• Title/Summary/Keyword: environment effect

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Distribution Model of the Wintering Red-crowned Crane and White-naped Crane in Cheorwon, Korea (철원지역에서 월동하는 두루미와 재두루미의 서식밀도모델)

  • Yoo, Seung-Hwa;Lee, Ki-Sup;Kim, Hwa-Jung;Hur, Wee-Haeng;Kim, Jin-Han;Park, Chong-Hwa
    • Korean Journal of Ecology and Environment
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    • v.47 no.4
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    • pp.282-291
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    • 2014
  • This study was conducted to make distribution model of the Red-crowned Crane and the White-naped Crane according to the anthropogenic and natural factors affecting distribution of crane in Cheorwon, Korea. It was investigated that the impact power and its range of the indirect anthropogenic influence to feeding flock density in cranes from the road, residential area, military facilities, civilian control zone (CCZ), greenhouse and natural influence such as roosting site and available feeding area. Available feeding area is the most important factor for the crane's feeding site selection. The feeding flock density of the cranes near the residential area was lower than that of area far from the area, and tended to increase within 2.5 km distance. The increasing tendencies of feeding flock density from military facilities and high traffic volume road were similar, but the density in military facilities increased within 800 m, and the density from high traffic volume road increased within 2 km. These results suggested that residential area, military facilities and the road with high traffic volume had significant effect on foraging densities to the certain range. As the distance from the road with low traffic volume and roosting site increased, feeding flock density tended to decrease. The density of Red-crowned crane and White-naped crane inside the CCZ were respectively higher than those of outside the CCZ, especially for the Red-crowned crane. As a result, density of Red crowned cranes inside the CCZ was 5.2 times higher than that of outside, while that of white-naped cranes was 2.2 times bigger. If the density of greenhouse is lower than $40km^{-2}$, crane's feeding flock density in the low greenhouses density area was higher than that of high greenhouses density area. However, there was no difference in the feeding flock density if the density of the green houses is higher than $40km^{-2}$. The model for the Red-crowned Crane was related with available feeding area, distance from residential area, civilian control zone and distance from high traffic road. The model of the White-naped Crane was related with available feeding area, distance from roosting site and distance from lake. Finally, the estimated feeding flock density of cranes significantly correlated with density model according to the natural and anthropogenic factors.

Relation of Stream Shape Complexity to Land Use, Water Quality and Benthic Diatoms in the Seom River Watershed (섬강 수계에서 하천 형태복잡도와 토지이용, 수질 및 부착규조류 군집 분포와의 관계)

  • Min, Han-Na;Kim, Nan-Young;Kim, Mi-Kyung;Lee, Sang-Woo;Hwang, Kil-Soon;Hwang, Soon-Jin
    • Korean Journal of Ecology and Environment
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    • v.45 no.1
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    • pp.110-122
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    • 2012
  • This study examined the benthic diatom community distribution, land cover/use and water quality in relation to stream shape complexity (SSC) in the Seom River watershed. SSC showed a significant relation to the riparian land cover/use pattern and also water quality variables of the studied streams. Streams with high stream shape complexity (HSC) appeared to have a high proportion of forest and farmland, while streams having a low stream shape complexity (LSC) appeared to have high proportion of city. Streams with lower SSC showed higher nutrients concentration in the stream waters. Benthic diatom species composition and dominant species appeared to be similar regardless of SSC differences among the studied streams, while the variation of diatom density was manifested with SSC. The relative abundance of dominant benthic diatoms varied with SSC. Saprophilic diatoms were dominant in the streams of LSC, while saproxenic diatoms were dominant in the streams of HSC. During the evaluation of biological water quality using the benthic diatom indices, Trophic Diatom Index (TDI) and Diatom Assemblage Index to organic water pollution (DAIpo), the streams of LSC generally showed poorer water quality than those of MSC (Middle stream shape complexity) and HSC. In particular, BOD, TP, and $PO_4$-P showed significant relationships with DAIpo. In conclusion, shape complexity of streams in the Seom River watershed showed a close relation with benthic diatom distribution. This relation seemed to primarily be resulted from the effect of proximate factors, such as water quality, which might be affected by the land use types determining the degree of SSC.

