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Sample records for alien invasive slider

  1. Alien invasive birds.

    Science.gov (United States)

    Brochier, B; Vangeluwe, D; van den Berg, T

    2010-08-01

    A bird species is regarded as alien invasive if it has been introduced, intentionally or accidentally, to a location where it did not previously occur naturally, becomes capable of establishing a breeding population without further intervention by humans, spreads and becomes a pest affecting the environment, the local biodiversity, the economy and/or society, including human health. European Starling (Sturnus vulgaris), Common Myna (Acridotheres tristis) and Red-vented Bulbul (Pycnonotus cafer) have been included on the list of '100 of the World's Worst Invasive Alien Species', a subset of the Global Invasive Species Database. The 'Delivering Alien Invasive Species Inventories for Europe' project has selected Canada Goose (Branta canadensis), Ruddy Duck (Oxyura jamaicensis), Rose-ringed Parakeet (Psittacula krameri) and Sacred Ibis (Threskiornis aethiopicus) as among 100 of the worst invasive species in Europe. For each of these alien bird species, the geographic range (native and introduced range), the introduction pathway, the general impacts and the management methods are presented. PMID:20919578

  2. Assessment and Management of Invasive Alien Predators

    OpenAIRE

    Kirsty Park

    2004-01-01

    Although invasive alien species have been identified as the second greatest threat to biodiversity after habitat loss, characterizing and quantifying their impacts on native species and habitats remains a fundamental problem in conservation biology. Here, I review the techniques that are currently used to assess the impact of invasive alien species on biodiversity, highlighting both their uses in invasive species ecology and their limitations in establishing a causal relationship. Adopting a ...

  3. Hydrological impacts of invasive alien plants

    OpenAIRE

    Calder, Ian R.; Dye, Peter

    2001-01-01

    It is now well recognised that invasive alien species, particularly tree species, often have much increased water usage compared with native vegetation. Perhaps less well understood are the reasons for this increased water use and whether such increases should be expected from all species of invading alien trees under all environmental conditions. This paper examines the reasons for increased water use from trees as compared with short crops. From a knowledge of these reasons and a knowledge ...

  4. Invasive alien birds in Denmark

    DEFF Research Database (Denmark)

    Fox, Anthony David; Heldbjerg, Henning; Nyegaard, Timme

    2015-01-01

    Avian Introduced Alien Species (IAS) constitute a threat to the integrity of native biodiversity, the economy and human health, so here we briefly review some of the problems posed by such species around the world in relation to such bird species in Denmark. A new European Union Regulation...... show the importance of mechanisms such as DOF’s (Dansk Ornitologisk Forening, BirdLife Denmark) Atlas project, Common Bird Census (breeding and wintering species) and DOFbasen to contribute data on the current geographical and numerical distribution of the few serious alien avian species already...

  5. Control techniques for invasive alien plants

    OpenAIRE

    Michele de Sá Dechoum; Sílvia Renate Ziller

    2013-01-01

    Invasive alien species are recognized as a major threat to the conservation of biodiversity. These species should be managed based on local and regional environmental conditions. Control techniques were tested for ten invasive species in Santa Catarina State: the trees Casuarina equisetifolia, Hovenia dulcis, Psidium guajava, Syzygium cumini, and Terminalia catappa, and shrubs and herbs Rubus fruticosus, Furcraea foetida, Hedychium coronarium, Impatiens walleriana, and Tradescantia zebrina. T...

  6. Little evidence of invasion by alien conifers in Europe

    OpenAIRE

    Carrillo-Gavilán, Amparo; Vilà, Montserrat

    2010-01-01

    Aim Conifers are invasive species in many parts of the world, especially in the Southern Hemisphere. There are many introduced conifers in Europe, but their status as alien species is poorly documented. We conducted a comprehensive literature review to ascertain the extent to which alien conifers can be considered invasive. Location Europe. Methods We reviewed the historical record of alien conifer invasion in Europe (i.e. species with a native range outside the continental boundar...

  7. The relationship between functional traits and invasiveness of alien plants

    OpenAIRE

    Jian Liu; Junmin Li; Hua Yu; Weiming He; Feihai Yu; Weiguo Sang; Guofang Liu; Ming Dong

    2010-01-01

    Understanding the functional traits and ecological mechanisms associated with successful invasions of alien plants is a key role of the field of invasion ecology. Through literature review and analysis of plant functional traits contributing to successful plant invasions and the demands for functional traits at different invasion stages, we discuss the relationships between the functional traits and invasiveness of alien plants as well as related ecological mechanisms. Functional traits that ...

  8. Uprooting and burial of invasive alien plants

    DEFF Research Database (Denmark)

    Kollmann, Johannes Christian; Brink-Jensen, Kasper; Frandsen, Sally I.;

    2011-01-01

    Invasive alien plants are a problem for conservation management, and control of these species can be combined with habitat restoration. Subsoil burial of uprooted plants is a new method of mechanical control, which might be suitable in disturbed habitats. The method was tested in Rosa rugosa...... (Japanese Rose), an invasive shrub in north-western Europe with negative effects on coastal biodiversity. Two months after uprooting and burial in dunes of north-eastern Denmark, 89% of the 58 shrubs resprouted from roots and rhizomes; on average 41 resprouts per shrub. Resprout density was twice as high...... increased with fragment dry mass (0.5–168.5 g). After 18 months with harrowing the species was still resprouting, flowering, and fruiting, albeit with no difference between shrub margin and center. Resprouts were taller (26 cm) and coverage was higher (0–4%) after two compared with three times harrowing...

  9. Modelling Hotspots for Invasive Alien Plants in India.

    Directory of Open Access Journals (Sweden)

    Dibyendu Adhikari

    Full Text Available Identification of invasion hotspots that support multiple invasive alien species (IAS is a pre-requisite for control and management of invasion. However, till recently it remained a methodological challenge to precisely determine such invasive hotspots. We identified the hotspots of alien species invasion in India through Ecological Niche Modelling (ENM using species occurrence data from the Global Biodiversity Information Facility (GBIF. The predicted area of invasion for selected species were classified into 4 categories based on number of model agreements for a region i.e. high, medium, low and very low. About 49% of the total geographical area of India was predicted to be prone to invasion at moderate to high levels of climatic suitability. The intersection of anthropogenic biomes and ecoregions with the regions of 'high' climatic suitability was classified as hotspot of alien plant invasion. Nineteen of 47 ecoregions of India, harboured such hotspots. Most ecologically sensitive regions of India, including the 'biodiversity hotspots' and coastal regions coincide with invasion hotspots, indicating their vulnerability to alien plant invasion. Besides demonstrating the usefulness of ENM and open source data for IAS management, the present study provides a knowledge base for guiding the formulation of an effective policy and management strategy for controlling the invasive alien species.

  10. Modelling Hotspots for Invasive Alien Plants in India.

    Science.gov (United States)

    Adhikari, Dibyendu; Tiwary, Raghuvar; Barik, Saroj Kanta

    2015-01-01

    Identification of invasion hotspots that support multiple invasive alien species (IAS) is a pre-requisite for control and management of invasion. However, till recently it remained a methodological challenge to precisely determine such invasive hotspots. We identified the hotspots of alien species invasion in India through Ecological Niche Modelling (ENM) using species occurrence data from the Global Biodiversity Information Facility (GBIF). The predicted area of invasion for selected species were classified into 4 categories based on number of model agreements for a region i.e. high, medium, low and very low. About 49% of the total geographical area of India was predicted to be prone to invasion at moderate to high levels of climatic suitability. The intersection of anthropogenic biomes and ecoregions with the regions of 'high' climatic suitability was classified as hotspot of alien plant invasion. Nineteen of 47 ecoregions of India, harboured such hotspots. Most ecologically sensitive regions of India, including the 'biodiversity hotspots' and coastal regions coincide with invasion hotspots, indicating their vulnerability to alien plant invasion. Besides demonstrating the usefulness of ENM and open source data for IAS management, the present study provides a knowledge base for guiding the formulation of an effective policy and management strategy for controlling the invasive alien species. PMID:26230513

  11. Control techniques for invasive alien plants

    Directory of Open Access Journals (Sweden)

    Michele de Sá Dechoum

    2013-03-01

    Full Text Available Invasive alien species are recognized as a major threat to the conservation of biodiversity. These species should be managed based on local and regional environmental conditions. Control techniques were tested for ten invasive species in Santa Catarina State: the trees Casuarina equisetifolia, Hovenia dulcis, Psidium guajava, Syzygium cumini, and Terminalia catappa, and shrubs and herbs Rubus fruticosus, Furcraea foetida, Hedychium coronarium, Impatiens walleriana, and Tradescantia zebrina. Treatments applied for trees were cut stump, frill and girdling or ring-barking followed by herbicide application, while the other species were treated with foliar spray, application of herbicide on the root system, cut stump and herbicide injection. The active ingredients tested were Triclopyr, Glyphosate, and the combination of Triclopyr + Fluroxipyr in concentrations from 2 to 6%, according to the species. The cut stump method was efficient for all of the woody species, while ring-barking and frilling followed by herbicide application and basal bark application resulted in different levels of efficiency for the species tested. The most efficient method for herbs and shrubs was foliar spray, and the least efficient methods were cut stump and herbicide injection.

  12. Retrospection of Alien Invasive Forest Insect Pests in China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Eleven species of alien invasive forest insect pests have been found since the early time that insect species had been taken recorded in China. Their origins, inland distribution, invasive time, hosts, causing damage are recorded in this paper for the evidence of biological invasion. Their control methods are also studied or discussed.

  13. Invasive alien species – framework for the identification of invasive alien species of EU concern

    OpenAIRE

    Roy, Helen; Schonrogge, Karsten; Dean, Hannah; Peyton, Jodey; Branquart, Etienne; Vanderhoeven, Sonia; Copp, Gordon; Stebbing, Paul; KENIS Marc; Rabitsch, Wolfgang; Essl, Franz; Schindler, Stefan; Brunel, Sarah; Kettunen, Marianne; Mazza, Leonardo

    2014-01-01

    Invasive alien species (IAS) are considered to be one of the greatest threats to biodiversity, particularly through their interactions with other drivers of change (MEA 2005, GBO 2011). In recent years the European Commission (EC) has intensified their commitment to provide a comprehensive, problem-oriented, well-balanced and manageable solution to IAS in Europe. The text of a European Union (EU) Regulation is expected to be adopted soon. A core component of the Regulation is a list of “IAS o...

  14. Native plant community response to alien plant invasion and removal

    OpenAIRE

    Andreu, Jara; Vilà, Montserrat

    2011-01-01

    Given the potential ecological impacts of invasive species, removal of alien plants has become an important management challenge and a high priority for environmental managers. To consider that a removal effort has been successful requires both, the effective elimination of alien plants and the restoration of the native plant community back to its historical composition and function. We present a conceptual framework based on observational and experimental data that compares invaded, non-inva...

  15. Invasive alien woody plants of the northern Cape

    Directory of Open Access Journals (Sweden)

    L. Henderson

    1991-12-01

    Full Text Available The frequency and abundance of invasive alien woody plants were recorded along roadsides and at watercourse crossings in 31% (90/286 of the quarter degree squares in the study area. The survey yielded 23 species of which the most prominent invaders were Prosopis spp. The most prominent remaining species were: Opuntia ficus-indica, Nicotiana glauca and Melia azedarach. The greatest abundance and diversity of alien invader plants were recorded near human settlements. More than half of the total recorded species have invaded perennial riverbanks. The episodic Molopo and Kuruman Rivers have been invaded almost exclusively by  Prosopis spp., which in places have formed extensive stands.

  16. Invasion and Management of Agricultural Alien Insects in China.

    Science.gov (United States)

    Wan, Fang-Hao; Yang, Nian-Wan

    2016-01-01

    China is the world's fourth-largest country in terms of landmass. Its highly diverse biogeography presents opportunities for many invasive alien insects. However, physical and climate barriers sometimes prevent locally occurring species from spreading. China has 560 confirmed invasive alien species; 125 are insect pests, and 92 of these damage the agricultural ecosystem. The estimated annual economic loss due to alien invasive species is more than $18.9 billion. The most harmful invasive insects exhibit some common characteristics, such as high reproduction, competitive dominance, and high tolerance, and benefit from mutualist facilitation interactions. Regional cropping system structure adjustments have resulted in mono-agricultural ecosystems in cotton and other staple crops, providing opportunities for monophagous insect pests. Furthermore, human dietary shifts to fruits and vegetables and smallholder-based farming systems result in highly diverse agricultural ecosystems, which provide resource opportunities for polyphagous insects. Multiple cropping and widespread use of greenhouses provide continuous food and winter habitats for insect pests, greatly extending their geographic range. The current management system consists of early-warning, monitoring, eradication, and spread blocking technologies. This review provides valuable new synthetic information on integrated management practices based mainly on biological control for a number of invasive species. We encourage farmers and extension workers to be more involved in training and further research for novel protection methods that takes into consideration end users' needs. PMID:26527302

  17. Management of freshwater invasive alien species

    Czech Academy of Sciences Publication Activity Database

    Francis, R. A.; Pyšek, Petr

    London : Earthscan, 2012 - (Francis, R.), s. 435-446 ISBN 978-1-84971-228-6 Institutional support: RVO:67985939 Keywords : biological invasions * management * freshwater habitats Subject RIV: EF - Botanics

  18. Invasive alien predator causes rapid declines of native European ladybirds

    OpenAIRE

    Roy, Helen E; Adriaens, Tim; Isaac, Nick J. B.; Kenis, Marc; Onkelinx, Thierry; Martin, Gilles San; Brown, Peter M. J.; Hautier, Louis; Poland, Remy; Roy, David B.; Comont, Richard; Eschen, René; Frost, Robert; Zindel, Renate; Vlaenderen, Johan Van

    2012-01-01

    Aim  Invasive alien species (IAS) are recognized as major drivers of biodiversity loss, but few causal relationships between IAS and species declines have been documented. In this study, we compare the distribution (Belgium and Britain) and abundance (Belgium, Britain and Switzerland) of formerly common and widespread native ladybirds before and after the arrival of Harmonia axyridis, a globally rapidly expanding IAS.Location  EuropeMethods  We used generalized linear mixed-effects models (GL...

  19. Native plant community response to alien plant invasion and removal

    Directory of Open Access Journals (Sweden)

    Jara ANDREU

    2011-01-01

    Full Text Available Given the potential ecological impacts of invasive species, removal of alien plants has become an important management challenge and a high priority for environmental managers. To consider that a removal effort has been successful requires both, the effective elimination of alien plants and the restoration of the native plant community back to its historical composition and function. We present a conceptual framework based on observational and experimental data that compares invaded, non-invaded and removal sites to quantify invaders’ impacts and native plant recover after their removal. We also conduct a meta-analysis to quantitatively evaluate the impacts of plant invaders and the consequences of their removal on the native plant community, across a variety of ecosystems around the world. Our results that invasion by alien plants is responsible for a local decline in native species richness and abundance. Our analysis also provides evidence that after removal, the native vegetation has the potential to recover to a pre-invasion target state. Our review reveal that observational and experimental approaches are rarely used in concert, and that reference sites are scarcely employed to assess native species recovery after removal. However, we believe that comparing invaded, non-invaded and removal sites offer the opportunity to obtain scientific information with relevance for management.

  20. Invasive alien woody plants of the eastern Cape

    Directory of Open Access Journals (Sweden)

    L. Henderson

    1992-12-01

    Full Text Available The frequency and abundance of invasive alien woody plants were recorded along roadsides and at watercourse crossings in 69.9% (151/216 of the quarter degree squares in the study area. The survey yielded 101 species of which the most prominent (in order of prominence in roadside and veld habitats were:  Opuntia ficus-indica, Acacia meamsii and A. cyclops. The most prominent species (in order of prominence in streambank habitats were:  A. meamsii, Populus x  canescens, Salix babylonica and  S. fragilis (fide R.D. Meikle.The greatest intensity of invasion was recorded in the wetter eastern parts and particularly in the vicinity of Port Elizabeth. Uitenhage, East London, Grahamstown, Hogsback and Stutterheim. There was relatively little invasion in the central and western dry interior except along watercourses.

  1. Invasive alien woody plants of the Orange Free State

    Directory of Open Access Journals (Sweden)

    L. Henderson

    1991-12-01

    Full Text Available The frequency and abundance of invasive alien woody plants were recorded along roadsides and at watercourse crossings in 66% (151/230 of the quarter degree squares in the study area. The survey yielded 64 species of which the most prominent (in order of prominence in streambank habitats were:  Salix babylonica, Populus x  canescens, Acacia dealbata and  Salix fragilis (fide R.D. Meikle pers. comm . The most prominent species (in order of prominence in roadside and veld habitats were:  Opunlia ficus-indica, Prunus persica, Eucalyptus spp..  Rosa eglanteria, Pyracantha angustifolia and Acacia dealbata.Little invasion was recorded for most of the province. The greatest intensity of invasion was recorded along the perennial rivers and rocky hillsides in the moist grassland of the eastern mountain region bordering on Lesotho and Natal.

