• Korean journal of applied entomology
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• v.34 no.3
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• pp.249-255
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• 1995

These experiments were conducted to investigate the life history and the seasonal fluctuation of population density of tea red spider mite, Tetranychus kanzawai Kishida and to observe its natural enemies in the southern area. Under field-cage conditions, tea red spider mite occurred 11~12 generations. The average periods from egg to adult emergence were 8.7~13.1 days in summer and 12.6~24.9 days in spring and autumn. The average longevities of adults were 15.5~21.9 days in summer and 25.1~31.6 days in spring and autumn. The average number of eggs laid per female were 45.1 in summer and 52.6 in spring and autumn. Tea red spider mite population showed two peaks during April-June, and appeared third or forth peak during October-November. The density of all the stages was the lowest in July through August. Tea red spider mites stayed at lower parts of tea plants in March but they moved to upper parts in April though June, and they again moved to lower parts after autumn. Tea red spider mite overwintered as all stages. Adults were the dominant overwintering stage during this stage. The surveyed natural enemies of the tea red spider mite were 7 species including Amblyseius longispinosus (Evans), A. eharai Amitei et Swirski, Anystis baccarun (L), Agistemus fleschneri Summers, Orius sauteri Poppius, Oligota yasumatsui Kistner and Scolothrips sp.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.65-70
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• 2000

Field collections were made from six gypsy moth (Lymantria dispar L.) Populations in Kyonggy and Cheju areas during the period 1987∼1997. Characteristics of gypsy moth populations at different phases were examined in terms of egg mass density, relative larval density, plant damage, and fecundity. Males captured in pheromone trap were recorded, and we examined if there was a relationship between numbers captured and the population density during the following generation. Egg mass density was closely related with larval density, and furthermore these densities were correlated with the level of plant damage, indicating that larval dispersion was limited in oviposition areas. The gypsy moth population cycle was short in Korea with the period from population development to innocuous level usually lasting 2∼3 years. Male caught by pheromone trap (mean number of males caught per trap per day in peak emergence period) was positively correlated with egg mass densities in the following season (r²=0.93). A low fecundity was detected from outbreak populations which accompanied defoliation. Fecundity of gypsy moth ranged from 538 to 601 at other phases.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.6
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• pp.57-69
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• 2011

The present paper deals with a research of life form and vegetation of the plants extant in the habitat of endangered Parnassius bremeri in Uiseong, Gyeongsangbuk-do with a view to restore their habitat and create substitute habitats. The research found that there are a total of 130 vascular plants including 47 families, 96 genera, 113 species, 1 subspecies and 16 varieties. In terms of their life form, hemicryptophytes (H) is the majority of dormancy form with 41 species or 31.54%, while $R_5$ is majority of radicoid form with 72 species or 55.38%, gravitational disseminule form ($D_4$) is majority among the disseminule forms with 68 species or 52.31% and erect type (e) is majority of growth form with 57 species or 43.85%. Major constituents of the habitat are Sedum kamtschaticum, Selaginella tamariscina, Orostachys japonica, Arundinella hirta, Cymbopogon tortilis var. goeringii, Themeda triandra var. japonica, Carex humilis, Indigofera kirilowii, Imperata cylindrica var. koenigii, Festuca ovina, Artemisia capillaris, etc., all of species which are in the initial stage of succession and show simultaneously features characteristic of vegetation on the rock. In the habitat 1. Sedum kamtschaticum- Selaginella tamariscina community and Pinus densiflora community are distributed whereas, in the habitat 2. Sedum kamtschaticum-Selaginella tamariscina community, Sedum kamtschaticum-Carex humilis community, Sedum kamtschaticum-Cymbopogon tortilis var. goeringii community and Sedum kamtschaticum-Imperata cylindrica var. koenigii community are growing and in the habitat 3. Sedum kamtschaticum-Selaginella tamariscina community, Selaginella tamariscina community, Sedum kamtschaticum-Indigofera kirilowii community and Quercus acutissima community are seen distributed there, too. Typical of food plants growing in the habitat is Sedum kamtschaticum, found mostly in the rocky area and its surroundings. Absorption plants are those that usually bloom in the season when imagoes emerge. From the research, it becomes evident that the blooming season of Sedum kamtschaticum, obviously a food plant, corresponds exactly to the emergence timing of imagoes. Cirsium japonicum var. ussuriense, Rosa multiflora, Erigeron annuus, Spiraea prunifolia var. simpliciflora are found to belong to these plants.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.437-442
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• 2015

