Exotic Weed Research Articles

Genetic and environmental effects on seed weight in subspecies of big sagebrush: applications for restoration

The sagebrush steppe is a patchwork of species and subspecies occupying distinct environmental niches across the intermountain regions of western North America. These ecosystems face degradation from disturbances and exotic weeds. Using sagebrush seed that is matched to its appropriate niche is a critical component to successful restoration, improving habitat for the threatened greater sage‐grouse and other species. The need for restoration is greatest in basin habitats composed of two subspecies: diploid basin big sagebrush (A. tridentata subsp. tridentata) and tetraploid Wyoming big sagebrush (subsp. wyomingensis). In this study we assess seed weights across five subspecies‐cytotype groups of big sagebrush and examine the genetic and environmental components. Our goal is to determine if seed weight can be used as a diagnostic test for subspecies and seed certification. Seed weight was measured from 55 wild collections and from progeny derived from these collections and grown in two common gardens. A linear mixed‐effect model showed 91% of the variation in seed weight is explained by genetic, genetic × environment and environmental effects (conditional R2 = 0.91). Moreover, genetic effects alone, subspecies‐cytotype groups, explained 39% of the variation (marginal R2 = 0.39). Of the five subspecies‐cytotype groups, most had overlapping weights using conservative 99% confidence intervals. However, diploid tridentata and wyomingensis had non‐overlapping 99% confidence intervals. To demonstrate the application of seed weighing to assess the subspecies purity of commercial seed lots, we compared confidence intervals of tridentata and wyomingensis developed from the experimental data to seed weights of commercial lots. The results showed that only 17% of the commercial seed lots certified as wyomingensis had mean seed weights that fell within the confidence intervals for this subspecies. The remaining lighter seed lots (83%) matched weights of tridentata. While restoring sagebrush ecosystems is a multifaceted problem, a fundamental component to restoration is ensuring the appropriate seed is used. We found seed weight is principally affected by genetic factors, with limited environmental effects. Seed weighing is an effective application to assess subspecies purity of wyomingensis and tridentata seed and could be used as a certification step for evaluating commercial collections used in restoration.

제주도 밭의 외래잡초 분포

We surveyed the distribution of exotic weeds in the 141 crop fields of Jeju island. The exotic weeds were summarized as 66 taxa including 18 families, 50 genera, 64 species and 2 varieties. In winter crop fields there were 45 species of exotic seeds in 18 families, in summer crop fields 50 species in 16 families, and in perennial crop fields 39 species in 17 families. Total exotic weeds were classified to 39.4% of summer annuals, 36.4% of winter annuals, 7.6% of summer and winter annuals, and 16.7% of perennials. The ratio of summer annuals were high in the summer crop fields. Compositae was dominant family, followed by Gramineae, Malvaceae and Solanaceae. Malvaceae did not appear in perennial crop fields. Dominant exotic weeds in winter crop fields were Chenopodium album, Amaranthus viridis, Senecio vulgaris and Coronopus didymus, in summer crop fields, Chenopodium album, Amaranthus viridis, Senecio vulgaris and Sonchus oleraceus and in perennial crop fields, Conyza sumatrensis, Gnaphalium calviceps and Senecio vulgaris. The dominant exotic weeds in the crop fields of Jeju island were Chenopodium album, followed by Amaranthus viridis, Senecio vulgaris, and Conyza sumatrensis. This information could be useful for establishment of exotic weed control methods in Jeju island.