  2. 外来侵袭物种的法律定义%Legal Definition on Alien Invasive Species

    Institute of Scientific and Technical Information of China (English)

    高敏

    2005-01-01

    Agriculture,economy,ecological environment and human health are heavily threatened by alien invasive species ,Alien invasive species is spreading in our country,How to prevent,control and destroy alien invasive species through systems and regulations is problem for related legislation to resolve,However,how to deline alien species,invasive and introduction is premise of legal control on alien invasive species,and determines scope and offect of legal control,through comparing and analyzing legal definition of other countries.legal definition on alien invasive species in our country is put forwarded in the article。

  3. Comparative Functional Responses Predict the Invasiveness and Ecological Impacts of Alien Herbivorous Snails

    Science.gov (United States)

    Xu, Meng; Mu, Xidong; Dick, Jaimie T. A.; Fang, Miao; Gu, Dangen; Luo, Du; Zhang, Jiaen; Luo, Jianren; Hu, Yinchang

    2016-01-01

    Understanding determinants of the invasiveness and ecological impacts of alien species is amongst the most sought-after and urgent research questions in ecology. Several studies have shown the value of comparing the functional responses (FRs) of alien and native predators towards native prey, however, the technique is under-explored with herbivorous alien species and as a predictor of invasiveness as distinct from ecological impact. Here, in China, we conducted a mesocosm experiment to compare the FRs among three herbivorous snail species: the golden apple snail, Pomacea canaliculata, a highly invasive and high impact alien listed in “100 of the World's Worst Invasive Alien Species”; Planorbarius corneus, a non-invasive, low impact alien; and the Chinese native snail, Bellamya aeruginosa, when feeding on four locally occurring plant species. Further, by using a numerical response equation, we modelled the population dynamics of the snail consumers. For standard FR parameters, we found that the invasive and damaging alien snail had the highest “attack rates” a, shortest “handling times” h and also the highest estimated maximum feeding rates, 1/hT, whereas the native species had the lowest attack rates, longest handling times and lowest maximum feeding rates. The non-invasive, low impact alien species had consistently intermediate FR parameters. The invasive alien species had higher population growth potential than the native snail species, whilst that of the non-invasive alien species was intermediate. Thus, while the comparative FR approach has been proposed as a reliable method for predicting the ecological impacts of invasive predators, our results further suggest that comparative FRs could extend to predict the invasiveness and ecological impacts of alien herbivores and should be explored in other taxa and trophic groups to determine the general utility of the approach. PMID:26771658

  4. Comparative functional responses predict the invasiveness and ecological impacts of alien herbivorous snails.

    OpenAIRE

    Meng Xu; Xidong Mu; Dick, Jaimie T. A.; Miao Fang; Dangen Gu; Du Luo; Jiaen Zhang; Jianren Luo; Yinchang Hu

    2016-01-01

    Understanding determinants of the invasiveness and ecological impacts of alien species is amongst the most sought-after and urgent research questions in ecology. Several studies have shown the value of comparing the functional responses (FRs) of alien and native predators towards native prey, however, the technique is under-explored with herbivorous alien species and as a predictor of invasiveness as distinct from ecological impact. Here, in China, we conducted a mesocosm experiment to compar...

  5. Worldwide Alien Invasion: A Methodological Approach to Forecast the Potential Spread of a Highly Invasive Pollinator.

    Science.gov (United States)

    Acosta, André L; Giannini, Tereza C; Imperatriz-Fonseca, Vera L; Saraiva, Antonio M

    2016-01-01

    The ecological impacts of alien species invasion are a major threat to global biodiversity. The increasing number of invasion events by alien species and the high cost and difficulty of eradicating invasive species once established require the development of new methods and tools for predicting the most susceptible areas to invasion. Invasive pollinators pose serious threats to biodiversity and human activity due to their close relationship with many plants (including crop species) and high potential competitiveness for resources with native pollinators. Although at an early stage of expansion, the bumblebee species Bombus terrestris is becoming a representative case of pollinator invasion at a global scale, particularly given its high velocity of invasive spread and the increasing number of reports of its impacts on native bees and crops in many countries. We present here a methodological framework of habitat suitability modeling that integrates new approaches for detecting habitats that are susceptible to Bombus terrestris invasion at a global scale. Our approach did not include reported invaded locations in the modeling procedure; instead, those locations were used exclusively to evaluate the accuracy of the models in predicting suitability over regions already invaded. Moreover, a new and more intuitive approach was developed to select the models and evaluate different algorithms based on their performance and predictive convergence. Finally, we present a comprehensive global map of susceptibility to Bombus terrestris invasion that highlights priority areas for monitoring. PMID:26882479

  6. Worldwide Alien Invasion: A Methodological Approach to Forecast the Potential Spread of a Highly Invasive Pollinator.

    Directory of Open Access Journals (Sweden)

    André L Acosta

    Full Text Available The ecological impacts of alien species invasion are a major threat to global biodiversity. The increasing number of invasion events by alien species and the high cost and difficulty of eradicating invasive species once established require the development of new methods and tools for predicting the most susceptible areas to invasion. Invasive pollinators pose serious threats to biodiversity and human activity due to their close relationship with many plants (including crop species and high potential competitiveness for resources with native pollinators. Although at an early stage of expansion, the bumblebee species Bombus terrestris is becoming a representative case of pollinator invasion at a global scale, particularly given its high velocity of invasive spread and the increasing number of reports of its impacts on native bees and crops in many countries. We present here a methodological framework of habitat suitability modeling that integrates new approaches for detecting habitats that are susceptible to Bombus terrestris invasion at a global scale. Our approach did not include reported invaded locations in the modeling procedure; instead, those locations were used exclusively to evaluate the accuracy of the models in predicting suitability over regions already invaded. Moreover, a new and more intuitive approach was developed to select the models and evaluate different algorithms based on their performance and predictive convergence. Finally, we present a comprehensive global map of susceptibility to Bombus terrestris invasion that highlights priority areas for monitoring.

  7. Whole-range studies on alien plant invasion: recent progress and future prospects

    OpenAIRE

    Hongyu Niu; Hao Shen; Wanhui Ye

    2010-01-01

    The regions invaded by alien species are normally disjunct from their native ranges, so it is difficult to understand the reasons for successful invasion through studies conducted only in native or invasive ranges. Many researchers have engaged in whole-range studies of invasive species, i.e. studying the exotics both in their introduced and native ranges, in order to explain the present geographical patterns and invasion mechanisms of alien plants. Here, we review progress in whole-range stu...

  8. Separating habitat invasibility by alien plants from the actual level of invasion.

    Science.gov (United States)

    Chytrý, Milan; Jarosik, Vojtech; Pysek, Petr; Hájek, Ondrej; Knollová, Ilona; Tichý, Lubomír; Danihelka, Jií

    2008-06-01

    Habitats vary considerably in the level of invasion (number or proportion of alien plant species they contain), which depends on local habitat properties, propagule pressure, and climate. To determine the invasibility (susceptibility to invasions) of different habitats, it is necessary to factor out the effects of any confounding variables such as propagule pressure and climate on the level of invasion. We used 20 468 vegetation plots from 32 habitats in the Czech Republic to compare the invasibility of different habitats. Using regression trees, the proportion of alien plants, including archaeophytes (prehistoric to medieval invaders) and neophytes (recent invaders), was related to variables representing habitat properties, propagule pressure, and climate. The propagule pressure was expressed as the proportion of surrounding urban and industrial or agricultural land, human population density, distance from a river, and history of human colonization in the region. Urban and industrial land use had a positive effect on the proportion of both archaeophytes and neophytes. Agricultural land use, higher population density, and longer history of human impact positively affected the proportion of archaeophytes. Disturbed human-made habitats with herbaceous vegetation were most invaded by both groups of aliens. Neophytes were also relatively common in disturbed woody vegetation, such as broad-leaved plantations, forest clearings, and riverine scrub. These habitats also had the highest proportion of aliens after removing the effect of propagule pressure and climate, indicating that they are not only the most invaded, but also most invasible. These habitats experience recurrent disturbances and are rich, at least temporarily, in available nutrients, which supports the hypothesis that fluctuating resources are the major cause of habitat invasibility. The least invaded habitats were mires and alpine-subalpine grasslands and scrub. After removing the effect of propagule

  9. Invasive alien predator causes rapid declines of native European ladybirds

    DEFF Research Database (Denmark)

    Roy, Helen E.; Adriaens, Tim; Isaac, Nick J.B.;

    2012-01-01

    Aim Invasive alien species (IAS) are recognized as major drivers of biodiversity loss, but few causal relationships between IAS and species declines have been documented. In this study, we compare the distribution (Belgium and Britain) and abundance (Belgium, Britain and Switzerland) of formerly...... common and widespread native ladybirds before and after the arrival of Harmonia axyridis, a globally rapidly expanding IAS. Location Europe Methods We used generalized linear mixed-effects models (GLMMs) to assess the distribution trends of eight conspicuous and historically widespread and common species...... surveys of deciduous trees in Belgium, Britain and Switzerland. Results Five (Belgium) and seven (Britain) of eight species studied show substantial declines attributable to the arrival of H. axyridis. Indeed, the two-spot ladybird, Adalia bipunctata, declined by 30% (Belgium) and 44% (Britain) over 5...

  10. Antagonistic interactions between an invasive alien and a native coccinellid species may promote coexistence

    OpenAIRE

    Hentley, William T.; Vanbergen, Adam J.; Beckerman, Andrew P; Brien, Melanie N.; Hails, Rosemary S.; Jones, T. Hefin; Johnson, Scott N.

    2016-01-01

    1. Despite the capacity of invasive alien species to alter ecosystems, the mechanisms underlying their impact remain only partly understood. Invasive alien predators, for example, can significantly disrupt recipient communities by consuming prey species or acting as an intraguild predator (IGP). 2. Behavioural interactions are key components of interspecific competition between predators,yet these are often overlooked invasion processes. Here, we show how behavioural, nonlethal IGP intera...

  11. European map of alien plant invasions based on the quantitative assessment across habitats

    OpenAIRE

    Chytrý, Milan; Pyšek, Petr; Pino, Joan; Maskell, Lindsay C.; Vilà, Montserrat

    2009-01-01

    Aim Recent studies using vegetation plots have demonstrated that habitat type is a good predictor of the level of plant invasion, expressed as the proportion of alien to all species. At local scale, habitat types explain the level of invasion much better than alien propagule pressure. Moreover, it has been shown that patterns of habitat invasion are consistent among European regions with contrasting climates, bio- geography, history and socioeconomic background. Here we use these findings as...

  12. Facilitating assessments of alien invasions in the Mediterranean: the European Alien Species Information Network (EASIN)

    OpenAIRE

    KATSANEVAKIS STYLIANOS MARIOS; SUMARES DA CRUZ NUNES ANA LUISA; TROMBETTI MARCO; DERIU IVAN; Cardoso, Ana

    2013-01-01

    The European Alien Species Information Network (EASIN) provides tools and services for the exploration of alien species information in Europe. Efficient widgets can be used for the easy creation of distribution maps of any aggregation of alien species. Herein, we investigated distribution patterns of marine alien species in the Mediterranean Sea, using EASIN tools and data from various sources. These patterns differ depending on the pathway of introduction, indicating that human activities sh...

  13. Seed dispersal networks in the Galápagos and the consequences of alien plant invasions

    DEFF Research Database (Denmark)

    Heleno, R. H.; Olesen, Jens Mogens; Nogales, M.;

    2013-01-01

    Alien plants are a growing threat to the Gala´pagos unique biota. We evaluated the impact of alien plants on eight seed dispersal networks from two islands of the archipelago. Nearly 10 000 intact seeds from 58 species were recovered from the droppings of 18 bird and reptile dispersers. The most......, followed by small ground finch, two mockingbirds, the giant tortoise and two insectivorous birds. Most animals dispersed alien seeds, but these formed a relatively small proportion of the interactions. Nevertheless, the integration of aliens was higher in the island that has been invaded for longest......, suggesting a time-lag between alien plant introductions and their impacts on seed dispersal networks. Alien plants become more specialized with advancing invasion, favouring more simplified plant and disperser communities. However, only habitat type significantly affected the overall network structure. Alien...

  14. The casual, naturalised and invasive alien flora of Zimbabwe based on herbarium and literature records

    Directory of Open Access Journals (Sweden)

    Alfred Maroyi

    2012-01-01

    Full Text Available Zimbabwe’s casual, naturalised and invasive alien plant species were analysed with regard to their habit, origin, mode or purpose of introduction and their invasion status in the country. This alien flora of 391 taxa belonged to 239 genera and 73 families, corresponding to 6.6% of the total flora of Zimbabwe. Of these, 153 (39.1% plant species were casual aliens, 154 (39.4% were naturalised and 84 (21.5% were invasive species. Most invasions in terms of numbers of alien species were in the central and eastern parts of the country. Asteraceae (53 species, Poaceae (48 species and Fabaceae sensu lato (49 species families were prominent in all the floristic regions of the country. Annual and perennial herbaceous species formed the majority of life forms of the casual, naturalised and invasive alien flora of Zimbabwe. Genera with the highest number of alien species were Ipomoea with nine species, Acacia and Euphorbia with eight species each, Chenopodium and Senna with seven species each, Eucalyptus with six species, Oenothera, Physalis and Solanum with five species each. More than 49.6% of the alien plants in Zimbabwe originated primarily from South, Central and North America, followed by Europe (24.6%, Asia (23.8%, Africa (10.5% and Australasia (5.9%.Conservation implications: This research provides baseline information and historical invasion patterns of casual, naturalised and invasive alien flora in Zimbabwe. This inventory is a crucial starting point in trying to understand and initiate the management of biological invasions. This is also important for monitoring new introductions and management of existing alien plants in Zimbabwe.

  15. Biological control of alien and invasive species in agriculture

    International Nuclear Information System (INIS)

    Agricultural production in Europe faces many challenges including limited availability of water, nitrogen input and fossil fuels. It is necessary, therefore, to identify methods of production and new technologies to increase the efficiency of the primary systems, guaranteeing amount of food, quality, safety and eco-sustainability . One of the most important aspects, though often undervalued in relation to the food chain, is the adversity of biological management of agricultural crops due to pests, pathogens or fitomizi with potential invasive already present in the territory or of recent origin alien. In this context, two main objectives should be implemented at the same time reduce production losses and protect the agro-ecosystem. To meet these expectations, as of January 1, 2015 all farms in the European Union countries are bound to the application of the Integrated Defense principles, as indicated by the Directive on the sustainable use of plant protection products (128/09 / EC) .In response to this and other new entomological emergencies plant health and medical-veterinary entomologist researchers of the Laboratory sustainable management of Agro-Ecosystems in ENEA, have directed their research towards the development of innovative systems for the sustainable control of invasive species of insects is in the agricultural sector that health.

  16. TRADABLE RISK PERMITS TO PREVENT FUTURE INTRODUCTIONS OF ALIEN INVASIVE SPECIES INTO THE GREAT LAKES

    OpenAIRE

    Horan, Richard D.; Lupi, Frank

    2003-01-01

    Alien invasive species contribute to biodiversity loss and cause billions of dollars of economic damage in the Great Lakes. We examine the design and efficiency of a tradeable permit system for biological pollution due to alien species that invade the Great Lakes through the ballast water of commercial ships.

  17. Invasions by alien plants in the Czech Republic: a quantitative assessment across habitats

    Czech Academy of Sciences Publication Activity Database

    Chytrý, M.; Pyšek, Petr; Tichý, L.; Knollová, I.; Danihelka, Jiří

    2005-01-01

    Roč. 77, - (2005), s. 339-354. ISSN 0032-7786 Institutional research plan: CEZ:AV0Z60050516 Keywords : habitat invasibility * alien species * Czech Republic Subject RIV: EF - Botanics Impact factor: 1.545, year: 2005

  18. State-space modeling indicates rapid invasion of an alien shrub in coastal dunes

    DEFF Research Database (Denmark)

    Damgaard, Christian Frølund; Nygaard, Bettina; Ejrnæs, Rasmus;

    2011-01-01

    Invasion by alien plants has negative effects on coastal dunes. Monitoring local spread of invasive species depends on long-term data with sufficient spatial resolution. Bayesian state-space models are a new method for monitoring invasive plants based on unbalanced permanent-plot data. The method...

  19. Minimizing Risks of Invasive Alien Plant Species in Tropical Production Forest Management

    OpenAIRE

    Michael Padmanaba; Corlett, Richard T.

    2014-01-01

    Timber production is the most pervasive human impact on tropical forests, but studies of logging impacts have largely focused on timber species and vertebrates. This review focuses on the risk from invasive alien plant species, which has been frequently neglected in production forest management in the tropics. Our literature search resulted in 114 publications with relevant information, including books, book chapters, reports and papers. Examples of both invasions by aliens into tropical prod...

  20. Horticultural markets promote alien species invasions: an Estonian case study of herbaceous perennials

    Directory of Open Access Journals (Sweden)

    Merle Ööpik

    2013-06-01

    Full Text Available Gardening is a popular pastime, but commercial horticulture is responsible for the introduction of alien species and contributes to invasions in a variety of ways. Although an extensive international literature is available on plant invasions, it is still important at the national level to examine the influence of local factors. Accordingly, 17 nurseries in Estonia that cultivated and sold perennial alien species were selected, and a list of species and prices was compiled. The relationships between species status, and factors such as their abundance in the wild were examined statistically. A qualitative list of the nationally problematic species among herbaceous perennials was also completed. A total of 880 taxa were recorded, of which 10.3% were native and 89.7% alien. In all, 87.3% of the alien species were still confined to cultivated areas. The ecological and socio-economic characteristics of the taxa were described, and lists of the families of casual, naturalised and invasive aliens were provided. Both native and increasing wild alien species have a very similar profile on the market. Alien species that are less expensive, widely available and have more cultivars per species on the market are also more likely to escape. The invasive status and abundance of escaped aliens in an area increases with residence time. In general, socio-economic factors create new and reflect previous propagule pressures from commercial horticulture, which continuously increase the likelihood of alien species surviving and invading new areas. Our findings suggest that these national socio-economic market-related factors explain much of the invasiveness of various perennial ornamental species, and therefore regional and national authorities urgently need to regulate and control the ornamental plant trade to diminish the risk of new invasions.

