- KOREAN
- P-ISSN2287-8327
- E-ISSN2288-1220
- SCOPUS, KCI
ISSN : 2287-8327
Vol.33 No.2
Abstract
This article focused on the environmental changes on atolls in Micronesia. First, we considered the problem. Second,we designed research that focused on the impacts of environmental changes especially in relation to globalization and global warming in the Federated States of Micronesia (FSM). The results were in accordance to the hypotheses that globalization had impacted prominently in communities on main islands and impact was lessened with increased distance from the centre. The fact that the islands are remotely situated and thus, in theory, do not have much outside influence,has not alleviated them from having societal concerns. The earth’s environmental change is causing an impact on the main islands as well. This has been governed by distinctive characteristics in their geographical, regional, and contents. Moreover, they showed stronger concerns about impacts on the environment than globalization. A set of questionnaires was used as the principal assessment method to quantify the concerns relating to the environmental changes.
Abstract
The archipelago in the southwest sea, Korea, was registered as Shinan Dadohae Biosphere Reserve by United Nations Educational, Scientific and Cultural Organization Man and the Biosphere (UNESCO MAB) on May 26, 2009. This study was conducted to determine a method of reconciling natural and anthropogenic processes and to enable sustainable development in the vicinity of the Shinan Dadohae Biosphere Reserve (SDBR). To accomplish this, the characteristics of SDBR with respect to biodiversity and cultural diversity were evaluated. In addition, a management plan regarding the wise use of the SDBR was developed while focusing on four parts: cultural support to induce motivation for native conservation and development; development and specification of fisheries and cultivation based on local community systems;restructuring of marine food products and resource transporting systems; activation and discovery of indigenous knowledge to enable networking between local residents, academia and the UNESCO-international society.
Abstract
The principal objective of this study was to characterize the relationships between geographical conditions (e.g., island area, distance to mainland) and landscape structures of uninhabited islands, and to evaluate the effects of islands and their landscape structures on species richness. One hundred randomly selected islands and 5,000 m buffered areas derived from the boundaries of each island were used to summarize the number of observed bird species, and landscape pattern indices, particularly patch density, edge density, shape index, and mean nearest neighboring distance. Spatial arrangements of individual patch type at the class level, which are markedly affected by the distance from an island to the mainland, have a superior ability to explain the variances in species richness, as compared to the geographical conditions and landscape pattern indices at the landscape level. The results demonstrate that the patch type landscape structure is the primary factor affecting species richness, as well as the distance to the mainland. In particular, landscape pattern indices of cropland/pasture and woody cover are statistically significant in terms of explaining species richness,which suggests that food resources and appropriate conditions in landscape structures of habitat types are assumed as important elements in attracting bird species. This study also proposes the importance of evaluation on the landscape structure of each island, in order to designate protected areas and to establish a management plan for species conservation in uninhabited islands.
Abstract
The Asian cultural landscape is a mirrored ecosystem of great complexity, formed by the interaction of man and nature,coupled with a host of ecological processes. The human dependencies on and environmental adaptation of the bio-organisms and the surrounding landscape constitute the typical cultural landscape. Islands are a good example of a cultural landscape, and each mosaic pattern of marine and coastal ecosystems reflects bio-cultural diversity. Along with land-use patterns, wise use of biological organisms and indigenous knowledge has expanded to islands in the Asia-Pacific region in several ways (sea current and human impact, etc.). Loss in biodiversity and landscape diversity as well as cultural diversity owing to global warming and rapid urbanization are emerging issues for island ecosystems all over the world. In order to sustain the historical coexistence between man and natural systems, we ecologists must continue to search for a holistic solution for academic consilience. In this paper, I present the vision and practical characteristics of island ecology with a view toward the conservation of the traditional landscape and bio-cultural diversities in the seascape.