우리나라 밭작물 재배지 잡초 발생 및 분포현황

우리나라 밭에 발생하는 잡초를 조사하여 각 작목별 문제잡초의 현황을 파악하고 잡초방제의 기초자료로 활용하기 위하여 2014년 4~5월 및 7~8월에 2회 실시하였다. 밭에 발생하는 잡초는 총 50과 375종으로 국화과 73종, 화본과 44종, 마디풀과 25종, 십자화과 21종, 콩과 20종 등의 순이었다. 이들 잡초를 생활형으로 구분하면, 일년생 162종, 월년생 78종, 다년생 135종이었다. 보리, 마늘, 양파 등 동계작물 재배지에는 45과 287종, 고추, 콩, 옥수수 등 하계작물 재배지에는 47과 339종이 발생되었다. 우점도별 상위 10초종은 바랭이, 쇠비름, 깨풀, 흰명아주, 속속이풀, 돌피, 한련초, 중대가리풀, 냉이, 참방동사니 순이었다. 외래잡초는 25과 129종으로 흰명아주, 개비름, 망초, 좀명아주, 미국가막사리, 털별꽃아재비 등이었다. 밭잡초 발생정보는 향후 잡초발생 예측, 잡초군락 변화 그리고 밭잡초 방제의 기초자료로 유용하게 사용될 수 있을 것이다. Surveys of weed species on upland fields were conducted in Korea to investigate the occurrence of weed flora from April to May 2014 for winter crop fields and from July to August 2014 for summer crop fields. From the nation-wide survey, 375 weed species in 50 families were identified and classified to 162 annuals, 78 biennials and 135 perennials. Based on the occurrence ratio, the most weed species belonged to Compositae (73 species). 44 and 25 weed species belonged to Poaceae and Polygonaceae, respectively, and these 183 weed species in the most five families accounted for 49% of total weed occurrence. While 287 weed species in 45 families occurred in the winter crop fields, 339 weed species in 47 families occurred in summer crop fields. The most dominant weed species in Korean upland fields were Digitaria ciliaris, followed by Portulaca oleracea, Acalypha australis, Chenopodium album, Rorippa palustris etc. 129 weed species in 25 families were considered as exotic weeds. Based on the importance analysis, the highest value was C. album followed by Amaranthus lividus, Conyza canadensis etc. This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in upland fields of Korea.

강원 횡성 및 제주지역 더덕밭 잡초발생양상

The weed flora in the Codonopsis lanceolata upland fields were surveyed in Hoengseong and Jeju in May, August, and October of 2014. The objectives of this study were to use the survey data for establishing weed control methods and to bring awareness of possible problematic weeds occurred in C. lanceolata upland fields in Korea. Altogether 207 weed species of 47 families were identified, of which 87 were annual, 47 species were biennial and 73 were perennial. Based on the morphological characteristic of the leaves, 182 species were broad leaves, 18 species were grasses, and 7 species were sedges. The dominance was highest in the Artemisia princeps followed by Digitaria ciliaris, Commelina communis, Persicaria longiseta and Echinochloa crus-galli etc. Fifty-nine species were exotic weeds with 29% of a total presence, of which Erigeron annuus was highest, followed by Crassocephalum crepidioides, Bidens frondosa, Hypochaeris radicata etc. In the PCA plot, weeds presented in the C. lanceolata upland fields of Hoengseong were divided into three groups, E. annuus, Sigesbeckia pubescence and C. communis communities and those of Jeju were divided into four groups, C. crepidioides-Cyperus iria, Spergula arvensis, Poa annua and Youngia japonica communities.

충북지역 주요 밭작물 재배지 발생 잡초 분포 현황

This study was conducted to investigate the weed occurrence and distribution on the upland crop fields (garlic, barley, potato, maize, red pepper, soybean and Chinese cabbage) at 795 sites in Chungbuk province of Korea from Apr. to Oct. in 2014. From the result of this survey, 188 weed species in 42 families were identified and classified to 96 annuals, 40 biennials and 52 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province upland crop fields were higher in the order of Portulaca oleracea (8.14%), Digitaria ciliaris (6.72%), Echinochloa crus-galli (6.55%), Rorippa palustris (6.00%) and Chenopodium album (5.89%). The composition of major occurred weed families, Compositae, Poaceae, Polygonaceae and Cruciferae were 19, 10, 7 and 6%, respectively. In the winter upland crop fields, the dominant weeds were in the order of Capsella bursa-pastoris (12.36%), Alopecurus aequalis (11.05%) and Stellaria alsine (8.42%). In the summer upland crop fields, the dominant weeds were in the order of Portulaca oleracea (8.58%), Digitaria ciliaris (7.18%) and Rorippa palustris (6.28%). Fiftythree exotic weed species were identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the upland crop fields in Chungbuk province of Korea.