  1. Effect of the internet commerce on dispersal modes of invasive alien species.

    Science.gov (United States)

    Lenda, Magdalena; Skórka, Piotr; Knops, Johannes M H; Moroń, Dawid; Sutherland, William J; Kuszewska, Karolina; Woyciechowski, Michał

    2014-01-01

    The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal. PMID:24932498

  2. Effect of the Internet Commerce on Dispersal Modes of Invasive Alien Species

    Science.gov (United States)

    Lenda, Magdalena; Skórka, Piotr; Knops, Johannes M. H.; Moroń, Dawid; Sutherland, William J.; Kuszewska, Karolina; Woyciechowski, Michał

    2014-01-01

    The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal. PMID:24932498

  3. Distribution patterns of invasive alien species in Alabama, USA

    Directory of Open Access Journals (Sweden)

    Xiongwen Chen

    2012-12-01

    Full Text Available Invasive alien species (IAS cause environmental and economical problems. How to effectively manage all IAS at a large area is a challenge.Hypotheses about IAS (such as the “human activity” hypothesis, the “biotic acceptance” and the “biotic resistance” have been proposedfrom numerous studies. Here the state of Alabama in USA, widely occupied by IAS, is used as a case study for characterizing the emergentpatterns of IAS. The results indicate that most IAS are located in metropolitan areas and in the Black Belt area which is a historical intensiveland use area. There are positive relationships between the richness of IAS and the change of human population, the species richness and thenumber of endangered species, as well as the total road length and farmland area across Alabama. This study partially supports the abovethree hypotheses and provides a general pattern of local IAS. Based on possible processes related with IAS, some implications forstrategically managing local IAS are discussed.

  4. Antagonistic interactions between an invasive alien and a native coccinellid species may promote coexistence.

    Science.gov (United States)

    Hentley, William T; Vanbergen, Adam J; Beckerman, Andrew P; Brien, Melanie N; Hails, Rosemary S; Jones, T Hefin; Johnson, Scott N

    2016-07-01

    Despite the capacity of invasive alien species to alter ecosystems, the mechanisms underlying their impact remain only partly understood. Invasive alien predators, for example, can significantly disrupt recipient communities by consuming prey species or acting as an intraguild predator (IGP). Behavioural interactions are key components of interspecific competition between predators, yet these are often overlooked invasion processes. Here, we show how behavioural, non-lethal IGP interactions might facilitate the establishment success of an invading alien species. We experimentally assessed changes in feeding behaviour (prey preference and consumption rate) of native UK coccinellid species (Adalia bipunctata and Coccinella septempunctata), whose populations are, respectively, declining and stable, when exposed to the invasive intraguild predator, Harmonia axyridis. Using a population dynamics model parameterized with these experimental data, we predicted how intraguild predation, accommodating interspecific behavioural interactions, might impact the abundance of the native and invasive alien species over time. When competing for the same aphid resource, the feeding rate of A. bipunctata significantly increased compared to the feeding in isolation, while the feeding rate of H. axyridis significantly decreased. This suggests that despite significant declines in the UK, A. bipunctata is a superior competitor to the intraguild predator H. axyridis. In contrast, the behaviour of non-declining C. septempunctata was unaltered by the presence of H. axyridis. Our experimental data show the differential behavioural plasticity of competing native and invasive alien predators, but do not explain A. bipunctata declines observed in the UK. Using behavioural plasticity as a parameter in a population dynamic model for A. bipunctata and H. axyridis, coexistence is predicted between the native and invasive alien following an initial period of decline in the native species. We

  5. Habitat invasions by alien plants: a quantitative comparison among Mediterranean, subcontinental and oceanic regions of Europe

    OpenAIRE

    Chytrý, Milan; Maskell, Lindsay C.; Pino, Joan; Pyšek, Petr; Vilà, Montserrat; Font, Xavier; Smart, Simon M

    2008-01-01

    1. Although invasions by alien plants are major threats to the biodiversity of natural habitats, individual habitats vary considerably in their susceptibility to invasion. Therefore the risk assessment procedures, which are used increasingly by environmental managers to inform effective planning of invasive plant control, require reliable quantitative information on the extent to which different habitats are susceptible to invasion. It is also important to know whether the leve...

  6. Ecological Risk Assessment with MCDM of Some Invasive Alien Plants in China

    Science.gov (United States)

    Xie, Guowen; Chen, Weiguang; Lin, Meizhen; Zheng, Yanling; Guo, Peiguo; Zheng, Yisheng

    Alien plant invasion is an urgent global issue that threatens the sustainable development of the ecosystem health. The study of its ecological risk assessment (ERA) could help us to prevent and reduce the invasion risk more effectively. Based on the theory of ERA and methods of the analytic hierarchy process (AHP) of multi-criteria decision-making (MCDM), and through the analyses of the characteristics and processes of alien plant invasion, this paper discusses the methodologies of ERA of alien plant invasion. The assessment procedure consisted of risk source analysis, receptor analysis, exposure and hazard assessment, integral assessment, and countermeasure of risk management. The indicator system of risk source assessment as well as the indices and formulas applied to measure the ecological loss and risk were established, and the method for comprehensively assessing the ecological risk of alien plant invasion was worked out. The result of ecological risk analysis to 9 representative invasive alien plants in China shows that the ecological risk of Erigeron annuus, Ageratum conyzoides, Alternanthera philoxeroides and Mikania midrantha is high (grade1-2), that of Oxalis corymbosa and Wedelia chinensis comes next (grade3), while Mirabilis jalapa, Pilea microphylla and Calendula officinalis of the last (grade 4). Risk strategies are put forward on this basis.

  7. Interactions between two invasive alien species, Procambarus clarkii and Dreissena polymorpha, in the aquatic ecosystems of central Italy

    OpenAIRE

    Vera Lúcia Ramos Gonçalves

    2014-01-01

    Interactions between two invasive alien species, Procambarus clarkii and Dreissena polymorpha, in the aquatic ecosystems of central Italy (DOTTORATO DI RICERCA IN ETOLOGIA, ECOLOGIA ANIMALE ED ANTROPOLOGIA)

  8. Loss or gain? Invasive aliens and biodiversity in the Mediterranean Sea

    International Nuclear Information System (INIS)

    More than 500 alien species were listed from the Mediterranean Sea. Though no extinction of a native species is known, sudden decline in abundance, and even local extirpations, concurrent with proliferation of aliens, had been recorded. Examination of the profound ecological impacts of some of the most conspicuous invasive alien species underscores their role, among multiple anthropogenic stressors, in altering the infralittoral communities. Local population losses and niche contraction of native species may not induce immediate extirpation, but they augur reduction of genetic diversity, loss of functions, processes, and habitat structure, increase the risk of decline and extinction, and lead to biotic homogenization. The relevant environmental policy and management framework is discussed

  9. Loss or gain? Invasive aliens and biodiversity in the Mediterranean Sea

    Energy Technology Data Exchange (ETDEWEB)

    Galil, B.S. [National Institute of Oceanography, Israel Oceanographic and Limnological Research, POB 8030, Haifa 31080 (Israel)]. E-mail: galil@post.tau.ac.il

    2007-07-01

    More than 500 alien species were listed from the Mediterranean Sea. Though no extinction of a native species is known, sudden decline in abundance, and even local extirpations, concurrent with proliferation of aliens, had been recorded. Examination of the profound ecological impacts of some of the most conspicuous invasive alien species underscores their role, among multiple anthropogenic stressors, in altering the infralittoral communities. Local population losses and niche contraction of native species may not induce immediate extirpation, but they augur reduction of genetic diversity, loss of functions, processes, and habitat structure, increase the risk of decline and extinction, and lead to biotic homogenization. The relevant environmental policy and management framework is discussed.

  10. The distribution of selected alien invasive plant species along the river Dreta

    OpenAIRE

    Obojnik, Nina

    2011-01-01

    The aim of this paper was to determine the occurrence, distribution and frequency of alien invasive plants along the river Dreta. Of interest were also the effects of environmental factors on the occurrence of invasive species. In the 2010 growing season, the state of the wider aquatic environment was examined, the invasive species along Dreta were surveyed, their phenological phases were identified, and their phytosociological classes and occurrence in different parts of the watercourse were...

  11. Fire and simulated herbivory have antagonistic effects on resistance of savanna grasslands to alien shrub invasion

    OpenAIRE

    te Beest, Mariska; Mpandza, Nokukhanya J.; Olff, Han

    2015-01-01

    Question Resistance of the native community has been identified as an important factor limiting invasion success and invader impact. However, to what extent resistance interacts with disturbance to control invasion success remains unclear. We studied the interaction between biotic resistance, fire and small-scale disturbances mimicking those of large mammalian herbivores (hoof action and grazing) on invasion success of the alien shrub Chromolaena odorata. Location Hluhluwe-iMfolozi Park, Sout...

  12. Invasive species information networks: Collaboration at multiple scales for prevention, early detection, and rapid response to invasive alien species

    Science.gov (United States)

    Simpson, A.; Jarnevich, C.; Madsen, J.; Westbrooks, R.; Fournier, C.; Mehrhoff, L.; Browne, M.; Graham, J.; Sellers, E.

    2009-01-01

    Accurate analysis of present distributions and effective modeling of future distributions of invasive alien species (IAS) are both highly dependent on the availability and accessibility of occurrence data and natural history information about the species. Invasive alien species monitoring and detection networks (such as the Invasive Plant Atlas of New England and the Invasive Plant Atlas of the MidSouth) generate occurrence data at local and regional levels within the United States, which are shared through the US National Institute of Invasive Species Science. The Inter-American Biodiversity Information Network's Invasives Information Network (I3N), facilitates cooperation on sharing invasive species occurrence data throughout the Western Hemisphere. The I3N and other national and regional networks expose their data globally via the Global Invasive Species Information Network (GISIN). International and interdisciplinary cooperation on data sharing strengthens cooperation on strategies and responses to invasions. However, limitations to effective collaboration among invasive species networks leading to successful early detection and rapid response to invasive species include: lack of interoperability; data accessibility; funding; and technical expertise. This paper proposes various solutions to these obstacles at different geographic levels and briefly describes success stories from the invasive species information networks mentioned above. Using biological informatics to facilitate global information sharing is especially critical in invasive species science, as research has shown that one of the best indicators of the invasiveness of a species is whether it has been invasive elsewhere. Data must also be shared across disciplines because natural history information (e.g. diet, predators, habitat requirements, etc.) about a species in its native range is vital for effective prevention, detection, and rapid response to an invasion. Finally, it has been our

  13. Seed dispersal networks in the Galápagos and the consequences of alien plant invasions.

    Science.gov (United States)

    Heleno, Ruben H; Olesen, Jens M; Nogales, Manuel; Vargas, Pablo; Traveset, Anna

    2013-01-01

    Alien plants are a growing threat to the Galápagos unique biota. We evaluated the impact of alien plants on eight seed dispersal networks from two islands of the archipelago. Nearly 10 000 intact seeds from 58 species were recovered from the droppings of 18 bird and reptile dispersers. The most dispersed invaders were Lantana camara, Rubus niveus and Psidium guajava, the latter two likely benefiting from an asynchronous fruit production with most native plants, which facilitate their consumption and spread. Lava lizards dispersed the seeds of 27 species, being the most important dispersers, followed by small ground finch, two mockingbirds, the giant tortoise and two insectivorous birds. Most animals dispersed alien seeds, but these formed a relatively small proportion of the interactions. Nevertheless, the integration of aliens was higher in the island that has been invaded for longest, suggesting a time-lag between alien plant introductions and their impacts on seed dispersal networks. Alien plants become more specialized with advancing invasion, favouring more simplified plant and disperser communities. However, only habitat type significantly affected the overall network structure. Alien plants were dispersed via two pathways: dry-fruited plants were preferentially dispersed by finches, while fleshy fruited species were mostly dispersed by other birds and reptiles. PMID:23173203

  14. Effectiveness of native bumblebees as pollinators of the alien invasive plant Impatiens glandulifera (Balsaminaceae in Ireland

    Directory of Open Access Journals (Sweden)

    Jane C. Stout

    2009-07-01

    Full Text Available Flowers of alien invasive plants can be pollen limited due to a lack of effective pollinators. The alien Impatiens glandulifera is predominantly visited by bumblebees in its invaded range. There bumblebees pollinate I. glandulifera, but it remains unclear whether foraging behaviour or bumblebee or flower morphology affects effectiveness. We investigated the effectiveness of native bumblebee (Bombus pascuorum pollinators in Ireland by quantifying pollen deposition and removal, and seed production after a single bumblebee visit. Morphological characteristics of flowers and bumblebee body parts were measured to determine their influence on pollen deposition and removal. B. pascuorum is a highly effective pollinator of the alien due to its high visitation frequency, the morphological fit with flowers and individuals removing large pollen quantities and inducing maximum seed set after a single visit. The impact of native bumblebees on I. glandulifera pollination and the implications of the pollination mechanism of the alien for its successful spread are discussed.

  15. A risk assessment system for alien plant bio-invasion in Xiamen of China

    Institute of Scientific and Technical Information of China (English)

    OU Jian; LU Changyi; DesmondK.O'TOOLE

    2008-01-01

    Bio-invasion has caused serious ecosystem damage and enormous economic losses in China, and it has been the greatest factor to island bio-diversity reduction. Xiamen, as an important seaport with a relatively high conservation value, is particularly vulnerable to bio-invasion for its typical island ecosystem as well as frequent human-made disturbance. As a result of field surveys, literature review, and consultation with experts, a list of 67 alien plants identified as major invaders (12 species) and emerging invaders (55 species) in Xiamen has been compiled. Based on the analysis of the current situation of bio-invasion in Xiamen, a risk assessment system for alien plant invasion has been designed using a ranking system and an analytic hierarchy process. The system consists of 17 secondary indices, grouped into 6 primary indices reflecting the different stages in the bio-invasion process: introduction, establishment, dispersion, current range, infestation, and artificial control. Biogeographical, ecological, and experience-linked aspects of the species as well as artificial disturbance were taken into account in the index selection and criterion development. The system was then validated (and worked well) using fifty well-known alien plant species as candidates. Appropriate recommendations are proposed to help local policy-makers prioritize their decisions on such alien plants.

  16. Minimizing Risks of Invasive Alien Plant Species in Tropical Production Forest Management

    Directory of Open Access Journals (Sweden)

    Michael Padmanaba

    2014-08-01

    Full Text Available Timber production is the most pervasive human impact on tropical forests, but studies of logging impacts have largely focused on timber species and vertebrates. This review focuses on the risk from invasive alien plant species, which has been frequently neglected in production forest management in the tropics. Our literature search resulted in 114 publications with relevant information, including books, book chapters, reports and papers. Examples of both invasions by aliens into tropical production forests and plantation forests as sources of invasions are presented. We discuss species traits and processes affecting spread and invasion, and silvicultural practices that favor invasions. We also highlight potential impacts of invasive plant species and discuss options for managing them in production forests. We suggest that future forestry practices need to reduce the risks of plant invasions by conducting surveillance for invasive species; minimizing canopy opening during harvesting; encouraging rapid canopy closure in plantations; minimizing the width of access roads; and ensuring that vehicles and other equipment are not transporting seeds of invasive species. Potential invasive species should not be planted within dispersal range of production forests. In invasive species management, forewarned is forearmed.

  17. Aliens in Transylvania: risk maps of invasive alien plant species in Central Romania

    OpenAIRE

    Heike Zimmermann; Jacqueline Loos; Henrik von Wehrden; Joern Fischer

    2015-01-01

    Using the MAXENT algorithm, we developed risk maps for eight invasive plant species in southern Transylvania, Romania, a region undergoing drastic land-use changes. Our findings show that invasion risk increased with landscape heterogeneity. Roads and agricultural areas were most prone to invasion, whereas forests were least at risk.

  18. Aliens in Transylvania: risk maps of invasive alien plant species in Central Romania

    Directory of Open Access Journals (Sweden)

    Heike Zimmermann

    2015-01-01

    Full Text Available Using the MAXENT algorithm, we developed risk maps for eight invasive plant species in southern Transylvania, Romania, a region undergoing drastic land-use changes. Our findings show that invasion risk increased with landscape heterogeneity. Roads and agricultural areas were most prone to invasion, whereas forests were least at risk.

