• Research in Plant Disease
• /
• v.18 no.4
• /
• pp.381-386
• /
• 2012

Nematode fauna in Dokdo island was investigated for two years between 2008 and 2009. Population density and biomass were $239,500m^2$ (26,000-836,000) and $103.9mg/m^2$ (3.0-388.6), respectively. Total of 31 species of nematodes were identified : Acrobeloides is the most important genus with prominence value (PV) of 117.8, followed by Rhabditidae (PV = 81.9), Prismatolaimus (PV = 39.0), and Aphelenchoides (PV = 31.4). Among feeding group, bacteriovorus nematode composed 77% of density and 62% of biomass followed by plant-parasitic and fungivorus nematodes. A species of Pratylenchus having distinctive tail terminus is under study as a new species. Biological indices, Shannon and Wiener index (2.46), Simpson's diversity index (0.86), Species evenness (0.73), Species richness (1.30) indicate that nematode fauna in Dokdo island is diverse and unique. This study may give a general idea of nematode fauna at the Dokdo island.

• Korean Journal of Microbiology
• /
• v.49 no.3
• /
• pp.282-285
• /
• 2013

Microbial diversities in the 300 m and 500 m deep seawaters near Goseong, Gangwon Province (South Korea), were investigated. Pyrosequencing of 16S rRNA genes of marine microbes resulted in 19,474 reads from the 300 m deep seawaters, which consisted of Alphaproteobacteria (57.41%) and Gammaproteobacteria (38.85%), and 82,806 reads from the 500 m deep seawaters, which consisted of Gammaproteobacteria (99.64%) mostly. Rhodobacterales (57.31%) were dominant in the 300 m deep seawaters, but Alteromonadales (45.65%) and Oceanospirillales (34.61%) were dominant in the 500 m deep seawaters. On the bases of operational taxonomic units and diversity indexes (Shannon and Simpson), biodiversity of marine bacteria in the 500 m deep seawaters was shown to be higher than that in the 300 m deep seawaters.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.12
• /
• pp.2089-2093
• /
• 2017

The past decades have been a golden era during which great tasks were accomplished in the field of microbiology, including food microbiology. In the past, culture-dependent methods have been the primary choice to investigate bacterial diversity. However, using culturein-dependent high-throughput sequencing of 16S rRNA genes has greatly facilitated studies exploring the microbial compositions and dynamics associated with health and diseases. These culture-independent DNA-based studies generate large-scale data sets that describe the microbial composition of a certain niche. Consequently, understanding microbial diversity becomes of greater importance when investigating the composition, function, and dynamics of the microbiota associated with health and diseases. Even though there is no general agreement on which diversity index is the best to use, diversity indices have been used to compare the diversity among samples and between treatments with controls. Tools such as the Shannon-Weaver index and Simpson index can be used to describe population diversity in samples. The purpose of this review is to explain the principles of diversity indices, such as Shannon-Weaver and Simpson, to aid general microbiologists in better understanding bacterial communities. In this review, important questions concerning microbial diversity are addressed. Information from this review should facilitate evidence-based strategies to explore microbial communities.

• Korean Journal of Weed Science
• /
• v.2 no.1
• /
• pp.57-62
• /
• 1982

This study was conducted to evaluate the important weed occurring in orchard and to establish on effective control method using combination of non-selective foliar applied herbicide followed by soil treated herbicide. In terms of quantity, Calysregia hederacea, Artemisia princeps, Ixeris chinensis, Cephalonopios segetum, Capsella bursa-pastoris, Setaria viridis, Chenopodium album, Trifolium repens, Digitarta sanguinalis in order were observed to be the most important weeds in May, In July the most dominant weeds were D. sanguinalis, Setaria viridis, Amaranthus lividus, Portulaca oleracea, Polygonum hydropiper, Acalypha australis, Artemlsia prtnceps, Miscanthus sinensis in order, showing D. sanguinalis to be the dominant species. D. sanguinalis was one single dominant species till autumn, followed by A. lividus, P. oleracea, A. australis. Simpson's index, 0.159 obtained in May just before herbicide application increased to 0.253 in July and again decreased to 0.233 in Sept. in the oxyfluorfen treated plot, meaning that no specific weed species were dominant, while in the untreated plot, D. saguinalis was relatively single dominant species, showing Simpson's index, 0.540 and this trend was mainained till autumn. The most effective herbicide to control D. sanguinalis and other annuals was oxyfluorfen at 0.47kg a.i./ha. when applied at preemergence treatment, showing more than 80% control of them for 65 days. The results suggest that paraquat at 32/ha (prod.) as the foliar application followed by oxyfluorfen 0.47kg a.i./ha applied as the preemergence at one week after paraquat treatment can maintain the clean orchard more than 65 days, showing one of the promising and applicable control system in orchard.

