• Korean Journal of Ecology and Environment
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• v.35 no.1 s.97
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• pp.28-35
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• 2002

The effect of physical parameters on water quality was analyzed using monitoring data of 193 agricultural reservoirs. The retention time of reservoirs ($t_d$) ranged between 10 and 140 days, and the ratio of drainage area (DA) to reservoir surface area (SA) was between 10 and 120. Both ratios of DA/SA and total area (TA)/ reservoir storage (ST) in Korean agricultural reservoirs were relatively greater than those in natural lakes in other countries. As retention time was plotted against DA/SA ratio, it was shorter in Korean reservoirs than natural lakes. The semi-logarithmic relationship between TA/SA and t>$t_d$ was $t_d\;=\;42.21(TA/ST)^{-1}$ (n = 50, $R^2\;=\;0.89$). While areal loading of total phosphorus (TP) was below $4\;gTP{\cdot}m^{-2}{\cdot}yr^{-1}$ in general, it exceeded $10\;gTP{\cdot}m^{-2}{\cdot}yr^{-1}$ in reservoirs where DA/SA ratio was greater than 100, which implies that areal loading of TP increases as DA/SA ratio increases. Chl-a concentration was positively related with the mean depth of reservoir, implying the higher Chl-a concentration with deeper the mean depth. Therefore, the deeper reservoir might be advantageous in water quality management perspective if other morphological conditions are similar. The empirical regression equation using physical parameters was also suggested in the estimation of TP concentration in the reservoirs. Combined information presented in this paper might be applicable to the water quality management in agricultural reservoirs.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.89-101
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• 2016

To elucidate occurrence patterns of $C_4$ plants in agroecosystems, we surveyed flora inside fields and embankments in 222 sites in farming lands in summer and fall, 2013. We also observed Kranz anatomy and analyzed carbon stable isotope to classify photosynthesis types. Our study observed total 54 species of $C_4$ plants in 33 genera and 9 families of vascular plants besides cultivated crops occurring in farming fields. The most common species was Portulaca oleracea L. followed by Digitaria ciliaris and Echinochloa crusgalli (L.) P. Beauv. var. crusgalli among the $C_4$ plants. The ratios of $C_3$ and $C_4$ species number to total number of species tended to maintain constant regardless of survey times and habitat types. The proportion of $C_4$ species to the total number of species were more influenced by the number of $C_3$ species than those of other types in the surveyed sites. Sizes of cultivation areas did not affect the proportions of $C_4$ plants. Increasing number of simultaneous weeding methods, especially with cutting method, appeared to decrease the number of $C_3$ plants. On the other hand, as the number of cultivated crops increased, both $C_3$ and $C_4$ plants increased but the proportions of $C_4$ species remained. We interpret our results that proportion of $C_4$ species in agroecosystems, appear to be dependent on the number of $C_3$ species, which in turn, appear to be affected by cultivation methods.

• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.221-230
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• 2022

The spread of invasive alien plants is one of the most important causes of habitat and biodiversity loss. This research was conducted to secure basic data for the control of the invasive alien plant Solidago altissima. The following research objects were examined: the control; one-time mowing in June (1M6); two-time mowing in June and July (2M6M7); one-time mowing in Jun plus one-time Uprooting in July (2M6U7). The length growth in October, when the growth of S. altissima was completed, was in the order of control (199±19.96 cm), 1M6 (152±13.41 cm), 2M6U7 (54±3.17 cm), and 2M6M7 (45±19.96 cm). The 2M6M7 and 2M6U7 treatment was the most effective at inhibiting S. altissima of density, of 50.8% and 26.2% compared to the control, respectively. In contrast, one-time mowing (1M6) resulted in an increase in density compared to the control by 119.7%. In addition, this treatment also reduced flowering rate (%) of S. altissima. The most effective treatment among those tested was 2M6U7.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.667-674
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• 2012

This study was conducted to understand landscape ecological characteristics on habitats of Nannophya pygmaea, an endangered species in South Korea. The ecological characteristics of the habitats were investigated in abandoned paddy fields where N. pygmaea populations have been found in Chungcheongnam-do Kongju, Gyeonggi-do Kwangju and Gyeongsangbuk-do Mungyeong from 2009 to 2010. We surveyed the dominant vegetation, areas, water depth and temperature, and plant height and coverage to compare the wetlands living N. pygmaea and not living N. pygmaea. As a result, habitats of N. pygmaea in all regions were dominated by Salix koreensis community. There is no signigicant difference in the water temperature, plant height and coverage among wetlands of the three different sites, but depth was varied within 2.5~9.5cm. The water depth of habitat was deeper in Gongju than the others. Percentage of open water was 1.7~6% in the wetlands living N. pygmaea. but it did not appear in the wetlands not living N. pygmaea. Therefore, the ecological characteristics of wetlands as abandoned paddy fields should be taken into account for N. pygmaea habitat conservation and restoration.