  19. Annotated list of marine alien species in the Mediterranean with records of the worst invasive species

    Directory of Open Access Journals (Sweden)

    A. ZENETOS

    2012-12-01

    Full Text Available This collaborative effort by many specialists across the Mediterranean presents an updated annotated list of alien marine species in the Mediterranean Sea. Alien species have been grouped into six broad categories namely established, casual, questionable, cryptogenic, excluded and invasive, and presented in lists of major ecofunctional/taxonomic groups. The establishment success within each group is provided while the questionable and excluded records are commented in brief. A total of 963 alien species have been reported from the Mediterranean until December 2005, 218 of which have been classified as excluded (23% leaving 745 of the recorded species as valid aliens. Of these 385 (52% are already well established, 262 (35% are casual records, while 98 species (13% remain “questionable” records. The species cited in this work belong mostly to zoobenthos and in particular to Mollusca and Crustacea, while Fish and Phytobenthos are the next two groups which prevail among alien biota in the Mediterranean. The available information depends greatly on the taxonomic group examined. Thus, besides the three groups explicitly addressed in the CIESM atlas series (Fish, Decapoda/Crustacea and Mollusca, which are however updated in the present work, Polychaeta, Phytobenthos, Phytoplankton and Zooplankton are also addressed in this study. Among other zoobenthic taxa sufficiently covered in this study are Echinodermata, Sipuncula, Bryozoa and Ascidiacea. On the contrary, taxa such as Foraminifera, Amphipoda and Isopoda, that are not well studied in the Mediterranean, are insufficiently covered. A gap of knowledge is also noticed in Parasites, which, although ubiquitous and pervasive in marine systems, have been relatively unexplored as to their role in marine invasions. Conclusively the lack of funding purely systematic studies in the region has led to underestimation of the number of aliens in the Mediterranean. Emphasis is put on those species that are

  20. Modeling Alien Invasions: Plasticity May Hold the Key to Prevention

    OpenAIRE

    Peacor, Scott D.; Allesina, Stefano; Riolo, Rick L; Pascual, Mercedes

    2006-01-01

    Understanding species invasion is a central problem in ecology because invasions of exotic species severely impact ecosystems, and because invasions underlie fundamental ecological processes. However, the influence on invasions of phenotypic plasticity, a key component of many species interactions, is unknown. We present a model in which phenotypic plasticity of a resident species increases its ability to oppose invaders, and plasticity of an invader increases its ability to displace resident...

  1. Status of biological control projects on terrestrial invasive alien weeds in California

    Science.gov (United States)

    In cooperation with foreign scientists, we are currently developing new classical biological control agents for five species of invasive alien terrestrial weeds. Cape-Ivy. A gall-forming fly, Parafreutreta regalis, and a stem-boring moth, Digitivalva delaireae, have been favorably reviewed by TAG...

  2. Missing the Boat on Invasive Alien Species: A Review of Post-Secondary Curricula in Canada

    Science.gov (United States)

    Smith, Andrea L.; Bazely, Dawn R.; Yan, Norman D.

    2011-01-01

    Invasive alien species (IAS) cause major environmental and economic damage worldwide, and also threaten human food security and health. The impacts of IAS are expected to rise with continued globalization, land use modification, and climate change. Developing effective strategies to deal with IAS requires a collaborative, interdisciplinary…

  3. Living with the enemy: parasites and pathogens of the invasive alien ladybird Harmonia axyridis

    Science.gov (United States)

    Harmonia axyridis is an invasive alien predator in many countries across the world. The rapid establishment and spread of this species is of concern because of the threat it poses to biodiversity as a generalist predator. Understanding the mechanisms that contribute to the success of this species ...

  4. The Impact of the Invasive Alien Plant, Impatiens glandulifera, on Pollen Transfer Networks

    OpenAIRE

    Carine Emer; Vaughan, Ian P.; Simon Hiscock; Jane Memmott

    2015-01-01

    Biological invasions are a threat to the maintenance of ecological processes, including pollination. Plant-flower visitor networks are traditionally used as a surrogated for pollination at the community level, despite they do not represent the pollination process, which takes place at the stigma of plants where pollen grains are deposited. Here we investigated whether the invasion of the alien plant Impatiens glandulifera (Balsaminaceae) affects pollen transfer at the community level. We aske...

  5. The impact of the invasive alien plant, impatiens glandulifera, on pollen transfer networks

    OpenAIRE

    Emer, Carine; Vaughan, Ian P.; Hiscock, Simon; Memmott, Jane

    2015-01-01

    Biological invasions are a threat to the maintenance of ecological processes, including pollination. Plant-flower visitor networks are traditionally used as a surrogated for pollination at the community level, despite they do not represent the pollination process, which takes place at the stigma of plants where pollen grains are deposited. Here we investigated whether the invasion of the alien plant Impatiens glandulifera (Balsaminaceae) affects pollen transfer at the community level. We aske...

  6. Impacts of alien plant invasions on biodiversity and evolutionary responses of native species

    OpenAIRE

    Yanbao Lei; Haifeng Xiao; Yulong Feng

    2010-01-01

    The impacts of invasive alien species on the genetic diversity and evolutionary responses of native species are poorly understood. Accumulating evidence shows that invasive plant species can lead to genetic erosion of natives directly through hybridization and gene infiltration, or even affect genetic diversity of natives through creation of new “genotypes”. Exotic species can also alter genetic diversity of natives indirectly through habitat fragmentation and modification, processes which in...

  7. Global threats from invasive alien species in the twenty-first century and national response capacities.

    Science.gov (United States)

    Early, Regan; Bradley, Bethany A; Dukes, Jeffrey S; Lawler, Joshua J; Olden, Julian D; Blumenthal, Dana M; Gonzalez, Patrick; Grosholz, Edwin D; Ibañez, Ines; Miller, Luke P; Sorte, Cascade J B; Tatem, Andrew J

    2016-01-01

    Invasive alien species (IAS) threaten human livelihoods and biodiversity globally. Increasing globalization facilitates IAS arrival, and environmental changes, including climate change, facilitate IAS establishment. Here we provide the first global, spatial analysis of the terrestrial threat from IAS in light of twenty-first century globalization and environmental change, and evaluate national capacities to prevent and manage species invasions. We find that one-sixth of the global land surface is highly vulnerable to invasion, including substantial areas in developing economies and biodiversity hotspots. The dominant invasion vectors differ between high-income countries (imports, particularly of plants and pets) and low-income countries (air travel). Uniting data on the causes of introduction and establishment can improve early-warning and eradication schemes. Most countries have limited capacity to act against invasions. In particular, we reveal a clear need for proactive invasion strategies in areas with high poverty levels, high biodiversity and low historical levels of invasion. PMID:27549569

  8. Research Progress on Invasion Mechanism of Alien Invasive Species%外来物种入侵机制的研究进展

    Institute of Scientific and Technical Information of China (English)

    张巧; 郝建锋

    2011-01-01

    To make foundation for further study of alien plant invasion and fundamentally control alien plant invasion, in this paper the invasion status of alien plants in China was generalized, the process and mechanisms of biological invasion were analyzed and prevention and control measures were proposed which is of great significance to prevention of malignant alien invasive species invasion.%为了从根本上有效控制外来植物的入侵,为外来植物入侵的深入研究提供参考,综述了我国外来物种入侵现状,分析外来物种入侵过程及入侵机制,提出对入侵物种的预防和控制措施,对于防治恶性外来入侵物种有重要意义.

  9. INVASIVESNET towards an International Association for Open Knowledge on Invasive Alien Species

    Science.gov (United States)

    Lucy, Frances E; Roy, Helen; Simpson, Annie; Carlton, James T.; Hanson, John Mark; Magellan, Kit; Campbell, Marnie L.; Costello, Mark J.; Pagad, Shyama; Hewitt, Chad L; McDonald, Justin; Cassey, Phillip; Thomaz, Sidinei M; Katsanevakis, Stelios; Zenetos, Argyro; Tricarico, Elena; Boggero, Angela; Groom, Quentin J; Adriaens, Tim; Vanderhoeven, Sonia; Torchin, Mark E.; Hufbauer, Ruth A.; Fuller, Pam; Carman, Mary R; Conn, David Bruce; Vitule, Jean R. S.; Canning-Clode, João; Galil, Bella S; Ojaveer, Henn; Bailey, Sarah A; Therriault, Thomas W; Claudi, Renata; Gazda, Anna; Dick, Jaimie T A; Caffrey, Joe; Witt, Arne; Kenis, Marc; Lehtiniemi, Maiju; Helmisaari, Harry; Panov, Vadim E

    2016-01-01

    In a world where invasive alien species (IAS) are recognised as one of the major threats to biodiversity, leading scientists from five continents have come together to propose the concept of developing an international association for open knowledge and open data on IAS—termed “INVASIVESNET”. This new association will facilitate greater understanding and improved management of invasive alien species (IAS) and biological invasions globally, by developing a sustainable network of networks for effective knowledge exchange. In addition to their inclusion in the CBD Strategic Plan for Biodiversity, the increasing ecological, social, cultural and economic impacts associated with IAS have driven the development of multiple legal instruments and policies. This increases the need for greater co-ordination, co-operation, and information exchange among scientists, management, the community of practice and the public.

  10. Clearing a Path Towards Effective Alien Invasive Control: the Legal Conundrum

    Directory of Open Access Journals (Sweden)

    AR Patterson

    2006-05-01

    Full Text Available Alien invasive plants pose significant ecological, social and economic challenges for South Africa. These species threaten South Africa’s rich biodiversity, deplete our scarce water resources, reduce the agricultural potential of land, cause soil erosion and intensify flooding and fires. According to recent estimations, over eight percent of land in South Africa has been invaded by these species and at current rates of expansion their impact could double in the next fifteen years. In an attempt to curb the impending crises, the South African government has promulgated eleven national and various provincial laws which contain mechanisms for regulating the different threats posed by alien invasive plants. Certain of these laws are framework in nature while the majority are sectoral and aimed at regulating these species for one of the following four main purposes: biodiversity conservation; water conservation; agricultural management; and fire risk management. The responsibility for administering these laws spans four national departments, nine provincial environmental authorities, provincial conservation authorities, numerous local and statutory authorities. This fragmented regime, coupled with the adoption of a command and control approach to regulation, has proven inept in effectively regulating the spread of alien invasive plants in South Africa. This reality led the previous Minister of Environmental Affairs and Tourism, Mr Valli Moosa, to call for the development of a “coherent legislative framework … streamlined along the lines of the principles endorsed by the Convention on Biological Diversity”. This article critically analyses the government’s attempts to develop such a “coherent legislative framework” to regulate alien invasive plants in light of recent legislative reform. It is divided into two parts. Part one critically considers South Africa’s current laws of relevance to alien invasive plants with specific emphasis on

  11. Putative linkages between below- and aboveground mutualisms during alien plant invasions.

    Science.gov (United States)

    Rodríguez-Echeverría, Susana; Traveset, Anna

    2015-01-01

    Evidence of the fundamental role of below-aboveground links in controlling ecosystem processes is mostly based on studies done with soil herbivores or mutualists and aboveground herbivores. Much less is known about the links between belowground and aboveground mutualisms, which have been studied separately for decades. It has not been until recently that these mutualisms-mycorrhizas and legume-rhizobia on one hand, and pollinators and seed dispersers on the other hand-have been found to influence each other, with potential ecological and evolutionary consequences. Here we review the mechanisms that may link these two-level mutualisms, mostly reported for native plant species, and make predictions about their relevance during alien plant invasions. We propose that alien plants establishing effective mutualisms with belowground microbes might improve their reproductive success through positive interactions between those mutualists and pollinators and seed dispersers. On the other hand, changes in the abundance and diversity of soil mutualists induced by invasion can also interfere with below-aboveground links for native plant species. We conclude that further research on this topic is needed in the field of invasion ecology as it can provide interesting clues on synergistic interactions and invasional meltdowns during alien plant invasions. PMID:26034049

  12. Invasive Alien Species of Terrestrial Vegetation of North-Eastern Uttar Pradesh

    Directory of Open Access Journals (Sweden)

    Sumit Srivastava

    2014-01-01

    Full Text Available The vegetational landscape of north-eastern Terai region at the foot hills of Central Himalayas is a mosaic of grassland, old-field, wasteland, and forest ecosystems. Like many other parts of the country, this region is also infested with alien intruders which not only interfere with the growth and production of food crops but also exercise adverse effects on the biodiversity of native species. The present study attempts to catalogue the invasive alien species of the terrestrial vegetation of north-eastern Uttar Pradesh especially with reference to their habit, taxonomic position, and nativity. A total of 1135 plant species within 580 genera under 119 families are so far known to occur in the region. Of these, only 149 species within 100 genera under 41 families have been found to be invasive aliens as evident from their center of origin, past history, nature of aggregation, and invasion observed under field conditions. About 80% of these invaders have been introduced from neotropics. Out of 173 invasive plants across India, this region shares 149 species, out of which 66% of species have come from Tropical America, 14% from African continent, and the rest from other countries. A better planning in the form of early identification and reporting of infestation and spread of noxious weeds is needed for their control.

  13. Are Photosynthetic Characteristics and Energetic Cost Important Invasive Traits for Alien Sonneratia Species in South China?

    Science.gov (United States)

    Li, Feng-Lan; Zan, Qi-Jie; Hu, Zheng-Yu; Shin, Paul-K. S.; Cheung, Siu-Gin; Wong, Yuk-Shan; Tam, Nora Fung-Yee; Lei, An-Ping

    2016-01-01

    A higher photosynthesis and lower energetic cost are recognized as important characteristics for invasive species, but whether these traits are also important for the ability of alien mangrove species to become invasive has seldom been reported. A microcosm study was conducted to compare the photosynthetic characteristics, energetic cost indices and other growth traits between two alien species (Sonneratia apetala and S. caseolaris) and four native mangrove species over four seasons in a subtropical mangrove nature reserve in Shenzhen, South China. The aim of the study was to evaluate the invasive potential of Sonneratia based on these physiological responses. The annual average net photosynthetic rate (Pn), stomatal conductance (Gs) and total carbon assimilation per unit leaf area (Atotal) of the two alien Sonneratia species were significantly higher than the values of the native mangroves. In contrast, the opposite results were obtained for the leaf construction cost (CC) per unit dry mass (CCM) and CC per unit area (CCA) values. The higher Atotal and lower CC values resulted in a 72% higher photosynthetic energy-use efficiency (PEUE) for Sonneratia compared to native mangroves, leading to a higher relative growth rate (RGR) of the biomass and height of Sonneratia with the respective values being 51% and 119% higher than those of the native species. Higher photosynthetic indices for Sonneratia compared to native species were found in all seasons except winter, whereas lower CC values were found in all four seasons. The present findings reveal that alien Sonneratia species may adapt well and become invasive in subtropical mangrove wetlands in Shenzhen due to their higher photosynthetic characteristics coupled with lower costs in energy use, leading to a higher PEUE. The comparison of these physiological responses between S. apetala and S. caseolaris reveal that the former species is more invasive than the latter one, thus requiring more attention in future. PMID

  14. Fire-driven alien invasion in a fire-adapted ecosystem

    Science.gov (United States)

    Keeley, Jon E.; Brennan, Teresa J.

    2012-01-01

    Disturbance plays a key role in many alien plant invasions. However, often the main driver of invasion is not disturbance per se but alterations in the disturbance regime. In some fire-adapted shrublands, the community is highly resilient to infrequent, high-intensity fires, but changes in the fire regime that result in shorter fire intervals may make these communities more susceptible to alien plant invasions. This study examines several wildfire events that resulted in short fire intervals in California chaparral shrublands. In one study, we compared postfire recovery patterns in sites with different prefire stand ages (3 and 24 years), and in another study we compared sites that had burned once in four years with sites that had burned twice in this period. The population size of the dominant native shrub Adenostoma fasciculatum was drastically reduced following fire in the 3-year sites relative to the 24-year sites. The 3-year sites had much greater alien plant cover and significantly lower plant diversity than the 24-year sites. In a separate study, repeat fires four years apart on the same sites showed that annual species increased significantly after the second fire, and alien annuals far outnumbered native annuals. Aliens included both annual grasses and annual forbs and were negatively correlated with woody plant cover. Native woody species regenerated well after the first fire but declined after the second fire, and one obligate seeding shrub was extirpated from two sites by the repeat fires. It is concluded that some fire-adapted shrublands are vulnerable to changes in fire regime, and this can lead to a loss of native diversity and put the community on a trajectory towards type conversion from a woody to an herbaceous system. Such changes result in alterations in the proportion of natives to non-natives, changes in functional types from deeply rooted shrubs to shallow rooted grasses and forbs, increased fire frequency due to the increase in fine fuels

  15. The evolution of fire and invasive alien plant management practices in fynbos

    Directory of Open Access Journals (Sweden)

    B.W. van Wilgen

    2010-01-01

    Full Text Available The history and development of fire and invasive alien plant management policies in fynbos during the 20th century are reviewed. Fire was initially condemned outright as a destructive force, but as its vital role became better understood, management policies switched from protection to active burning in 1968. During the 1970s, large, coordinated research programmes were established, resulting in a solid basis of knowledge on which to develop fire management policies. Despite policies of prescribed burning, wild fires remain the dominant feature of the region, fortunately driving a variable fire regime that remains broadly aligned with conservation objectives. The problem of conserving fire-adapted fynbos is complicated by invading alien trees that are also fire-adapted. Research results were used to demonstrate the impacts of these invasions on water yields, leading to the creation of one of the largest alien plant control programmes globally. Despite improvements in control methods, alien trees, notably pines, continue to spread almost unchecked. Biological control offered some hope for controlling pines, but was ruled out as too high a risk for these commercially-important trees. Failure to address this problem adequately will almost certainly result in the severe degradation of remaining fynbos ecosystems.

  16. Insect Eradication and Containment of Invasive Alien Species

    Science.gov (United States)

    Insect eradication programs are nearly always targeted at recently arrived invasive species with significant pest potential. They attempt to contain a pest to a defined area and then completely eliminate the pest from that area. From a Federal regulatory standpoint, eradication programs are undert...