The Effect of Hydrology on Phytoplankton Assemblages and Its Adaptive Strategies in Lake Hwaseong, Estuarine Reservoir with Seawater Exchange, Korea (해수유통 중인 간척담수호 화성호에서 식물플랑크톤의 군집과 적응전략에 대한 수문학적 영향)

  • Song, Tae Yoon;Yoo, Man Ho;Lee, In Ho;Kang, Eue-Tae;Kim, Mi Ok;Choi, Joong Ki
    • Korean Journal of Ecology and Environment
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    • v.47 no.2
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    • pp.71-81
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    • 2014
  • A survey was carried out to understand the influence of hydrology on the composition, abundance and adaptive strategies of phytoplankton in artificial Lake Hwaseong, an estuarine reservoir with seawater exchange through a sluice. Samples were collected seven times from May to October 2012. Hydrological events (seawater exchange, rainfall) resulted in a wide variation in salinity along with nutrients and turbidity. Shifts in the dominant phytoplankton composition occurred on every survey. Chlorophyll-a ranged from 9.7 to $104.1{\mu}g\;L^{-1}$. Multivariate analysis allowed us to identify the four phases on phytoplankton community change. Phase I (May~June) was characterized by small-sized Gymnodinium sp. and Heterosigma akashiwo dominated in warm temperature and high salinity derived from seawater exchange, and followed by Cylindrotheca closterium blooms due to rainfall and winds during phase II (July and September). During phase III (August), the dominance of Oscillatoria spp. was correlated with high temperature and low salinity. Abundant cryptomonads were associated with lower temperature during phase IV (October). Adaptive strategies were identified in the phytoplankton as morphological and physiological characteristics. These strategies identified small-sized flagellates as CR-strategists, fast-growing opportunistic species, which might favor the weak stratification of lake due to the seawater exchange during phase I and IV. Dominant species during phase II and III were characterized with R-strategists, medium-sized stress-tolerant species, which might favor turbulence by river flow. The results indicate that stronger stratification following the termination of seawater exchange for the freshening might intensify the predominance of smaller flagellates. In conclusion, this study suggests that hydrology may drive phytoplankton community change and blooms through the controls of salinity, turbulence and nutrients.

Phytoplankton Community Change of Lake Paldang by Increasing $CO_2$ and Temperature during Spring Cold Water Season ($CO_2$와 수온 증가에 대한 봄철 저수온기 팔당호 식물플랑크톤군집 변화)

  • Lee, Ka-Ram;Sung, Eun-Ju;Park, Hye-Jin;Park, Chae-Hong;Park, Myung-Hwan;Hwang, Soon-Jin
    • Korean Journal of Ecology and Environment
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    • v.46 no.4
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    • pp.588-595
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    • 2013
  • This study investigated the influence of temperature and $CO_2$ increase on phytoplankton growth and community structure during cold water season (spring) in Lake Paldang, Korea. Four experimental treatments of temperature and $CO_2$ manipulation were prepared in the laboratory batch culture: (1) Control; ambient low temperature ($6{\pm}2^{\circ}C$) and low $CO_2$ (air level, $400mgL^{-1}$), (2) T1; low temperature and high $CO_2$ ($800mgL^{-1}$), (3) T2; high temperature ($20{\pm}2^{\circ}C$) and low $CO_2$, (4) T3; high temperature and high $CO_2$. Algal growth experiment was carried out for 10 days under the light intensity of $70{\mu}mol\;m^{-2}s^{-1}$ (L :D=24 : 0). The level of pH decreased in both T1 and T3, due to dissolution of added $CO_2$. The dominant phytoplankton species of ambient water, Cyclotella meneghiniana succeeded to Fragilaria capucina var. gracilis in high-temperature treatment groups (T2 and T3). Cyanobacteria were very rare at the beginning of the experiment, while Oscillatoria limnetica appeared in only high-temperature groups (T2 and T3) at $6{\sim}7^{th}$ day. $CO_2$ addition in ambient temperature (T1) induced the highest phytoplankton growth, and thereby producing the highest average cell density of $3.27{\pm}0.33\;10^4\;cells\;mL^{-1}$, followed by T2 ($2.65{\pm}0.26\;10^4\;cells\;mL^{-1}$), T3 ($2.09{\pm}0.16\;10^4\;cells\;mL^{-1}$), and Control ($1.86{\pm}0.13\;10^4\;cells\;mL^{-1}$) (F=7.167, p=0.000). In summary, temperature increase changed the phytoplankton community structure and $CO_2$ increase promoted the phytoplankton growth during the cold spring season in Lake Paldang, suggesting a potential effect of climate change on freshwater phytoplankton.