English

A new exotic weed, Flaveria bidentis, is spreading in central China where it forms dense monospecific patches modifying the structure of different native ecosystems and threatening native aboveground biodiversity. However, little is known about the consequences of such an invasion for soil bacterial community, especially its effect pattern at different invasion stages. In this study, soil samples were taken in native ecosystems that were uninvaded, partially invaded (transition), and severely invaded by F. bidentis. The bacterial richness and diversity in F. bidentis in rhizospheres soil was evaluated using denaturing gradient gel electrophoresis (DGGE) analysis. Different stages of F. bidentis invasion can trigger changes in soil physicochemical properties in particularly in available N and P F. bidentis invasion significantly decreased the richness of soil bacterial community, and the decline contents were positively correlated with invasion progress. In the invaded soils, bacterial species in Proteobacteria , Chloroflexi and Actinomycetes decreased with invasion, with the greatest reduction in relative abundance occurring for Proteobacteria, which was the dominant species in the native soils. Invasion of F. bidentis corresponded with an alteration in the structure of soil bacterial community, and soil microbial biomass as well, thus soil environment modification was expected to promote spreading of this exotic weeds in turn. Key words : Biological invasion, Flaveria bidentis, soil nutrients, soil bacteria, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE).

The Red-whiskered Bulbul Pycnonotus jocosus in Australia – a global perspective, history of introduction, current status and potential impacts

The Red-whiskered Bulbul Pycnonotus jocosus naturally occurs from the Indian subcontinent to the northern Malay Peninsula. Its anthropogenic spread also encompasses Australia, Japan, the southern Malay Peninsula, Singapore, Florida, California, 11 islands in the Indian Ocean, and Oahu, Hawaii. The earliest known introduction occurred in Sydney in 1865, with subsequent releases in the 1900's leading to establishment. It was first released in Melbourne, Victoria in 1915, with a population establishing in the late 1950's. Sightings have been reported in Coffs Harbour since 1972, forming a population in the Northern Rivers region. There has also been a small population in Mackay, Queensland since 1983. Red-whiskered Bulbuls had been recorded in South Australia between the 1940's and 1980's, but did not proliferate and are no longer present. The main ecological impact identified is the dispersal of exotic weeds, although evidence in Australia remains anecdotal. There has also been preliminary evidence of inter...

Occurrence and distribution of weed species on horticulture fields in Chungnam province of Korea

Abstract A survey of weed occurrence was conducted to identify problematic weed species in a horticultural crop field to get basic information for effective weed control. Surveys of weed species occurring in horticultural crop fields (garlic, onion, red pepper and Chinese cabbage) were conducted in Chungnam province of Korea from April to October in 2014. A total of 516 sites of the 17 regions were identified as having 114 weed species belonging to 32 families. The most dominant weed species in the horticultural crop fields were Chenopodium album var . centrorubrum (8.83 %), followed by Digitaria ciliaris (5.71%), Conyza canadensis (5.46 %) and Capsella bursa-pastoris (4.67 %). Specifically, as a result of this study, the occur-rence of 35 species of exotic weeds, such as Chenopodium album and Taraxacum officinale, were confirmed. Almost 68% of the investigation sites was determined under dominance value 1 (range of cover < 10; numerous individuals) by Braun-Branquet cover-abundance scale, indicating a proper weed control in horticultural crop field. As a result of scientific and technological advances, an improved cultivation method is changing the weed occurrence in agricultural land. Additional research needs to be undertaken for the development of weed control methods through such periodic monitoring of occurrence of weeds.