  17. Riparian vegetation: degradation, alien plant invasions, and restoration prospects

    Czech Academy of Sciences Publication Activity Database

    Richardson, D. M.; Holmes, P. M.; Esler, K. J.; Galatowitsch, S. M.; Stromberg, J. C.; Kirkman, S. P.; Pyšek, Petr; Hobbs, R. J.

    2007-01-01

    Roč. 13, č. 1 (2007), s. 126-139. ISSN 1366-9516 Institutional research plan: CEZ:AV0Z60050516 Keywords : riparian habitats * plant invasions * biogeography Subject RIV: EF - Botanics Impact factor: 2.965, year: 2007

  18. Alien interference: disruption of infochemical networks by invasive insect herbivores

    Czech Academy of Sciences Publication Activity Database

    Desurmont, G.A.; Harvey, J.; Van Dam, N. M.; Cristescu, S. M.; Schiestl, F.P.; Cozzolino, S.; Anderson, P.; Larsson, M. C.; Kindlmann, Pavel; Danner, H.; Turlings, C. J.

    2014-01-01

    Roč. 37, č. 8 (2014), s. 1854-1865. ISSN 0140-7791 Institutional support: RVO:67179843 Keywords : invasive species * multitrophic interactions * plant–insect interactions * plant volatiles Subject RIV: EH - Ecology, Behaviour Impact factor: 6.960, year: 2014

  19. The application of the European strategy on invasive alien species: an example with introduced squirrels

    OpenAIRE

    Sandro Bertolino; Piero Genovesi

    2005-01-01

    Abstract We assessed the cases of squirrel species already introduced into Italy inside the framework proposed by the European strategy on invasive alien species. We collected information on 9 introductions that originated 8 populations: 3 of grey squirrels (Sciurus carolinensis), 2 of Finlayson's squirrels (Callosciurus finlaysonii), and 3 of Siberian chip-munks (Eutamias sibiricus). Food opportunism...

  20. The evolution of fire and invasive alien plant management practices in fynbos

    OpenAIRE

    B.W. van Wilgen

    2010-01-01

    The history and development of fire and invasive alien plant management policies in fynbos during the 20th century are reviewed. Fire was initially condemned outright as a destructive force, but as its vital role became better understood, management policies switched from protection to active burning in 1968. During the 1970s, large, coordinated research programmes were established, resulting in a solid basis of knowledge on which to develop fire management policies. Despite policies of presc...

  1. Invasion success of alien plants: do habitat affinities in the native distribution range matter?

    Czech Academy of Sciences Publication Activity Database

    Hejda, Martin; Pyšek, Petr; Pergl, Jan; Sádlo, Jiří; Chytrý, M.; Jarošík, Vojtěch

    2009-01-01

    Roč. 18, č. 3 (2009), s. 372-382. ISSN 1466-822X R&D Projects: GA MŠk LC06073 Grant ostatní: Evropská komise(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : biological invasions * casual aliens * Central Europe Subject RIV: EF - Botanics Impact factor: 5.913, year: 2009

  2. Relative abundance of an invasive alien plant affects insect-flower interaction networks in Ireland

    Science.gov (United States)

    Stout, Jane C.; Casey, Leanne M.

    2014-02-01

    Invasive alien flowering plants may affect native plant pollinator interactions and have knock on impacts on populations of native plants and animals. The magnitude of these impacts, however, may be modified by the relative abundance of the invasive plant and the number of flowers it presents.We tested this by examining the structure of insect-flower interaction networks in six sites with increasing levels of invasion by Rhododendron ponticum in Ireland.Neither flower-visiting insect abundance, species richness nor diversity were related to R. ponticum flower abundance, but the composition of insect communities was. The total number of flowers in a site increased with the relative abundance of R. ponticum flowers but the number of co-flowering native plant species in these sites was low (interaction networks relatively small.As a result, changes in interaction network properties (connectance, interaction evenness and network level specialisation), which correlated with R. ponticum flower abundance, were a result of the small network size rather than due to changes in the resilience of networks.Overall, we conclude that the impacts of invasive alien plants on native plant-pollinator interactions are not only species specific, but site specific, according to the abundance of flowers produced by both the invasive and the native plants.

  3. Invasive alien predator causes rapid declines of native European ladybirds

    Czech Academy of Sciences Publication Activity Database

    Roy, H. E.; Adriaens, T.; Isaac, N. J. B.; Kenis, M.; Onkelinx, T.; San Martin, G.; Brown, P. M. J.; Hautier, L.; Poland, R.; Roy, D. B.; Comont, R.; Eschen, R.; Frost, R.; Zindel, R.; Van Vlaenderen, J.; Nedvěd, Oldřich; Ravn, H. P.; Grégoire, J.-C.; de Biseau, J.-C.; Maes, D.

    2012-01-01

    Roč. 18, č. 7 (2012), s. 717-725. ISSN 1366-9516 Grant ostatní: MZe ČR(CZ) QH82047; Swiss Federal Office for the Environment(SE) F232-0377; project ALARM(BE) GOCE-CT-2003-506675 Institutional support: RVO:60077344 Keywords : biological control * biological invasions * citizen science Subject RIV: EH - Ecology, Behaviour Impact factor: 6.122, year: 2012 http://onlinelibrary.wiley.com/doi/10.1111/j.1472-4642.2012.00883.x/pdf

  4. Impact of invasive alien plants on ecosystem functionning in Belgium

    OpenAIRE

    Dassonville, Nicolas

    2008-01-01

    Les invasions biologiques sont une cause majeure de perte de biodiversité à l’échelle mondiale. L’impact direct des espèces exotiques envahissantes (EEE) sur la structure et la composition des communautés a été bien documenté. Par contre, leur impact sur le fonctionnement des écosystèmes a été comparativement moins étudié. Dans le présent travail, j’ai mesuré sur le terrain et en conditions expérimentales l’impact de 7 espèces de plantes exotiques particulièrement envahissantes en Europe sur ...

  5. Savanna aliens

    NARCIS (Netherlands)

    Masocha, M.

    2010-01-01

    Numerous alien plant species are invading African savannas causing loss of biodiversity and altering ecosystem functioning. The ecological factors and underlying mechanisms causing these invasions are poorly understood. This hinders invasive species management and biodiversity conservation. In this

  6. Release from belowground enemies and shifts in root traits as interrelated drivers of alien plant invasion success: a hypothesis.

    Science.gov (United States)

    Dawson, Wayne

    2015-10-01

    Our understanding of the interrelated mechanisms driving plant invasions, such as the interplay between enemy release and resource-acquisition traits, is biased by an aboveground perspective. To address this bias, I hypothesize that plant release from belowground enemies (especially fungal pathogens) will give invasive plant species a fitness advantage in the alien range, via shifts in root traits (e.g., increased specific root length and branching intensity) that increase resource uptake and competitive ability compared to native species in the alien range, and compared to plants of the invader in its native range. Such root-trait changes could be ecological or evolutionary in nature. I explain how shifts in root traits could occur as a consequence of enemy release and contribute to invasion success of alien plants, and how they could be interrelated with other potential belowground drivers of invasion success (allelopathy, mutualist enhancement). Finally, I outline the approaches that could be taken to test whether belowground enemy release results in increased competitive ability and nutrient uptake by invasive alien plants, via changes in root traits in the alien range. PMID:26668717

  7. Effectiveness of native bumblebees as pollinators of the alien invasive plant Impatiens glandulifera (Balsaminaceae) in Ireland

    OpenAIRE

    Stout, Jane C.; Caroline M. Nienhuis

    2009-01-01

    Flowers of alien invasive plants can be pollen limited due to a lack of effective pollinators. The alien Impatiens glandulifera is predominantly visited by bumblebees in its invaded range. There bumblebees pollinate I. glandulifera, but it remains unclear whether foraging behaviour or bumblebee or flower morphology affects effectiveness. We investigated the effectiveness of native bumblebee (Bombus pascuorum) pollinators in Ireland by quantifying pollen deposition and...

  8. Direct and indirect effects of invasion by the alien tree Ailanthus altissima on riparian plant communities and ecosystem multifunctionality

    OpenAIRE

    Constán Nava, Soraya; Soliveres, Santiago; Torices, Rubén; Serra, Lluís; Bonet Jornet, Andreu

    2015-01-01

    Most existing studies addressing the effects of invasive species on biodiversity focus on species richness ignoring better indicators of biodiversity and better predictors of ecosystem functioning such as the diversity of evolutionary histories (phylodiversity). Moreover, no previous study has separated the direct effect of alien plants on multiple ecosystem functions simultaneously (multifunctionality) from those indirect ones mediated by the decrease on biodiversity caused by alien plants. ...

  9. Stakeholder Perceptions of an Ecosystem Services Approach to Clearing Invasive Alien Plants on Private Land

    Directory of Open Access Journals (Sweden)

    Lauren S. Urgenson

    2013-03-01

    Full Text Available Incentivizing private landowners and other stakeholders is central to the effective conservation of ecosystem services in working landscapes. To better understand how to design effective incentives, the perceptions of landowners and other stakeholders are explored regarding a proposed approach to clearing invasive alien plants on private land in the Western Cape Province, South Africa. The public funded national program, Working for Water, conserves ecosystem services while employing and training people from marginalized sectors of society to clear these plants. Private landowner involvement is a key conservation challenge, because without adequate landowner involvement, invasive alien plants persist on the landscape and continuously reinvade cleared areas. We collected interview data from private landowners in three study sites, and web-survey data from conservation professionals and Working for Water managers, in order to compare stakeholder perceptions of (1 government and landowners' responsibilities for clearing invasive alien plants; (2 existing and proposed policy tools; and (3 the extent to which stakeholders consider the proposed financial incentive to be sufficient. There was significant consensus among stakeholders concerning their preference for shared landowner and government responsibility and for a policy mix that combines incentives with disincentives. Landowners from the three study sites differed in the level of responsibility they were willing to assume. Stakeholders also diverged in terms of their perceptions of the proposed financial incentives. Furthermore, the perspectives of landowners were strongly associated with ecological and social features of the landscapes in which they are located. Understanding stakeholders' points of view within their differing contexts is shown to be a valuable means of gaining insight into the opportunities and constraints that face ecosystem service conservation in working landscapes.

  10. Alien plant invasions and native plant extinctions: a six-threshold framework.

    Science.gov (United States)

    Downey, Paul O; Richardson, David M

    2016-01-01

    Biological invasions are widely acknowledged as a major threat to global biodiversity. Species from all major taxonomic groups have become invasive. The range of impacts of invasive taxa and the overall magnitude of the threat is increasing. Plants comprise the biggest and best-studied group of invasive species. There is a growing debate; however, regarding the nature of the alien plant threat-in particular whether the outcome is likely to be the widespread extinction of native plant species. The debate has raised questions on whether the threat posed by invasive plants to native plants has been overstated. We provide a conceptual framework to guide discussion on this topic, in which the threat posed by invasive plants is considered in the context of a progression from no impact through to extinction. We define six thresholds along the 'extinction trajectory', global extinction being the final threshold. Although there are no documented examples of either 'in the wild' (Threshold 5) or global extinctions (Threshold 6) of native plants that are attributable solely to plant invasions, there is evidence that native plants have crossed or breached other thresholds along the extinction trajectory due to the impacts associated with plant invasions. Several factors may be masking where native species are on the trajectory; these include a lack of appropriate data to accurately map the position of species on the trajectory, the timeframe required to definitively state that extinctions have occurred and management interventions. Such interventions, focussing mainly on Thresholds 1-3 (a declining population through to the local extinction of a population), are likely to alter the extinction trajectory of some species. The critical issue for conservation managers is the trend, because interventions must be implemented before extinctions occur. Thus the lack of evidence for extinctions attributable to plant invasions does not mean we should disregard the broader threat. PMID

  11. Alien invasions and the game of hide and seek in Patagonia.

    Directory of Open Access Journals (Sweden)

    Martin Lindegren

    Full Text Available The introduction, establishment and spread of alien species is a major threat to biodiversity and the provision of ecosystem services for human wellbeing. In order to reduce further loss of biodiversity and maintain productive and sustainable ecosystems, understanding the ecological mechanisms underlying species invasions and avoiding potentially harmful effects on native communities is urgently needed, but largely lacking. We here demonstrate, by means of hydroacoustics and advanced spatial modelling, how native fish species as a result of previous exposure to native predators may successfully respond to invasive novel predators through a complicated game of hide and seek, minimizing spatio-temporal overlap with predators, and potentially facilitating coexistence between native prey species (Galaxiids and introduced novel predators (Salmonids in a deep Andean lake, Patagonia.

  12. The Impact of the Invasive Alien Plant, Impatiens glandulifera, on Pollen Transfer Networks.

    Directory of Open Access Journals (Sweden)

    Carine Emer

    Full Text Available Biological invasions are a threat to the maintenance of ecological processes, including pollination. Plant-flower visitor networks are traditionally used as a surrogated for pollination at the community level, despite they do not represent the pollination process, which takes place at the stigma of plants where pollen grains are deposited. Here we investigated whether the invasion of the alien plant Impatiens glandulifera (Balsaminaceae affects pollen transfer at the community level. We asked whether more alien pollen is deposited on the stigmas of plants on invaded sites, whether deposition is affected by stigma type (dry, semidry and wet and whether the invasion of I. glandulifera changes the structure of the resulting pollen transfer networks. We sampled stigmas of plants on 10 sites invaded by I. glandulifera (hereafter, balsam and 10 non-invaded control sites. All 20 networks had interactions with balsam pollen, although significantly more balsam pollen was found on plants with dry stigmas in invaded areas. Balsam pollen deposition was restricted to a small subset of plant species, which is surprising because pollinators are known to carry high loads of balsam pollen. Balsam invasion did not affect the loading of native pollen, nor did it affect pollen transfer network properties; networks were modular and poorly nested, both of which are likely to be related to the specificity of pollen transfer interactions. Our results indicate that pollination networks become more specialized when moving from the flower visitation to the level of pollen transfer networks. Therefore, caution is needed when inferring pollination from patterns of insect visitation or insect pollen loads as the relationship between these and pollen deposition is not straightforward.

  13. The Impact of the Invasive Alien Plant, Impatiens glandulifera, on Pollen Transfer Networks.

    Science.gov (United States)

    Emer, Carine; Vaughan, Ian P; Hiscock, Simon; Memmott, Jane

    2015-01-01

    Biological invasions are a threat to the maintenance of ecological processes, including pollination. Plant-flower visitor networks are traditionally used as a surrogated for pollination at the community level, despite they do not represent the pollination process, which takes place at the stigma of plants where pollen grains are deposited. Here we investigated whether the invasion of the alien plant Impatiens glandulifera (Balsaminaceae) affects pollen transfer at the community level. We asked whether more alien pollen is deposited on the stigmas of plants on invaded sites, whether deposition is affected by stigma type (dry, semidry and wet) and whether the invasion of I. glandulifera changes the structure of the resulting pollen transfer networks. We sampled stigmas of plants on 10 sites invaded by I. glandulifera (hereafter, balsam) and 10 non-invaded control sites. All 20 networks had interactions with balsam pollen, although significantly more balsam pollen was found on plants with dry stigmas in invaded areas. Balsam pollen deposition was restricted to a small subset of plant species, which is surprising because pollinators are known to carry high loads of balsam pollen. Balsam invasion did not affect the loading of native pollen, nor did it affect pollen transfer network properties; networks were modular and poorly nested, both of which are likely to be related to the specificity of pollen transfer interactions. Our results indicate that pollination networks become more specialized when moving from the flower visitation to the level of pollen transfer networks. Therefore, caution is needed when inferring pollination from patterns of insect visitation or insect pollen loads as the relationship between these and pollen deposition is not straightforward. PMID:26633170

  14. Preference and prey switching in a generalist predator attacking local and invasive alien pests.

    Directory of Open Access Journals (Sweden)

    Coline C Jaworski

    Full Text Available Invasive pest species may strongly affect biotic interactions in agro-ecosystems. The ability of generalist predators to prey on new invasive pests may result in drastic changes in the population dynamics of local pest species owing to predator-mediated indirect interactions among prey. On a short time scale, the nature and strength of such indirect interactions depend largely on preferences between prey and on predator behavior patterns. Under laboratory conditions we evaluated the prey preference of the generalist predator Macrolophus pygmaeus Rambur (Heteroptera: Miridae when it encounters simultaneously the local tomato pest Bemisia tabaci (Gennadius (Hemiptera: Aleyrodidae and the invasive alien pest Tuta absoluta (Meyrick (Lepidoptera: Gelechiidae. We tested various ratios of local vs. alien prey numbers, measuring switching by the predator from one prey to the other, and assessing what conditions (e.g. prey species abundance and prey development stage may favor such prey switching. The total predation activity of M. pygmaeus was affected by the presence of T. absoluta in the prey complex with an opposite effect when comparing adult and juvenile predators. The predator showed similar preference toward T. absoluta eggs and B. tabaci nymphs, but T. absoluta larvae were clearly less attacked. However, prey preference strongly depended on prey relative abundance with a disproportionately high predation on the most abundant prey and disproportionately low predation on the rarest prey. Together with the findings of a recent companion study (Bompard et al. 2013, Population Ecology, the insight obtained on M. pygmaeus prey switching may be useful for Integrated Pest Management in tomato crops, notably for optimal simultaneous management of B. tabaci and T. absoluta, which very frequently co-occur on tomato.

