- ENGLISH
- P-ISSN2287-8327
- E-ISSN2288-1220
- SCOPUS, KCI
37권 3호
초록
Abstract
The purpose of this study is to compare soil CO2 efflux between burned site and unburned site dominated by Pinus densiflora forest in the Samcheok area of the East Coast fire in 2000 and measure soil CO2 efflux and environmental factors between April 2011 to March 2012. Soil CO2 efflux was measured with LI-6400 once a month, and the 10cm depth soil temperature, air temperature, and soil moisture contents were measured in continuum with Data Loggers. Soil CO2 efflux showed the maximum value in August as 417.8 mg CO2•m-2•h-1 (burned site) and 1175.1 mg CO2•m-2•h-1 (unburned site), while it showed the minimum value as 41.4 mg CO2•m-2•h-1 (burned site) in December and 42.7 mg CO2•m-2•h-1 (unburned site) in February. The result showed the high correlation between soil CO2 efflux and the seasonal changes in temperature. More specifically, soil temperature showed higher correlation with soil CO2 efflux in burned site (R2 = 0.932, P < 0.001) and unburned site (R2 = 0.942, P < 0.001) than the air temperature in burned site (R2 = 0.668, P < 0.01) and unburned site(R2 = 0.729, P < 0.001). Q10 values showed higher sensitivity in unburned site (4.572) than in burned site (2.408). The total soil CO2 efflux was obtained with the exponential function between soil CO2 efflux and soil temperature during the research period, and it showed 2.5 times higher in unburned site (35.59 ton CO2•ha-2•yr-1) than burned site (14.69 ton CO2•ha-2•yr-1).
초록
Abstract
Ant communities are well suited for monitoring changes in ecosystems. Although numerous studies have examined the responses of ant communities to environmental disturbance, relatively few long-term studies on ant communities have been undertaken in urban environments. We examined species richness in nine urban parks in Hiroshima, Japan, and compared the survey results with data collected at the same sites using the same methods in 1999. In both surveys, total of 25 species was recorded: 23 species in 1999 and 20 species in 2012. Non-metric multidimensional scaling analysis revealed that the ant communities consisted of two distinct groups, which could in turn be characterized by three patterns of ant community changes in between the two groups. The first of these community change patterns was characterized by a shift within group 1, but the number of species remaining constant (approx. 10 species). The second pattern was characterized by a shift within group 2, but the number of species remained low (approx. 4 species). The third pattern was characterized by a shift from group 1 to group 2 as the abundance of Linepithema humile (Mayr) increased over time. Unlike the first and second patterns, the number of ant species in communities of the third type decreased significantly. These findings suggest that L. humile has a marked effect on the species diversity of indigenous ant communities in urban environments.
초록
Abstract
To investigate the solute pattern of salt marsh plants in Suncheon Bay in Korea, plants and soil samples were collected at three sites (Carex scabrifolia and Phragmites communis, site 1; Suaeda malacosperma, site 2; Suaeda japonica, site 3) once a month from July to September. The soil pH around the investigated species was weakly alkaline, 6.9–8.1. The total ion and Cl- content of site 1 gradually increased, while those of site 2 and site 3 were lowest in August and highest in September. The exchangeable Ca2+, Mg2+ and K+ in the soil was relatively constant during the study period, but the soil exchangeable Na+ content was variable. Leaves of the investigated plant species were collected once a month in their natural habitats from July to September. Carex scabrifolia and Pharagmites communis had constant leaf water content during the period. Suaeda malacosperma and Suaeda japonica had high leaf water content, but this decreased after August. C. scabrifolia and P. communis had very high concentrations of soluble carbohydrates. However, S. malacosperma and S. japonica had very low, but constant soluble carbohydrate concentrations. C. scabrifolia accumulated similar amounts of Na+ and K+ ions in its leaves. P. communis contained a high concentration of K+ ions. S. japonica and S. malacosperma had more Na+ and Cl- ions than K+ ions in their leaves. S. japonica had higher levels of glycine betaine in its leaves under saline conditions than Carex scabrifolia and Phragmites communis. According to these results, it can be concluded that the physiological characteristics of salt marsh chenopodiaceous plants (S. japonica and S. malacosperma) are the high storage capacity for inorganic ions (especially alkali cations and chloride) and accumulation of glycine betaine, but monocotyledonous plant species (C. scabrifolia and P. communis) show high K+ concentrations, efficient regulation of ionic uptake (exclusion of Na+ and Cl-), and accumulation of soluble carbohydrates. These characteristics enable salt marsh plants to grow in saline habitats.
초록
Abstract
Denitrification permanently removes nitrate from aquatic ecosystems, so construction of denitrification walls to enhance denitrification activity is often suggested to reduce the nitrate levels from tributary ecosystems. However, little information is available to guide the choice of appropriate organic materials to increase denitrification rates in the walls. This study investigated how differences in organic substrates originating from litter and organic materials affected denitrification and carbon mineralization rates in riparian sediments. Potential denitrification rates were highest in riparian sediments that contained large quantities of extractable organic carbon (Ext. Org C) and that had high anaerobic carbon mineralization rates, but were negatively correlated with C:N ratios. Therefore, this research suggested that the both carbon quantity and quality should be considered when assessing the efficiency of organic substrates to remove nitrate from tributary ecosystems.
초록
Abstract
Structural heterogeneity results in different spatial distributions of microcrustaceans. Thus, in ecosystems with excessive macrophyte development, it may be difficult to determine the microcrustacean species composition. Given the importance of microcrustaceans in the food web, the elucidation of microcrustacean diversity is essential. In vegetated habitats, bluegill sunfish can prey on microcrustaceans, and therefore have a potential role as microcrustacean monitoring agents. In the present study, we compared microcrustacean species compositions in the field with those in the guts of bluegill, in Jangcheok Lake, South Korea. Our results showed that the number of microcrustacean species was higher in bluegill guts than in the field. Further, some species (Daphnia galeata, Graptoleveris testudinaria, Leydigia leydigii, Rhynchotalona sp., and Simocephalus exponisus) were found only in bluegill guts. Our findings verify the validity of using fish gut analysis to monitor microcrustacean species compositions and to clarify spatial distributions of microcrustacean species in structurally heterogeneous ecosystems with excessive macrophyte development.