• Korean Journal of Weed Science
• /
• v.5 no.2
• /
• pp.114-120
• /
• 1985

This study was conducted to investigate the important weeds occurring in onion and garlic planted in paddy field as the succeeding crop of rice and to evaluate the effect of competition between these crops and weeds on the yield of onion and garlic. In terms of quantity occurred, Persicaria hydropiper, Chenopodium ficifolium, Alopecurus aequalis, Poligonum aviculare, Echinochloa crus-galli, and Bothrisospermum tenellum appeared to be the major weeds in onion and garlic fields. Annual broadleaves were composed of 90.0 and 94.3% of total weed dry weight in onion and in garlic fields, respectively. Among these weeds, P. hydropiper was the most dominant species in onion and C. ficifolium in garlic fields. The higher Simpson's index such as 0.67 in garlic as compared to 0.40 in onion can be attributed to the presence of a C. ficifolium, which is existed in a single dominant species. The full season competition between the crops and these weeds resulted in yield reduction of onion by 23.9% and garlic by 31.9%, showing weed dry weight, 448.18 and 418.40 g/$m^2$ in onion and garlic fields, respectively. The maintenance of weed free condition for about 4 weeks after weed emergence could be the prerequisite to obtain the maximum yield of these two crops.

• Journal of Ecology and Environment
• /
• v.43 no.2
• /
• pp.183-190
• /
• 2019

Background: In the Philippines, the practice of planting mangroves over seagrass has been a practice done to promote coastline protection from damages done by storms. Despite the added protection to the coastline, the addition of an artificial ecosystem gradually inflicts damage to the ecosystem already established. In this study, seagrass communities that had no history of mangrove planting were compared with those that had mangrove planting. The percent substrate cover of seagrass in the sampling areas was determined, and the macroinvertebrates present in the sampling areas were also observed. The study was conducted based on reports of mangrove planting activity that disrupted seagrass functions on Santa Fe, Bantayan Island, Cebu. Transect-quadrat method sampling was done to assess the chosen sites. Results: Six species of seagrass was found on the site without mangrove planting which was barangay Ocoy (Cymodocea sp., Thalassia sp., Halodule sp., Enhalus sp., Halophila sp., and Syringodium sp.) and had a higher percent cover, while only four were found on the site with mangrove planting (barangay Marikaban). It was also found that barangay Marikaban had a lesser Shannon-Wiener and Simpson's index compared to barangay Ocoy. Jaccard's index of similarity between the two sites was low. Conclusion: With the results of the assessment, we recommend proper monitoring of future mangrove planting activities and that these activities should not disrupt another ecosystem as all ecosystems are important.

• The Korean Journal of Ecology
• /
• v.18 no.4
• /
• pp.441-449
• /
• 1995

The abundance of coarse woody debris (CWD) has been hypothesized to increase niche for forest dwelling insectivores, concentration of nutrients, and the diversity of invertebrates. However, no abjective assessment based on replication in the field has yet been done. this study was carried out to test the relationships between invertebrate availability and the abundance of four insectivores (Sorex trowbridgii, S. vagrans, S. monticolus and Neurotrichus gibbsii) in western Washington, USA. Pitfall traps were used to determine abundance and diversity of invertebrates. Abundance of insectivores was not different between habitats except for S. vagrans which was more abundant in habitats with low amounts of CWD than in habitats with high amounts of CWD. Simpson’s diversity index computed for invertebrates did not differ between habitats. There were no significant relationships between the diversity indices of invertebrates and the abundance of shrews. Shrew abundance and the Coleoperan beetles also did not show any significant relationship. The results suggested insectivores might select a wide range of prey items in addition to surface-active invertebrates.

