• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.276-288
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• 2013

The present study investigates the effects of elevated soil nitrogen on growth and decomposition of Oryza sativa shoots. The plants were cultivated in greenhouse until leaf senescence and the total biomass of the plant increased 1.9 times at nitrogen addition plot. Total C and N content in shoot increased; however, lignin, C/N, and lignin/N levels decreased in the N-treated soil. The shoot litters collected from the control and N-treated soil were tested for decay and microbial biomass, $CO_2$ evolution, and enzyme activities during decomposition on the control and N-treated soil at $25^{\circ}C$ microcosm. The remaining mass of the shoot litter was approximately 6% higher in the litter collected from the control soil (53.0%) than the litter collected from high N-treated soil (47.1%). However, the high N-containing litter exhibited faster decay in the control soil than in the N-treated soil. The litter containing high N, low C/N, and low lignin/N showed a higher decomposition rate than that of low quality litter. The N-addition showed decreased microbial biomass C and dehydrogenase activity in soil; however, it exhibited high microbial biomass N and urease activity in soil. When the high N-containing litter decays on the N-treated soil, the microbial biomass C increased rapidly at the initial phase of decomposition and decreased thereafter, and dehydrogenase activity was less that of other treatment; however, there was no effect on the microbial biomass N. The urease in the decomposing litter was highest during the early decomposition stage and dramatically decreased thereafter. The present findings suggested that the N-addition increased N content in litter, but inhibited the decomposition process of above-ground biomass in terrestrial ecosystems.

• The Korean Journal of Ecology
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• v.24 no.3
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• pp.157-168
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• 2001

Herbicides have been used to control weeds for decades. If detoxification upon exposure to herbicides requires considerable amounts of energy, it could affect the pattern of resource allocation to growth and reproduction of crops. We examined the effects of three levels of a herbicide (Control, Low, and High) on germination, growth and reproductive characters of Glycine max treated twice, i.e., before and after seed germination. Since flowering time of G. max was separated into two groups, flowering time was also considered as a variable in this study. The rate of seed germination tended to be higher at the low level of herbicide compared to other levels. Chlorosis and shape variation of leaves were apparent after the second herbicide treatment, but completely disappeared after six weeks of treatment. The herbicide effects on growth characters were somewhat different between early and late flowering plants, but plants treated with both low and high levels of herbicide reduced their growth compared to those in the control group regardless of flowering time. Plants at the high level of herbicide exhibited the highest growth rate later in the season, suggesting that plants compensated to some extent for reduced growth. However, growth reduction among plants at the high level of herbicide was persistent until the end of growing season. Among plants flowered late in the season, plants in the control level bore a higher number of nodules per plant than those in other levels; such a pattern did not exist among plants flowered early in the season. Plants treated with low and high levels of herbicide produced a lower number of flowers than those in the control. Thus, the herbicide examined affected not only the growth and reproductive characters of non-target crops but also the development and growth of root nodules.

• Korean Journal of Ecology and Environment
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• v.49 no.1
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• pp.31-41
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• 2016

Deutzia paniculata is an endemic species to the Korean Peninsula. Despite of importance for conservation, the population structure and habitat characteristics of D. paniculata have not been determined yet. We analyzed the ecological characteristics of the species based on the literature review and field survey. Field survey was conducted on May to October 2014 during which 11 quadrats of size $15{\times}15m$ were studied in six regions. Each of the quadrats were further divided into $5{\times}5m$ small quadrats and population characteristics were recorded. The population and habitat characteristics were analyzed, including species abundance (density and coverage), demographic attributes (flowering rates and fruiting plants), vegetation (structure, species composition), light availability (transmitted light and canopy openness) and soil characteristics (temperature and humidity). We found that D. paniculata mainly distributed in Gyeongsangdo (including Taebaek in Gangwondo) along a broad elevational range of 290~959 m (mean: 493 m) above sea level. In preferred habitat the species grows within the slope range of $7^{\circ}$ and $35^{\circ}$ with the average of $16^{\circ}$. D. paniculata was generally distributed on talus deposits and low adjacent slopes. The average number of individual plants per small quadrat was 12.5 with the mean density $0.5stems\;m^{-2}$. The vegetative reproduction was frequent in D. paniculata and mean flowering rate was as low as 15%. Altogether 138 taxa were found in whole observation area with the dominant tree species mainly spring ephemerals, such as Cornus controversa (importance value: 25.5%) and Fraxinus rhynchophylla (importance value: 15.8%). Although, C. controversa usually grows on steep slopes and F. rhynchophylla mostly distributed at high-altitudes, however, both species distributed in disturbed environments and among talus deposits. Thus based on our results, we concluded that D. paniculata is a disturbance-prone species, primarily existing in habitats subjected to natural disturbances, such as floods. The species occurs less at anthropogenically disturbed sites, thus there is no apparent threat to the populations and habitat of D. paniculata.