Water quality variation along streams with similar agricultural development but contrasting riparian vegetation

We measured water quality along four Australian tropical streams in two catchments with similar agricultural development (mainly sugarcane growing) but contrasting riparian vegetation (intact native rainforest vs. exotic weeds). There were strong gradients in water quality and consistent differences between streams. The most significant pattern was an increase in nitrate+nitrite (NOx) concentration with distance downstream, reflecting the increasing discharge and proportion of fertilized agricultural land in the catchment, and indicating continuous export of contaminated groundwater along all streams. Measuring water quality along the longitudinal gradient was critical to the interpretation of the data and enabled us to confidently detect differences between streams. NOx concentrations and loads were significantly lower in streams with greater riparian vegetation and regression analysis suggested some N-stripping in the riparian zone, albeit insufficient to meet regional water-quality guidelines. Our results demonstrate the benefit of accounting for longitudinal gradients in comparing water quality among streams and in detecting the effect of riparian vegetation at a catchment scale, but that adequate reduction in NOx in streams can only be achieved by reduced fertilizer application rates in the catchments.

뽕밭에서 발생하는 잡초 양상

소면적으로 재배하고 있는 뽕밭의 문제잡초 현황을 파악하고 잡초방제의 기초자료로 활용하기 위하여 경기 수원, 전북 부안을 중심으로 2014년 5월, 7월, 9월에 3회에 걸쳐 뽕밭에 발생하는 잡초를 조사하였다. 뽕밭에 발생하는 잡초는 37과 153초종으로 국화과 37종, 벼과 17종, 마디풀과 14종, 메꽃과 10종, 배추과 8종 등의 순이었다. 이들 잡초를 생활형으로 구분하면, 일년생 68종, 월년생 39종, 다년생 46종이었다. 지역별 발생잡초를 보면, 수원에서는 31과 91초종, 전주는 19과 50초종, 그리고 부안에서는 32과 114초종이 발생되었다. 우점잡초로는 바랭이, 개망초, 흰명아주, 돌피, 깨풀, 닭의장풀 등이었다. 외래잡초는 44초종으로 전체의 28.8%를 점유하였으며, 개망초, 흰명아주, 미국 자리공, 망초 순으로 우점도가 높았다. 특히 외래잡초 중 개쑥갓은 미국, 캐나다, 독일 등에서 트리아진계 제초제 저항성 잡초로 일부 농가에서 비선택성 제초제인 글루포시 네이트암모늄액제에도 방제가 되지 않아 추가적인 연구가 필요하다. 발생한 잡초를 대상으로 PCA 공변량 분석을 한 결과, 뽕밭을 대표하는 잡초군락은 한련초 군락과 쇠별꽃 군락으로 유형화되었다. The weed flora in the mulberry fields were investigated in Suwon, Jeonju, and Buan in May, July, and September of 2014. The objectives of this study were to use the survey data for establishing weed control methods and to bring awareness of possible problematic weeds in the Korean mulberry fields. The survey was conducted in 53 regions, covering approximately <TEX>$145,925m^2$</TEX>. Altogether 153 weed species of 37 families were identified, of which 68 were annual, 39 species were biennial and 46 were perennial. The dominance was the highest with Digitaria ciliaris followed by Erigeron annuus, Chenopodium album, Echinochloa crus-galli var.crus-galli, Acalypha australis, Commelina communis etc. Exotic weeds presented 44 species with 28.8% of a total presence, of which Erigeron annuus was the highest, followed by Chenopodium album, Phytolacca americana, Conyza canadensis, Oxalis corymbosa etc. Especially, we should aware Senecio vulgaris, not controlled with glufosinate ammonium SL in the Korean mulberry fields because it was known as atrazine resistance in US, Canada, Germany etc. In the PCA plot, weeds presented in the mulberry fields were divided into two groups, Eclipta prostrata community and Stellaria aquatic community and weed flora of Suwon and Buan were different due to those only presented in Suwon.

