• Title/Summary/Keyword: NMS ordination

Search Result 9, Processing Time 0.02 seconds

Comparison of Four Different Ordination Methods for Patterning Water Quality of Agricultural Reservoirs

  • Bae, Mi-Jung;Kwon, Yong-Su;Hwang, Soon-Jin;Park, Young-Seuk
    • Korean Journal of Ecology and Environment
    • /
    • v.41 no.spc
    • /
    • pp.1-10
    • /
    • 2008
  • We patterned water quality of agricultural reservoirs according to the differences of six physico-chemical environmental factors (TN, TP, DO, BOD, COD, and SS) using four different ordination methods: Principal Components Analysis (PCA), Detrended Correspondence Analysis (DCA), Nonmetric Multidimensional Scaling (NMS), and Isometric Feature Mapping (Isomap). The data set was obtained from the water quality monitoring networks operated by the Ministry of Agriculture and Forestry and the Ministry of Environments. Chlorophyll-${\alpha}$ displayed the highest correlation with COD, followed by TP, BOD, SS, and TN (p<0.01), while negatively correlated with altitude and bank height of the reservoirs (p<0.01). Although four different ordination methods similarly patterned the reservoirs according to the gradient of nutrient concentration, PCA and NMS appeared to be the most efficient methods to pattern water quality of reservoirs based on the explanation power. Considering variable scores in the ordination map, the concentration of nutrients was positively correlated with Chl-${\alpha}$, while negatively correlated with altitude and bank height. These ordination methods may help to pattern agricultural reservoirs according to their water quality characteristics.

Study on Plant Indicator Species of Picea jezoensis (Siebold & Zucc.) Carrière Forest by Topographic Characters - From China (Baekdu-san) to South Korea - (가문비나무림의 지형특성에 따른 식물 지표종에 관한 연구 - 중국 백두산 일대에서 남한까지 -)

  • Byeong-Joo, Park;Tae-Im, Heo;Jun-Gi, Byeon;Kwang-il, Cheon
    • Journal of Environmental Impact Assessment
    • /
    • v.31 no.6
    • /
    • pp.388-408
    • /
    • 2022
  • This study was conducted to select the indicator species (plant) according to the topographical characteristics in the Picea jezoensis forests, endangered subalpine coniferous trees. In South Korea and China (close to Baekdusan), the southern tree line limit of Picea jezoensis has meaningful geographical and latitudinal values for analyzing the ecological characteristics of P. jezoensis forests. Latitude greatly affects the geographical values of plant ecology, and the difference in latitude and habitat affects the change in species composition in forests. With prolonged environmental change, the habitat of subalpine plants will become smaller, and the plants may become extinct. As the P. jezoensis forests of South Korea and China, in particular, are in danger of disappearing without protection, it is important to monitor the population and develop a conservation strategy. Eighty-seven circular plots were established in P. jezoensis forests in South Korea and China. Through processes such as MRPP-test and NMS ordination, indicator species were selected based on this, and basic data for biodiversity assessment were presented. As a result of the Indicator Species Analysis (ISA), 5 taxa were selected from the upperstory vegetation and 18 taxa from the understory vegetation at the altitude(p<0.05). Indicator species by aspect were analyzed as 3 taxa for upperstory vegetation and 16 taxa for understory vegetation (p<0.05). In the case of indicator species according to the slope, 6 taxa for upper vegetation and 24 taxa for understory vegetation were selected(p<0.05). As for the indicator species according to their habitat, 8 taxa in upper vegetation and 65 taxa on understory vegetation were selected. As a result of MRPP-test, it was analyzed that the species composition was heterogeneous in the group of understory vegetation than that of upperstory vegetation. As a result of NMS ordination, the correlation with environmental factors of indicator species was analyzed by rock exposure for upperstory vegetation and latitude for understory vegetation (cut off level=0.3).

Community Structure of Abies nephrolepis Habitats and Characteristics of Understory Vegetation in Mt. Gyebang and Mt. Odae (계방산과 오대산 일대 분비나무 자생지 군집 구조 및 하층식생 특성)

  • Cheon, KwangIl;Byeon, Jun-Gi;Kim, Jung-In;Park, Byeong-Joo
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.25 no.5
    • /
    • pp.59-76
    • /
    • 2022
  • This study was conducted to investigated woody species community classification and understory vegetation characteristics of Abies nephrolepis forest in Mt. Gyebang and Mt. Odae designated as Protected Area for Forest Genetic Resource Conservation and National Park. Vascular plants were surveyed as following; 55 family, 148 species, 3 sub species, 14 variety, 2 form 167 taxa. As an analysis of the species estimator of Jackknife 1, 29 survey plots could be representative of vegetation in study site. Results of the woody species, 3 communities were divided by cluster analysis(A=Abies nephrolepis-Tilia amurensis, B=Betula ermanii-Abies nephrolepis, C=Quercus mongolica-Abies nephrolepis). Using MRPP-test, there were significant differences between the communities indicating analysis of the appropriate group classification(p<0.01). The basal area and altitude were analyzed by negative relationship for NMS ordination. By analyzing plexus diagram of woody species, Acer pseudosieboldianum is strong associated with Quercus mongolica and Rhododendron schlippenbachii. Magnolia sieboldii is strong associated with Acer pictum subsp. mono etc.

