• Korean Journal of Environmental Biology
• /
• v.24 no.2 s.62
• /
• pp.160-165
• /
• 2006

The purpose of this study was to ascertain the prey composition and utilization of the Eurasian otter, Lutra lutra, in the ecosystem conservation region of the Seomjin River. The study was conducted for a 12-month period from March 2003 to February 2004 by spraints analysis and an investigation using artificial holts. We found seasonal variation in the number of spraints and composition of prey items. Fish were the main prey items throughout the period (82%), and other prey items included birds (14%), amphibians (2%) and arthropods (1%). In addition to prey identification, we investigated habitat utilization by otters through spraints distribution. The traces of otters were discovered in five of the six total artificial holts. However, the utilization of the artificial holts in the study area seemed to be limited as evidenced by the low frequency of traces in the holts.

• Environmental Analysis Health and Toxicology
• /
• v.16 no.4
• /
• pp.197-204
• /
• 2001

Endocrine disruption in crucian carp (Carassius auratus) living in the branch of Han River were examined. Vitellogenin level in plasma was measured using ELISA system and aromatase mRNA level in brain was observed using RT-PCR technique. In all female fish, vitellogenin levels were in the range of 20∼40 $\mu\textrm{g}$/ml and aromatase mRNA expression could be detected on the agarose gel after RT-PCR. However, in case of males, vitellogenin level was elevated in only one fish, while vitellogenin was hardly detected in others. Aromatase was expressed in all males although the levels were relatively lower than the level in female fish. Testis-ova and any other histological changes of reproductive organ were not shown in both sexes.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2001.05a
• /
• pp.129-129
• /
• 2001

1,2-Dibromo-3-chloropropane (DBCP), a soil fumigant against nematodes, is a genotoxic carcinogen and also is classified by World Wildlife Fund as endocrine disruptors. DBCP has been extensively studied on genotoxicity, carcinogenicity, and damage in male reproductive-related organs. However, information on precise mechanism of mutagenesis and carcinogenesis of DBCP is yet unknown. (omitted)

• The Korean Journal of Pesticide Science
• /
• v.6 no.2
• /
• pp.51-57
• /
• 2002

Cyanogenic glycosides are secondary plant metabolites that are known as plant defense chemicals. They are found in cassava, bamboo, flax, and other plants. In this paper, the role of cyanogenic glycosides, their characteristics, and their interactions with insects are discussed. Previous and current research in our laboratory found that several natural and synthetic cyanohydrins were effective against stored-product insects as fumigants. Due to their insecticidal activity to insects, cyanohydrins can be used as an alternative fumigant and also as soil fumigants. Risk assessment, however, should be done to account for possible environmental problems, non-target wildlife effects, and human health effects.

• Korean Journal of Plant Taxonomy
• /
• v.41 no.3
• /
• pp.249-252
• /
• 2011

Scutellaria tuberifera C. Y. Wu & C. Chen belonging to Lamiaceae, a species previously unrecorded for Korean flora, was collected streamside in the Andeok valley of Seogwipo-Si, on Jeju island. This species can be distinguished from others of Scutellaria from Korea by having rhizomes with leafless and branching stolons at the nodes, globose to ovoid tubers 5-7 mm in diameter at the terminal parts, and stems densely spreading pilose. Photos of the habit and illustration are provided.

• The Korean Journal of Malacology
• /
• v.17 no.1
• /
• pp.57-61
• /
• 2001

The present study examines the potential involvement of Biomphalaria glabrata, a known molluscan intermediate host of Schistosoma mansoni, in the life cycle of Echinostoma cinetorchis, one of the echinostomes that are ubiquitous parasites of vertebrates and are of importance in human and veterinary medicine and wildlife diseases. Echinostomes can be maintained easily and inexpensively in the laboratory and provide good models for biological research ranging from the molecular to the organismal. In the present study, no echinostome cercariae were released from the B. glabrata experimentally infected with E. cinetorchis miracidia, whereas all the Biomphalaria snails infected with E. cinetorchis cercariae were found to be infected with the metacercariae. This is the first report that B. glabrata can experimentally serve as the second intermediate host of E. cinetorchis, and that it might be employed as one of the target molluscs for establishing a biological research model with E. cinetorchis in the laboratory.

• The Korean Journal of Ecology
• /
• v.18 no.4
• /
• pp.512-523
• /
• 1995

The central theme of Habital heterogeneity is to provide animals with habital complexity or structural diversity and to allow resource partitioning among individuals. In turn, the leads to population stability because prey can escape more easily with more hiding places causing less population fluctuation. Species diversity is characterized due to more potential niches both horizontally and verticall. Empirically, in homogeneous habitats population was less abundant, reproduction and survival were lower, spacing behavior, competition and dispersal were higher than in heterogeneous habitats. The results imply that diversity and conservation of species can be maintained through providing heterogeneous habitats.

• Journal of Forest and Environmental Science
• /
• v.28 no.2
• /
• pp.63-67
• /
• 2012

Crown ratio is the ratio of live crown length to tree height. It is often used as an important predictor variable for tree growth equation. It indicates tree vigor and is a useful parameter in forest health assessment. The objective of the study was to develop crown ratio prediction models for Tectona grandis. Based on the data set from the temporary sample plots, several non linear equations including logistics, Chapman Richard and exponential functions were tested. These functions were evaluated in terms of coefficient of determination ($R^2$) and standard error of the estimate (SEE). The significance of the estimated parameters was also verified. Plot of residuals against estimated crown ratios were observed. Although the logistic model had the highest $R^2$ and the least SEE, Chapman-Richard and Exponential functions were observed to be more consistent in their predictive ability; and were therefore recommended for predicting crown ratio in the stand.

• The Korean Journal of Ecology
• /
• v.20 no.4
• /
• pp.251-258
• /
• 1997

Few attempts have been made to discover the ecological function of coarse woody debris (CWD) despite its importance to small mammal population. Twenty-five pitfall traps and a hundred live traps were placed in three sites with high amounts of CWD and three sites with low amounts of CWD. Eleven species were caught, and Peromyscus maniculatus was the most abundant (45.6%, n=605). Among 11 speices, abundance of Tamias townsendii and Clethronomys gapperi were higher in sites with high amounts of CWD than in sites with low amounts of CWD. Home range size was larger in breeding season than in non-breeding season indicating mating search. Resident time of Peromyscus maniculatus was longer in sites with high amounts of CWD implying better stability in population. The increasing amount of coarse woody debris (CWD) enhanced the habitat use by small mammals, and animals in high amounts of CWD were more abundant and stable in population fluctuation. This study, therefore, concludes that CWD is a critical habitat element for small mammals in forest ecosystem.

• Korean journal of applied entomology
• /
• v.31 no.3
• /
• pp.289-303
• /
• 1992

Investigation of the environmental impact of widespread pesticide use has revealed a virtue/vice relationship. Although many pesticides perform their function and disappear without harm to the environment, others persist beyond their useful purpose and cause direct of indirect hazard to man, domestic animals and wildlife. Concurrently, many pests have rapidly adjusted to chemical control practices through changes in behavior that avoid exposure to pesticides of throuth genetic selection for populations resistant to the toxicants. The prospect of losing control over insect herbivores and desease vectors and returning to the days of global hunger and disease is unthinkable. Fortunately, from basic studies of insect and plant biology many opportunities for the development of safe, selective and environmentally pacific strategies for insect pest management are being realized.