  15. Preference and prey switching in a generalist predator attacking local and invasive alien pests.

    Science.gov (United States)

    Jaworski, Coline C; Bompard, Anaïs; Genies, Laure; Amiens-Desneux, Edwige; Desneux, Nicolas

    2013-01-01

    Invasive pest species may strongly affect biotic interactions in agro-ecosystems. The ability of generalist predators to prey on new invasive pests may result in drastic changes in the population dynamics of local pest species owing to predator-mediated indirect interactions among prey. On a short time scale, the nature and strength of such indirect interactions depend largely on preferences between prey and on predator behavior patterns. Under laboratory conditions we evaluated the prey preference of the generalist predator Macrolophus pygmaeus Rambur (Heteroptera: Miridae) when it encounters simultaneously the local tomato pest Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and the invasive alien pest Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). We tested various ratios of local vs. alien prey numbers, measuring switching by the predator from one prey to the other, and assessing what conditions (e.g. prey species abundance and prey development stage) may favor such prey switching. The total predation activity of M. pygmaeus was affected by the presence of T. absoluta in the prey complex with an opposite effect when comparing adult and juvenile predators. The predator showed similar preference toward T. absoluta eggs and B. tabaci nymphs, but T. absoluta larvae were clearly less attacked. However, prey preference strongly depended on prey relative abundance with a disproportionately high predation on the most abundant prey and disproportionately low predation on the rarest prey. Together with the findings of a recent companion study (Bompard et al. 2013, Population Ecology), the insight obtained on M. pygmaeus prey switching may be useful for Integrated Pest Management in tomato crops, notably for optimal simultaneous management of B. tabaci and T. absoluta, which very frequently co-occur on tomato. PMID:24312646

  16. PHYTOSOCIOLOGY OF INVASIVE ALIEN THEROPHYTIC FLORA OF PEDDAGATTU, THE PROPOSED SITE FOR URANIUM MINING IN NALGONDA DISTRICT, TELANGANA, INDIA

    Directory of Open Access Journals (Sweden)

    A. BALEESHWAR REDDY1*, V. HANUMANTHA RAO AND V. VASUDEVA RAO2

    2014-10-01

    The present investigation reflects the findings of invasive alien species and phytosociological attributes at Peddagattu (Lambapur, Nalgonda district, Telangana, India. Phytosociology studies on Invasive alien species were collected during 2010-2012. Of 30 species of taxa are belonging to 29 genera and 17 families. Compositae is the most dominant family representing   with 6 species (20% followed by Malvaceae 4 species (13%, Solanaceae 3 species (10%, Amaranthaceae  and Leguminaceae with 2 species (7% each. About 60% of these alien species were introduced from Tropical America followed by Tropical Africa (13%, and Trop. C. America (7%. Among the species, Tridax procumbens shows the highest IVI value (12.94 and followed by Cleome viscose (7.12, Waltheria indica (6.13 and Parthenium hysterophorus (5.57 and Typha angustata (5.22.

  17. Evidence, Perceptions, and Trade-offs Associated with Invasive Alien Plant Control in the Table Mountain National Park, South Africa

    Directory of Open Access Journals (Sweden)

    Brian W. van Wilgen

    2012-06-01

    Full Text Available The Table Mountain National Park is a 265 km2 protected area embedded within a city of 3.5 million people. The park contains an extremely diverse flora with many endemic species, and has been granted World Heritage Site status in recognition of this unique biodiversity. Invasive alien plants are arguably the most significant threat to the conservation of this biodiversity, and the past decade has seen the implementation of aggressive programs aimed at the removal of invasions by these plants. These invasive alien plants include several species of trees, notably pines (Pinus species and eucalypts (Eucalyptus species, which historically have been grown in plantations, and which are utilized for recreation by the city's residents. In addition, many citizens regard the trees as attractive and ecologically beneficial, and for these reasons the alien plant control programs have been controversial. I briefly outline the legal obligations to deal with invasive alien plants, the history of control operations and the scientific rationale for their implementation, and the concerns that have been raised about the operations. Evidence in support of control includes the aggressive invasive nature of many species, and the fact that they displace native biodiversity (often irreversibly and have negative impacts on hydrology, fire intensity, and soil stability. Those against control cite aesthetic concerns, the value of pine plantations for recreation, the (perceived unattractive nature of the treeless natural vegetation, and the (incorrect belief that trees bring additional rainfall. The debate has been conducted through the press, and examples of perceptions and official responses are given. Despite opposition, the policy promoting alien plant removal has remained in place, and considerable progress has been made towards clearing pine plantations and invasive populations. This conservation success story owes much to political support, arising largely from job

  18. Resilience to disturbance and resistance to alien grass invasions in the cold desert of western North America

    Science.gov (United States)

    Alien grass invasions are resulting in ecosystem-level transformations of entire landscapes in arid and semi-arid ecosystems. The cold desert of western US is undergoing such a transformation, and is considered one of the most imperiled large ecosystems in the US. To address the rapid and complex ch...

  19. Impacts of alien invasive plants on soil nutrients are correlated with initial site conditions in NW Europe

    OpenAIRE

    Dassonville, Nicolas; Vanderhoeven, Sonia; Vanparys, Valerie; Hayez, Mathieu; Gruber, Wolf; Meerts, Pierre

    2008-01-01

    Alien invasive plants are capable of modifying ecosystem function. However, it is difficult to make generalisations because impacts often appear to be species- and site-specific. In this study, we examined the impacts of seven highly invasive plant species in NW Europe (Fallopia japonica, Heracleum mantegazzianum, Impatiens glandulifera, Prunus serotina, Rosa rugosa, Senecio inaequidens, Solidago gigantea) on nutrient pools in the topsoil and the standing biomass. We tested if the impacts fol...

  20. Release from belowground enemies and shifts in root traits as interrelated drivers of alien plant invasion success : a hypothesis

    OpenAIRE

    Dawson, W.

    2015-01-01

    Abstract Our understanding of the interrelated mechanisms driving plant invasions, such as the interplay between enemy release and resource‐acquisition traits, is biased by an aboveground perspective. To address this bias, I hypothesize that plant release from belowground enemies (especially fungal pathogens) will give invasive plant species a fitness advantage in the alien range, via shifts in root traits (e.g., increased specific root length and branching intensity) that increase resource u...

  1. Lack of sex-specific movement patterns in an alien species at its invasion front - consequences for invasion speed.

    Science.gov (United States)

    Herfindal, Ivar; Melis, Claudia; Åhlén, Per-Arne; Dahl, Fredrik

    2016-08-01

    Efficient targeting of actions to reduce the spread of invasive alien species relies on understanding the spatial, temporal, and individual variation of movement, in particular related to dispersal. Such patterns may differ between individuals at the invasion front compared to individuals in established and dense populations due to differences in environmental and ecological conditions such as abundance of conspecifics or sex-specific dispersal affecting the encounter rate of potential mates. We assessed seasonal and diurnal variation in movement pattern (step length and turning angle) of adult male and female raccoon dog at their invasion front in northern Sweden using data from Global Positioning System (GPS)-marked adult individuals and assessed whether male and female raccoon dog differed in their movement behavior. There were few consistent sex differences in movement. The rate of dispersal was rather similar over the months, suggesting that both male and female raccoon dog disperse during most of the year, but with higher speed during spring and summer. There were diurnal movement patterns in both sexes with more directional and faster movement during the dark hours. However, the short summer nights may limit such movement patterns, and long-distance displacement was best explained by fine-scale movement patterns from 18:00 to 05:00, rather than by movement patterns only from twilight and night. Simulation of dispersing raccoon dogs suggested a higher frequency of male-female encounters that were further away from the source population for the empirical data compared to a scenario with sex differences in movement pattern. The lack of sex differences in movement pattern at the invasion front results in an increased likelihood for reproductive events far from the source population. Animals outside the source population should be considered potential reproducing individuals, and a high effort to capture such individuals is needed throughout the year to prevent

  2. Analyzing the Social Factors That Influence Willingness to Pay for Invasive Alien Species Management Under Two Different Strategies: Eradication and Prevention

    Science.gov (United States)

    García-Llorente, Marina; Martín-López, Berta; Nunes, Paulo A. L. D.; González, José A.; Alcorlo, Paloma; Montes, Carlos

    2011-09-01

    Biological invasions occur worldwide, and have been the object of ecological and socio-economic research for decades. However, the manner in which different stakeholder groups identify the problems associated with invasive species and confront invasive species management under different policies remains poorly understood. In this study, we conducted an econometric analysis of the social factors influencing willingness to pay for invasive alien species management under two different regimes: eradication and prevention in the Doñana Natural Protected Area (SW Spain). Controlling for the participation of local residents, tourists and conservationists, email and face-to-face questionnaires were conducted. Results indicated that respondents were more willing to pay for eradication than prevention; and public support for invasive alien species management was influenced by an individual's knowledge and perception of invasive alien species, active interest in nature, and socio-demographic attributes. We concluded that invasive alien species management research should confront the challenges to engage stakeholders and accept any tradeoffs necessary to modify different conservation policies to ensure effective management is implemented. Finally, our willingness to pay estimates suggest the Department of Environment of Andalusian Government has suitable social support to meet the budgetary expenditures required for invasive alien species plans and adequate resources to justify an increase in the invasive alien species management budget.

  3. Effects of invasive alien kahili ginger (Hedychium gardnerianum) on native plant species regeneration in a Hawaiian rainforest

    Science.gov (United States)

    Minden, V.; Jacobi, J.D.; Porembski, S.; Boehmer, H.J.

    2010-01-01

    Questions: Does the invasive alien Hedychium gardnerianum (1) replace native understory species, (2) suppress natural regeneration of native plant species, (3) increase the invasiveness of other non-native plants and (4) are native forests are able to recover after removal of H. gardnerianum. Location: A mature rainforest in Hawai'i Volcanoes National Park on the island of Hawai'i (about 1200 m. a.s.l.; precipitation approximately 2770mm yr-1). Study sites included natural plots without effects of alien plants, ginger plots with a H. gardnerianum-domimted herb layer and cleared plots treated with herbicide to remove alien plants. Methods: Counting mature trees, saplings and seedlings of native and alien plant species. Using nonparametric H-tests to compare impact of H. gardnerianum on the structure of different sites. Results: Results confirmed the hypothesis that H. gardnerianum has negative effects on natural forest dynamics. Lower numbers of native tree seedlings and saplings were found on ginger-dominated plots. Furthermore, H. gardnerianum did not show negative effects on the invasive alien tree species Psidium cattleianum. Conclusions: This study reveals that where dominance of H. gardnerianum persists, regeneration of the forest by native species will be inhibited. Furthermore, these areas might experience invasion by P. cattleianum, resulting in displacement of native canopy species in the future, leading to a change in forest structure and loss of other species dependent on natural rainforest, such as endemic birds. However, if H. gardnerianum is removed the native Hawaiian forest is likely to regenerate and regain its natural structure. ?? 2009 International Association for Vegetation Science.

  4. Separating habitat invasibility by alien plants from the actual level of invasion

    Czech Academy of Sciences Publication Activity Database

    Chytrý, M.; Jarošík, Vojtěch; Pyšek, Petr; Hájek, O.; Knollová, I.; Tichý, L.; Danihelka, Jiří

    2008-01-01

    Roč. 89, č. 6 (2008), s. 1541-1553. ISSN 0012-9658 R&D Projects: GA MŠk(CZ) LC06073 Grant ostatní: ALARM(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : archaeophyte * biological invasions * Central Europe Subject RIV: EF - Botanics Impact factor: 4.874, year: 2008

  5. Perception and Understanding of Invasive Alien Species Issues by Nature Conservation and Horticulture Professionals in Belgium

    Science.gov (United States)

    Vanderhoeven, Sonia; Piqueray, Julien; Halford, Mathieu; Nulens, Greet; Vincke, Jan; Mahy, Grégory

    2011-03-01

    We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated with invasive plant species. We developed and utilized a questionnaire that addressed the themes of awareness, concept and use of language, availability of information, impacts and, finally, control and available solutions. Using co-inertia analyses, we tested to what extent the perception of invasive alien species (IAS) was dependent upon the perception of Nature in general. Only forty-two percent of respondent horticulture professionals and eighty-two percent of nature reserve managers had a general knowledge of IAS. Many individuals in both target groups nonetheless had an accurate understanding of the scientific issues. Our results therefore suggest that the manner in which individuals within the two groups view, or perceive, the IAS issue was more the result of lack of information than simply biased perceptions of target groups. Though IAS perceptions by the two groups diverged, they were on par with how they viewed Nature in general. The descriptions of IAS by participants converged with the ideas and concepts frequently found in the scientific literature. Both managers and horticulture professionals expressed a strong willingness to participate in programs designed to prevent the spread of, and damage caused by, IAS. Despite this, the continued commercial availability of many invasive species highlighted the necessity to use both mandatory and voluntary approaches to reduce their re-introduction and spread. The results of this study provide stakeholders and conservation managers with practical information on which communication and management strategies can be based.

  6. Preliminary results of studies on the distribution of invasive alien vascular plant species occurring in semi-natural and natural habitats in NW Poland

    OpenAIRE

    Popiela Agnieszka; Łysko Andrzej; Sotek Zofia; Ziarnek Krzysztof

    2015-01-01

    In Western Pomerania, as in other areas of Europe, alien species play an increasingly important role. In particular, invasive plants tend to spread rapidly and in large numbers which may reduce diversity of native species, leading to the phenomenon of “trivialisation of flora”, and transform ecosystems. The list of invasive species (32 taxa) includes alien species occurring throughout Western Pomerania, and penetrating natural or semi-natural habitats. The second group consists of potentially...

  7. Manipulating alien plant species propagule pressure as a prevention strategy for protected areasimpacts of alien plant invasions in protected areas

    Czech Academy of Sciences Publication Activity Database

    Meyerson, L. A.; Pyšek, Petr

    Dordrecht: Springer Science+Business Media, 2013 - (Foxcroft, L.; Pyšek, P.; Richardson, D.; Genovesi, P.), s. 473-486. (Book series: Invading Nature-Springer Series in Invasion Ecology). ISBN 978-94-007-7749-1 Institutional support: RVO:67985939 Keywords : plant invasions * protected areas * propagule pressure Subject RIV: EH - Ecology, Behaviour

  8. Invasive alien species in the food chain: Advancing risk assessment models to address climate change, economics and uncertainty

    OpenAIRE

    Darren Kriticos; Robert Venette; Frank Koch; Trond Rafoss; Wopke Van der Werf; Sue Worner

    2013-01-01

    Pest risk maps illustrate where invasive alien arthropods, molluscs, pathogens, and weeds might become established, spread, and cause harm to natural and agricultural resources within a pest risk area. Such maps can be powerful tools to assist policymakers in matters of international trade, domestic quarantines, biosecurity surveillance, or pest-incursion responses. The International Pest Risk Mapping Workgroup (IPRMW) is a group of ecologists, economists, modellers, and practising risk analy...

  9. Ecdysteroids in the pupae of Opogona sacchari (Bojer), a new invasive alien pest

    Institute of Scientific and Technical Information of China (English)

    WANG Fanghai; ZHANG Guren; WEN Ruizhen; HE Guofeng

    2006-01-01

    In order to understand the composition and quantitative variation of ecdysteriods in the pupae of Opogona sacchari (Bojer), a new invasive alien pest, we analyzed the pupal ecdysteroid composition and titers in this pest. The main component of ecdysteriods in the pupae of O. sacchari is 20-hydroxyecdysone. The titre of ecdysteriods in both male pupae and female pupae get higher gradually, and then decreased slowly after reaching a peak (80 ng/pupa). The titre of ecdysteriods was about 30 ng/pupa in the later stage of pupae. The peak of male pupae appeared on the third day, but the peak of female pupae lasted from the second day to the fourth day during pupal developments. The ecdysteroid content was higher in female pupae than in male pupae during specific pupal time (the 1st, 2nd, 4th, 5th, 6th day). We also found that the titre of ecdysteroids in posterior part of pupae was higher than in anterior part of pupae obviously.

  10. Ecdysteroids in the adults and eggs of Opogona sacchari (Bojer),an invasive alien pest

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to understand the composition and quantitative variation of ecdysteriods in the adults and eggs of Opogona sacchari (Bojer), an invasive alien pest, we analyzed the ecdysteroid composition and titers in the adult and egg of this pest. On day 4 after eclosion, the titer of ecdysteriods in the male adult was 0.080 ng/adult, much lower than 5.978 ng/adult in the female adult. During the development of ovaries, the titer of ecdysteriods was low on the first two days, and high in the late period, with the peak (10.48 ng/ovary) appearing on day 3. During the development of eggs, the titer of ecdysteriods was about 0.010 ng/egg from day 1 to day 3, and then decreased to 0.006 ng/egg on day 4. In both adults and eggs, three main components of ecdysteriods were found by identification of HPLC/RIA. They were 20-hydroxyecdysone, 26-hydroxyecdysone, and an unidentified component.

