• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.4
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• pp.201-209
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• 2007

Line transect sampling in a sighting survey is one of most widely used methods for assessing animal abundance. This study applied distance data, collected from three sighting surveys using line transects for finless porpoise that were conducted in 2004 and 2005 off the west coast of Korea, to four models (hazard-rate, uniform, half-normal and exponential) that can use a variety of detection functions, g (x). The hazard-rate model, a derived model for the detection function, should have a shoulder condition chosen using the AIC (Akaike Information Criterion), as the most suitable model. However, it did not describe a shoulder shape for the value of g(x) near the track tine and underestimated g (x), just as the exponential model did. The hazard-rate model showed a bias toward overestimating the densities of finless porpoises with a higher coefficient of variation (CV) than the other models did. The uniform model underestimated the densities of finless porpoise but had the lowest CV. The half-normal model described a detection function with a shape similar to that of the uniform model. The half-normal model was robust for finless porpoise data and should be able to avoid density underestimation. The estimated abundance of finless porpoise was 3,602 individuals (95% CI=1,251-10,371) inshore in 2005 and 33,045 individuals (95% CI=24,274-44,985) offshore in 2004.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.1
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• pp.45-57
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• 2015

Soil moisture is critical for understanding the spatial-temporal variability of hydrologic processes. The distributions of soil moisture have been explored along transect line in hillslope hydrology. In this study, we measured several soil moistures along transect lines during ten-month period at a hillslope located the Cheong-mi catchment. The soil moisture properties were expressed by simple statistical methods (average, standard deviation, and recession slope) and analyzed in terms of soil depths and transects from the seasonal context. Supplementary studies were also performed about the effect of location, topography and soil texture to the soil moisture responses. The spatial distributions of average soil moisture at deep soil layer were distinguished from those at near surface due to the possibility of expected factors such as subsurface lateral flow from upslope, preferential flow and existence of bedrock. The soil moistures in combined line affected from significant contribution of upper transect line were relatively higher(wetter), low variability compared to those in other transect lines and seemed to be under stabilization process. There are confirmed heterogeneity of soil moisture variation related with preferential flow and significant influence of soil texture for soil moisture properties in upslope.

• Korean Journal of Environmental Biology
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• v.37 no.1
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• pp.82-87
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• 2019

Global warming has a significant impact on diverse ecosystems including agroecosystem through; changing of phenology, physiology and distribution. Monitoring of biological responses emanating from global warming is required to understand the challenges of biological diversity conservation posed by climate change. The Korean government selected four butterfly species as indicators of climate change in agroecosystem: Papilio xuthus, Pieris rapae, Colias erate, and Eurema mandarina. The aim of this study was to investigate the different monitoring methods of the butterflies in Korea and suggest a suitable monitoring method to track the population trends of butterflies in the agroecosystem. Butterfly monitoring was conducted in eight sites throughout Korea from April to October, 2018 using three survey methods: point census at rice paddy area, point census at the border between rice paddy and hill and line transect along the rice paddy and hill. Each method took approximately 30 min. to count the butterflies. A total of 4,691 butterflies and 92 species were counted: The most dominant species was Pieris rapae with a total count of 1,205 individuals followed by Polygonia c-aureum, Zizeeria maha, Colias erate, Cupido argiades and Papilio xuthus. Among the three census methods, the total number of species and individuals when using line transect method was statistically higher than in the other methods. However, the numbers of the four butterflies indicators showed no difference throughout three census methods. Based on the number of species and the total individuals butterflies in agroecosystem, we advocate for the application of line transect method as it can find more butterflies in agroecosystem. In addition, we advised for the implementation of education programs on the line transect method in butterfly identification to participants of the national monitoring program.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.368-378
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• 1983