Abstract
Betula platyphylla var. japonica and Betula ermanii segregate vertically at an elevation of approximately 1,850 m on Mt. Neko in Nagano Prefecture, Japan. B. platyphylla var. japonica and B. ermanii were the dominant species below and above this altitude, at which the mean-annual and growing-season air temperatures were 4°C and 14.1°C, respectively. Based on a modification of Kira's warmth index which employs cumulative temperature represented as °C day, leaf unfolding in both species was observed to be initiated at 58°C day and 169°C day, respectively. In 1996, leaf unfolding was initiated on 18 May in B. platyphylla var. japonica (+/-6 days) and on 5 June in B. ermanii (+/-8 days), shortly after the last frost which occurred on 5 May 1995 above 1,850 m; below this elevation there was no risk of frost at the time. At elevations above 1,850 m, the unfolded leaves of B. platyphylla were damaged by late frost, while B. ermanii escaped injury because the leaves were still protected by winter buds. The optimum temperature for seed germination in both B. platyphylla and B. ermanii was 30°C. Temperature alternation from 10 to 30°C and moist storage of seeds at 4°C (stratification) prior to incubation increased germination rates in both species. The seedlings of B. ermanii had a greater survival rates than those of B. platyphylla var. japonica when planted above 1,850 m. Comparisons of the timing of leaf unfolding and the latest frost at a site appeared to be the main factors affecting the vertical distribution of these species.
Abstract
Atmospheric CO₂ concentrations have increased exponentially over the last century and, if continued, are expected to have significant effects on plants and soil. In this study, we investigated the effects of elevated CO₂ on the growth of Pinus densiflora seedling and microbial activity in soil. Three-year-old pine seedlings were exposed to ambient as well as elevated levels of CO₂ (380 and 760 ppmv, respectively). Growth rates and C:N ratios of the pine seedlings were also determined. Dissolved organic carbon content, phenolic compound content, and microbial activity were measured in bulk soil and rhizosphere soil. The results show that elevated CO₂ significantly increased the root dry weight of pine seedling. In addition, overall N content decreased, which increased the C:N ratio in pine needles. Elevated CO₂ decreased soil moisture, nitrate concentration, and the concentration of soil phenolic compounds. In contrast, soil enzymatic activities were increased in rhizosphere soil, including β-glucosidase, N-acetylglucosaminidase and phosphatase enzyme activities. In conclusion, elevated CO₂ concentrations caused distinct changes in soil chemistry and microbiology
Abstract
This study compared the antimicrobial activity and chemical composition of two plants used as “Injin” (Korean herbal medicine), namely, Injinho (Artemisia capillaris Thunberg) and Haninjin (Artemisia iwayomogi Kitamura). The ethyl acetate and ether fractions of crude methanol extracts from A. capillaris and A. iwayomogi were tested against three grampositive bacteria (Bacillus cereus, Bacillus subtilis, Staphylococcus aureus), two gram-negative bacteria (Escherichia coli,Pseudomonas fluorescens), and a yeast (Saccharomyceus cerevisiae). The antimicrobial activity of the ethyl acetate and ether fraction of both plants was strong, but that of A. iwayomogi extracts was higher than that of A. capillaris extract for the microbes tested. The minimum inhibitory concentration of the ether and ethyl acetate fraction of A. iwayomogi was highest for P. fluorescens and lowest for S. aureus and E. coli. We analyzed the chemical composition of the ethyl acetate fraction of A. capillaris and A. iwayomogi using gas chromatography-mass spectrometry. The main components of A. capillaris and A. iwayomogi were escoparone (86.82%) and scopoletin (20.47%), respectively.
Abstract
This study was conducted to investigate the feeding efficiency of the cattle egret (Bubulcus ibis) and the intermediate egret (Ardea intermedia) in relation to the stage of rice culture during two breeding seasons, 2006 and 2007, in Asan city,Chungcheongnam-do, South Korea. Cattle egrets caught mainly small invertebrate prey (insects and spiders, 98.4%)during all stages of rice cultivation, and had a higher prey capture rate in the plowing stage (14.98 prey/min) than in other stages (2.82-3.51 prey/min). Therefore, the biomass intake rate of cattle egrets was highest in the plowing stage. The intermediate egret captured both loaches (43.4%) and small invertebrates (50.6%). The prey capture rates of intermediate egrets increased gradually from the flooding stage (0.38 prey/min) to the planting stage (1.09 prey/min), and decreased in the growing stage (1.04 prey/min). However, intermediate egrets had the highest biomass intake rates in the plowing stage because more loaches were caught in the plowing stage (0.54 loaches/min) than other stages (0.23-0.36loaches/min). Consequently, both intermediate egrets and cattle egrets had high energy intakes in the plowing stage and rice fields provided an important feeding habitat for both species.