  11. Forestry and horticulture as pathways of plant invasions: a database of alien woody plants in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Křivánek, Martin; Pyšek, Petr

    Leiden: Backhuys Publisher, 2008 - (Tokarska-Guzik, B.; Brock, J.; Brundu, G.; Child, L.; Daehler, C.; Pyšek, P.), s. 21-38 ISBN 978-3-8236-1528-6. [8th International conference Ecology and Management of Alien Plant Invasions.. Silesian University Katowice, Poland (PL), 05.09.2005-12.09.2005] Grant ostatní: ALARM(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * EMAPi * research topics Subject RIV: EF - Botanics

  12. Potential Distribution of Alien Invasive Species and Risk Assessment: a Case Study of Erwinia amylovora in China

    Institute of Scientific and Technical Information of China (English)

    CHEN Chen; CHEN Juan; HU Bai-shi; JIANG Ying-hua; LIU Feng-quan

    2007-01-01

    Alien invasive species represent a severe risk to biodiversity and economy, as in the case of fire blight (Erwinia amylovora), a bacterial disease that originated in North America, which may be released into new locations by means of fruit trade. On the basis of the knowledge of Erwinia amylovora's biophysical characteristics and environmental data, the geographic information system (GIS) has been applied to determine areas where Erwinia amylovora can potentially invade China. Temperature and precipitation, during the blossoming period, are considered to be two critical factors affecting the Erwinia amylovora's suitable climatic zones. This spatial modeling approach was validated from a case study in Europe, where the occurrence of Erwinia amylovora has been proven. The model prediction agreed with the occurrence of the bacteria recorded in Europe, and the same procedure has been applied to produce a potential establishment area in China's two preferential apple cultivation regions, Bohai Bay region and Huangtu Altiplano region. It has been found that areas belonging to the high-risk category are more or less the main apple producing areas, accounting for their great economic importance in China. This methodology provides an initial baseline for assessment, prevention, and management of alien species that may become invasive under certain environmental conditions. In addition, this modeling approach provides a tool for policy makers to use, in making decisions on management practices where alien species are involved.

  13. Conserving a geographically isolated Charaxes butterfly in response to habitat fragmentation and invasive alien plants

    Directory of Open Access Journals (Sweden)

    Casparus J. Crous

    2015-03-01

    Full Text Available In South Africa, much of the forest biome is vulnerable to human-induced disturbance. The forest-dwelling butterfly Charaxes xiphares occidentalis is naturally confined to a small forest region in the south-western Cape, South Africa. Most of the remaining habitat of this species is within a fragmented agricultural matrix. Furthermore, this geographical area is also heavily invaded by alien plants, especially Acacia mearnsii. We investigated how C. x. occidentalis behaviourally responds to different habitat conditions in the landscape. We were particularly interested in touring, patrolling and settling behaviour as a conservation proxy for preference of a certain habitat configuration in this agricultural matrix. Remnant forest patches in the agricultural matrix showed fewer behavioural incidents than in a reference protected area. Moreover, dense stands of A. mearnsii negatively influenced the incidence and settling pattern of this butterfly across the landscape, with fewer tree settlings associated with more heavily invaded forest patches. This settling pattern was predominantly seen in female butterflies. We also identified specific trees that were settled upon for longer periods by C. x. occidentalis. Distance to a neighbouring patch and patch size influenced behavioural incidences, suggesting that further patch degradation and isolation could be detrimental to this butterfly. Conservation implications: We highlight the importance of clearing invasive tree species from vulnerable forest ecosystems and identify key tree species to consider in habitat conservation and rehabilitation programmes for this butterfly. We also suggest retaining as much intact natural forest as possible. This information should be integrated in local biodiversity management plans.

  14. DEVELOPMENT OF AN INDEX OF ALIEN SPECIES INVASIVENESS: AN AID TO ASSESSING RIPARIAN VEGETATION CONDITION

    Science.gov (United States)

    Many riparian areas are invaded by alien plant species that negatively affect native species composition, community dynamics and ecosystem properties. We sampled vegetation along reaches of 31 low order streams in eastern Oregon, and characterized species assemblages at patch an...

  15. The Bifurcation and Control of a Single-Species Fish Population Logistic Model with the Invasion of Alien Species

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2014-01-01

    Full Text Available The objective of this paper is to study systematically the bifurcation and control of a single-species fish population logistic model with the invasion of alien species based on the theory of singular system and bifurcation. It regards Spartina anglica as an invasive species, which invades the fisheries and aquaculture. Firstly, the stabilities of equilibria in this model are discussed. Moreover, the sufficient conditions for existence of the trans-critical bifurcation and the singularity induced bifurcation are obtained. Secondly, the state feedback controller is designed to eliminate the unexpected singularity induced bifurcation by combining harvested effort with the purification capacity. It obviously inhibits the switch of population and makes the system stable. Finally, the numerical simulation is proposed to show the practical significance of the bifurcation and control from the biological point of view.

  16. Alien and invasive species in plant communities of the Vistula and Brennica rivers gravel bars (Western Carpathians, Poland

    Directory of Open Access Journals (Sweden)

    Wilczek Zbigniew

    2015-06-01

    Full Text Available Gravel bars are the initial habitats, inseparably connected to the mountain streams. On the one hand, they are an unstable substrate, influenced by the overflows and high waters; however, they are also exposed to strong sunlight and heat. This situation determines specific vegetation which, due to dynamic changes in the habitat, has a pioneer character. What is more, gravel bars are areas where many river migratory species and many random species appear. Among them, there are also synanthropic species. In years 2011-2012, floristic and phytosociological studies were conducted in the Silesian Beskids. The goal of these studies was to recognize the vegetation of the gravel bars of the Vistula and the Brennica rivers - from their springs in the Silesian Beskids to the point where the Brennica River flows into the Vistula River in the Silesian Foothills. The studied section of the two rivers is regulated. Particular attention was paid to the synanthropic species that pose a threat to the native flora. In 9 recognized types of plant communities, 293 vascular plant species were recognized. More than 15% of the flora were alien species (45 and 22 of them were considered to be invasive. The most common invasive species that were spotted included: Impatiens glandulifera, Heracleum mantegazzianum and Reynoutria japonica. Plant communities with the biggest number and share of alien species were Plantago major-Barbarea vulgaris community and Phalaridetum arundinaceae.

  17. Impacts of alien invasive plants on soil nutrients are correlated with initial site conditions in NW Europe.

    Science.gov (United States)

    Dassonville, Nicolas; Vanderhoeven, Sonia; Vanparys, Valérie; Hayez, Mathieu; Gruber, Wolf; Meerts, Pierre

    2008-08-01

    Alien invasive plants are capable of modifying ecosystem function. However, it is difficult to make generalisations because impacts often appear to be species- and site-specific. In this study, we examined the impacts of seven highly invasive plant species in NW Europe (Fallopia japonica, Heracleum mantegazzianum, Impatiens glandulifera, Prunus serotina, Rosa rugosa, Senecio inaequidens, Solidago gigantea) on nutrient pools in the topsoil and the standing biomass. We tested if the impacts follow predictable patterns, across species and sites or, alternatively, if they are entirely idiosyncratic. To that end, we compared invaded and adjacent uninvaded plots in a total of 36 sites with widely divergent soil chemistry and vegetation composition. For all species, invaded plots had increased aboveground biomass and nutrient stocks in standing biomass compared to uninvaded vegetation. This suggests that enhanced nutrient uptake may be a key trait of highly invasive plant species. The magnitude and direction of the impact on topsoil chemical properties were strongly site-specific. A striking finding is that the direction of change in soil properties followed a predictable pattern. Thus, strong positive impacts (higher topsoil nutrient concentrations in invaded plots compared to uninvaded ones) were most often found in sites with initially low nutrient concentrations in the topsoil, while negative impacts were generally found under the opposite conditions. This pattern was significant for potassium, magnesium, phosphorus, manganese and nitrogen. The particular site-specific pattern in the impacts that we observed provides the first evidence that alien invasive species may contribute to a homogenisation of soil conditions in invaded landscapes. PMID:18491146

  18. An assessment of alien invasive plant species in Gonarezhou National Park, Zimbabwe

    NARCIS (Netherlands)

    Sithole, D.; Zisadza-Gandiwa, P.; Gandiwa, E.

    2012-01-01

    This study investigated the occurrence of alien plant species in Gonarezhou National Park (GNP), Zimbabwe. We focused on two main habitat types, namely riparian areas of the major rivers and dry land areas. Sampling was carried out from 42 sampling plots in both habitat types. Variables studied incl

  19. How the Yellowhammer became a Kiwi: the history of an alien bird invasion revealed

    Directory of Open Access Journals (Sweden)

    Pavel Pipek

    2015-01-01

    Full Text Available New Zealand harbours a considerable number of alien plants and animals, and is often used as a model region for studies on factors determining the outcome of introductions. Alien birds have been a particular focus of research attention, especially to understand the effect of propagule pressure, as records exist for the numbers of birds introduced to New Zealand. However, studies have relied on compilations of bird numbers, rather than on primary data. Here, we present a case study of the alien yellowhammer (Emberiza citrinella introduced from the UK to New Zealand, to demonstrate how recourse to the primary literature highlights significant data gaps and misinterpretations in these compilations. We show that the history of the introduction, establishment and spread of the yellowhammer in New Zealand can be reconstructed with surprising precision, including details of the ships importing yellowhammers, their survival rates on board, the numbers and locations of release, and the development of public perception of the species. We demonstrate that not all birds imported were released, as some died or were re-transported to Australia, and that some birds thought to be introductions were in fact translocations of individuals captured in one region of New Zealand for liberation in another. Our study confirms the potential of precise historical reconstructions that, if done for all species, would address criticisms of historical data in the evidence base for the effect of propagule pressure on establishment success for alien populations.

  20. Key elements towards a Joint Invasive Alien Species Strategy for the Dutch Caribbean

    NARCIS (Netherlands)

    Smith, S.R.; Burg, van der W.J.; Debrot, A.O.; Buurt, van G.; Freitas, de J.A.

    2014-01-01

    Recent inventories have documented no less than 211 exotic alien species in the wild for the Dutch Caribbean. These amount to no less than 27 introduced marine species, 65 introduced terrestrial plants, 72 introduced terrestrial and freshwater animals and 47 introduced agricultural pests and disease

  1. Alien plant invasion in water systems in Shanghai, China 【Review】

    OpenAIRE

    Yang, Fenghui; Nakagoshi, Nobukazu

    2004-01-01

    Biological invasion is one of the most three critical environmental problems in the world. Biotas inwater system are always changing rapidly because of being weak at invasion resistant. In this paper, twotypical invasive plant species in water systems in Shanghai was discussed. (1) Eichhornia crassipes, infreshwater system, whose invasion process, invasion mechanism, harm, and control strategies were elu-cidated; (2) Spartina alterniflora, in estuarine water system, whose transplanting in Cho...

  2. Preventing a new invasive alien plant from entering and spreading in the Euro-Mediterranean region: The case study of Parthenium hysterophorus

    NARCIS (Netherlands)

    Brunel, S.; Panetta, D.; Fried, G.; Kriticos, D.; Prasad, R.; Oude Lansink, A.G.J.M.; Shabbir, A.; Yaacoby, T.

    2014-01-01

    Parthenium or famine weed (Parthenium hysterophorus L.) is an annual plant originating from the Americas, which is a major invasive alien plant in almost all continents. While the deleterious impacts of the species on agriculture, human and animal health have been well documented, information on the

  3. Survivorship and feeding preferences among size classes of outplanted sea urchins, Tripneustes gratilla, and possible use as biocontrol for invasive alien algae

    OpenAIRE

    Westbrook, Charley E.; Ringang, Rory R.; Cantero, Sean Michael A.; ,; Toonen, Robert J.

    2015-01-01

    We investigate the survivorship, growth and diet preferences of hatchery-raised juvenile urchins, Tripneustes gratilla, to evaluate the efficacy of their use as biocontrol agents in the efforts to reduce alien invasive algae. In flow-through tanks, we measured urchin growth rates, feeding rates and feeding preferences among diets of the most common invasive algae found in Kāneʻohe Bay, Hawaiʻi: Acanthophora spicifera, Gracilaria salicornia, Eucheuma denticulatum and Kappaphycus clade B. Post-...

  4. Torrefaction of invasive alien plants: Influence of heating rate and other conversion parameters on mass yield and higher heating value.

    Science.gov (United States)

    Mundike, Jhonnah; Collard, François-Xavier; Görgens, Johann F

    2016-06-01

    With the aim of controlling their proliferation, two invasive alien plants, Lantana camara (LC) and Mimosa pigra (MP), both widespread in Africa, were considered for torrefaction for renewable energy applications. Using thermogravimetric analysis, the influence of heating rate (HR: 2.18-19.82°Cmin(-1)) together with variable temperature and hold time on char yield and HHV (in a bomb calorimeter) were determined. Statistically significant effects of HR on HHV with optima at 10.5°Cmin(-1) for LC and 20°Cmin(-1) for MP were obtained. Increases of HHV up to 0.8MJkg(-1) or energy yield greater than 10%, together with a 3-fold reduction in torrefaction conversion time could be achieved by optimisation of HR. Analysis of the torrefaction volatiles by TG-MS showed that not only hemicelluloses, but also lignin conversion, could influence the optimum HR value. PMID:26954309

  5. Differences Found in the Macroinvertebrate Community Composition in the Presence or Absence of the Invasive Alien Crayfish, Orconectes hylas.

    Science.gov (United States)

    Freeland-Riggert, Brandye T; Cairns, Stefan H; Poulton, Barry C; Riggert, Christopher M

    2016-01-01

    Introductions of alien species into aquatic ecosystems have been well documented, including invasions of crayfish species; however, little is known about the effects of these introductions on macroinvertebrate communities. The woodland crayfish (Orconectes hylas (Faxon)) has been introduced into the St. Francis River watershed in southeast Missouri and has displaced populations of native crayfish. The effects of O. hylas on macroinvertebrate community composition were investigated in a fourth-order Ozark stream at two locations, one with the presence of O. hylas and one without. Significant differences between sites and across four sampling periods and two habitats were found in five categories of benthic macroinvertebrate metrics: species richness, percent/composition, dominance/diversity, functional feeding groups, and biotic indices. In most seasons and habitat combinations, the invaded site had significantly higher relative abundance of riffle beetles (Coleoptera: Elmidae), and significantly lower Missouri biotic index values, total taxa richness, and both richness and relative abundance of midges (Diptera: Chironomidae). Overall study results indicate that some macroinvertebrate community differences due to the O. hylas invasion were not consistent between seasons and habitats, suggesting that further research on spatial and temporal habitat use and feeding ecology of Ozark crayfish species is needed to improve our understanding of the effects of these invasions on aquatic communities. PMID:26986207

  6. Differences Found in the Macroinvertebrate Community Composition in the Presence or Absence of the Invasive Alien Crayfish, Orconectes hylas

    Science.gov (United States)

    Freeland-Riggert, Brandye T.

    2016-01-01

    Introductions of alien species into aquatic ecosystems have been well documented, including invasions of crayfish species; however, little is known about the effects of these introductions on macroinvertebrate communities. The woodland crayfish (Orconectes hylas (Faxon)) has been introduced into the St. Francis River watershed in southeast Missouri and has displaced populations of native crayfish. The effects of O. hylas on macroinvertebrate community composition were investigated in a fourth-order Ozark stream at two locations, one with the presence of O. hylas and one without. Significant differences between sites and across four sampling periods and two habitats were found in five categories of benthic macroinvertebrate metrics: species richness, percent/composition, dominance/diversity, functional feeding groups, and biotic indices. In most seasons and habitat combinations, the invaded site had significantly higher relative abundance of riffle beetles (Coleoptera: Elmidae), and significantly lower Missouri biotic index values, total taxa richness, and both richness and relative abundance of midges (Diptera: Chironomidae). Overall study results indicate that some macroinvertebrate community differences due to the O. hylas invasion were not consistent between seasons and habitats, suggesting that further research on spatial and temporal habitat use and feeding ecology of Ozark crayfish species is needed to improve our understanding of the effects of these invasions on aquatic communities. PMID:26986207

  7. Differences found in the macroinvertebrate community composition in the presence or absence of the invasive alien crayfish, Orconectes hylas

    Science.gov (United States)

    Freeland-Riggert, Brandye T.; Cairns, Stefan H.; Poulton, Barry C.; Riggert, Chris M.

    2016-01-01

    Introductions of alien species into aquatic ecosystems have been well documented, including invasions of crayfish species; however, little is known about the effects of these introductions on macroinvertebrate communities. The woodland crayfish (Orconectes hylas (Faxon)) has been introduced into the St. Francis River watershed in southeast Missouri and has displaced populations of native crayfish. The effects of O. hylas on macroinvertebrate community composition were investigated in a fourth-order Ozark stream at two locations, one with the presence of O. hylas and one without. Significant differences between sites and across four sampling periods and two habitats were found in five categories of benthic macroinvertebrate metrics: species richness, percent/composition, dominance/diversity, functional feeding groups, and biotic indices. In most seasons and habitat combinations, the invaded site had significantly higher relative abundance of riffle beetles (Coleoptera: Elmidae), and significantly lower Missouri biotic index values, total taxa richness, and both richness and relative abundance of midges (Diptera: Chironomidae). Overall study results indicate that some macroinvertebrate community differences due to the O. hylas invasion were not consistent between seasons and habitats, suggesting that further research on spatial and temporal habitat use and feeding ecology of Ozark crayfish species is needed to improve our understanding of the effects of these invasions on aquatic communities.