This study, examined Chilocorus kuwanae for biological control of Saissetia coffeae. We measured basic developmental characteristics of C. kuwanae and its capability to prey on the second-instar larvae of S. coffeae by indoor breeding under the following conditions: $25^{\circ}C{\pm}2^{\circ}C$, humidity $70%{\pm}5%$, and day length 16L : 8D. The average daily consumption of the second-instar larvae of S. coffeae by C. kuwanae adults was approximately 77.5 larvae/day, which was significantly 2.8 and 2.9 times higher than consumption by Chrysoperla carnea and Cryptolaemus montrouzieri, respectively. During the nymphal period, C. kuwanae consumed a total of 659.0 second-instar larvae of S. coffeae. The interaction between C. kuwanae and the second-instar larvae of S. coffeae varied according to their densities, with the increase in C. kuwanae consumption rate noted to decelerate and gradually level off at the maximum, rsembling Holling's Type II functional response. Duration of egg to adult development varied from 21.1 days to nearly 27.9 days at temperatures of $25^{\circ}C{\pm}2^{\circ}C$. Hatchability, pupation rate, and adult emergence were greater than 72.3%, 77.8% and 83.3%, respectively.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.109-115
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• 1984

This study was conducted to investigate the bionomics, host range and damage aspect of Japanese juniperus bark borer, Semanotus bifasciatus M., which shoves the severe damage for the Juniperace in Chonnam province, recently. Host plants were Juniperus virginiana, J. chinensis var. kaizuka, J. chinensis, Biata orientalis var. nepalensis, Chamaccyparis ostus and Thujopsis dolabrata. Out of those, J. chinensis var. kaizuka is newly investigated in this study. Damage rate in each area was $16.5\%$ in Kwangju, $4.25\%$ in Damyang ana $6.5\%$ in Hwasoon. Adults appear once a year, with a peak at late March to early April. Adults emergence during the day showed the peak at 13 to 15 hours and were influenced in the maximum temperature in a day. Attack direction of larva after invasion in the stem was $62\%$ toward base, $22\%$ toward tip and $16\%$ toward horizon, and the damage in each DBH (Diameter of breast height) was the greatest at $30\~40mm$. At period of each stage, egg was $15.8\~19.7$ days, larva was $l12\~126$ days and pupa was $15\~21$ days. Longevity of adult was 19 days for female and 16 days for male.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.315-326
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• 2021

The clear-water phase (CWP) is a notable limnological phenomenon in freshwater systems caused by predatory interactions between large filter-feeding zooplankton and phytoplankton. However, the mechanisms and factors that influence the extent of CWP, particularly in complex water systems with both fluvial and lacustrine characteristics, remain poorly understood. The present study evaluated CWP occurrence patterns at different sites in a large reservoir located in a temperate monsoon region (Lake Paldang, Korea); the relationships among factors associated with CWP occurrence, such as transparency, zooplankton diversity, and chlorophyll a concentration were investigated. Transparency exhibited significant correlations with precipitation and retention time, as well as the relative abundance of zooplankton (p<0.01), suggesting that a change in the retention time due to precipitation can alter CWP. Data collected before and after CWP occurrence were analyzed using paired t-test to determine variations in CWP occurrence based on the water system characteristics. The results demonstrated that various factors were associated with CWP occurrence in the fluvial-type and lacustrine-type sites. The correlation between zooplankton biomass and transparency was stronger in the lacustrine-type sites than in the fluvial-type sites. The lacustrine-type sites, where cladoceran emergence is common and is associated with long retention times, favored CWP occurrence. The results suggest that lacustrine-type sites, which are conducive to zooplankton development and have relatively long retention times, enhance CWP occurrence. Furthermore, CWP occurrence was notable in spring, and the present study revealed that site-specific CWP could occur throughout the year, regardless of the season.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.684-693
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• 2016