Effects of Soil Nitrogen Addition on Microbial Activities and Litter Decomposition (토양 내 질소 증가가 미생물 활성 및 식물체의 분해에 미치는 영향)

  • Chae, Hee Myung;Lee, Sang Hoon;Cha, Sang Sub;Shim, Jae Kuk
    • 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.

Water Quality and Epilithic Diatom Community in the Lower Stream near the South Harbor System of Korean Peninsula (한반도 서남부 하천 하구역의 수질 및 부착돌말 군집 특성)

  • Kim, Ha-Kyung;Lee, Min-Hyuk;Kim, Yong-Jae;Won, Du-Hee;Hwang, Soon-Jin;Hwang, Su-Ok;Kim, Sang-Hoon;Kim, Baik-Ho
    • Korean Journal of Ecology and Environment
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    • v.46 no.4
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    • pp.551-560
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    • 2013
  • Environmental factors and epilithic diatom communities in the lower streams near the harbor region of South Korean peninsula were examined during no monsoon period in May 2013. The sampling of water and epilithic diatoms was conducted at both streams, 19 regulated streams (RS) that there are one or several dams constructed in the river system, and 19 un-regulated streams (US) that there are no dams within the river. A cluster analysis based on the number of species and abundance of epilithic diatoms through the stations, divided into three groups such as groups I (mainly US), II (mixed with US and RS) and III (mainly RS), respectively. Group I showed that water quality is good and high diversity of diatom, while Group II and III was water quality is relatively poor, but not differed in biomass of diatom from Group I. In addition, Group II that had high conductivity, nitrogen and phosphorus, was the lowest in diatom diversity among them. Dominant species were Nitzschia palea (17%) and Navicula seminuloides (11%) in Group I, Nitzschia inconspicua (19%) and Navicula perminuta (9%) in Group II, and Nitzschia inconspicua (15%) and Nitzschia palea (14%) in Group III, respectively. These taxa were widely distributed in brackish water, and not closely related with specific water quality, like eutrophic water. However, the groups II and III belonged to RS, had not only little biomass, but bad water quality such as high concentrations of nutrient and chlorophyll-a. Therefore, to determine the effect of dam construction on the lower water ecosystem, the planktonic algae, which can occur algal bloom in the estuary, also was considered to be a parallel investigation.

The Effect of Vigor of a Bearing Shoot in ‘Bluecrop’ Highbush Blueberry (Vaccinium corymbosum L.) on Growth Characteristics of Shoots and Fruits (하이부시 블루베리 ‘블루크롭’의 결과지 세력이 신초와 과실 생장에 미치는 영향)

  • Kwon, Yeuseok;Lee, Sung-Hee;Shin, Hyunman;Nam, Sang-Yeong;Oh, Youngjae;Kim, Daeil
    • Korean Journal of Plant Resources
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    • v.29 no.5
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    • pp.598-603
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    • 2016
  • The aim of this study was to elucidate the influence of vigor of a bearing shoot in ‘Bluecrop’ Highbush Blueberry (Vaccinium corymbosum L.) on growth characteristics of shoots and fruits. Bearing shoots were classified with BS (bearing shoot) and BMB (bearing mother branch). The vigor of bearing shoots were divided into four arbitrary categories; A was thin (< 6.0 ㎜) BMB and short (< 10 ㎝) BS, B was thin BMB and long (≥ 10 ㎝) BS, C was thick (≥ 6 ㎜) BMB and short BS and D was thick BMB and long BS. Shoots from D were longer (6.5 ㎝) and thicker (1.70 ㎜) than those from the others. Shoots of D had more leaves (5.8 ea) than those of the others. Leaf area of D was larger (13.5 ㎠) than those of the others. The first harvest of D was one week faster than the others. Ratio of big berry (>14 ㎜) from the long BSs was higher (B : 41.7, D : 46.8%) than that from the short BSs. Soluble solid content of small berrys did not show any different according to vigor of bearing shoots, but soluble solid content of big berrys of the long BSs was higher (B : 16.2, D : 15.6°Bx) than those of the short BSs. The thickness of BMB did not affect ratio of fruit size and soluble soild content. The long BSs would be proper than the short BSs for bearing bigger fruits.

