- KOREAN
- P-ISSN2287-8327
- E-ISSN2288-1220
- SCOPUS, KCI
ISSN : 2287-8327
Vol.30 No.2
Abstract
The effect of water flow on the growth of Gafrarium tumidum was studied in the field using open cages constructed with stainless steel net and perspex in which holes were drilled. Cages with different flows (25, 50 and 75% of the control) were made by varying the area of perspex being drilled. Reduction in flow rate was directly proportional to the undrilled area, and the mean flow rate of the different treatment groups varied from 3.12 cm/s for the 25% exposure to 12.48 cm/s for the control cages. At the end of the 3-month experiment, no significant differences in sediment characteristics were found among the treatments. Growth in shell length, shell weight and tissue dry weight was, however, positively correlated with flow rate. Percentage increases ranged from 3.0～8.3% for shell length, 9.9～23.1% for shell weight and 17.2～53.3% for tissue dry weight. Condition index of the clam was not significantly different among the treatments. Seston depletion effect could reduce growth in G. tumidum only when water flow was reduced to 25% of the control. G. tumidum also exhibited different responses in shell and tissue growth at low flow rates, in which shell growth continued to decrease as flow rate decreased whereas tissue growth was relatively independent of low flows at 25 and 50% of the control. It was suggested that when seston flux was reduced at slow flows, it would be a better strategy for G. tumidum to channel energy for gonad development instead of shell growth during the reproductive stage.
Abstract
We monitored gold-spotted pond frog (Rana chosenica ) populations near the Korea NationalUniversity of Education in Chungbuk, Korea, from 19 May to 8 August, 2006 to examine the spatial distribution of populations in local areas and to investigate patterns of migration of adult gold-spotted pond frogs from terrestrial hibernation sites to breeding sites, We captured individuals from the largest population using a drift fence with 22 pitfall traps surrounding the breeding site. A total of 2 individuals (19 males and 3 females) were eeding migration was detected, but the onset of the breeding migration may correspond with increased humidity. Male body weights were negatively correlated with sampling dates. Seven of 22 individuals were captured at the 4th pitfall trap, which was placed between two culverts. The capture rate per pitfall trap was higher in traps close to the rice field banks (1.44, traps 1∼9) than in traps facing hilly land (0.33, traps 13∼18). Comparative data from the Korean frog (Rana coreana ), a sympatric species in the study area, were also collected and compared with those of the gold-spotted pond frog.
Abstract
The effects of water flow rate and phytoplankton concentration on the growth of the sandy shoreclam Gafrarium tumidumdays, shell length, shell weight and tissue dry weight increased significantly with phytoplankton concentration. For the effect of flow rate, growth was faster when flow rate increased from low to medium level; further increases in flow rate, however, either did not sustain faster growth or resulted in a reduction in growth. The condition index (CI) of a standard-sized clam was significantly higher at low flow rate than at medium and high flow rates and was negatively correlated with phytoplankton concentration. The uncoupled growth of shell and tissue in response to flow rate and phytoplankton concentration may be adaptations to low food environments, so that energy can either be stored to sustain life or reserved for gametogenesis during the reproductive period.
Abstract
We used the Braun-Blanquet method to study coastal dune vegetation of South Korea. Coastalvegetation was monitored in thirty sites from April 2004 to September 2005. Seventeen plant comunities were classified into five groups as follows: A. Two associations of herbaceous sand dune plants in Salsoletea komarovii Ohba, Miyawaki et Tx. 1973 (Calystegia soldanella comunity, Lathyrus japonicus-Calystegia solda-nella comunity), B. Twelve associationsMiyawaki et Tx. 1973 (Carex pumila community, Elymus mollis community, Vitex rotundifolia-Elymus mollis com-munity, Ixeris repens community, Elymus mollis-Ixeris repens comunity, Lathyrus japonicus community, Messershmidia sibirica community, Glehnia littoralis community, Carex kobomugi community, Calystegia solda-nella-Carex kobomugi community, Ishaemum anthephoroides community, Zoysia macrostachya community), C. One association of shrubby perennial sand dune plant in Viticetea rotundifoliae Ohba, Miyawaki et Tx. 1973 (Vitex rotundifolia community), D. One association of shrubby perennial sand dune plant in Rosetea multiflorae Ohba, Miyawaki et Tx. 1973 (Rosa rugosa comunity), E. The naturalized comunity ( Diodia teres community).
