• Journal of Forest and Environmental Science
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• v.25 no.1
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• pp.49-55
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• 2009

The present study analyses the effect of land use on the vegetation of some desert ecosystems in Abu Dhabi, United Arab Emirates (UAE). Three sites were selected to represent different types of land use, inside Umm Al-Banadeq forest, outside the forest and along Abu Dhabi-Al Ain Trucks Road. In total, fifty-two stands were examined; including a matrix of 14 species ${\times}$ 52 stands. Based on species cover data, stands were classified using TWINSPAN and ordinated using DCA. Four vegetation groups were generated at level three of classification. Zygophyllum mandavillei was dominant in most vegetation groups; Heliotropium bacciferum dominated vegetation groups inhabited the forest. Species richness, species turnover, relative evenness and relative concentration of dominance of forest vegetation groups were 2.8, 5.7, 0.7, and 2.0, respectively. The differences were attributed to both natural variability and forestry-induced changes, including change in land use, drainage and ploughing and shading by trees. Vegetation group inhabited Abu Dhabi-Al Ain Trucks Road, that were dominated by Haloxylon salicornicum and Zygophyllum mandavillei have high total cover (8.8 m per $m^{-1}$). Most community and vegetation attributes were significantly higher inside the forest than outside. Human interventions and environmental factors affected species diversity and abundance of these communities.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.2
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• pp.71-79
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• 1998

Fish larvae and environmental variables were collected in the sea around Cheju Island of Korea in November, 1986. Fish larvae were found at the 43 of 44 stations. Abundance of fish larvae rangεd from 3 to 259 indiv./$10^3\;m^3$ (average 50 indiv./$10^3\;m^3$) Dominant species were Engraulis japonicus, Champsodon snyderi, Gobiidae, Sebastiscus marmoratus, and Synagrops philippinensis, which comprised 56.6% of total fish larvae abundance. 43 stations were c1assified into two groups by c1uster analysis based on the abundance of fish taxa. Most stations of Group I were located in the middle reach of Tsushima Current and had higher number of species and abundance than the sites of Group II which cover the marginal areas of Tsushima Current, Korean Coastal Waters, and coastal water of China. The dominant taxa in the sites of the Group I were E. japonicus, Gobiidae, S. philippinensis, Aulops japonicus, Bregmaceros spp., Benthosema pterotum, Lampanctus spp., etc., all of which are typical warm-water species. Therefore, Tsushima Current seems to be the most critical factor regulating the structure of fish larvae community in the study area. The discriminant analysis using the environmenta1 variables (temperature, salinity, and dissolved oxygen) produced result with a difference only of 11.6% from that of c1uster analysis using the taxa composition and abundance data. Consequently, the structural type of fish larvae community can be used for predicting the changes of environmental conditions in the study area.

• The Korean Journal of Ecology
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• v.15 no.4
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• pp.411-431
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• 1992

The present study was undertaken to classify and describe the vegetation around andong dam area, kyong-buk, korea$(36^{\circ}\;35^{\prime}\;N, \;128^{\circ}\;47^{\prime}\;E)$ by methods of the ZM school of phytosociology. The investigations were carried out in the plot. The homogeneous part of forest and grass communities was analyzed by recording the combined scale of cover-abundance and sociability of all species found in the plot. The community data obtained were classified into two associations and seven communities; festuco onvinae-pinetum densiflorae assoc. nov., quercetum variabili-serratae, quercus acutissima community, larix leptolepis, populus tomentiglandulosa, acer canadensis, prunus spp. afforestations, robinia pseudo-acacia-commelina communis community and acer palmatum cv. afforestation. The grass vegetation was divided into six associations and seventeen communities; lactuco indicae- humuletum japonicae, eragrostio ferruginei-plantaginetum asiaticae, polygonetum thunbergii, phragmitetum japonicae, eragrostio ferruginei-plantaginetum asiaticae, polygonetum thunbergii, phragmitetum japonicae, artemisio-potentilletum chinesis, eleusinetum indicae, amorpha freticosa, artemisia princeps, achyranthes fauriei and other fourteen communities. amoung the above vegetationship of the vegetation units with their environments was outlined.

