• Korean Journal of Environment and Ecology
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• v.12 no.1
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• pp.1-8
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• 1998

To investigate the structure and the conservation strategy of Taxus cuspidata forest at Janggunbong area in Taebaeksan, 18 plots(20m$\times $20m) set up with random sampling method were surveyed. Major woody species growing with Taxus cuspidata were Acer pseudo- sieboldianum, Euonymus macroptera, Prunus padus, Abies nephrolepis. High positive correlations was proved between abies nephrolepis and Pinus doraiensis, Betula ermanii and Magnolia sieboldii, and high negative correlations was proved between Acer pseudo- sieboldianum and Tripterygium regelii, Weigela subsessilis and Acer tschonoskii var. rubripes, Taxus cuspidata and Acer tschonoskii var. rubripes. Species diversity(H') of investigated area was calculated 2.3015(0.9991) and this value was relatively lower than that of other subalpine forest. Taxus cuspidata trees were severely stressed and vigor-lossed and 8.22% of surveyed Tacus cuspidata trees were dead tree. Dead trees were distributed mainly in 20~60cm DBH class and a few seedlings of Taxus cuspidata were observed. To conserve Taxus cuspidata forest at Janggunbong area in Taebaeksan, intensive research, prescription on the decline of Taxus cuspidata and proper forest management were needed.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.724-729
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• 2016

Environmental factors that affect the singing of cicadas have not been studied extensively, especially those affecting the cicadas' singing during the nighttime. Therefore, the objective of this study is to identify the effects of tropical night and light pollution on the cicadas' singing in a downtown area. The study sites were an apartment complex in Seocho-gu, Seoul, and the Chiaksan National Park in Wonju-si. The study subjects were Hyalessa fuscata and Cryptotympana atrata, which are the dominant species in Korea during summer. Cicada songs were recorded 24 hours a day, every day. The recording period was between July and August, lasting 25 days at the Seoul site and 14 days at the Chiaksan National Park. Temperature, precipitation, humidity, and amount of sunshine were selected as the environmental factors that potentially affect the cicadas' singing. Statistical analyses included correlations of meteorological factors with the cicadas' singing per hour, per 24 hours, and at nighttime (21:00~04:00). The results showed that: 1) H. fuscata began singing during the dawn hours, and the singing increased in intensity early in the morning. C. atrata's singing reached its peak in the morning and afternoon, ceased during sunset hours, thereby exhibiting a difference in the singing pattern of the two species. 2) The frequency of singing by H. fuscata decreased when C. atrata began to sing intensively in numbers, thereby exhibiting interspecific influence. 3) The results of the correlation analysis between meteorological factors and the singing of H. fuscata and C. atrata showed that both species tended to sing more when the temperature was higher and sang less on rainy days. 4) When limited to nighttime only, C. atrata showed a tendency of singing when the nighttime temperature was high ($24-30^{\circ}C$, average $27^{\circ}C$), whereas H. fuscata did not show a correlation with meteorological factors. However, since H. fuscata sang during the night in areas with artificial lighting, it was concluded that its singing was due to light pollution.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.182-196
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• 2014

In this study, for the forest vegetation classification and the quantitative analysis of the Picea jezoensis and Abies hollophylla stand, the type classification of the vegetation structure was performed with Z-M phytosociological method, and as a result, it was classified into the Picea jenoensis community and the Abies holophylla community in the community unity. The Picea jezoensis community was subdivided into the Rosa koreana group and the Acer ukurunduense group in the group unity and the Abies holophylla community was subdivided into the Acer mandshuricum group and the Lindera obtusiloba group. In the results of estimating the importance value based on the classified vegetation unity, it was deemed that the dominance of the Picea jezoensis would be continued for a while as the importance value from the tree layers of vegetation unity 1 and 2 represented relatively high with 30.73% and 20.25%. In addition, in the results of analyzing the species diversity to estimate the maturity of the community, the species diversity index of the vegetation unity 4 was the lowest with 0.6976 and that of vegetation unity 2 was the highest with 1.1256. As in the similarity between the communities, the vegetation unit 1 and 4 and the vegetation unit 2 and 4 represented low with 0.2880 and 0.3626, respectively, and the similarity between the vegetation unit 1 and 2 and between 2 and 4 represented 0.5411 and 0.5041, respectively, it was deemed that they were the communities that the difference in the composition species between the communities was not big. In the results of analyzing the Chi-square matrix and the catalog of constellations for the interspecific, they were divided mainly into two types, and type 1 plant species were mostly differential species and the characteristic species, which appeared in the Picea jezoensis community classified phytosociologically, and type II plant species were mostly the species appearing in the Abies holophylla community growing in the relatively damp places. Such results is deemed that the positive (+) correlation is recognized among the species, of which growing environments are similar, and the negative (-) correlation .represents among the species, of which preferential environments are different.