Abstract
To certify predictability for the times of phenological stages from cumulative air temperature in springtime, the first times of budding, leafing, flower budding, flowering and deflowering for 14 woody plants were monitored and air temperature was measured from 2005 to 2006 at Namsan. Year day index (YDI) and Nuttonson's Index (Tn) were calculated from daily mean air temperature. Of the 14 woody species, mean coefficient of variation was 0.04 in Robinia pseudo-acacia and 0.09 in Alnus hirsuta. However, mean coefficient of variation was 0.30 in Forsythia koreana and Stephanandra incisa and 0.32 in Zanthoxylum schinifolium. Therefore, the times of each phenological stage could be predicted in the former two species but not in latter three species by two indices. Of the five phenological stages, mean coefficient of variation was the smallest at deflowering time and the largest at budding time. In five phenological stages, mean coefficient of variation of YDI was in the range of 0.11～0.21 but that of Tn was in the range of 0.15～0.26. Therefore, the former was a better index than the latter. Of the species-phenological stage pair, coefficient of variation of YDI was 0.01 in Acer pseudo-sieboldianum - flower budding and below 0.05 in 11 pairs, whereas the YDIs over 0.40 were 4 pairs comprising of Prunus leveilleana - budding (0.51). Coefficient of variation of Tn was 0.01 in A. hirsuta - budding and below 0.05 in 8 pairs. The Tns over 0.40 were 5 pairs comprising of F. koreana - flower budding (0.66)
Abstract
We studied the optimal ranges of water and soil characteristics for wetland plants, particularlyScirpus tabernaemontani (softstem bulrush) and Typha latifolia (broadleaf cattail), which are dominant species with potential for restoration of Korean wetlands. We observed vegetation in S. tabernaemontani and T. latifolia depth (WD), temperature (WT), conductivity (WC), and concentration of several ions (NO3--N, Ca2+, Na+, Mg2+, and K+), and characteristics of soil environments such as soil texture, organic matter (loss on ignition, LOI), conductivity, and pH. The S. tabernaemontani comunity was accompanied by Zizania latifolia (Manchurian wildrice), Persicaria thunbergii (Korean persicary), Actinostemma lobatum (lobed actinostemma), and Beck-mania syzigachne (American slough grass), while the T. latifolia community was accompanied by P. thunbergii, T. angustifolia (narrowleaf cattail), and (wild soybean). We defined the optimal range for distribution (ORD) as the range that each plant was crowded. The optimal range of water characteristics for the S. tabernaemontani community was a WD 10 ∼50 cm, WT 24.0∼32.0℃, WC 10 ∼500 μS/cm, NO3--N 0∼60 ppb, K+0.00∼1.50 ppm, Ca2+7.50∼17.50 ppm, Na+2.50∼12.50 ppm, and Mg2+3.0 ∼7.00 ppm. In addition, the optimal range of soil characteristics for the S. tabernaemontaniand loamy sand, LOI 8.0∼16.0%, pH 5.25∼6.25, and conductivity 10∼70 μS/cm. The optimal range of water characteristics for the T. latifolia comunity was a WD 10 ∼30 cm, WT 22.5∼27.5℃, WC 100∼400 μS/cm, NO3--N 0∼60 ppb, K+0.00∼1.50 ppm, Ca2+0.00∼17.50 ppm, Na+0.0 ∼12.50 ppm, and Mg2+0.00∼5.00 ppm, T. latifolia comunity was a soil texture of loam, sandy loam, and silty loam, LOI 3.0∼9.0%, pH 5.25∼7.25, and conductivity 0∼70 μS/cm.
Abstract
The ultimate target of restoring waste landfills is revegetation. The most effective method forthe present study was to investigate the effects of nitrogen fertilizer, and the addition of carbon through sawdust, sucrose and litter, on vegetation dynamics at a representative municipal waste landfill in South Korea: Kyongseodong. A total of 288 permanent plots (0.25 m2) were established and treated with nitrogen fertilizer (5, 10 and 20 N g/m2), sawdust (289 g/m2), sucrose (222 g/m2) and litter (222 g/m2). The aboveground biomass was significantly enhanced by nitrogen fertilizer at 5 and 10 N g/ m2, compared with the control plots. The total 2, as well as on those treated with sawdust and sucrose, compared with the control plots. The higher species richness after nitrogen fertilization of 10 to 20 N g/m2,and the sawdust and sucrose treatment demonstrated that this was an ap-propriate restoration option for nutrient deficient waste landfills. This study demonstrated positive nutrient impacts on plant biomass and species richness, despite the fact that municipal waste landfills are ecosystems that are highly disturbed by anthropogenic and internal factors (landfill gas and leachate). Adequate N and C combined treatments will accelerate species succession (higher species richness and perennial increase) for restoration of waste landfills.
