• Korean Journal of Weed Science
• /
• v.4 no.2
• /
• pp.135-142
• /
• 1984

To obtain the basic information for weed management in polder land, a colligated assessment on weed distribution and it`s plant sociological indices on Gyewha polder land were arranged. At the situation of assessment, the Gyewha polder land was reclaimed with aim with paddy-rice production. As a result of reclamation, the salinity of most soil samples were below 0.3%, and acidity ranged from pH 5.5 to 6.5. Total weed species were counted as much as 17 species (3 gramineae, 7 cyperucese, and 8 broad-leaved species), and a most dominant species, Scirpus maritimus, were succeeded with Monochoria v., Eleocharis a., and Cyperus d., etc. by reclamation. Declining of soil salinity and soil pH, the number of weed species, individuals, biomass, species diversity, evenness, sociability index were increased, but the population particularity was weaken in tendencies. By developing of reclamation, the weed species which is summer annual broad leaf, wind and water disseminating, and tussock formed species are increased instead of salt-resistant, perennial cyperus, and rhizomatous extending species.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.2 no.2
• /
• pp.129-138
• /
• 2021

Living modified organisms (LMOs) are managed by seven government agencies according to their use in South Korea. The Ministry of Environment is responsible for LMOs used for environmental remediation. This study aimed to develop guidelines for assessing potential risks posed by transgenic plants used for remediation to insect ecosystems by investigating arthropod communities in sunflower fields. A total of 2,350 insects and spiders belonging to 134 species of 10 orders and 71 families were collected from sunflower fields over four growth stages ranging from anthesis to seed maturity. At the R3 phase of flower-bud formation, Chironomidae sp. of a decomposer insect guild presented the highest density, while Apis mellifera of a pollinator guild was the most abundant in the R5.8 phase of flowering. During the R7 seed-filling phase and the R9 phase of seed maturity, herbivorous Pochazia shantungensis predominated. During the R9 phase, richness and diversity indices of arthropod communities were distinctly lower whereas their dominance indices were significantly higher than those at other phases. In addition, the composition of arthropod communities was strongly correlated not only with the sampling date, but also with the sampling method depending on the growth stage of sunflowers. Our results suggest that appropriate sampling timing and methods should be considered in advance and that long-term field trials that cover a variety of environmental conditions should be carried out to evaluate potential risks to insect ecosystems.

• Korean Journal of Ichthyology
• /
• v.11 no.2
• /
• pp.184-190
• /
• 1999

A total of 43 species, 493 individuals, and 89,367.1 g of fishes were collected by a gill net in the coastal water off Goeje Island. Samples were collected by bimonthly from February to October, 1996. The dominant species were Stephanolepis cirrhifer, Ditrema temmincki, Hexagrammos otakii, Limanda yokohamae, Sebastes schlegeli, Paralichthys olivaceus, which accounted for 61.7% of the total numbers and 66.3% of biomass of fish collected. Fishes collected in the study area were mainly consisted of coastal species, but a few fishes were migratory species including Stephanolepis cirrhifer, Pleuroniohthys cornutus, Paralichthys oliuaceus, Thamnaconus modestus, Pagrus major, Engraulis japonicus. The number of species and abundance showed a peak in October, and low in February. Monthly species diversity indices ranged between 1.99 and 2.81, and high in June.

• Korean Journal of Ecology and Environment
• /
• v.42 no.2
• /
• pp.145-152
• /
• 2009

The fish community was investigated from March to October 2007 in Gwangneung Arboretum. During the survey period, 22 species belonging to 9 families were collected. Among them, one species (Coitus koreanus) was classified as an endangered species in Korea, and exotic fish was Micropterus salmoides. Nine species (40.9%) were endemic species of Korea. Dominant species was R. oxycephalus (St. 1) and Z. platypus (St. 2-7). According to analysis of community based on the diversity, evenness and richness indices, fish community seems to be more stable in the St. 3. The distributions of Silurus microdorsalis, Cottus koreanus and Odontobutis platycephala were confined to the Bongseonsa Stream in the Wangsuk Stream watershed. When our data were compared with the previous data (1932), 17 species were not sampled, but 7 species could new taxa fiend its existence at the Bongseonsa Stream. We believe that Hemibarbus mylodon, Acheilognathus signifer and Zacco koreanus disappeared in the Wangsuk Stream watershed and A. signifer and Z. koreanus need to be restored at the Bongseonsa Stream.

• Korean Journal of Ecology and Environment
• /
• v.54 no.2
• /
• pp.108-119
• /
• 2021

We aimed to develop a naturalness index for forest-dwelling birds in four national parks in Korea and to simulate the effect of species loss on this naturalness index. Five bird specialists were asked to give 112 bird species a disturbance susceptibility score (DSS), and the naturalness index was calculated based on this. The 112 bird species represented 8 orders (Cuculiformes, Piciformes, Accipitriformes, Falconiformes, Columbiformes, Caprimulgiformes, Strigiformes, and Passeriformes). DSS was the highest for Terpsiphone atrocaudata and Pitta nympha, and lowest for Pica pica, Hypsipetes amaurotis, and Streptopelia orientalis. There was a significant negative relationship between a species' population number and its DSS. Among the four national parks, Mt. Songni had the highest naturalness index, followed by Mt. Wolak, Mt. Juwang, and Mt. Wolchul. We investigated the change in biodiversity indices under four scenarios, which assumed the extinction of species with less than 5 (Scenario 1), 10 (Scenario 2), 50 (Scenario 3), and 100 individuals (Scenario 4). The results showed that although all biodiversity indices decreased as the species loss increased, they all behaved differently. Fisher's alpha diversity decreased as the number of species proportionally decreased. There was almost no change in Shannon-Wiener H' index in Scenarios 1 and 2. The naturalness index showed increased sensitivity in Scenarios 1 and 4. Our future aims are to obtain the DSS for all forest-dwelling bird species, and to adopt the naturalness index to evaluate temporal and spatial changes in biodiversity.