• Korean Journal of Environment and Ecology
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• v.15 no.2
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• pp.118-124
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• 2001

본 연구의 목적은 도식에 식재된 두 침엽수조인 소나무와 잣나무 단목의 연간 $CO_2$, $SO_2$, $NO_2$ 흡수 및 $O_2$ 생산을 계량화하는 것이다. 자연환경 조건하에서 운반형 적외선가스분석기로 연간 $CO_2$교환율을 측정하여 $CO_2$흡수 및 $O_2$ 생산량을 그리고 $CO_2$와 SO$_2$EH는 $NO_2$간 흡수속도비를 적용하여 $SO_2$ 및 $NO_2$흡수량을 각각 산정하였다. 흉고직경을 독립변수로 단목의 생장에 다른 연간 $CO_2$흡수 및 대기 정화량을 추정하는 활용 용이한 방정식을 유도하였다. 연구대상 수목 중, 흉고직경 20cm인 잣나무는 연간 양 35kg의 $CO_2$, 11g의 $SO_2$, 19g의 $NO_2$를 각각 흡수하였고 25kg의 $O_2$를 생산하였다. 동일 직경의 소나무는 유도한 방정식을 적용하면, 연간 약 30kg의 $CO_2$, 9g의$ SO_2$, 15g의 $NO_2$를 각각 흡수하였고 22kg의 $O_2$를 생산하였다. 생상기간 중 단위엽면적당 $CO_2$흡수량은 잣나무가 소나무보다 적었으나, 단목의 연간 $CO_2$흡수 및 대기정화량은 총엽면적의 차이로 잣나무가 동일 직경의 소나무보다 많았다. 본 연구결과는 도시 침엽수의 연간 대기정화 가치를 용이하게 계량화학고 도시공간내 수목식재의 환경적 중요성을 홍보하는데 활용될 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.65-65
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• 2020

기후변화에 관한 IPCC 제5차 평가보고서에 따르면 최근 나타난 기후 관련 극한 현상인 폭염, 홍수, 가뭄 등의 영향에 대해 생태계가 현재의 기후 변동성에 상당히 취약하게 반응하며, 기후변화를 위험에 초점을 맞추어 평가함으로써 대응책을 마련해야 한다고 강조하였다. 기후변화에 따라 강수량 패턴과 수문학적 시스템이 변하면서 수자원의 미치는 영향과 취약성, 적응에 대한 연구의 필요성이 요구되고 있으며, 농업용수를 비롯한 수자원 관리 기술 및 적응역량을 강화하는 것이 필요하다. 수리답 면적에 대한 농업용수 공급의 61%를 차지하는 농업용 저수지의 경우 과거 10년 한발빈도로 설계되어 최근의 연속적인 가뭄 사상으로 인한 낮은 저수율을 나타내어 가용 수자원의 부족이 발생하였다. 이에 따라 저수지 설계 당시와 상이한 환경 및 기후의 변화로 농업용수 공급체계의 상황변화에 따른 용수공급능력 및 이수안전도의 재평가가 요구된다. 일부 가뭄대책지구에 대하여 기후변화에 따른 현장여건 변화 (논면적, 영농패턴, 작부시기 등)를 반영한 이수안전도를 재평가함으로써 농업용 저수지의 용수공급에 대한 정량적 분석이 수행되었다. 저수지별로 기후변화 및 현장여건 변화에 따른 영향이 다르므로 전국 농업용 저수지를 대상으로 확대, 적용하기 위해서는 저수지 특성을 분석하여 비슷한 패턴을 갖는 저수지로 유형화하기 위한 작업이 필요하다. 본 연구에서는 농어촌공사 관할 3,394개의 농업용 저수지를 대상으로 지역에 따라 인자별 군집분석을 실시하여 국내 농업용 저수지의 이수안전도 변화에 따른 물 공급 잠재능을 재평가하고자 한다. 본 연구의 결과는 기후와 영농방식, 지역별 특성 등 상호간의 관계를 고려한 농업용수관리와 유사한 특성을 갖는 지역계획의 추진단위를 결정하거나 지역간의 비교우위를 고려한 한해 대책 등과 같은 농촌지역개발계획 등에 활용할 수 있을 것으로 기대한다.