A novel role of ethephon in controlling the noxious weed Ipomoea cairica (Linn.) Sweet.

Several auxin herbicides, such as 2, 4-D and dicamba, have been used to eradicate an exotic invasive weed Ipomoea cairica in subtropical China, but restraining the re-explosion of this weed is still a challenge. Since ethylene is one of the major intermediate functioning products during the eradication process, we explored the possibility, mechanism and efficiency of using ethephon which can release ethylene to control Ipomoea cairica. The results of the pot experiment showed that 7.2 g /L ethephon could totally kill Ipomoea cairica including the stems and roots. The water culture experiment indicated that ethephon released an abundance of ethylene directly in leaves and caused increases in electrolyte leakage, 1-aminocyclopropane-1-carboxylic acid (ACC), abscisic acid (ABA) and H2O2 and decreases in chlorophyll content and photosynthetic activity, finally leading to the death of Ipomoea cairica. The field experiment showed that the theoretical effective concentration of ethephon for controlling Ipomoea cairica (weed control efficacy, WCE = 98%) was 4.06 g/L and the half inhibitory concentration (I50) was 0.56 g/L. More than 50% of the accompanying species were insensitive to the phytotoxicity of ethephon. Therefore, ethephon is an excellent alternative herbicide for controlling Ipomoea cairica.

A survey for the Critically Endangered Liben Lark Heteromirafra archeri in Somaliland, north-western Somalia

The Critically Endangered Archer's Lark (now Liben Lark) Heteromirafra archeri was formerly considered to be endemic to north-western Somalia and known only from the Tog Wajaale Plain, where 18 specimens were collected between 1918 and 1922. Fifteen visits between 1970 and 2008 failed to relocate the species there, although popula- tions are now known from adjacent Ethiopia. We conducted three days of intensive surveys on the Tog Wajaale Plain in May 2010. Despite the three other lark species present being in full display, and H. archeri being recorded to have bred in early June, no Liben Larks were found. Vegetation structure surveys indicated that the plain has a taller and denser growth of grass than either of the other known localities for Liben Lark (the Liben and Jijiga Plains) making Tog Wajaale Plain seem superficially more suitable for the species, which prefers areas of taller grass elsewhere. However, previous large-scale agricultural activities may have altered the composition of grass species and precipitated the observed invasion of exotic weeds, notably Parthenium hysterophorus. Importantly, the Tog Wajaale Plain has a greater density of bushes than either the Liben or Jijiga Plains, possibly making ground-nesting birds more susceptible to predation by perch hunters.

High precipitation and seeded species competition reduce seeded shrub establishment during dryland restoration.

Drylands comprise 40% of Earth's land mass and are critical to food security, carbon sequestration, and threatened and endangered wildlife. Exotic weed invasions, overgrazing, energy extraction, and other factors have degraded many drylands, and this has placed an increased emphasis on dryland restoration. The increased restoration focus has generated a wealth of experience, innovations and empirical data, yet the goal of restoring diverse, native, dryland plant assemblages composed of grasses, forbs, and shrubs has generally proven beyond reach. Of particular concern are shrubs, which often fail to establish or establish at trivially low densities. We used data from two Great Plains, USA coal mines to explore factors regulating shrub establishment. Our predictor data related to weather and restoration (e.g., seed rates, rock cover) variables, and our response data described shrub abundances on fields of the mines. We found that seeded non-shrubs, especially grasses, formed an important competitive barrier to shrub establishment: With every one standard deviation increase in non-shrub seed rate, the probability shrubs were present decreased ~0.1 and shrub cover decreased ~35%. Since new fields were seeded almost every year for > 20 years, the data also provided a unique opportunity to explore effects of stochastic drivers (i.e., precipitation, year effects). With every one standard deviation increase in precipitation the first growing season following seeding, the probability shrubs were present decreased ~0.07 and shrub cover decreased ~47%. High precipitation appeared to harm shrubs by increasing grass growth/competition. Also, weak evidence suggested shrub establishment was better in rockier fields where grass abundance/competition was lower. Multiple lines of evidence suggest reducing grass seed rates below levels typically used in Great Plains restoration would benefit shrubs without substantially impacting grass stand development over the long term. We used Bayesian statistics to estimate effects of seed rates and other restoration predictors probabilistically to allow knowledge of the predictors' effects to be refined through time in an adaptive management framework. We believe this framework could improve restoration planning in a variety of systems where restoration outcomes remain highly uncertain and ongoing restoration efforts are continually providing new data of value for reducing the uncertainty.