Environmental Risk Assessment of Watermelon Grafted onto Transgenic Rootstock Resistant to Cucumber Green Mottle Mosaic Virus (CGMMV) on Non-Target Insects in Conventional Agro-Ecosystem

  • Yi, Hoon-Bok;Park, Ji-Eun;Kwon, Min-Chul;Park, Sang-Kyu;Kim, Chang-Gi;Jeong, Soon-Chun;Yoon, Won-Kee;Park, Sang-Mi;Han, Sang-Lyul;Harn, Chee-Hark;Kim, Hwan-Mook
    • Journal of Ecology and Environment
    • /
    • v.29 no.4
    • /
    • pp.323-330
    • /
    • 2006
  • We investigated the impact of watermelon grafted onto Cucumber Green Mottle Mosaic Virus (CGMMV)-resistant transgenic watermelon rootstock on insects as non-target organisms in a greenhouse in 2005. We quantitatively collected insect assemblages living on leaves and flowers, and we used sticky traps to collect alate insects. We compared the patterns of insect assemblages and community composition, cotton aphid (Aphis gossypii Glover) on watermelon leaves and western flower thrip (Frankliniella occidentalis Trybom) on watermelon male flowers, between CGMMV-resistant transgenic watermelon (TR) and non-transgenic watermelon (nTR). Non-parametric multidimensional scaling (NMS) ordination verified that insect assemblages on leaves and sticky traps were different between TR and nTR (P<0.05). The insect assemblages on male flowers were not statistically significant. Multi-response permutation procedures proofed our results from NMS results (P>0.05). Conclusively, TR watermelons appear to have some adverse effects on the population of cotton aphids on leaves and sticky traps, but watermelon male flowers do not show an adverse effect. Further research is required to assess the effect of TR on the aphid and western flower thrip. Life table experiments might support the specific reason for the adverse effects from leaf assemblages. Assessment of non-target impacts is an essential part of the risk assessment of non-target insects for the impact of transgenic organisms.

Effect of island geography on plant species on uninhabited islands in southeastern South Korea

  • Choi, Sei-Woong;An, Jeong-Seop;Yang, Hyo-Sik
    • Journal of Ecology and Environment
    • /
    • v.38 no.4
    • /
    • pp.451-459
    • /
    • 2015
  • We investigated the pattern of floral diversity including naturalized plant species and three ecological factors (area, elevation and distance from mainland) of plant species on 53 uninhabited islands in Gyungsangnam-do, southeastern South Korea. A total of 206 taxa in 67 families were observed, and the species of Compositae was most common. Thirteen taxa in eight families of the naturalized plants were observed on 33 islands. The numbers of total plant species, area and elevation were significantly correlated, but no relationship with distance from the mainland was observed. In addition, no relationship was found among the numbers of naturalized plants, area and elevation. However, the average rate of naturalization on islands with different elevations differed significantly, indicating the smallest proportion of naturalized plant species was on high islands. Multiple regression of total species richness identified elevation as a significant factor, while no significant variables were correlated with naturalized plant species. Nonmetric multidimensional scaling (NMS) ordination identified three major variables, distance from mainland, number of naturalized plant species and elevation. These findings indicate that the geography of islands such as area and elevation affected the species richness of plants on uninhabited islands, while human disturbance had a greater effect than geography on the species richness of naturalized plants on islands in southeastern South Korea.

Species Composition and Species Diversity of Moths (Lepidoptera) on Quercus mongolica forests sand Pinus densiflora forests, in Korean National Long-term Ecological Research Sites (Mt. Nam, Mt. Jiri, Mt. Wolak) (국가 장기 생태 연구지(남산, 지리산, 월악산)의 신갈나무림과 소나무림에서 포획된 나방류의 종조성 및 종다양도)

  • Yi, Hoon-Bok;Kim, Hyun-Jung
    • Korean journal of applied entomology
    • /
    • v.49 no.2
    • /
    • pp.105-113
    • /
    • 2010
  • Moths were collected using a 22W UV black light trap in June through September in 2005 and May, June, August and September in 2006. The study sites were Namsan (Mt. Nam), Jirisan (Mt. Jiri), Woraksan (Mt. Worak) which are part of the Korean National Long Term Ecological Research (KNLTER). There were two common forest communities, Quercus mongolica and Pinus densiflora. The purpose of this study was to compare species diversity of the major plant feeding Lepidoptera in the two forest types at the regional KNLTER sites. We collected a total of 435 species from the KLTER sites in 2005 and 2006. Abundance of moths was highest at Woraksan (Mt. Worak) followed by Jirisan (Mt. Jiri). The Namsan (Mt. Nam) site had the lowest, with five families (Arctiidae, Geometridae, Noctuidae, Notodontidae, and Pyralidae). Analysis of variance (ANOVA) showed statistically significant differences at sampling date in species abundance as a response variable and at site in species richness as another response variable. Although we expected a distinct cluster with the forest type at each study site, one of ordination analyses, nonmetric multidimensional scaling (NMS), showed distinct clusters with the moth assemblages at each site only but NMS did not show any distinct cluster with the different forest types at each site as we expected.