• The Korean Journal of Ecology
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• v.24 no.5
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• pp.289-296
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• 2001

Community structure of the Salix and physico-chemical properties of sediment were studied from July to September, 2000 in Nam-River watershed for the purpose of inquiring niche breadth, niche overlap and the environmental factors affecting the distribution of Salix species. Among eleven Salix species, the dominant species was Salix koreensis, while the rests were such order as S. nipponica, S. gracilistyla and S. glandulosa by the relative abundance based on the basal area. Mean values and the ranges of sediment properties such as pH, conductivity, water content, organic matter, total nitrogen, available phosphorus, clay, silt and sand were 5.3∼6.3, 14∼351 μmho/cm, 0.1∼3.4%, 0.5∼7.3%, 0.01∼0.2%, 0.1∼0.4 mg/100 g, 1.7∼22.0%, 0.2∼40.8%, 39.7∼98.0%, respectively. Altitude and annual mean temperature of each site were 20∼620 m and 9.3∼13.0℃, respectively. Niche breadth was estimated by considering the differences of the soil texture as the differences of state of source. S. glandulosa was the broadest at the level of 0.77, while the rests were such order as S. koreensis, S. nipponica were 0.69, 0.54, respectively. The niche overlap showing the level of interspecific competition was the largest as 0.94 between S. purpurea var. japonica and S. purpurea var multinervis, while S. graciliglans and S. purpurea var. japonica 0.92, S. graciliglans and S. purpurea var. multinervis 0.87, respectively. According to the analysis of the correlation between eleven species of Salix and eleven environmental factors, S. gracilistyla showed the negative correlation with conductivity, water content, total nitrogen, clay, silt and annual mean temperature, and showed the positive correlation with total nitrogen, sand and altitude. S. graciliglans showed the negative correlation with conductivity, water content, organic matter, clay, silt and annual mean temperature, and showed the positive correlation with total nitrogen, sand and altitude. S. nipponica showed the negative correlation with sand and altitude, and showed the positive correlation with water content, total nitrogen, clay, silt and annual mean temperature. S. nipponica showed the opposite results of S. gracilistyla. Soil texture, total nitrogen, water content, altitude and annual mean temperature were affecting the distribution of Salix species in Nam-River watershed.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.698-708
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• 2018

The purpose of this study was to investigate differences in the breeding call characteristics of cicada species found in urban and forest areas in the central region of Korea by examining the interspecific effects and environmental factors affecting the breeding calls and breeding call patterns. The selected research sites were Gyungnam Apartment in Bangbae-dong, Seoul for the urban area and Chiak Mountain National Park in Wonju for the forest area. The research method for both sites was to record cicada breeding calls for 24 hours with a recorder installed at the site and analyze the results. Data from the Korea Meteorological Administration were used for environmental factors. The research period was from June 19, 2017 to September 30, 2017. As a result of the study, there were differences in the emergence of species between the two research sites: while Platypleura kaempferi, Hyalessa fuscata, Meimuna opalifera, Graptopsaltria nigrofuscata, and Suisha coreana were observed at both sites, Cryptotympana atrata was observed in the urban area and Leptosemia takanonis in the forest area only. The emergence periods of cicadas at the two sites were also different. The activities of P. kaempferi and L. takanonis were noticeable in the forest area. In the urban area, however, L. takanonis was not observed and the duration of activity of P. kaempferi was short. In the urban area, C. atrata appeared and sang for a long period; H. fuscata, M. opalifera, and G. nigrofuscata appeared earlier than in the forest area. S. coreana appeared earlier in the forest area than in the urban area. According to the daily call cycle analysis, even cospecific cicada showed a wide variation in their daily cycle depending on the region and the interspecific effects between different cicadas, and the environmental differences between the urban and forest areas affected the calls of cicadas. The results of correlation analysis between each cicada breeding calls and environmental factors of each site showed positive correlation with average temperature of most cicadas except P. kaempferi and C. atrata. The same species of each site showed positive correlations with more diverse weather factors such as solar irradiance. Logistic regression analysis showed that cicadas with overlapping calling times had significant effects on each other's breeding calls. C. atrata, which appeared only in the urban area, had a positive effect on the calling frequency of H. fuscata, M. opalifera, and G. nigrofuscata, which called in the same period. Additionally, L. takanonis, which appeared only in the forest area, and P. kaempferi had a positive effect on each other, and M. opalifera had a positive effect on the calling frequency of H. fuscata and G. nigrofuscata in the forest area. For the environmental factors, the calling frequency of cicadas was affected by the average temperatures of the urban and forest areas, and cicadas that appeared in the forest area were also affected by the amount of solar radiation. According to the results of statistical analysis, urban cicadas with similar activity periods are influenced by species, especially with respect to urban dominant species, C. atrata. Forest cicadas were influenced by species, mainly M. opalifera, which is a forest dominant species. The results of the meteorological impact analysis were similar to those of the correlation analysis, and were influenced mainly by the temperature, and the influence of the insolation was more increased in the forests.