• Korean Journal of Ecology and Environment
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• v.41 no.2
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• pp.188-197
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• 2008

This research was a preliminary case study to determine the levels of total mercury in the tissues of sentinel species (Zacco platypus) and ecological health in relation to habitat characteristics and chemical conditions. We collected fishes in Gap Stream during June$\sim$October 2007 and analyzed the total mercury from five types of tissues such as liver, kidney, gill, vertebrae and muscle of Zaceo platypus using Direct Mercury Analyzer (DMA-80, US EPA Method 7473). Mean concentrations of total [Hg], based on all tissues, was 67.2 and $20.7\;{\mu}g\;kg^{-1}$, in the upstream and downstream site, respectively, indicating 3 times greater level in the upstream. In other words, the levels were higher in the pristine upstream than the downstream influenced by the wastewater disposal plant. Chemical water quality, based on BOD, COD and nutrients (TN, TP) showed that severe degradation occurred in the downstreams than the upstreams. Index of Biological Integrity (IBI) using fish multi-metric model averaged 32, indicating a "good$\sim$fair" condition and varied from 42 (excellent$\sim$good) at S2 to 22 (fair$\sim$poor) at S5 depending on the sites sampled. Qualitative Habitat Evaluation Index (QHEI) in the all sites averaged 142, which was judged as "good" habitat health, but showed a high variation (181 in Site 2 vs. 67 in Site 5). Overall data suggest that health conditions, based on IBI and QHEI, was better in the upstream sites but the mercury bioaccumulation levels in the fish tissues were opposite. We believe that measurements of various parameters are required for a diagnosis of integrative ecosystem health.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.29-45
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• 2017

This study explored spatiotemporal variability of water quality in correspondence with hydro-meteorological factors in the four stations of Euiam Reservoir located in the upstream region of the North-Han River from May 2012 to December 2015. Seasonal effect was apparent in the variation of water temperature, DO, electric conductivity and TSS during the study period. Stratification in the water column was observed in the near dam site every year and vanished between August and October. Increase of nitrogen nutrients was observed when inflowing discharge was low, while phosphorus increase was distinct both during the early season with increase of inflowing discharge and the period of severe draught persistent. Duration persisting high concentration of Chl-a (>$25mg\;m^{-3}$: the eutrophic status criterion, OECD, 1982) was 1~2 months of the whole year in 2014~2015, while it was almost 4 months in 2013. Water quality of Euiam Reservoir appeared to be affected basically by geomorphology and source of pollutants, such as longitudinally linked instream islands and Aggregate Island, inflowing urban stream, and wastewater treatment plant discharge. While inflowing discharge from the dams upstream and outflow pattern causing water level change seem to largely govern the variability of water quality in this particular system. In the process of spatiotemporal water quality change, factors related to climate (e.g. flood, typhoon, abruptly high rainfall, scorching heat of summer), hydrology (amount of flow and water level) might be attributed to water pulse, dilution, backflow, uptake, and sedimentation. This study showed that change of water quality in Euiam Reservoir was very dynamic and suggested that its effect could be delivered to downstream (Cheongpyeong and Paldang Reservoirs) through year-round discharge for hydropower generation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.4
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• pp.307-316
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• 2010

Complex terrain refers to irregular surface properties of the earth that influence gradients in climate, lateral transfer of materials, landscape distribution in soils properties, habitat selection of organisms, and via human preferences, the patterning in development of land use. Complex terrain of mountainous areas represents ca. 20% of the Earth's terrestrial surface; and such regions provide fresh water to at least half of humankind. Most major river systems originate in such terrain, and their resources are often associated with socio-economic competition and political disputes. The goals of the TERRECO-IRTG focus on building a bridge between ecosystem understanding in complex terrain and spatial assessments of ecosystem performance with respect to derived ecosystem services. More specifically, a coordinated assessment framework will be developed from landscape to regional scale applications to quantify trade-offs and will be applied to determine how shifts in climate and land use in complex terrain influence naturally derived ecosystem services. Within the scope of TERRECO, the abiotic and biotic studies of water yield and quality, production and biodiversity, soil processing of materials and trace gas emissions in complex terrain are merged. There is a need to quantitatively understand 1) the ecosystem services derived in regions of complex terrain, 2) the process regulation occurred to maintain those services, and 3) the sensitivities defining thresholds critical in stability of these systems. The TERRECO-IRTG is dedicated to joint study of ecosystems in complex terrain from landscape to regional scales. Our objectives are to reveal the spatial patterns in driving variables of essential ecosystem processes involved in ecosystem services of complex terrain region and hence, to evaluate the resulting ecosystem services, and further to provide new tools for understanding and managing such areas.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.271-283
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• 2006

