determine per capita grazing rate (PCGR; g seaweeds/individual/day). Relationship between the biomass of individual grazers and fourth-root transformed PCGR was fitted to power curve ($y=0.2310x^{0.3290}$, r=0.8864). This finding supported that the grazing efficiency was not even as individual grazers increase in size (biomass). Therefore, the biomass-normalized PCGR was estimated and revealed that smaller size herbivores were more effective grazers. Grazing impact considering density of each taxon was calculated. The sea hare Aplysia kurodai had greatest grazing impact on the seaweed bed and the sea urchin Strongylocentrotus nudus and S. intermedius were ranked in descending order of the impact. The amount of seaweed grazed by the amphipod Elasmopus sp. (>4,000 $ind./m^2$) and Jassa falcata (>2,000 $ind./m^2$) were 3.435 and $1.697mg/m^2/day$ respectively. The combined grazing amount of herbivores was $5,045mg/m^2/day$ in the seaweed bed. Although sea hare and sea urchin had strong impacts on seaweeds, the effects of dense, smaller species could not be seen as negligible. Surprisingly, the calculated grazing potential of sea urchins with a mean density of 3 $ind./m^2$ exceeded the mean production of seaweed cultured in domestic coastal waters in Korea (ca., 5 ton/ha). Small crustaceans were also expected to consume up to 16% of the seaweed production if their densities were rising under weak predation conditions. Considering that the population density of herbivores are strongly controlled by fish, human interference like overfishing may have strong negative effects on persistence of seaweeds communities.