Daemyung retarding basin located near the confluence floodplain of the Nakdong and Kumho River is a large spawning site for the endangered Kaloula borealis, and needs for protecting the habitat of the endangered species are increasing. However, scientific studies are rarely conducted on the population characteristics and ecological knowledge on the species in the basin. This paper aims to estimate the population size and spatial distribution of the species that inhabited at the Daemyung retarding basin, using the capture-recapture method. Also, pitfall traps were installed in each habitat types classified with micro-topographic features, slope aspects, and vegetation communities to identify the spatial distribution characteristics of the Kaloula borealis of each habitat in the retarding basin. Field survey on the species was conducted from May 2013 to October 2014, showing that the species emerged in May, became more active during July and August and started to hibernate at the end of October. Using capture-recapture method, the first survey was carried out from July to August, 2014. Ninety-eight toads were captured, marked, and released back into the site. In the second survey, 68 toads including 5 marked toads of the previous survey were captured. Based on these two-sample surveys, around 535-2,131 individual toads are estimated to inhabit the Daemyung retarding basin. Fifty-seven pitfall traps were installed in four habitat types: mounded and vegetated flatland, lowland swamps, and slope areas of both the southern and western parts of the basin in order to delineate spatial abundance of the endangered Kaloula borealis during the rainy season when the species is actively spawning. Pitfall traps at the spatially explicit array indicated that the species gradually move to the slope areas near the Daemyung stream, showing high occurrence density of the Kaloula borealis compared to the lowland swamps after the spawning season. The emergence of Kaloula borealis in the lowland swamps appeared to be comparatively higher during the spawning season. However, after the spawning season the toads species rapidly moved into the neighboring land of relatively high elevation such as the slope area towards the Dalsung protected wetlands and Daemyung River. These results are closely related to the migration patterns that toads tend to return to the sheltering sites and/or hibernating grounds after the spawning season. Also, the Kaloula borealis moved to the nearest high-level vegetated areas as the lowland swamps of their spawning grounds deteriorated with the expansion of permanent ponds due to the rise in the groundwater level.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.215-234
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• 2014

The purpose of this study is to identify the type and characteristics of the domestic natural streams in order to establish a basis for stream restoration and evaluation. To this end, 95 domestic natural stream areas, which have various natural environments, were selected except for the province of island and then the characteristics of natural environment, hydromorpholoy, plant and vegetation were investigated and analyzed in each stream area. As a result, 95 stream areas were classified into total 24 types according to 3 criteria such as stream size (4 types), altitude (3 types), bed material (5 types). Depending on altitude class that is the environmental factor showing the highest correlation with each stream types, the emergence of vegetation and plant, 24 stream types were reclassified into 3 types such as lowland (altitude less than 200m), mountain (altitude from 200m to 500m), highland (altitude more than 500m), and hydromorpholoy, plant and vegetation characteristics of each stream type were compared. First, when compared to the mountain and highland streams, the typical features of lowland streams were as follows: Stream size was large but bed material size was small and there were many valley forms where flood plane were developed well. In addition, the more large stream size was, the more cross-section width variability, bars and sinuosity were in good conditions. In lowland stream, representative vegetation community was Salix koreensis community. On the other hand, when compared to the lowland streams, the typical features of mountain and highland streams were as follows: Stream size was small but bed material was coarse-grained and its size was large. Mountain and highland streams valley form where flood plane was not developed well was narrow, and sinuosity and bars development were weak. Representative vegetation communities of mountain streams were Quercus serrata -, Quercus variabilis -, Styrax japonica community and representative vegetation communities of highland streams were Pinus densiflora -, Quercus mongolica -, Fraxinus rhynchophylla community.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.506-514
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• 2019