The community structure of intertidal benthic marine algae were studied seasonally at Odongdo, southern coast of Korea, from June 1982 to May 1983. Algal coverage in $50{\times}50\;cm$ quadrat were recorded for each species by line transect method. The vertical zonation investigated by line transects is recognized into three groups : Upper, middle, and lower zones. The representative species are Gelidium divaricatum, Enteromorpha linza, Porphyra yezoensis, Scytosiphon lomentaria, Blidingia nana, Ectocarpus confervoides in the upper, Ulva pertusa, Chondria crassicaulis in the middle, and Sargassum sagamianum, S. thunbergii, Undaria pinnatifida, Gelidium amansii and various other red algae in the lower zone. The number of algal species and coverage were generally highest in April and lowest in August. Species which appear dominant at least once a year were all of the spring type and the others were autumn type. According to the cluster analysis by similarity index community coefficient(SICC) among 5 transects, the algal communities are divided into two groups, i. e. open-sea group and inland-sea group.

• Korean Journal of Environment and Ecology
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• v.10 no.2
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• pp.171-183
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• 1997

Diversity, abundance, species distributions and distributions of two strategists (specialist and geceralist) of butterflies were investigated monthly from June 1996 to Oct. 1996 by line transect method in the Chunbul-dong valley from park gate to Yangpok Sanjang. The butterfly faunas of the eight regions in Kwangwon province, Gyunggi proavince and Pusan were also studied by the same method to assess diversity and abundance of butterfly community in the study region. The 18 butterfly species in 7 families were found in this study and the 48 butterfly species in 7 families were distributed in the study area from thes study and the other researches. The 30 butterfly species reported in the other studies were not found in this study and Kaniska canace L. of them would be to decrease in density. In the study area, the common species were Artogeia melete M., Neptis sappho P. and Libythea celtis F.. The representative Korean common butterflies such as Artogeia rapae L., Colias erate E. and Papillio xuthus L. were rare. The PCA(Principal Component Analysis) ordinations indicate that habitat disturbance by human would be major factor for butterfly community and species distribution. Difference was not found in diversity according to habitat disturbance. Abundance, however, was higher in the disturbed region than the undisturbed region. Compared with the other regions, abundance was greatly lower and diversity was slightly lower than that of the other regions. Two strategists exhibited different distribution patterns. Generalists were found more commonly in the disturbed region and widely distributed in both of the disturbed region and the undisturbed region than specialists.

• Korean Journal of Plant Resources
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• v.25 no.5
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• pp.550-560
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• 2012

The aim of this study is to research spatial diffusion, a condition for spread of Ailanthus altissima, and conduct flora analysis to provide useful information for management of it. Three research spots where the community dominance value was found to be high and habitat was homogeneous according to a 2010 in-depth species study were selected, and census was conducted using a line-transect method. The diffusion area included 1,435 $m^2$ in Yangpyeong, 1,118 $m^2$ in Gimcheon and 760 $m^2$ in Sancheong, in order of increasing size, and a total of 510 trees were found to be randomly diffused in space. An average of 83.2% of Ailanthus altissima were found to be included in DBH classes I (1.0-3.4 cm) and II (3.5-6.4 cm), showing that young trees were dominant in Ailanthus altissima communities and there was an age diffusion pattern according to degree of disturbance in habitats. A total of 41 families 75 genera and 91 species of flora made up the list, and Therophytes were most widely found in all of the three areas. This shows that habitats in these areas have recently been disturbed. It was evaluated that elimination of roadside population and mountainous area population was necessary to prevent diffusion of Ailanthus altissima.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.642-649
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• 2009