• Atmosphere
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• v.24 no.3
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• pp.303-315
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• 2014

Terrestrial ecosystem plays the important role as carbon sink in the global carbon cycle. Understanding of interactions of terrestrial carbon cycle with climate is important for better prediction of future climate change. In this paper, terrestrial carbon cycle is investigated by Hadley Centre Global Environmental Model, version 2, Carbon Cycle (HadGEM2-CC) that considers vegetation dynamics and an interactive carbon cycle with climate. The simulation for future projection is based on the three (8.5/4.5/2.6) representative concentration pathways (RCPs) from 2006 to 2100 and compared with historical land carbon uptake from 1979 to 2005. Projected changes in ecological features such as production, respiration, net ecosystem exchange and climate condition show similar pattern in three RCPs, while the response amplitude in each RCPs are different. For all RCP scenarios, temperature and precipitation increase with rising of the atmospheric $CO_2$. Such climate conditions are favorable for vegetation growth and extension, causing future increase of terrestrial carbon uptakes in all RCPs. At the end of 21st century, the global average of gross and net primary productions and respiration increase in all RCPs and terrestrial ecosystem remains as carbon sink. This enhancement of land $CO_2$ uptake is attributed by the vegetated area expansion, increasing LAI, and early onset of growing season. After mid-21st century, temperature rising leads to excessive increase of soil respiration than net primary production and thus the terrestrial carbon uptake begins to fall since that time. Regionally the NEE average value of East-Asia ($90^{\circ}E-140^{\circ}E$, $20^{\circ}N{\sim}60^{\circ}N$) area is bigger than that of the same latitude band. In the end-$21^{st}$ the NEE mean values in East-Asia area are $-2.09PgC\;yr^{-1}$, $-1.12PgC\;yr^{-1}$, $-0.47PgC\;yr^{-1}$ and zonal mean NEEs of the same latitude region are $-1.12PgC\;yr^{-1}$, $-0.55PgC\;yr^{-1}$, $-0.17PgC\;yr^{-1}$ for RCP 8.5, 4.5, 2.6.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.2
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• pp.258-268
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• 1976

This study was conducted in order to know the ecology and to establish the control method of Potamogeton distinctus A. BENN. The tubers of Bog pond weed was almostly located at soil depth of 10 cm to 20cm, germination rates and number of formed tubers were different according to transplanting depth of soil. Effects of herbicides application on weeds were different according to leaf-stage of pondweed, and the pondweed were withered to death by absorption of Avirosan into the leaves. It was suitable to keep water depth at 3cm level until about a week after Avirosan application.

• Journal of Environmental Impact Assessment
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• v.17 no.6
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• pp.367-372
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• 2008

소하천의 식생분포특성을 조사하기 위하여 경북 상주시 내서면 서원리에서 낙동강 본류가 만나는 함창읍 신흥리까지 이안천의 약 25km 구간에서 7개의 정점을 선정하였다. 각 조사정점에서 상 하 약 1.5km 구간에 대하여 식물상 및 식생분포현황을 중점조사 하였다. 7개 조사정점에서 출현한 식물은 모두 49과 54속 145종 12변종 1품으로 도합 158종류가 확인되었다. 출현 식물 중 한국 특산식물인 환경부 1등급종 쥐방울덩굴, 물오리나무, 왕버들, 낙지다리 4종류가 출현하였다. 17종류가 출현하였으며 귀화율은 10.8%, 도시화지수는 6.1%로 나타났다. 식생도상에 표시된 식생유형을 경관생태학적으로 분석하기위하여 식생유형별 조각수를 비교하였다. 이안천의 전체 조사정점의 식생 조각 수는 183개로 나타났으며, 육상식물인 명아주군락을 제외한 수변군락의 식생수는 총 181개로서 전체의 98.9%를 나타내었다. 군락별로는 달뿌리풀군락이 76개로서 전체의 42.5%로서 가장 높고, 갯버들군락이 67개로서 35.8%, 삿갓사초가 26개로서 26.0%, 고마리가 3개로서 1.1%를 나타내었다. 각 조사지점별 식생면적의 구성비에서도 달뿌리풀이 가장 높고, 갯버들, 삿갓사초의 순으로 나타났다.

• Journal of Wetlands Research
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• v.6 no.1
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• pp.117-132
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• 2004

Despite its significance in understanding ecological structure and biogeochemical element cycles, there have been few studies on the microbial mineralization of organic matter and mineralization pathway in the intertidal flat of Korea. We measured anaerobic mineralization of organic matter and sulfate reduction rate, and evaluated the significance of sulfate reduction in total anaerobic carbon respiration at the southern part of Ganghwa Island. Depth-integrated carbon mineralization rate down to 6 cm depth ranged from 41.9 to $89.4mmol\;m^{-2}d^{-1}$, which accounted for approximately 216 tons of organic matter mineralization in entire intertidal flat area of Ganghwa($300km^2$). The results indicated that capacity for the organic matter mineralization in the Ganghwa tidal flat is comparable to highly productive salt marsh environments. Mineralization rates in the sediment amended with acetate were 2~5 times higher than in unamended sediment. The results implied that microbial mineralization was limited by the availability of organic substrates, and the organic matter mineralization capacity seems to be higher than estimated at ambient organic substrate level. Depth-integrated sulfate reduction rates within 6 cm depth of the sediment ranged from 20.7 to $45.1mmol\;SO{_4}^{2-}m^{-2}d^{-1}$, and sulfate reduction was mostly responsible for organic matter remineralization. It should be noticed that the increase of $H_2S$ in the sulfate reduction dominated tidal flat may result in the decrease of biological diversity.