• Publications of The Korean Astronomical Society
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• v.8 no.1
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• pp.243-263
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• 1993

One hundred forty two digital spectra of 110 standard stars with 1 A resolution in ${\lambda}{\lambda}\;3000\;A\;{\sim}4150\;A$ region were analyzed to determine the spectral indices sensitive to the atmospheric parameters. The standard stars cover the temperature in the range of $T_eff$ from ${\sim}4000^{\circ}$ to ${\sim}7000^{\circ}\;K$ and the surface gravity in the range of log g from 0 to 5 and the metal abundance [Fe/H] from -2.7 to 0.4. We have derived physical parameters, theta(=T/5040), log g, and [Fe/H] for the standard stars using indices, P(38/93), Fe I(A), Fe I(B), SrII, and $H{\delta}$, with overall accuracies of 0.067, 0.617, and 0.466, respectively. However for some region of spectral type and metallicity, those can be obtained with better accuracies. Those indices are found to be useful especially for stellar gravity determination.

• ALGAE
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• v.19 no.4
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• pp.339-347
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• 2004

Seaweed community of the sub tidal rocky habitats along the coast of Geumo Archipelago in the central South Sea of Korea is described. This area is characterized by archipelago in which islets are separated by shallow bottom sediments (primary, muddy sand), and turbidity is generally high due to the resuspension of bottom sediments. The hard substrata available for algal attachment are limited to less than 10 m in depth. Thirty sites were randomly chosen along the coast from August 2003 to September 2003 and a 50 m long transect was established at each site. The transect began at a depth of 1 m and ended at the depth of 9 m. The percent cover of all species other than crustose coralline algae was estimated at 2 m depth intervals along the transect using a 0.25 m$^2$ PVC quadrat with 25 squares. Thirty-six species were identified including 6 Chlorophyta, 10 Phaeophyta and 20 Rhodophyta. Species with more than 5% mean bottom cover were Gelidium amansii, Corallina pilulifera, Amphiroa dilatata and Carpopeltis cornea, which formed dense turf-forming algal assemblages at 1-5 m depth. At all sites except S11-S15 located in the western coast of Sorido, bottom covers of seaweed species at the depth deeper than 7 m were less than 6%. The lower limit of algal assemblages was 9 m in depth. We speculate that the limited water clarity and vertical extent of hard substrata available for the settlement of seaweed species are the direct cause of reducing the diversity, abundance and distributional extent of algal assemblages in the area.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.353-360
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• 2015

A survey of weed occurrence was conducted to identify problematic weed species in a horticultural crop field to get basic information for effective weed control. Surveys of weed species occurring in horticultural crop fields (garlic, onion, red pepper and Chinese cabbage) were conducted in Chungnam province of Korea from April to October in 2014. A total of 516 sites of the 17 regions were identified as having 114 weed species belonging to 32 families. The most dominant weed species in the horticultural crop fields were Chenopodium album var. centrorubrum (8.83%), followed by Digitaria ciliaris (5.71%), Conyza canadensis (5.46%) and Capsella bursa-pastoris (4.67%). Specifically, as a result of this study, the occurrence of 35 species of exotic weeds, such as Chenopodium album and Taraxacum officinale, were confirmed. Almost 68% of the investigation sites was determined under dominance value 1 (range of cover < 10; numerous individuals) by Braun-Branquet cover-abundance scale, indicating a proper weed control in horticultural crop field. As a result of scientific and technological advances, an improved cultivation method is changing the weed occurrence in agricultural land. Additional research needs to be undertaken for the development of weed control methods through such periodic monitoring of occurrence of weeds.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.65-74
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• 2020

BACKGROUND: Soil carbon sequestration has been investigated for a long time because of its potential to mitigate the greenhouse effect. No- or reduced tillage, crop rotations, or cover crops have been investigated and practiced to sequester carbon in soils but the roles of soil biota, particularly microorganisms, have been mostly ignored although they affect the amount and stability of soil organic matters. METHODS AND RESULTS: In this study we analyzed the organic matter and microbial community in organically cultivated corn field soils where no-tillage (NT) or conventional tillage (CT) had been practiced for about three years. The amounts of organic matter and recalcitrant carbon pool were 18.3 g/kg dry soil and 4.1 g C/kg dry soil, respectively in NT soils, while they were 12.4 and 2.5, respectively in CT soils. The amounts of RNA and DNA, and the copy numbers of bacterial 16S rRNA genes and fungal ITS sequences were higher in NT soils than in CT soils. No-tillage treatment increased the diversities of soil bacterial and fungal communities and clearly shifted the bacterial and fungal community structures. In NT soils the relative abundances of bacterial phyla known as copiotrophs, Betaproteobacteria and Bacteroidetes, increased while those known as oligotrophs, Acidobacteria and Verrucomicrobia, decreased compared to CT soils. The relative abundance of a fungal phylum, Glomeromycota, whose members are known as arbuscular mycorrhizal fungi, was about two time higher in NT soils than in CT soils, suggesting that the higher amount of organic matter in NT soils is related to its abundance. CONCLUSION: This study shows that no-tillage treatment greatly affects soil microbial abundance and community structure, which may affect the amount and stability of soil organic matter.