SCREENING OF SOME MEDICINAL PLANT EXTRACTS AGAINST Thielaviopsis spp-A DISEASE CAUSING PLANT FUNGUS

Medicinal plants have been used in the prevention, treatment and cure disorders and diseases in ancient times and they provide abundant resources of antimicrobial compounds, has been used for centuries to inhibit the microbial growth. Diseases of medicinal plants were caused by the pathogenic microbes: especially fungi are common throughout the world. Microbial diseases of plants cause malfunctions such as disturb normal functions by degrading enzymes, toxin and growth substances, reduce the yield, survival capacity and resulting to death. In recent times, the medicinal plants were affected by exogenous, endogenous and microbial infections. The medicinal plant plant Argemone mexicana L. (Mexican poppy) is an annual exotic weed flora used for medicine in several countries throut the world and chosen for this study.This plant was frequently affected by many fungal pathogens. The present investigation focuses the isolation of frequent disease causing fungal pathogen(Thielaviopsis spp)from infected leaves and their control measures by using herbal extracts(Acalypha indica ,Catharanthus roseus  and Murraya koenigii  ) via. Invitro approach.

Plant composition modulates arthropod pest and predator abundance: Evidence for culling exotics and planting natives

We investigate the role of plant species in crops, pasture and native vegetation remnants in supporting agronomic pests and their predators. The study was conducted in three Australian States and across 290 sites sampled monthly for two years. Pastures played a key role in harbouring pest species consistent across States, while native vegetation hosted relatively more predators than other habitat types within each State. Furthermore, native plant species supported the lowest pest density and more predators than pests; in contrast, 75% of the exotic weed species surveyed hosted more pests than predators. Despite the role of pasture in harbouring pests, we found in NSW that pasture also supported the highest proportion of juvenile predators, while native vegetation remnants had the lowest.Our results indicate that non-crop habitat (native remnants or pasture) with few exotic weeds supports high predator and low pest arthropod densities, and that weeds are associated with high pest densities. By linking broad response variables such as ‘all pests’ with specific predictors such as ‘plant species’, our study will inform on-farm management actions of which weeds to control and which natives to plant or regenerate. This study shows the importance of knowing the function of habitats and plants species in supporting pests and predators in agricultural landscapes across multiple regions.

Response of invasive Chromolaena odorata and two coexisting weeds to contrasting irradiance and nitrogen

Chromolaena odorata is a widespread exotic weed in southern China and other regions of the world. To better understand its invasive strategies, we compared leaf pigment contents and gas-exchange traits of the invader with its two coexisting species (native Urena lobata and invasive Bidens pilosa) under combined conditions of irradiance (full, medium, and low) and nitrogen (full, medium, and low) supplies. The chlorophyll (Chl) a+b content of U. lobata was the highest and the Chl a/b ratio of C. odorata was the lowest among the three weed species. In most treatments, leaf pigment, light-saturated photosynthetic rate (P max), and light saturation point (LSP) of all the species increased, while their Chl a/b ratios decreased with the increasing nitrogen. The P max and LSP of U. lobata were greater than those of the coexisting weeds under full irradiance (FI), but significantly declined with the decreasing irradiance. The invasive weeds, especially C. odorata, showed lower P max and LSP under FI, but they showed slight decrease under low irradiance. Compared to U. lobata, C. odorata exhibited the lower light compensation point (LCP) in most treatments, higher LSP under low and medium irradiance, and lower dark respiration rate under FI. In addition, all the three species showed similar responses to different irradiance and nitrogen conditions, mean phenotypic plasticity index (MPPI) of most photosynthetic variables of the two invasive species was lower than that of U. lobata. These results suggested that C. odorata behaved as a facultative shadetolerant weed, being able to grow in moderately sheltered environments; the lower MPPI might be one of the important competitive strategies during its invasion. However, its invasion should be limited to some very shady habitats. In the field, control should be mainly directed against populations growing in the open or nutrient-rich habitats, where its expansion speed could be much faster. Deep shade by intact canopies or luxuriant forests might be an effective barrier against its invasion.