Abstract
We evaluated the restoration effect by introducing willows as a means of controlling invasions of giant ragweed (Ambrosia trifida L.) on a riparian site. Our preliminary survey demonstrated that a problematic exotic species, giant ragweed and the representative riparian species, Salix koreensis are in competitive exclusive relationship. We planted willows at 1 m intervals on the bank of the Dongmun stream at Munsan, Paju, in Central Western Korea as an experimental restoration practice. We installed two 50 m ⅹ 5 m sized restored and non-restored for this experimental study. The non-restored plots were located on river banks, which were covered with concrete blocks and left in itself without any treatment. The height of willow was measured after each of three consecutive growing seasons and compared with the height of the giant ragweed. Although the height of Salix gracilistyla did not achieve the height of the giant ragweed, the height of S. koreensis surpassed that of giant ragweed in the third year after introduction. The results were also reflected in the relative light intensity on the herb layer of willow stand, and thereby the relative light intensities of stands, which were dominated by S. koreensis or restored by introducing S. koreensis, 1.99 ± 0.33 (%, mean ± SD) and 1.92 ± 0.50 (%,mean ± SD), respectively were lower than those in the stands treated by S. gracilistyla, 3.01 ± 0.43 (%, mean ± SD). The giant ragweed stands receive full sunlight as there are no any vegetation layers higher than the herb layer formed by the giant ragweed. As the result of Detrended Correspondence analysis ordination based on naturally established vegetation,the stands dominated by willows and giant ragweed showed different species composition between both stands. The species composition of the restoratively treated sites resembled the reference sites more than the non-treated sites. The species diversity (H’) of the sites restored by introducing S. koreensis and S. gracilistyla was higher than the non-restored site dominated by A. trifida. On the basis of our results, the restoration of riparian vegetation equipped with integrated features could contribute not only to the control of exotic plants including giant ragweed but also to ensure the diversity and stability of riverine ecosystems.
Abstract
Soil respiration (RS) is a critical component of the annual carbon balance of forests, but few studies thus far have attempted to evaluate empirical regression models in RS. The principal objectives of this study were to evaluate the relationship between RS rates and soil temperature (ST) and soil water content (SWC) in soil from a cool-temperate deciduous broad-leaved forest, and to evaluate empirical regression models for the prediction of RS using ST and SWC. We have been measuring RS, using an open-flow gas-exchange system with an infrared gas analyzer during the snowfree season from 1999 to 2001 at the Takayama Forest, Japan. To evaluate the empirical regression models used for the prediction of RS, we compared a simple exponential regression (flux = aebt: Eq. [1]) and two polynomial multiple-regression models (flux = aebt × (θν – c) × (d – θν)f: Eq. [2] and flux = aebt × (1 – (1 – (θν/c))2): Eq. [3]) that included two variables (ST:t and SWC: θν) and that utilized hourly data for RS. In general, daily mean RS rates were positively well-correlated with ST, but no significant correlations were observed with any significant frequency between the ST and RS rates on periods of a day based on the hourly RS data. Eq. (2) has many more site-specific parameters than Eq. (3) and resulted in some significant underestimation. The empirical regression, Eq. (3) was best explained by temporal variations, as it provided a more unbiased fit to the data compared to Eq. (2). The Eq. (3) (ST × SWC function) also increased the predictive ability as compared to Eq. (1) (only ST exponential function), increasing the R2 from 0.71 to 0.78.
Abstract
This study was designed to evaluate changes in the terpene composition of 3 types of pines (Pinus densiflora, Pinus thunbergii and Pinus rigida), while decomposing their leaf litter. Needle litters were placed at two different organic layer depths, one on the surface and the other beneath the litter layer. Changes in the terpene composition of this litter were detected using a gas chromatograph-mass spectrometer. Among the monoterpenes acquired from the fresh needles of P. densiflora and P. rigida, α-pinene (12.05% and 19.87%, respectively) was the major one, followed by β-pinene (2.90%and 14.07%). However, from the needles of P. thunbergii, β-pinene (20.77%) was the major one, followed by α-pinene (10.79%). Among the sesquiterpenes detected in P. densiflora, trans-caryophyllene (3.12%) was the highest composition compound, whereas germacrene-D (6.09%) for P. thunbergii and 1,6-cyclodecadiene (7.41%) and endo-1-bourbonanol (7.41%) for P. rigida were the highest content compounds. However, the total amounts of terpenes decreased sharply by 40-85.4% in all three types of pine needle after 90-120 days of the experiment. The concentration of each terpene differed during decomposition, and the majority of compounds disappeared from beneath the litter layer. It was determined that three types of reducing patterns of each compound appeared on the rate of loss of concentration during decomposition;one pattern decreasing sharply during the initial period, another pattern steadily or slowly decreasing, and a newly detected pattern at low concentration occurring during decomposition.