Earticle

Global environmental changes have the capacity to make dramatic alterations to floral and faunal composition, and elucidation of the mechanism is important for predicting its outcomes. Studies on global climate change have traditionally focused on statistical summaries within relatively wide scales of spatial and temporal changes, and less attention has been paid to variability in microclimates across spatial and temporal scales. Microclimate is a suite of climatic conditions measured in local areas near the earth’s surface. Environmental variables in microclimatic scale can be critical for the ecology of organisms inhabiting there. Here we examine the effect of spatial and temporal changes in microclimates on those of carabid beetle communities in Hyangnobong, Korea. We found that climatic variables and the patterns of annual changes in carabid beetle communities differed among sites even within the single mountain system. Our results indicate the importance of temporal survey of communities at local scales, which is expected to reveal an additional fraction of variation in communities and underlying processes that has been overlooked in studies of global community patterns and changes.

주암호는 광주·전남지역의 주요 상수원이나 흑수현상을 일으키는 망간이 고농도로 발생할 때마다 주암호를 대상으 로 한 망간연구 자료가 불충분하여 정수장에서는 이러한 상황을 대처하는데 어려움을 겪고 있는 실정이다. 따라서 본 연 구의 목적은 주암호의 망간농도 변화를 시공간적으로 측정하여 고농도 망간이 발생하는 원인을 규명하고 그 발생시기를 추정하는 방법을 개발하는 것이다. 주암호의 고농도 망간발생은 심수층에 농축되어 있던 망간이 호수 전도에 의해 부상· 확산될 때에 일어났으며, 또한 호수의 동절기 전도는 수온저하, 하절기 전도는 낮은 수위일 때 집중강우에 의한 수체교란 때문이다. 전도기간에 망간은 (1) 퇴적물과 수체 경계의 빈산소 기간이 길수록, (2) 집중강우 시에 호수의 수위가 낮을수 록, (3) 동절기에 기온이 낮을수록 그 농도가 증가하는 것으로 나타났다.

The lake Juam is a major water source for people in Gwangju and Chonnam area. But whenever manganese with high concentration occurs, the operators of water treatment plant have a difficulty in treating the manganese because the data of the manganese research related to the lake are insufficient. Thus the purpose of this study is to establish the cause of high manganese concentration and also develop a method of estimating its occurrence time by investigating the temporal and spatial variation of manganese distribution for Juam lake. The results of this study show that the high manganese in the whole area of the lake occurs when the high manganese condensed in the hypolimnion is surfaced and diffused by the turn over of the lake. Also, the turn overs in winter and summer seasons are because of the drop of water temperature and the water disturbance by intensive rainfall, respectively. In addition, the manganese concentration in turn over period is higher and higher when (1) the period of oxygen deficient state in the sediment-water interface is longer, (2) the water level of lake in intensive rainfall time is lower and (3) the water temperature in winter season falls more.

Temporal and spatial variation of soil moisture is important for understanding patterns of climate change, for developing and evaluating land surface models, for designing surface soil moisture observation networks, and for determining the appropriate resolution for satellite-based remote sensing instruments for soil moisture. In this study, we measured several soil moistures in upland soil using Advanced Microwave Scanning Radiometer 2 (AMSR2) Soil Moisture Content (SMC) during eight-month period in Chungbuk province. The upland soil moisture properties were expressed by simple statistical methods (average, standard deviation and coefficient of variation) from the monthly context. Supplementary studies were also performed about the effect of top soil texture on the soil moisture responses. If the results from this study were utilized well in specific cities and counties in Korea, it would be helpful to establish the countermeasures and action plans for preventing disasters because it was possible to compare with the relationship between soil moisture and top soil texture of each region. And it would be the fundamental data for estimating the effect of future agricultural plan.

The Agricultural Land Remodeling Project was launched for agricultural fields with potential risk of flooding which were placed in low-lying area as a part of agricultural sectors of the National 4 River Project. It induced of the reclaimed agricultural fields on a national scale. The arable lands reestablished by reclamation have caused several big problems such as destruction of soil physicochemical properties, and thus the techniques to solve disadvantages were urgently required. In this study, we collected experimental samples from top soils in three agricultural areas, one from conventional agricultural fields (Hwasun, Jeollanam-do) and the others from reclaimed (remodelled) agricultural fields (Naju, Jeollanam-do and Gumi, Gyeongsangbuk-do), The soil chemistry data were analyzed using statistic tools such as semi-variance and kriging, and differences between natural and reconstructed soils were examined. The score, R (Ao) which indicates a dependence distance between each chemical element, was as follows; 21.8~43.5 (Conventional, Hwasoon), 4.4~70.6 (Remodelled, Naju) and 5.3~43.6 (Remodelled, Gumi). These results suggested that chemical properties of the reclaimed agricultural fields had a huge variation. Moreover, the result of kiriging maps also represented a ununiform pattern in the reclaimed lands. As a result of this study, it is strongly required to build up the soil type-specific management techniques for the reclaimed agricultural lands.