A systematic water quality survey was conducted in August, 2005 for a drinking water supply reservoir (the Jeolgol reseuoir located in an island), which is at an early stage of impoundment, to investigate the causes of water color deterioration of the reservoir and the clogging of filter beds of a water treatment plant. The reservoir shape was simple and its average depth was 5.5 m, increasing from upreservoir toward the downreservoir end near the dam. Dissolved oxygen (DO) and chloropllyll-a (chi-a) showed a large variation while water temperature had a smaller range. Transparency ranged from 0.6 to 0.9 m (average 0.7 m). The average value of turbidity was 9.3 NTU, ranging from 8.0 ${\sim}$ 12.1 NTU. The transparency and the turbidity appear to be affected by a combination of biological and non-biological factors. The poor transparency was explained by an increase of inorganic colloids and algal bloom in the reservoir. The blockage of the filter bed was attributed to the oversupply of phytoplanktons from the reservoir. The range and the average concentration of chi-a within the reservoir were 31.6 ${\sim}$ 258.9 ${\mu}g\;L^{-1}$, 123.6 ${\mu}g\;L^{-1}$ for the upper layer, and 17.0 ${\sim}$ 37.4 ${\mu}g\;L^{-1}$, 26.5 ${\mu}g\;L^{-1}$ for the bottom layer, respectively. A predominant species contributing the algal bloom was Dinophyceae, Peridinium bipes f. occultatum. The distribution of Peridinium spp. was correlated with chi-a concentrations. The standing crop of phytoplankton was highest in the upreservoir with $8.5\;{\times}\;103\;cells\;mL^{-1}$ and it decreased toward the downresevoir. Synedra of Bacillariophyceae and Microcystis aeruginosa of Cyanophyceae appeared to contribute to the algal bloom, although they are not dominated. It is mostly likely that sloped farmlands located in the watershed of the reservoir caused water quality problems because they may contain a significant amount of the nutrients originated from fertilizers. In addition, the aerators installed in the reservoir and a shortage of the inflowing water may be related to the poor water quality. A long-term monitoring and an integrated management plan for the water quality of the watersheds and the reservoir may be required to improve the water quality of the reservoir.

• Korean Journal of Ecology and Environment
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• v.35 no.2 s.98
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• pp.63-70
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• 2002

Long-term changes of the fish fauna and its community structure from the Jungrang Creek of the Han River system in Seoul were investigeted from 1990 to 2000. Total species occurred during the survey period were 14 species in 6 families, and total individual number was 108,366. Fishes at the Jungrang Creek had not been distributed in the 1980s and 1990 because of heavy water pollution as well as environmental damage in the riparian areas. However, Cyprinus carpio and Carassius auratus in cyprinidae were rehabitated since the early 1990s when the water quality was improved because of foundation of sewage division pipe. Species nombers gradually increased to 6 species in 1996, 9 species in 1998, and 11 species in 2000. Individual numbers rapidly increased to 164 individuals in 1996, 146 individuals in 1998, and 108,094 individuals in 2000. A large number of Cyprinus carpio and Carassius auratus, which are abundantly distributed in the main course of the Han River, were found when they migrate to the upper reaches of the Jungrang Creek for spawning. Mass fish floatings were occurred on the 21st of April and the 11th of June in 2000 due to DO depletion at the lower site (Site 4) of discharging point of Jungrang sewage treatment plant and stagnant spot(Site 3) of dammed pool. Major dominant species were Cyprinus carpio and Carassius auratus (Cyprinidae). Others dominant species were Pseudorasbora lab대 (Cyprinidae) and Silurus asotus (Siluridae). Dominance indices were relatively high (0.79 to 1.00). Species diversity andrichness indices were relatively low (0 to 1.66and 0 to 1.41, respectively). Species diversity and richness indices were slightly higher at the middle reaches (Site 2 and Site 3) than the upper reaches and the mouth of the Jungrang Creek. However, the fish fauna of the Jungrang Creek was very poor and its community structure was very simple.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.288-297
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• 2010