• Korean Journal of Weed Science
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• v.3 no.1
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• pp.39-49
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• 1983

By use of three paddy rice lines as the near-isogenic in plant type (Broom, Open, and Spread type in tillering angle), the interspecific competition patterns of rice plants with three important weed species (Cyperus serotinus, Eleocharis kuroguwai, and Potamogeton distinctus) under the three densities of weed standing (0.25 and 50 percent of the rice plants), were observed. Under the experimented conditions, paddy yields were varied more significantly with weed competition descriptions than with plant types of paddy rice. And spread typed rice was more competitive to the detected weed species, however, the broom and spread typed rice were to Potamogeton SP, among others. The result of the clustering analysis of crop-weed competition patterns, estimated by 1-Q mode correlation coefficients, indicated that the first-order component affecting the competition patterns of crop-weed was rather the plant types of rice than either weed species or weed standing densities.

• Journal of Life Science
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• v.12 no.6
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• pp.821-834
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• 2002

In order to measure the inter- and intraspecific genetic divergences within the genus Alexandrium, the variations within the internal transcribed spacer (ITS1 and ITS2) regions and 5.85 ribosomal RNA gene of eight Alexandrium species were examined for 33 strains from diverse geographical locations by direct sequencing. Five isolates of A. tamarense (AT-2, AT-6, AT-10, AT-A and AT-B) from Jinhae Bay, Korea were found to be completely identical to a Japanese strain OFX151-A. The length of the amplified ITSI-5.85-ITS2 region varied from 481 nucleotides (in A. margalefi) to 528 nucleotides (in A. affine CU1-1). ITS1 and ITS2 nucleotide lengths were negatively correlated, whereas a positive correlation was found between their G＋C content. The degree of sequence divergence ranged from 0.3% (1 bp) to a maximum of 53% (305 Up). Pairwise sequence comparisons revealed a small degree of divergence between A. tamarense and A. Pundyense isolates (1.2 - 2.3% ＝ 6-12 bp), but a high degree of divergence between A. tamarense and A. catenella (19.8% ＝ 102 bp), and between A. catenella and A. Pundyense (19.7%). Although most nodes were weakly supported by bootstrap values, some types tend to form independent molecular groups. A. catenella isolates also formed an independent molecular sub-group, with relaticula strong bootstrap values (94% or 85% and 79% or 98%, respectively in PAUP and NJ trees). Interestingly, A. cohorticula and A. frateculus always clustered within the same sub-group, this result being supported by strong bootstrap values. Our results indicate that the ITS regions provide useful informations on hierarchical population genetic structure and a high phylogenetic resolution in intraspecific and interspecific Alexandrium population.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.6
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• pp.640-649
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• 1996

This study was conducted to obtain fundamental informations necessary to breed forage sorghum at the field of the Livestock Experiment Station from 1988 to 1991. Heterosis was discussed in crossing groups of sorghum X sweet sorghum, sorghum X sudangrass, and (sorghum X sweet sorghum) X sudangrass. Leaf dry weight and stalk dry weight per plant in sweet sorghum crossing group, stalk dry weight per plant in sorghum X sudangrass crosses and leaf area per plant in three way crosses showed the greatest Heterobeltiosis(H$_{b}$). There were significant differences in plant height, stalk diameter and number of tillers per plant between sweet sorghum and sudangrass crosses. H$_{b}$ for total dry matter yield in sweet sorghum and sudangrass crosses were 45.9% and 95.0%, respectively. On the other hand, heterosis for total dry matter yield in three way crosses was smaller than H$_{b}$. There was no relationship between dry matter yield of parents and heterosis of hybrids in sweetsorghum crosses. However, positive correlations between parental yield and hybrid yields were observed. In sudangrass crosses, there were negative correlations between parental yields and heterosis of hybrids. However, no correlation between parental yields and hybrid yields were observed. In three way crosses, there were no correlations between parental yields and heterosis, and between parental yields and hybrids yields.