Thirty populations of Chondrus crispus Stackhouse from Nova Scotia were collected during the years 1993 to 2011. Taken from estuaries, wave exposed open coasts, high intertidal rock pools and shallow subtidal habitats, the populations were evaluated for relative abundance of tetrasporophytic and gametophytic life history phases. Over 2,800 thalli were characterized using the resorcinol-acetal test to distinguish the kappa- and lambda-carrageenan containing fronds of gametophytes and tetrasporophytes, respectively. These populations had $77{\pm}5%$ gametophytes (mean ${\pm}95%$ confidence interval), with most populations having gametophyte : sporophyte ratios ranging from 2 : 1 to 9 : 1. No population had a dominance of tetrasporophytes, although two populations had 1 : 1 ratios. A meta-analysis of our data along with previously published accounts showed no significant changes in gametophyte dominance with respect to hypothesized gradients of wave exposure, salinity, or water depth. Significant changes occurred in ratios at five sites where replicate sampling occurred in different years. We conclude that C. crispus in Maritime Canada has a natural ratio of 3 : 1 or greater in stable conditions, and that lower ratios represent recovery from disturbance in which bare substratum is created that is subsequently colonized by carpospores from remaining gametophytic thalli.

Fish larvae were collected monthly with an ichthyoplankton net from 18 stations (including four stations located in eelgrass beds) in Gamak Bay and Yeoja Bay, southern Korea, in 2007. In total, 33 species of fish larvae were collected, of which Engraulis japonicus (48.5%), Tridentiger trigonocephalus (21.5%), and Omobranchus elegans (9.2%) were dominant. Dominant species varied seasonally: Hexagrammos otakii during December and January, Pholis nebulosa during January and March, Acanthogobius flavimanus in April, T. trigonocephalus in May, E. japonicus during June, July, September, and November, and Sillago japonica in August. Dominant species also differed between sites inside and outside the bays. Leiognathus nuchalis, O. elegans, and T. trigonocephalus were more abundant inside, while H. otakii was more abundant outside. From cluster analysis, three groups were identified according to sampling months (January-April, May-September, and October-December) and two groups according to station (inside and outside bays). The occurrence of small larvae of almost all major fish species indicated that the bays were used as spawning and nursery grounds. An exception was Lateolabrax japonicus, whose specimens were relatively large (>19 mm TL), suggesting that this fish may spawn offshore, with its juveniles approaching the bays with growth.

In this study, the temporal and spatial variation in precipitable water vapor (PWV) was analyzed for typhoon Ewiniar which had made landfall in the Korean peninsula in 2006. To make a contour map of PWV, zenith total delay (ZTD) was calculated using about 60 GPS permanent stations in Korea, and the pressure and temperature data of nearby AWS stations were interpolated and applied to the equation for calculating the PWV. While Typhoon Ewiniar was migrating north from the southern coast to the eastern coast of Korea, the PWV migrated showing a spatial distribution similar to that of rainfall. Also, the fluctuating pattern of the normalized PWV was analyzed, and the moving speed of the PWV was estimated using the delay time of the increase/decrease pattern in the eight-test stations. The result indicated that the moving speed of the PWV was about 35 km/h, which was similar to the average moving speed of the typhoon (38.9 km/h).

For developing the site-specific fertilizer management strategies of crop, it is essential to know the spatial variability of soil factors and to assess their influence on the variability of crop growth and yield. In 2002 and 2003 cropping seasons within-field spatial variability of rice growth and yield was examined in relation to spatial variation of soil properties in the· two paddy fields having each area of ca. $6,600m^2$ in Suwon, Korea. The fields were managed without fertilizer or with uniform application of N, P, and K fertilizer under direct-seeded and transplanted rice. Stable soil properties such as content of clay (Clay), total nitrogen (TN), organic mater (OM), silica (Si), cation exchange capacity (CEC), and rice growth and yield were measured in each grid of $10\times10m$. The two fields showed quite similar spatial variation in soil properties, showing the smallest coefficient of variation (CV) in Clay $(7.6\%)$ and the largest in Si $(21.4\%)$. The CV of plant growth parameters measured at panicle initiation (PIS) and heading stage (HD) ranged from 6 to $38\%$, and that of rice yield ranged from 11 to $21\%$. CEC, OM, TN, and available Si showed significant correlations with rice growth and yield. Multiple linear regression model with stepwise procedure selected independent variables of N fertilizer level, climate condition and soil properties, explaining as much as $76\%$ of yield variability, of which $21.6\%$ is ascribed to soil properties. Among the soil properties, the most important soil factors causing yield spatial variability was OM, followed by Si, TN, and CEC. Boundary line response of rice yield to soil properties was represented well by Mitcherich equation (negative exponential equation) that was used to quantify the influence of soil properties on rice yield, and then the Law of the Minimum was used to identify the soil limiting factor for each grid. This boundary line approach using five stable soil properties as limiting factor explained an average of about $50\%$ of the spatial yield variability. Although the determination coefficient was not very high, an advantage of the method was that it identified clearly which soil parameter was yield limiting factor and where it was distributed in the field.