Abstract
Korean rivers and their surrounding environments have been used excessively for rice production in the past and more recently for construction of urban areas to accomodate the rapidly increasing population. Affected Korean rivers experience dramatic fluctuations in their water levels and have faster currents compared with those in other countries. In order to restore more natural conditions in rivers experiencing such conditions, we employed a partial restoration method, which is designed to achieve physical and biological stability simultaneously. Concrete blocks were introduced to increase the river’s physical stability during floods, and terra cottem, a soil enhancer, was used to reduce water loss due to intense heat. These interventions increased the river’s ability to hold water and thereby promoted plant growth. This restoration method increased vegetation coverage and species diversity in treated areas, and changed the species composition in treated areas to more closely approximate that of the control site. These results suggest that this method is effective in restoring damaged habitats to more natural conditions.
Abstract
The diversity of spider communities was investigated in the pine forest of Pinus densiflora in Songri-san, where chemical pesticides had been applied to control pine gall midge (Thecodiplosis japonensis). Spider communities were surveyed in four areas: a pesticide-untreated natural forest (area A), a forest with vinyl-covered ground surface (area B), an aldicarb-treated forest (area C) and a forest treated with a systemic pesticide (phosphamidon) (area D). A total of 74 spider species from 17 families were collected from the four survey areas. There were 54 species from 15 families in area A, 27 species from 12 families in area B, 29 species from 9 families in area C and 34 species from 9 families in area D, respectively. The species diversity of spider communities was highest in pesticide-untreated area A, and much lower in the other three areas. The monthly species diversity of spider communities was highest in May and lowest in January. The similarity of the spider communities was highest in areas B and D. The monthly similarity of the spider communities was highest in November and February. The dominant species was Clubiona jucunda (12.71%, N=304 individuals). According to our results, the application of aldicarb and phosphamidon dramatically decreased spider diversity and the number of individuals in the forests. Thus, the application of these two pesticides to natural forests should be restricted, or alternative pesticides need to be developed. Our results also indicated that application of the pesticides should be avoided in May and June when high spider diversity is expected.
Abstract
Statistical tools for determining sex in the sexually monomorphic black-billed magpie based on morphological characters have been developed based on studies of European and North American populations. However, since no morphological method has been developed for black-billed magpies in Korea, it has been difficult to conduct field studies that require information about the sex of individuals. We present two discriminant equations for determining sex of second-year (SY) and after-second-year (ASY) magpies in north- and mid- western part of South Korea. Based on morphological measurements on 105 SY (56 females, 49 males) and 72 ASY (36 females, 36 males) individuals, we found body mass, wing chord, and head length to be the most useful features for morphological sex determination. The accuracy of our method was 86.5% for SYs and 93.1% for ASYs, which is similar to values reported previously from American and European magpies. Since the equations contain morphological traits which are only minimally susceptible to seasonal variation and measurement errors, our discriminant equations should be both useful and robust for sex determination on black-billed magpies in the northern and mid-western regions of South Korea.
Abstract
Researchers have used a variety of methods to measure patterns of animal movement, includingthe use of spatial data (mapping the position of a moving of travel path length by pacing under a moving animal or group. I collected movement data from five groups of siamangs (Symphalangus syndactylus ) using two different methods concurrently to estimate the effects of the method of data collection on estimates of daily path length (DPL). Estimates of DPL produced from spatial data collected at 15-minute intervals were 12% lower than estimates of DPL produced by pacing under the traveling animal. The actual magnitude of the difference was correlated with the travel distance, but there was no corre-lation between the proportional difference and the travel distance. While the collection of spatial data is generally relatively small difference between the DPLs produced using different methods suggests that pacing is an acceptable substitute where the collection of spatial data is impractical. I also subsampled the spatial data at increasing time intervals to assess the effect of sampling interval on the calculation of daily path lengths. Longer sampling intervals produced significantly shorter estimates of travel paths than shorter sampling intervals. These results suggest that spatial data should be collected at short time intervals wherever possible, and that sampling intervals should not exceed 30 minutes. Researchers should be cautious when comparing data generated using different methods.