• Korean Journal of Weed Science
• /
• v.17 no.2
• /
• pp.139-146
• /
• 1997

The experiment was conducted at Gyeongbuk Provincial Rural Development Administration in 1996 to obtain basic information on weed ecology and effective weed control in direct-seeded rice fields under different seeding types and seeding times. A large number of upland weeds such as Echinochloa crus-galli, Digitaria sanguinalis, Capsella bursa-pastoris and Stetaria viridis etc occurred at early growth stage, while Eleocharis kuroguwai, Aneilema keisak and Cyperus serotinus dominated at late stage in dry seeded rice field. In wet seeded rice field, the dominance of E. crus-galli was lower and the occurrence of M. vaginalis and A. keisak were higher than in dry seeded field. Amount of weed occurrence in dry seeded field was 1.8 to 2.4 times greater than in wet seeded field and it increased with delaying seeding time. Increasing rate of weed occurrence through whole life cycle was the highest at 20 days after seeding (DAS) to 40 DAS, regardless of seeding types and seeding times. Simpson index in wet seeded field was higher than in dry seeded field and it gradually increased as growing of dominant species. For F-value test, it was recognized as statistical significant in seeding types, seeding times and interaction of two factors.

• Journal of Forest and Environmental Science
• /
• v.27 no.1
• /
• pp.1-15
• /
• 2011

The present study was undertaken in middle altitudinal (1500 to 2500 masl) moist temperate forest of Mandal-Chopta area in the Garhwal region of Uttarakhand, India. The aim of the present study was to assess the variation in species composition and diversity in different vegetation layers viz. herb, shrub and tree, at different altitudes. Shannon-Wiener diversity index ($\bar{H}$), $Nha^{-1}$, total basal cover per hectare (G), Simpson concentration of dominance, Pielou Equitability, species richness (SR), Margalef index, Menheink index of species richness and ${\beta}$-diversity were calculated to understand community composition. Tree G ranged from 84.25 to 35.08 $m^2ha^{-1}$ and total stem density varied from 990 to 1470 Nha-1. Total SR (herb, shrub and trees) among different forest types ranged between 31 and 58. Maximum G of herb and shrub layers was recorded at lower altitudes between 1500 and 1650 masl. ${\beta}$-diversity was higher in herb layers as compared to tree and shrub layers. Dominance-diversity curves were also drawn to ascertain resource apportionment among various species in different forest types. Values of species diversity, $\bar{H}$, $Nha^{-1}$ and G were higher in the study area as compared to similar forests growing in other parts of Uttarakhand Himalaya.

• Korean Journal of Microbiology
• /
• v.41 no.1
• /
• pp.60-66
• /
• 2005

To select the rapid and efficient molecular subtyping method for epidemiologic monitoring of Staphylococcus aureus (S. aureus) strains at clinical laboratory levels, a total 116 of S. aureus and MRSA (methicillin-resistant S. aureus) strains from diverse animal species [Korean cattle, goat, pig, dog, chicken, mouse] and also humans were analyzed. To evaluate the discriminatory ability (DA) of individual PCR methods, random amplified polymorphic of DNA [RAPD; 4M & RA primer], repetitive extragenic palindromic sequences PCR (REP-PCR), and enterobacterial repetitive intergenic consensus sequences PCR (ERIC-PCR) methods were conducted and then compared on their Simpson's index of diversity (SID) values based on the dendrogram patterns, which was produced by software program (BiolD2+ & GelCompar II). In first, RAPD using the 4M primer (SID 0.915) was expressed more higher SID value than that of RA primer (SID 0.874). 4M primer was expressed more powerful DA than RA. Both REP-PCR (SID 0.930) and ERIC-PCR (SID 0.929) methods showed much more higher DA than that of RAPD. According to the present results, both REP-PCR and ERIC-PCR among the tested analysis methods were found as the most reliable and discriminative molecular subtyping method, because they expressed the highest DA for the present S. aureus and MRSA strains.