Characterising riparian buffer zones of an agriculturally modified landscape

Riparian buffer zones are viewed as an important management tool for waterway protection. However, little qualitative or quantitative assessment has been made of their dimensions or composition. We surveyed 88 small agricultural waterways within the Canterbury region to characterise the width and vegetative composition of riparian ‘buffer’ zones. Less than 20% of buffer zones were 10 m or wider and approximately 65% ≤ 5 m wide. Mean plant diversity was lowest in buffers ≤ 5 m (four taxa) and highest in buffers 25–30 m wide (11 taxa), although 98% of all taxa recorded in the survey occurred within 5 m of waterways. Exotic pasture grasses, weeds and adventive trees and shrubs dominated riparian areas at all distances from the -side. Furthermore, buffer width and vegetation type did not differ with adjacent land use despite regional efforts to plant native vegetation and regulatory emphasis on reducing water contamination from intensifying land use practices.

제주지역 목초지에 발생하는 잡초양상

This study was conducted to investigate the occurrence of weed flora in pastures in Jeju island of Korea and to establish the basic data for controlling them occurred in the pastures. Weed flora was investigated twice, May and July on 2003. There were a total of 207 weed species including 49 families. Among them 67 species were annual, 39 species were biennial and 101 species were perennial. The compositions of major plant families, Asteraceae, Poaceae, Polygonaceae, Rosaceae, Fabaceae were 17, 15, 8, 7, 6%, respectively. Sixty-eight species of exotics were occurred, as well. Rumex obtusifolius was the highest in importance analysis and the followings were in order of Trifolium repens, Artemisia princeps, Plantago asiatica, Potentilla anemonefolia and Rumex acetosella etc. Among the exotic weeds, R. obtusifolius, T. repens, R. acetosella and C. holosteoides var. hallaisanense might be most problematic weeds species in pastures in Jeju island in the future. And at the boundary of some pastures and mountains Smilax china, Duchesnea indica, Rosa maximowicziana, etc. 17 shrub species were also occurred.