This study was to evaluate the ecological stream health through the Multimetric Fish Assessment Index (MFAI) along with fish fauna analysis based on the tolerance and trophic guilds at Miho stream in 2008 and 2009. Also, we analysed total mercury concentration in fish tissues to examine heavy metal contamination. Total sampled fish were 40 species and 2,557 individuals and Zacco platypus was the most dominant with 35% relative abundance. It was sampled with 11.4% RA for Korean endemic species (10 species 291 individuals) less than average RA 39.3% for the Geum river watersheds. According to the tolarance guild analysis, tolerant species was more dominant with 58.9% RA (15 species, 1,507 individuals) than sensitive species with 6.6% RA. Trophic guild analysis also suggested that omnivores were more dominant (60.5% RA) than insectivores (31.5% RA). Riffle-benthic species was also sampled with 7.7% RA. Ecological stream health based on the MFAI were averaged 25.3 (n=3) with fair-poor condition in 2008 and also 26.3 (n=3) with fair condition in 2009, just slightly increased than 2008. Qualitative habitat evaluation index was averaged 134 (n=3) with fair condition but most of sites had sediment accumulation that reflected substrate degradations proceeding. From the result of total mercury accumulation in fish tissues, kidney and liver tissues showed the highest but the lowest for gill tissues. Overall mercury concentration were not exceed the national standards by Korean Federation of Drug and Administration (KFDA). Consequently, our result could correspond with the characteristics of Miho stream where point sources such industrial complexes and wastewater treatment plant widely distributed around the stream along the gradient of up and downstream.

• Proceedings of the Ginseng society Conference
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• 1978.09a
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• pp.149-157
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• 1978

Ginseng is the English common name for the species in the genus Panax. This article gives a broad botanical review including the morphological characteristics, ecological amplitude, and the ethnobotanical aspect of the genus Panax. The species of Panax are adapted for life in rich loose soil of partially shaded forest floor with the deciduous trees such as linden, oak, maple, ash, alder, birch, beech, hickory, etc. forming the canopy. Like their associated trees, all ginsengs are deciduous. They require annual climatic changes, plenty of water in summer, and a period of dormancy in winter. The plant body of ginseng consists of an underground rhizome and an aerial shoot. The rhizome has a terminal bud, prominent leafscars and a fleshy root in some species. It is perennial. The aerial shoot is herbaceous and annual. It consists of a single slender stem with a whorl of digitately compound leaves and a terminal umbel bearing fleshy red fruits after flowering. The yearly cycle of death and renascence of the aerial shoot is a natural phenomenon in ginseng. The species of Panax occur in eastern North America and eastern Asia, including the eastern portion of the Himalayan region. Such a bicentric generic distributional pattern indicates a close floristic relationship of the eastern sides of two great continental masses in the northern hemisphere. It is well documented that genera with this type of disjunct distribution are of great antiquity. Many of them have fossil remains in Tertiary deposits. In this respect, the species of Panax may be regarded as living fossils. The distribution of the species, and the center of morphological diversification are explained with maps and other illustrations. Chemical constituents confirm the conclusion derived from morphological characters that eastern Asia is the center of species concentration of Panax. In eastern North America two species occur between longitude $70^{\circ}-97^{\circ}$ Wand latitude $34^{\circ}-47^{\circ}$ N. In eastern Asia the range of the genus extends from longitude $85^{\circ}$ E in Nepal to $140^{\circ}$ E in Japan, and from latitude $22^{\circ}$ N in the hills of Tonkin of North Vietnam to $48^{\circ}$ N in eastern Siberia. The species in eastern North America all have fleshy roots, and many of the species in eastern Asia have creeping stolons with enlarged nodes or stout horizontal rhizomes as storage organs in place of fleshy roots. People living in close harmony with nature in the homeland of various species of Panax have used the stout rhizomes or the fleshy roots of different wild forms of ginseng for medicine since time immemorial. Those who live in the center morphological diversity are specific both in the application of names for the identification of species in their communication and in the use of different roots as remedies to relieve pain, to cure diseases, or to correct physiological disorders. Now, natural resources of wild plants with medicinal virtue are extremely limited. In order to meet the market demand, three species have been intensively cultivated in limited areas. These species are American ginseng (P. quinquefolius) in northeastern United States, ginseng (P. ginseng) in northeastern Asia, particularly in Korea, and Sanchi (P. wangianus) in southwestern China, especially in Yunnan. At present hybridization and selection for better quality, higher yield, and more effective chemical contents have not received due attention in ginseng culture. Proper steps in this direction should be taken immediately, so that our generation may create a richer legacy to hand down to the future. Meanwhile, all wild plants of all species in all lands should be declared as endangered taxa, and they should be protected from further uprooting so that a. fuller gene pool may be conserved for the. genus Panax.