• Parasites, Hosts and Diseases
• /
• v.61 no.3
• /
• pp.272-281
• /
• 2023

Chigger mites are the vector of scrub typhus. This study estimates the infestation status and ecological characteristics of chiggers on the chestnut white-bellied rat Niviventer fulvescens in Southwest China between 2001 and 2019. Chiggers were identified under the microscope, and infestation indices were calculated. The Preston's log-normal model was used to fit the curve of species abundance distribution. A total of 6,557 chiggers were collected in 136 of 342 N. fulvescens rats, showing high overall infestation indices (prevalence=39.8%, mean abundance=19.2, mean intensity=48.2) and high species diversity (S=100, H'=3.0). Leptotrombidium cangjiangense, Neotrombicula japonica, and Ascoschoengastia sifanga were the three dominant chigger species (constituent ratio=42.9%; 2,736/6,384) and exhibited an aggregated distribution among different rat individuals. We identified 100 chigger species, with 3 of them (Leptotrombidium scutellare, Leptotrombidium wenense, and Leptotrombidium deliense) as the main vectors of scrub typhus in China and nine species as potential vectors of this disease. Disease vector occurrence on N. fulvescens may increase the risk of spreading scrub typhus from rats to humans. Chigger infestation on N. fulvescens varied significantly in different environments. The species abundance distribution showed a log-normal distribution pattern. The estimated number of chigger species on N. fulvescens was 126 species.

• Journal of Life Science
• /
• v.17 no.3 s.83
• /
• pp.328-333
• /
• 2007

Genetic diversity and population structure of eleven Liriope platyphylla (Liliaceae) populations in Korea were determined using genetic variation at 20 allozyme loci. The percent of polymorphic loci within the enzymes was 55.9%. Genetic diversity at the species level and at the population level was high(Hes = 0.178; Hep = 0.168, respectively), whereas the extent of the population divergence was relatively low ($G_{ST}$ = 0.064). $F_{IS}$, a measure of the deviation from random mating within the 11 populations, was 0.311. Total genetic diversity values ($H_T$) varied between 0.0 and 0.535, giving an average over all polymorphic loci of 0.323. The interlocus variation in within population genetic diversity ($H_S$) was high (0.305). An indirect estimate of the number of migrants per generation (Nm = 3.66) indicates that gene flow is high among Korean populations of the species. In addition, analysis of fixation indices revealed a substantial heterozygosity deficiency in some populations and at some loci. Mean genetic identity between populations was 0.988. It is highly probable that directional toward genetic uniformity in a relatively the homogenous habitat is thought to be operated among Korean populations of L. platyphylla.

• Korean Journal of Ichthyology
• /
• v.22 no.3
• /
• pp.179-185
• /
• 2010

This is a study of the fish assemblages in eelgrass beds of Geoje Bay on Geoje Island, Korea. Samples were collected by surf net monthly from June 2006 to May 2007. A total 26 species, 1,825 individuals, and 4,483.1 g of fishes were collected. The dominant species were Acentrogobius pflaumii, Aulichthys japonicus, Gymnogobius heptacanthus, Rudarius ercodes, Chaenogobius annularis, Gymnogobius urotaenia, Syngnathus schlegeli, Pterogobius elapoides, Zoarchias glaber, Takifugu niphobles, Zoarchia suchidai. These species accounted for 90.6% of the total number of individuals and 76.2% of the biomass of the fishes collected. The fish assemblages in the eelgrass beds showed clear seasonal changes; the number of fish species and individuals increased in March and were highest in September, whereas the biomass attained its highest level in May and subsequently decreased. Meanwhile the species diversity indices showed their highest value in December.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.4
• /
• pp.366-379
• /
• 2002

The monthly collected fish samples by three sides tyke nets were analyzed in order to study species composition and seasonal variation of fish assemblage in the coastal water off Gadeok-do, Korea through a year of 1998, During the study period, a total of 136 fish species of 69 families were collected. Trachums japonicus, Konosims punctatus and Mugil cephaus were three dominant species in the fish assemblage and they accounted for $63.7\%$ and $83.1\%$ in the number of individuals and biomass, respectively. Fish species of secondary importance in abundance were Leiognathus nuchalis, Takifugu niphobles, Somber japonious, Trichiurus lepturus, Chelon affinis, Apogon lineatus, Nibea aibiflora and Acanthopagrus schlegeli. The highest number of species was collected in July and the lowest in february. Abundance was high in spring, and low in winter. Species diversity indices showed that the fish assemblage was less diverse in spring than any other seasons.

• Korean Journal of Ichthyology
• /
• v.18 no.3
• /
• pp.251-265
• /
• 2006

To investigate the impingement of fish on the traveling screens, fishes were collected from the traveling screens at Hadong Power Plant through the year of 1999. A total of 84 fish species were collected during the study period. The dominant species were Leiognathus nuchalis, Engraulis japonicus, Trichiurus lepturus and Takifugu niphobles. These four species accounted for 78.2% of the total number of individuals and 52.0% of total biomass collected. The number of fish species, number of individuals, biomass and species diversity indices fluctuated with the seasons. The number of species and biomass were high in April and August, and the number of individuals was high in April and July. However, the number of fish species, number of individuals and biomass of fishes showed low values in winter.