수로와 강변의 습지에 발생한 수생잡초의 분포 및 방제 현황

수로, 하천, 호수, 강 주변에서 발생하는 수생잡초는 왕성한 생장으로 관개, 배수에서 유속 감소, 수생 생태계에 영향 등으로 막대한 피해를 입히고 수생잡초를 방제하기 위하여 많은 비용을 지출하고 있다. 따라서 본 연구는 수로, 하천, 강 주변 습지와 수중에서 발생하는 수생잡초와 침입식물의 분포 및 방제에 관한 정보를 분석하여 수생잡초의 효과적인 관리대책 수립에 필요한 자료를 제공하고자 하였다. 수로, 저수지, 호수 주변의 수생잡초는 갈대, 나도겨풀, 줄, 망초, 개망초, 소리쟁이, 개기장, 미국가막사리, 부들, 주요 강변의 습지에서는 바랭이, 갈대, 소리쟁이, 쑥, 환삼덩굴, 피, 미국가막사리, 고마리가 우점하였다. 수로 및 호수에서 발생한 침수잡초는 검정말, 나자스말, 대가래, 말즘, 붕어마름, 생이가래, 마름이 우점하였다. 습지에서 외래잡초는 토끼풀, 달맞이꽃, 개망초, 망초, 미국가막사리, 메귀리, 돼지풀, 도꼬마리, 미국개기장, 소리쟁이가 우점하였다. 수생잡초 방제는 기계적, 화학적, 생물적 방법에 의존하고 있으며, 앞으로 우리나라에서 습지에서 수생잡초와 외래잡초를 방제하기 위하여 수생잡초의 주기적인 모니터링과 기계적, 화학적 방제를 포함한 종합잡초관리 체계에 관한 연구가 요망된다. Many irrigated and drainage canals, reservoirs, lakes, and rivers are choked by the explosive growth of aquatic weeds, resulting in enormous direct loss in Korea. Distribution of aquatic weeds and exotic invasive plant species in irrigation and drainage waterways, and riparian wetlands was reviewed to provide basic information for management of aquatic weeds and invasive plant species in wetlands. Dominant emergent weeds in canals, reservoirs and lakes were Phragmites communis, Leersia japonica, Zizania latifolia, Conyza canadensis, C. annuus, Rumex crispus, Panicum dichotomiflorum, Bidens frondosa, and Oenothera odorata. Dominant emergent weeds in wetlands of rivers include Digitaria sanguinalis, P. communis, R. crispus, Artemisia princeps, Humulus japonicus, Echinochloa crusgalli, B. frondosa, and Persicaria thunbergii. In irrigation and drainage canals and lakes, dominant submersed weeds were Hydrilla verticillata, Najas minor, Potamogeton malaianus, P. crispus, Ceratophyllum demersum, Myriophyllum verticillatum, Salvinia natans, and Trapa natans. Dominant exotic weeds in wetlands include Trifolium repens, O. odorata, C. annuus, B. frondosa, Avena fatua, Ambrosia artemisiifolia, X. strumarium, and P. dichotomiflorum. Approaches to aquatic weed control were mechanical, chemical and biological control techniques. Periodic monitoring of aquatic weeds and exotic weeds, and their integrated management studies are needed in waterways and riparian wetlands in Korea.

Sacred Grove of Punyagiri Hill, Vizianagaram District, AP, India: Ecological And Sociological Study

Sacred groves are important repositories of rare endangered endemic plants and floral diversity that have been conserved by the local people or communities in a sustainable manner. Sri Umakotilingeswara Swami Temple is a famous Siva Kshetra located in Vizianagaram district of the Andhra Pradesh, India. This holy shrine is situated in the Punyagiri hills, 4 kms away from the Srungavarapu Kota and 62 kms away from the Visakhapatnam (a coastal city of Andhra Pradesh). Two study sites were selected, one was in the sacred grove region another was in forest region. Line transects were used for collection of data on species richness and diversity of the flora. Density and basal area were more in the sacred grove region than the nearby forest region. Some important medicinal and valuable plants were reported in this region, plants such as Saraca asoca (Roxb.), Diospyros peregryna (L.), Sterculia urens (Roxb.), Cleistanthus collinus (Roxb.), Ficus relisiosa (L.), Strublus aspera (L.), Chloroxylon swietenia (L.), Firmiana colorata (Roxb.), Albizia odoratissima (L.), Dalbergia paniculata (Roxb.), Dalbergia sisso (Roxb.), Azadiricta indica A. Juss., Diospyros chloroxylon (L.), Holoptelea integrifolia (Roxb.), Mangifera indica (L.), Eucalyptus globulesv(Labelle), Bombax ceieba (L.), Aegle marmelos, Ailanthus excelsa and some important pteridophytes and Bryophytes were reported in the sacred forest of the Punyagiri hills. Extension of the temple buildings and other developmental activities may be threat to the sacred groves. Invasion by the exotic weeds may further degrade the structure and composition of the sacred forests as a whole.DOI: http://dx.doi.org/10.3126/ije.v4i1.12176 International Journal of Environment Volume-4, Issue-1, Dec-Feb 2014/15, page: 30-47