• Journal of Plant Biology
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• v.13 no.1
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• pp.33-46
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• 1970

Pinus densiflora stands are common secondary forest communities on infertile soils in Korea. The stands are results of long severe past biotic pressure such as cutting, burning and grazing. These could be regarded as biotic climax in Korea. Because of their prevalent occurrence, relatively simple species and age composition, and their domestic economic importance, study of their distributional patterns may give some basic knowledge for better utilization of land resources in Korea. To detect distributional patterns and interspecific associations ten pine stands, each of which was homogenious with respect to topography and physiognomy, were subjectively selected from pine stands in Kyunggi Province near Seoul in 1969 and were made object of this study. Four contiguous systematic samples of count for trees, shrubs and seedlings from belt transects were collected from homogeneous areas within ten natural pine stands. The belt transect was 64m or 128m in length, and 1m, 2m or 4m in width. Basic units within the transect ranged from 64 to 256. The data from the contiguous transects were analysed in terms of multiple split-plot experiment. Departure from randomness of stem distribution, i.e., pattern, was tested in terms of variance mean ratio. For the detection of association between species, correlation coefficient was calculated for different block sizes. The values of ${\gamma}$ were tested by the usual t-test. Fine trees within one of the stands showed significant regular distribution through out the blocks. Within other eight stands pines were randomly distributed at basic unit with 4$\times$4m, 2$\times$2m, 2$\times$1m and 1$\times$1m. One significantly clumped distribution at basic unit 2$\times$2m, however, was observed from one of the pine stands. These randomly distributed groups were themselves significantly regularly distributed throughout the blocks for four pine stands. For the other four pine stands, in addition to the random distribution at the basie unit(the primary random group), randomly distributed groups with 32m dimension(the secondary random groups) were also observed. Both the primary and the secondary random groups were significantly regularly distributed at the rest of blocks. Pine seedlings were not distributed randomly thoughout the blocks. Within three of the ten stands they were contagiously distributed. Important shrub species underneath pines such as Querus serrata, Q. acutissima, Leapedeza intermedia, Rhododendron Yedoense var. poukhanenae, Juniperus utilis, Rhododendron mucronulatum var. ciliatum shnwed consistently similar distributional pattern with the pine at each stand. The shrub species pairs; Rhododendron Yedoense var. poukhanenae/Quercus serrata, Rhododendron mucronulatum var. ciliatum/Lespedeza intermedia were significantly negatively associated from 1m to 4m dimensional block sizes but became significantly positively associated from 8m sized blocks on. On the other hand the shrub species pairs; Lespedeza intermedia/Robinia Pseudoacacia, and Lespedeza bicolor var, japonica/Lespedeza intermedia were also significnalty negatively associated from 1m to 8m sized blocks but became significantly positively associated from 16m sized blocks on. The associational pattern between Rhododendron mucronul tun var. poukhanenae and Lespedeza intermedia was not consistent throughout the stands. In some stands negative associations were observed throughout the blocks except NS 32. From these observatons micro-edaphic variation within the pine stands seems not to be great enough to cause distributinal difference of pine trees within the ten pine stands. Among each species and pine seedings, however, the edaphic variation within the pine stands may be great enought to cause distributional variation.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.386-393
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• 1994

To investigate taxonomical relationships of Fusarium species, $esterase-{\alpha},\;-{\beta}$, acid phosphatase, malate dehydrogenase, peroxidase and polygalacturonase were extracted and the isozyme patterns were compared by using polyacrylamide gel electrophoretic analysis. Only polygalacturonase was monozyme and the other enzymes showed little differences in banding patterns. Genetic similarities based on the isozyme banding patterns were as follows: the interspecific similarity between F. subglutinans and F. moniliforme in Liseola showed the closest relationship of 74.3% of all species studies. And the similarity between section Elegans and section Liseola was 45.4%. F. napiforme and F. nygamai showed the similarity of 64.7%, similar to the correlation between species in the same section. The similarity of these two species to Liseola and Elegans showed 55.2% and 45.4%, being revealed that they would be closer to Liseola than Elegans. However, these results were similar to those of any other sections. Therefore it suggested that these 2 species should be in a different section from any other sections. And F. graminearum showed the similarity of 28.2% to the other 6 species.