Restoration effects influenced by plant species and landscape context in Young-il region, Southeast Korea: Structural and compositional assessment on restored forest

  • Cho, Yong-Chan;Kim, Kyung-Soon;Pi, Jung-Hun;Lee, Chang-Seok
    • Journal of Ecology and Environment
    • /
    • v.39 no.1
    • /
    • pp.1-10
    • /
    • 2016
  • Despite it has been mentioned that the successful restoration in landscape level was achieved in the Young-il soil erosion control project, quantitative evaluation of restored plant communities (Alnus firma as introduced species and Pinus thunbergii as native species) was hardly founded. Light availability, litter and woody debris cover, and forest structure and composition were determined for 500 m2 band-quadrat in three forest types. Abiotic factors of Q. serrata stands, as reference forest, and A. firma stands were similar but not for P. thunbergii stands. There were no significant difference on mean stem density (stems ha-1, H = 3.6, p = 0.162), and the mean basal area of each stand had marginal significance (m2 ha-1, H = 5.7, p = 0.058) among stands as total basal area was higher with the order of A. firma (21.4 m2 ha-1), P. thunbergii (19.8 m2 ha-1) and Q. serrata (16.2 m2 ha-1). Restoration of vegetation structure was more effective in fast-growing and N-fixing A. firma, as introduced species plantation. However, result of MRPP, NMS ordination and ISPAN for herbaceous layer, not for tree and shrub species composition, indicated that restoration of ground vegetation was likely influenced highly from local environment. Propagule availability from landscape context such as connectedness to natural vegetation and management practices in restored isolated stands are available explanations for restoration effects and gaps between restored plantations and secondary oak forest.

The Character of Community Structure and Distribution for Thuja koraiensis Nakai, South Korea (눈측백의 군집구조와 분포특성)

  • Byeon, Jun-Gi;Cheon, KwangIl;Lee, Dong-Hyuk;Heo, Tae-Im;Lee, Jun-Woo;Kim, Ji-Dong;Park, Byeong-Joo
    • Korean Journal of Plant Resources
    • /
    • v.33 no.2
    • /
    • pp.93-105
    • /
    • 2020
  • The study was investigated in vegetation and environmental factors of Thuja koraiensis habitats where provided for ecological evidence data for conservation and management. Study plots were located at altitudes of 1,000~1,588 m with inclinations of 10~30°. A total of 150 taxa was identified 22 quadrates in 6 study sites. The highest basal area was analyzed in Mt. Gariwangsan 49.98 ㎡/㏊ with the lowest Mt. Hwaaksan 3.46 ㎡/㏊. Thuja koraiensis forest was classified into two communities; Abeis nephrolepis-Taxus cuspidata community, Betula ermanii-Thuja koraiensis community. As a result of Multi-Response Permutation Procedures test, there was significant difference among the communities.

Growing Environment Characteristics and Vegetational Structure of Sageretia thea, Medicinal Plant (약용식물 상동나무 자생지 생육환경 특성과 식생구조)

  • Son, Yonghwan;Son, Ho Jun;Park, Gwang Hun;Lee, Dong Hwan;Cho, Hyejung;Lee, Sun-Young;Kim, Hyun-Jun
    • Korean Journal of Plant Resources
    • /
    • v.35 no.5
    • /
    • pp.594-606
    • /
    • 2022
  • This study was conducted to figure out the environment factors including vegetation structure and soil characteristics in natural habitats of Sageretia thea, and offers the basic information for habitats conservation and proliferation. The natural habitats of Sageretia thea were located at altitudes between 0~370 m with inclinations ranged as 3~35°. Through the vegetation research, the dominant species of tree layers were found to be divided into four communities. Cornus macrophylla (Com. I), Pinus thunbergii - Cinnamomum camphora (Com. II), Machilus thunbergii (Com. III), and Pinus thunbergii (Com. IV). The Species diversity (H') was 1.397~1.455, evenness (J') was 0.972~0.986, and dominance (D) was found to be 0.014~0.028. As a result of the physicochemical characteristics of soils, habitats soil mainly consisted of sandy soil and sandy loam soil. The average soil pH was 5.28~5.98, electronic conductivity was 0.22~63 ds/m, soil organic matter was 13.33~19.33 cmol+/kg, Exchange cations were appeared in the order of Ca2+, Mg2+, K+, and Na+. The Ordination result showed that Correlation coefficient between communities and environmental factors were significantly correlated with 4 main factors altitude, electronic conductivity, cation exchange capacity, exchangeable Na+. As expected, The result of this study will be helpful information on the preservation and mass production for use.