A Study on Teaching-Learning and Evaluation Methods of Environmental Studies in the Middle School (중학교 "환경" 교과의 교수.학습 및 평가 방법 연구)

  • 남상준
    • Hwankyungkyoyuk
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    • v.7 no.1
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    • pp.1-17
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    • 1994
  • This study was performed to determine appropriate teaching-learning and evaluation methods for Environmental Studies. To promote the relevance of our study to the needs of the schools and concerned educational communities of environmental education, we reviewed related literature, conducted questionnaire surveys, interviewed related teachers and administrator, held meetings with experts, and field-tested our findings. For selecting and developing teaching-learning methods of Environmental Studies, findings of educational research in general are considered. moreover, principles of environmental education, general aim of environmental education, orientations of environmental education, and developmental stages of middle school students in educational psychology were attended. In addition, relevance to the purpose of the Environmental Studies curriculum, appropriateness for value inquiry as well as knowledge inquiry, small group centered class organization, social interaction centered teaching-learning process, regional environmental situation, significance of personal environment, evaluation methods of Environmental Studies, multi- and inter-disciplinary contents of the Environmental Studies textbook, suitability to the evaluation methods of Environmental Studies, and emphasis on the social interaction in teaching-learning process were regarded. It was learned the Environmental Studies can be taught most effectively in via of holding discussion sessions, conducting actual investigation, doing experiment-practice, doing games and plate, role-playing and carrying out simulation activities, and doing inquiry. These teaching-learning methods were field-tested and proved appropriate methods for the subject. For selecting and developing evaluation method of Environmental Studies, such principles and characteristics of Environmental Studies as objective domains stated in the Environmental Studies curriculum, diversity of teaching-learning organization, were appreciated. We categorized nine evaluation methods: the teacher may conduct questionnaire surveys, testings, interviews, non-participatory observations; they may evaluate student's experiment-practice performances, reports preparation ability, ability to establish a research project, the teacher may ask the students to conduct a self-evaluation, or reciprocal evaluation. To maximize the effect of these methods, we further developed an application system. It considered three variables, that is, evaluates, evaluation objectives domains, and evaluation agent, and showed how to choose the most appropriate methods and, when necessary, how to combine uses of different methods depending on these variables. A sample evaluation instrument made on the basis of this application system was developed and tested in the classes. The system proved effective. Pilot applications of the teaching-learning methods and evaluation method were made simultaneously; and the results and their implications are as follows. Discussion program was applied in a lesson dealing with the problems of waste disposal, in which students showed active participation and creative thinking. The evaluation method used in this lesson was a multiple-choice written test for knowledge and skills. It was shown that this evaluation method and device are effective in helping students' revision of the lesson and in stimulating their creative interpretations and responces. Pupils showed great interests in the actual investigation program, and this programme was proved to be effective in enhancing students' participation. However, it was also turned out that there must be pre-arranged plans for the objects, contents and procedures of survey if this program is to effective. In this lesson, non-participatory observation methods were used with a focus on the attitudes of students. A scaled reported in general description rather than in grade. Experiment-practice programme was adopted in a lesson for purifying contaminated water and in this lesson, instruction objectives were properly established, the teaching-learning process was clearly specified and students were highly motivated. On the other hand, however, it was difficult to control the class when some groups of students require more times to complete their experiment, and sometimes different results. As regards to evaluation, performance observation test were used for assessing skills and attitudes. If teachers use well-prepared Likert scale, evaluation of all groups within a reasonablely short period of time will be possible. The most effective and successful programme in therms of students' participation and enjoyment, was the 'ah-nah-bah-dah-market' program, which is kind of game of the flea market. For better organized program of this kind, however, are essential, In this program, students appraise their own attitudes and behavior by responding to a written questionnaire. In addition, students were asked to record any anecdotes relating to self-appraisal of changes on one's own attitudes and behaviours. Even after the lesson, students keep recording those changes on letters to herself. Role-playing and simulation game programme was applied to a case of 'NIMBY', in which students should decide where to located a refuse dumping ground. For this kind of programme to e successful, concepts and words used in the script should be appropriate for students' intellectual levels, and students should by adequately introduced into the objective and the procedures of the lessons. Written questionnaire was used to assess individual students' attitudes after the lesson, but in order to acquire information on the changes of students' attitudes and skills, pre-test may have to be made. Doing inquiry programme, in which advantages in which students actually investigated the environmental influence of the areas where school os located, had advantages in developing students' ability to study the environmental problems and to present the results of their studies. For this programme to be more efficient, areas of investigation should be clearly divided and alloted to each group so that repetition or overlap in areas of study and presentation be avoided, and complementary wok between groups bee enhanced. In this programme, teacher assessed students' knowledge and attitudes on the basis of reports prepared by each group. However, there were found some difficults in assessing students' attitudes and behaviours solely on the grounds of written report. Perhaps, using a scaled checklist assessing students' attitudes while their presentation could help to relieve the difficulties.