Unlike natural ecosystems, the urban ecosystem proVides an interdependent enVironment in which wild organisms and urban people co-exist. Hornets (genus Vespa) appearing in urban green and parks haVe a positiVe effect on urban ecosystems, but they also cause ecosystem disserVices that cause physical and psychological discomforts to the urban people. Children's parks, for example, are Very popular among children and residents for easy accessibility, and hornets also use them as bases and habitats. HoweVer, there is still a lack of spatial analysis of habitats and appearance characteristics of hornets in children's parks. This study installed hornet traps in 27 children's parks in Cheonan from April to NoVember 2018 in consideration of the life cycle of hornets. We captured a total of fiVe Vespa species (Vespa crabro, V. analis, V. mandarinia, V. ducalis, and V. Velutina) for 32 weeks and analyzed the emergence of hornets in relation to the composition of seasonal characteristics, species characteristics, and enVironmental spatial information. We captured a total of 818 hornets during the study period. They included 290 V. analis (35.4%), 260 V. crabro (31.8%), 100 V. ducalis (12.1%), 87 V. mandaninia (10.6%), and 81 V. Velutina(9.9%). Most of the hornets showed a common feature that queen hornets were largely captured in May through June after they awake from hibernation, and the number of caught hornets decreased sharply beginning in mid-June, which was the cooperatiVe period. HoweVer, V. Velutina showed a seasonal specificity that more than 80% were captured beginning in the third week of October when other hornet species had already entered a decline phase. The analysis of the number of hornets caught in each spot in children's parks showed significant difference among the spots as 363 hornets (44.3%) were captured in top children's parks, and 35 hornets (4%) were captured in bottom children's parks. In particular, the mean NDVI (Normalized difference Vegetation index) of the top six children's parks was 0.79, and that of the bottom six children's parks was 0.38 (t=2.67*, *=p<0.05), indicating a significant difference. The frequency of capturing hornets was high when the ground around the children's parks was grass or bare land. This study is meaningful as a reference study that confirms the ecological characteristics of hornets appearing in green and parks in the city. We expect it to be a foundation for effectiVe urban green area management in the future.

• Korean Journal of Environment and Ecology
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• v.33 no.1
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• pp.28-51
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• 2019

The purpose of this study was to analyze forest vegetation structure in Marugeum (the ridge line) area between Dakmokryeong and Daetjae in Baekdudaegan through vegetation classification, importance value, species diversity, and CCA using the data that were collected from 245 quadrates through Braun-Blanquet vegetation survey method from May to September in 2017. The results of the forest vegetation classification identified 8 vegetation units with Quercus mongolica community group at the highest level. Q. mongolica community group was classified into the Cornus controversa community, Buxus koreana community, Sasa borealis community, Abies nephrolepis community, and Q. mongolica typical community. C. controversa community was further classified into Quercus dentata group, Filipendula glaberrima group, Larix kaempferi group, and C. controversa typical group. The result of the important value analysis showed that Q. dentata had the highest importance value at 19.1% in vegetation unit 1 while Q. mongolica had the highest importance value at 22.7%, 38.3%, 25.6%, 41.3%, 27.9%, and 41.6% in vegetation unit 2, 4, 5, 6, 7, and 8, respectively, and L. kaempferi had the highest importance value at 27.6% in vegetation unit 3. As such, Q. mongolica species generally represented the communities of Marugeum (the ridge line) area of Dakmokryeong to Daetjae in Baekdudaegan. The results of species diversity showed that vegetation unit 1 and 2 were 3.305 and 3.236, respectively, which were relatively higher than other vegetation units. It was considered that this result was due to the influence of high emergence of present species. The results of the CCA analysis of the correlations between biotic environmental factors and vegetation types showed that vegetation unit 1 was mainly correlated with the megaphanerophyte ratio and vine plant ratio. In the correlations between abiotic environmental factors and vegetation types, vegetation unit 7 was significantly correlated with altitude. From the perspective of ecological management, vegetation unit 5 represented by B. koreana community was inhabited by a variety of plants due to the species composition and location environment due to the geological characteristics that are typical of limestone area. Vegetation unit 7 represented by A. nephrolepis community was typified as subalpine vegetation widely distributed by relict species and endemic species. We concluded that it is necessary to manage these vegetation units with an ecologically differentiated approach.