Line transect data from sighting surveys conducted in the East Sea, Korea in 2000, 2002, 2003, 2005 and 2006 were analysed to estimate densities and numbers of minke whale. The half-normal model was fit to the survey in 2000 and the uniform model was the most fitable to the survey in 2002 and 2006, and the surveys in 2003 and 2005 were fit by the hazard-rate model. The estimated density of minke whale in the survey in 2000 was estimated as 0.026 individuals/$km^2$ (CV=0.409; 95% CI 0.011-0.065) and was higher than the survey in 2002 estimated as 0.018 individuals/$km^2$ (CV=0.329; 95% CI: 0.009-0.034). The estimated density of minke whale in the survey in 2003 was estimated as 0.033 individuals/$km^2$ (95% CI: 0.008-0.139) with the highest CV 0.760. The highest density was estimated in the survey in 2005 with 0.053 individuals/$km^2$ (95% CI: 0.020-0.141). The Lowest CV (0.306) was estimated in the survey in 2006 with 0.025 individuals/$km^2$ (95% CI: 0.014-0.046). A total of 500 bootstrap samples were generated within each stratum. Density, CV and 95% CI of each surveys were increased than analytic results except the survey in 2003. There were no increasing or decreasing annual trends in the density of minke whales observed during the study period. A long-term monitor and survey is needed to assess project minke whale abundance in the East Sea.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.543-551
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• 2000

This study was conducted to understand Pinus densiflora regeneration characteristics from canopy gaps due to disturbance in natural forests located at Mt. Joongwang in Kangwon-do. The line-transect method was adopted to analyze crown architecture of Pinus densiflora. The saplings of Pinus densiflora in the canopy gap showed high adaptation to growth environment at their early regeneration stage, and showed different characteristics in crown architecture. Variation of branching angle in the main branch of Pinus densiflora was small in canopy gap. Primary branch growth showed was high during 4~5 year-old period and slowly low after that period. Average 5 of primary branch were generated from stem in canopy. Average 4 of secondary branch were generated from primary branch in canopy gap. Primary branches generated from the stem were uniformly distributed at all cardinal directions. When canopy gap size is $100{\sim}120m^2$, secondary branches generated from primary branch had mostly high numbers between $S44^{\circ}E$ and $S90^{\circ}W$.

• ALGAE
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• v.22 no.1
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• pp.37-44
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• 2007

In order to understand the impact of the heavy-oil pollution by the 1997 Nakhodka oil spill on the intertidal macroalgal vegetation, we have been monitoring succession in the intertidal flora since 1997 at Oh-ura, Takno, and Imago-Ura Cove, Kasumi in Hyogo Prefecture, northwestern coast of Honshu, Japan. We employed two different monitoring methods: 1) The percent cover of macro-algae (seaweeds) in 1 x 1 m quadrats along 450 m intertidal transects parallel to the shoreline were assessed and recorded by photographic imaging until 2002, and for 30-40 m transects of the most heavily polluted areas in 2004 and 2006; 2) The percent cover of macro-algae in 0.5 x 0.5 m quadrats along a transect line perpendicular to the shore were recorded and all macrophytes within the quadrat were completely removed to record the wet weight of each taxon (1997-2006). Based on the monitoring data, we conclude that the high intertidal zone at Imago-ura, where a large part of the stranded oil accumulated, suffered the heaviest damage and experienced the slowest recovery. In addition, although the original status of macroalgal vegetation before the impact was not well-documented, it appeared that recovery from the damage caused by the oil pollution required four to five years.

• Korean Journal of Environment and Ecology
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• v.4 no.1
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• pp.51-62
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• 1990

This study was to investigate the user's effects on the avifauna in Sokri Mountain National Park. The survey was carried over 4 districts which were divided with main trail(valley, ridge), subtrail(ridge), un-used trail (valley) by line transect method from December 1989 to October 1990. The observed birds were 36 species and 570 individuals, these consist of 23 species for residents. 7 species for summer visitor. 2 species for winter visitor, 4 species for passage migrant. The average density of birds was 2.35 ea/ha., and main dominant species were Parus major minor, Porus palustris hellmayri, Parus varius varius and Sitta europaea amurensis in order. The observed frequency of wild birds was 3.4 times/km in average. No. of species, species diversity and observed frequency of summer and autumn were lower than winter and spring in 4 survey routes. Therefore, from now, in Sokri Mountain National Park manegement, the enjoyment oriented activities will be regulated and control of trail use on main trail are necessary during breeding periods of wild birds protection, especially in summer.