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Agronomic Characteristics of A Mutant for Genic Male Sterility-Chalky Endosperm and Its Utilization on $F_1$ Hybrid Breeding System in Rice (벼 유전자적 웅성불임-심백 돌연변이체의 특성과 그를 이용한 일대잡종 육성체계)

  • ;Mun-Hue Heu
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.40 no.6
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    • pp.684-696
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    • 1995
  • A mutant for chalky endosperm and genetic male sterility (GMS) was newly developed in rice. The two characters were found to be controlled by single recessive gene which has pleiotropic effect, indicating that chalky seeds should be GMS seeds in segregating populations. Chalky seeds showed the same shape and size as normal seeds. However, starch composition of central part of endosperm was looser and shape of starch granules was rounder compared with normal endosperm, resulting in significantly lower grain weight, absolute density and grain hardness in chalky grains than in normal ones. Amylose content and gel consistency of chalky grains were much lower and harder, respectively. Male sterile plants showed much shorter plant height, poorer panicle exsertion and lesser panicle number compared with normal plants. Microspore abortion stage in pollen developmental process was observed as before meiosis. Male sterility of the mutant was stable regadless of temperature and day length. A system breeding hybrid rice using this mutant was discussed, comp ring with other systems utilizing cytoplasmic-genic male sterility(CGMS) and environment sensitive GMS(EGMS). Separation of GMS seeds in mixed seed bulks by specific gravity (1.14∼1.16g / cm3) was successful about 85∼90%. But some mixed normal plants were seemed to be easily removed by the apparent difference in growth characters at seedling stage. The highest natural outcrossing rate of this GMS line was as 17.3 % in a plot treated with 2-row pollinator, I-row GMS, and GA3 + cutting of flag leaf + pollen-scattering by rope.

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Influence of Different Nitrogen Fertilizer Application Levels and Application Timing on Gluten Fraction and Bread Loaf Volume During Grain Filling (빵용 밀 품종의 등숙기 질소 시비 시기와 양이 글루텐 분획 및 빵 부피에 미치는 영향)

  • Cho, Seong-Woo;Kang, Taek-Gyu;Park, Chul Soo;Son, Jae-Han;Choi, Chang-Hyun;Cheong, Young-Keun;Yoon, Young-Mi;Kim, Kyong-Ho;Kang, Chon-Sik
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.63 no.3
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    • pp.229-238
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    • 2018
  • The purpose of this study was to evaluate the effects of nitrogen fertilization amount and timing of application on protein content, dough properties, change in protein fraction, and bread loaf volume for Korean wheat cultivars, Baekkang, Joongmo2008, and Saekeumkang, for bread with a superior gluten composition during the grain filling stage. Protein content increased with an increase in the amount of N and timing of application. The SDS segmentation volume (SDSS) increased with an increase in N, but there was no effect of the timing of N application on SDSS. An increase in N amount and timing of application caused a difference in dough properties, such as water absorption, mixing time, and tolerance, among the cultivars. Soluble and insoluble polymeric and monomeric protein contents increased with an increase in N amount and timing of application the three Korean wheat cultivars. The effects of N amount and application timing on bread loaf volume (BLV) varied among the cultivars. The BLV of Saekeumkang increased regardless of the N amount and timing of application, but that of Baekkang and Joongmo2008 cultivars was reduced. However, there was a positive correlation between protein content with the addition of N fertilization and BLV. In addition, SDSS, mixing time, and protein fractions were positively correlated with BLV. Since the response of fertilizer conditions was different for each wheat cultivar, it is necessary to build a suitable fertilizing system for each of them. Additionally, since the environment is changing, such as abnormal climate during the maturing period, research is needed to establish appropriate fertilizer conditions for varieties of bread wheat.