• Journal of Plant Biology
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• v.14 no.3
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• pp.1-20
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• 1971

Ecological factors limiting Stipa pulchra have been determined in experimental gardens and at several sites in the hills south and east of Monterey, California. The Stipa pulchrafacies of Valley Grassland communities were found to be dominated by that species, though a total of 36 grasses and forbs were collected and identified. Basal area was not large, but aerial cover by Stipa alone averaged over 50 per cent. Across an ecotone between a Stipa association and the California Annual Type a sudden and dramatic change was recorded. Soil measurements there, and in other nearby areas, showed a much higher clay content with more available water and elemental phosphorus at the Stipa sites. Germination of Stipa seeds was high under all laboratory and field conditions, though growth of seeldings was highly variable. Seedlings grown in Stipa woil with an abundance of water were vigorous and reached anthesis the first year. In other soils they grew less, and when grown in competition with Avena fatua they scarcely grew at all. These findings indicate that when established on desirable soils, Stipa competes well and apparently precludes the dominance of Avena fatua and other large annual grasses. On the other hand, because of a lack of vigor in its seedlings, Stipa cannot reinvade the rich more friable soils on which it was once found, and on which it was shown to grow satisfactorily. This supports the contention that Sipa pulchra was the dominant grass through much of the Valley Grassland and Foothill Woodland, but also indicates that well-drained soils and those poor in mineral nutrients probalby never supported such associations.

• The Korean Journal of Ecology
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• v.28 no.6
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• pp.365-373
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• 2005

Understanding the relation of water environmental factors and vegetation is critical to restoration and management of wetlands. To reveal relationships between representative plant groups and water environments, we measured cover and abundance of plant species, water depth, temperature, pH, conductivity, dissolved oxygen, $NH_4$-N, $NO_3$-N, and $PO_4-P$ concentration in water in Wangsuk stream (WS) and Gwarim reservoir (GR). This study was conducted monthly from May to October, 2004. Six vegetation groups $(W1{\sim}W6)$ in WS and five vegetation groups $(G1{\sim}G5)$ in GR were identified using TWINSPAN. WS was characterized by Phragmites japonica, Digitaria sanguinalis, Phalaris arundinacea, Beckmannia xyzigachne and Persicara hydropiper, Persicaria thunbergii, Typha angustifolia. GR was characterized by T. angustifolia, Scirpus tabernaemontani, P. thunbergii, Humulus japonicus and Scirpus fluviatilis, Typha orientalis, Zizania latifolia. The vegetation in WS experienced greater seasonal changes than in GR. A correspondence analysis suggests that water depth was the major environmental factor influencing the distribution of most plants communities in both wetlands.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.256-265
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• 1995

The effect ground-cover weeds on the occurrence of apple pests and their natural enemies was studied in an apple orchard in Ahnsung, Kyung-gi do during seasons of 1993 and 1994. The major apple pests and their parasitoids and predators were surveyed on the apple tree canopy in tow experimental plots; a weed-free lot where all weeds were removed by herbicide treatment, and a mowed plot where weeds were allowed restrictly by cutting with an asickle. Also, a sweep net sampling was taken from ground-cover weeds in the mowed plot. There were no significant differences in the abundance of mite and aphids between two plots, although mite densities tend to be lower in the mowed plot. The apple leaf miner, Phyllonorycter ringoniella, was significantly fewer in the mowed plot,. The densities of natural enemies of mites and aphids were slightly higher in the mowed plot. The parasitism of apple leaf miner in the mowed plot was 6~10% and 20~25% higher than that in the weed-free plot in 1993 and 994, respectively. Several natural enemies such as Apanteles kuwayamai (Braconidae), Orius sauteri (Anthocoridae), Chrysopa sp. (Chrysopidae), coccinellidae, and Eulophidae were collected both from weeds and the apple trees, However, potential apple pests were not observed on weeds. The development of insect community on the apple tree canopy was restricted by the pesticide spray on apple trees, while the insect community on weeds was maintained without significant destruction by pesticides spray on apple trees. Consequentely, the ground-cover weeds under apple trees affected occurrences of apple pests and their natural enemies in apple trees. te specialist natural enemies such as apple leaf miner's parasitoids dispersed from weeds to the apple canopy and affected apple leaf miner density significantly. However, generalist predators that have preys available on weeds stayed on weeds, hence their control effects for mites and aphids on the apple canopy were low.