  8. Does mutualism drive the invasion of two alien species? The case of Solenopsis invicta and Phenacoccus solenopsis.

    Directory of Open Access Journals (Sweden)

    Aiming Zhou

    Full Text Available Although mutualism between ants and honeydew-producing hemipterans has been extensively recognized in ecosystem biology, however few attempts to test the hypothesis that mutualism between two alien species leads to the facilitation of the invasion process. To address this problem, we focus on the conditional mutualism between S. invicta and P. solenopsis by field investigations and indoor experiments. In the laboratory, ant colony growth increased significantly when ants had access to P. solenopsis and animal-based food. Honeydew produced by P. solenopsis also improved the survival of ant workers. In the field, colony density of P. solenopsis was significantly greater on plots with ants than on plots without ants. The number of mealybug mummies on plants without fire ants was almost three times that of plants with fire ants, indicating a strong effect of fire ants on mealybug survival. In addition, the presence of S. invicta successfully contributed to the spread of P. solenopsis. The quantity of honeydew consumption by S. invicta was significantly greater than that of a presumptive native ant, Tapinoma melanocephalum. When compared with the case without ant tending, mealybugs tended by ants matured earlier and their lifespan and reproduction increased. T. melanocephalum workers arrived at honeydew more quickly than S. invicta workers, while the number of foraging S. invicta workers on plants steadily increased, eventually exceeding that number of T. melanocephalum foragers. Overall, these results suggest that the conditional mutualism between S. invicta and P. solenopsis facilitates population growth and fitness of both species. S. invicta tends to acquire much more honeydew and drive away native ants, promoting their predominance. These results suggest that the higher foraging tempo of S. invicta may provide more effective protection of P. solenopsis than native ants. Thus mutualism between these two alien species may facilitate the invasion

  9. Invasive alien plants in protected areas: threats, opportunities, and the way forward

    Czech Academy of Sciences Publication Activity Database

    Foxcroft, L. C.; Richardson, D. M.; Pyšek, Petr; Genovesi, P.

    Dordrecht: Springer Science+Business Media, 2013 - (Foxcroft, L.; Pyšek, P.; Richardson, D.; Genovesi, P.), s. 621-639. (Book series: Invading Nature-Springer Series in Invasion Ecology). ISBN 978-94-007-7749-1 Institutional support: RVO:67985939 Keywords : plant invasions * protected areas * way forward Subject RIV: EH - Ecology, Behaviour

  10. The bottom line: impacts of alien plant invasions in protected areas

    Czech Academy of Sciences Publication Activity Database

    Foxcroft, L. C.; Pyšek, Petr; Richardson, D. M.; Pergl, Jan; Hulme, P. E.

    Dordrecht: Springer Science+Business Media, 2013 - (Foxcroft, L.; Pyšek, P.; Richardson, D.; Genovesi, P.), s. 19-41. (Book series: Invading Nature-Springer Series in Invasion Ecology). ISBN 978-94-007-7749-1 Institutional support: RVO:67985939 Keywords : plant invasions * protected areas * impact Subject RIV: EH - Ecology, Behaviour

  11. Fire and simulated herbivory have antagonistic effects on resistance of savanna grasslands to alien shrub invasion

    NARCIS (Netherlands)

    te Beest, Mariska; Mpandza, Nokukhanya J.; Olff, Han

    2015-01-01

    Question Resistance of the native community has been identified as an important factor limiting invasion success and invader impact. However, to what extent resistance interacts with disturbance to control invasion success remains unclear. We studied the interaction between biotic resistance, fire a

  12. Quantifying the Establishment Likelihood of Invasive Alien Species Introductions Through Ports with Application to Honeybees in Australia.

    Science.gov (United States)

    Heersink, Daniel K; Caley, Peter; Paini, Dean R; Barry, Simon C

    2016-05-01

    The cost of an uncontrolled incursion of invasive alien species (IAS) arising from undetected entry through ports can be substantial, and knowledge of port-specific risks is needed to help allocate limited surveillance resources. Quantifying the establishment likelihood of such an incursion requires quantifying the ability of a species to enter, establish, and spread. Estimation of the approach rate of IAS into ports provides a measure of likelihood of entry. Data on the approach rate of IAS are typically sparse, and the combinations of risk factors relating to country of origin and port of arrival diverse. This presents challenges to making formal statistical inference on establishment likelihood. Here we demonstrate how these challenges can be overcome with judicious use of mixed-effects models when estimating the incursion likelihood into Australia of the European (Apis mellifera) and Asian (A. cerana) honeybees, along with the invasive parasites of biosecurity concern they host (e.g., Varroa destructor). Our results demonstrate how skewed the establishment likelihood is, with one-tenth of the ports accounting for 80% or more of the likelihood for both species. These results have been utilized by biosecurity agencies in the allocation of resources to the surveillance of maritime ports. PMID:26482012

  13. Field growth comparisons of invasive alien annual and native perennial grasses in monocultures

    Science.gov (United States)

    Medusahead is rapidly invading native grassland and cheatgrass dominated grassland throughout the western US. Understanding growth dynamics of medusahead relative to bluebunch wheatgrass and cheatgrass is central to predicting and managing medusahead invasion. We hypothesized that medusahead would...

  14. Impact of invasions by alien plants on soil seed bank communities: emerging patterns

    Czech Academy of Sciences Publication Activity Database

    Gioria, Margherita; Jarošík, Vojtěch; Pyšek, Petr

    2014-01-01

    Roč. 16, č. 3 (2014), s. 132-142. ISSN 1433-8319 R&D Projects: GA ČR(CZ) GAP504/11/1028; GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : plant invasions * impact * soil seed bank Subject RIV: EF - Botanics Impact factor: 3.606, year: 2014

  15. How the Yellowhammer became a Kiwi: the history of an alien bird invasion revealed

    Czech Academy of Sciences Publication Activity Database

    Pipek, P.; Pyšek, Petr; Blackburn, T. M.

    2015-01-01

    Roč. 24, č. 1 (2015), s. 1-31. ISSN 1619-0033 Grant ostatní: AV ČR(CZ) Praemium Academiae Institutional support: RVO:67985939 Keywords : bird invasions * historical records * New Zealand Subject RIV: EH - Ecology, Behaviour

  16. Habitat invasions by alien plants: a quantitative comparison between Mediterranean, subcontinental and oceanic regions of Europe

    Czech Academy of Sciences Publication Activity Database

    Chytrý, M.; Maskell, L. C.; Pino, J.; Pyšek, Petr; Vila, M.; Font, X.; Smart, S. M.

    2008-01-01

    Roč. 45, č. 2 (2008), s. 448-458. ISSN 0021-8901 R&D Projects: GA MŠk(CZ) LC06073 Grant ostatní: ALARM(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : invasibility * neophyte * habitat Subject RIV: EF - Botanics Impact factor: 4.560, year: 2008

  17. Alien plant invasions in tropical and sub-tropical savannas: patterns, processes and prospects

    Czech Academy of Sciences Publication Activity Database

    Foxcroft, L. C.; Richardson, D. M.; Rejmánek, M.; Pyšek, Petr

    2010-01-01

    Roč. 12, č. 12 (2010), s. 3913-3933. ISSN 1387-3547 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60050516 Keywords : savannas * plant invasions * world Subject RIV: EF - Botanics Impact factor: 3.474, year: 2010

  18. Past and estimated future impact of invasive alien mammals on insular threatened vertebrate populations.

    Science.gov (United States)

    McCreless, Erin E; Huff, David D; Croll, Donald A; Tershy, Bernie R; Spatz, Dena R; Holmes, Nick D; Butchart, Stuart H M; Wilcox, Chris

    2016-01-01

    Invasive mammals on islands pose severe, ongoing threats to global biodiversity. However, the severity of threats from different mammals, and the role of interacting biotic and abiotic factors in driving extinctions, remain poorly understood at a global scale. Here we model global extirpation patterns for island populations of threatened and extinct vertebrates. Extirpations are driven by interacting factors including invasive rats, cats, pigs, mustelids and mongooses, native species taxonomic class and volancy, island size, precipitation and human presence. We show that controlling or eradicating the relevant invasive mammals could prevent 41-75% of predicted future extirpations. The magnitude of benefits varies across species and environments; for example, managing invasive mammals on small, dry islands could halve the extirpation risk for highly threatened birds and mammals, while doing so on large, wet islands may have little benefit. Our results provide quantitative estimates of conservation benefits and, when combined with costs in a return-on-investment framework, can guide efficient conservation strategies. PMID:27535095

  19. Are the aliens taking over? Invasive species and their increasing impact on biodiversity

    Czech Academy of Sciences Publication Activity Database

    Hulme, P. E.; Vila, M.; Nentwig, W.; Pyšek, Petr

    Sofia: Pensoft Publishers, Sofia-Moscow, 2010 - (Settele, J.; Penev, L.; Georgiev, T.; Grabaum, R.; Grobelnik, V.; Hammen, V.; Klotz, S.; Kotarac, M.; Kühn, I.), s. 132-133 ISBN 978-954-642-446-4 Institutional research plan: CEZ:AV0Z60050516 Keywords : biological invasions * Europe * DAISIE Subject RIV: EF - Botanics

  20. Selective logging and fire as drivers of alien grass invasion in a Bolivian tropical dry forest

    NARCIS (Netherlands)

    Veldman, J.W.; Mostacedo, B.; Peña-Claros, M.; Putz, F.E.

    2009-01-01

    Logging is an integral component of most conceptual models that relate human land-use and climate change to tropical deforestation via positive-feedbacks involving fire. Given that grass invasions can substantially alter fire regimes, we studied grass distributions in a tropical dry forest 1-5 yr af

  1. Aliens in Antarctica: Assessing transfer of plant propagules by human visitors to reduce invasion risk

    NARCIS (Netherlands)

    Huiskes, A.H.L.; Gremmen, N.J.M.; Bergstrom, D.M.; Frenot, Y.; Hughes, K.A.; Imura, S.; Kiefer, K.; Lebouvier, M.; Lee, J.E.; Tsujimoto, M.; Ware, C.; Van de Vijver, B.; Chown, S.L.

    2014-01-01

    Despite considerable research on biological invasions, key areas remain poorly explored, especially ways to reduce unintentional propagule transfer. The Antarctic represents a microcosm of the situation, with the numbers of established non-native species growing. Information to help reduce potential

  2. Survey and documentation of the potential and actual invasive alien plant species and other biological threats to biodiversity in Awash National Park, Ethiopia

    OpenAIRE

    Demissew, Sebsebe; Awas, Tesfaye; Tamene YOHANNES , and

    2011-01-01

    The study was conducted at the Awash National Park (ANP) Ethiopia, todocument Invasive Alien Species (IAS) and to assess the spread of Prosopis juliflora (Sw.) DC. A total of 64 sample plots were laid systematically along the altitudinal gradient of 750 to 1916 m.Potential IAS were recorded. IAS which may threaten biodiversity of the park includes species such as Prosopis juliflora, Parthenium hysterophorus L., Cryptostegia grandiflora Roxb. ex R. Br., Parkinsonia aculeata L., Senna occidenta...

  3. The impact of invasive alien species impatiens glandulifera on environmental conditions in the habitat

    OpenAIRE

    Ropret, Bojana

    2014-01-01

    This thesis provides an overview of literature together with the results of field measurements of a non-native species called Himalayan Balsam, Impatiens glandulifera. Since the measurements were conducted near the Tržiška Bistrica river, a short description of its characteristics is provided and so is the importance of the riparian zone. A description of a non-native and invasive species follows combined with its characteristics. Hereinafter, the physical conditions which affect the growt...

  4. Is there a need for a more explicit accounting of invasive alien species under the Water Framework Directive?

    Directory of Open Access Journals (Sweden)

    Jochen Vandekerkhove

    2013-01-01

    Full Text Available Through ratification of the Water Framework Directive (WFD, EU Member States committed themselves to a pressure-based assessment ofthe ecological status of their water bodies. Invasive alien species (IAS constitute a major pressure in many aquatic ecosystems, yet are notexplicitly accounted for by the majority of WFD assessment methods. Most Member States argue that no explicit assessment of IAS isrequired, assuming that significant IAS pressures will affect the WFD biological quality elements (BQEs, and be detected by generic WFDstatus assessments. We tested this assumption for a selection of country-by-surface-water category combinations, covering nearly 40,000water bodies. For each of the combinations, the pressure by high-impact IAS is higher in water bodies with ecological status varying from bad to moderate than in water bodies in good or high ecological status. Most high-impact IAS show strong associations with low status class categories. Of the 17 most frequently occurring high-impact IAS, only Mustela vison (Schreber, 1777 and Potamopyrgus antipodarum(Gray, 1853 are disproportionately frequent in high status water bodies. The sensitivity of WFD methods varies across BQEs, withmacrophyte-based methods showing a consistently high sensitivity to IAS pressures. However, significant pressures are observed in anumber of high status water bodies. This points to a need for further optimization of existing methods so that they address the full range of pressures exerted by IAS.

  5. Biotic Resistance to an Alien Amphibian: Larval Competition between Japanese Frogs and Invasive Cane Toads

    Science.gov (United States)

    2016-01-01

    Understanding negative effects of native species on introduced taxa may suggest novel ways to control the invasive species by enhancing such effects. Previous studies have reported that the larvae of invasive cane toads (Rhinella marina) are suppressed by competition with the larvae of native anurans in Australia, but not in North America. We conducted laboratory trials to measure the effect of exposure to the larvae of Japanese frogs (Microhyla ornata, Fejervarya sakishimensis, Rhacophorus owstoni) on rates of survival, growth and development of cane toad tadpoles in Ishigaki Island, in southern Japan. Survival rates were not affected by native species, but competition with Dicroglossids and Rhacophorids (but not Microhylids) strongly reduced rates of growth and development in the tadpoles of cane toads. Dicroglossid tadpoles also reduced the body condition to toad tadpoles in addition to effects on SVL and mass. Encouraging populations of native frogs in toad-invaded areas of Japan thus may help to reduce the numbers of invasive cane toads. PMID:27253973

  6. Effects of an alien ant invasion on abundance, behavior, and reproductive success of endemic island birds.

    Science.gov (United States)

    Davis, Naomi E; O'Dowd, Dennis J; Green, Peter T; Nally, Ralph Mac

    2008-10-01

    Biological invaders can reconfigure ecological networks in communities, which changes community structure, composition, and ecosystem function. We investigated whether impacts caused by the introduced yellow crazy ant (Anoplolepis gracilipes), a pantropical invader rapidly expanding its range, extend to higher-order consumers by comparing counts, behaviors, and nesting success of endemic forest birds in ant-invaded and uninvaded rainforest on Christmas Island (Indian Ocean). Point counts and direct behavioral observations showed that ant invasion altered abundances and behaviors of the bird species we examined: the Island Thrush (Turdus poliocephalus erythropleurus), Emerald Dove (Chalcophaps indica natalis), and Christmas Island White-eye (Zosterops natalis). The thrush, which frequents the forest floor, altered its foraging and reproductive behaviors in ant-invaded forest, where nest-site location changed, and nest success and juvenile counts were lower. Counts of the dove, which forages exclusively on the forest floor, were 9-14 times lower in ant-invaded forest. In contrast, counts and foraging success of the white-eye, a generalist feeder in the understory and canopy, were higher in ant-invaded forest, where mutualism between the ant and honeydew-secreting scale insects increased the abundance of scale-insect prey. These complex outcomes involved the interplay of direct interference by ants and altered resource availability and habitat structure caused indirectly by ant invasion. Ecological meltdown, rapidly unleashed by ant invasion, extended to these endemic forest birds and may affect key ecosystem processes, including seed dispersal. PMID:18637918

  7. Neighbour Origin and Ploidy Level Drive Impact of an Alien Invasive Plant Species in a Competitive Environment

    Science.gov (United States)

    Sun, Yan; Müller-Schärer, Heinz; Schaffner, Urs

    2016-01-01

    Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids, allo-polycarpic tetraploids). However, only tetraploids have been found in its introduced range in North America, where C. stoebe has become a most prominent plant invader. Here, we focus on the ploidy level of C. stoebe and origin of neighbouring community in explaining the high impact during the invasion of new sites in the introduced range. We conducted a mesocosm experiment under open-field conditions with the diploid (EU2x) and tetraploid (EU4x) cytotype of Centaurea stoebe from its native European (EU) range, and with the invasive tetraploid (NA4x) cytotype from the introduced North American (NA) range in competition with EU (old) or NA (new) neighbouring plant communities. In the presence of competition, the biomass of EU neighbouring community was reduced to a comparable level by all three geo-cytotypes of C. stoebe. In contrast, the biomass of the NA neighbouring community was reduced beyond when competing with tetraploid, but not with diploid C. stoebe. The fact that the biomass of all three geo-cytotypes of C. stoebe was correlated with the biomass of the EU neighbouring community, but not with that of the NA neighbouring community suggests that different mechanisms underlie the competitive interactions between C. stoebe and its old vs. new neighbouring communities, such as competition for the same limiting resources at home vs competition through novel allelo-chemicals or differential resource uptake strategies in the introduced range. We therefore caution to simply use the ecosystem impact assessed at home to predict impact in the introduced range. PMID:27203687

  8. Invasive, naturalized and casual alien plants in southern Africa: a sum­mary based on the Southern African Plant Invaders Atlas (SAPIA

    Directory of Open Access Journals (Sweden)

    L. Henderson

    2007-12-01

    Full Text Available The primary objective of this publication is to provide an overview of the species identity, invasion status, geographical extent, and abundance of alien plants in South Africa, Swaziland and Lesotho, based on field records from 1979 to the end of 2000. The dataset is all the species records for the study area in the Southern African Plant Invaders Atlas (SAPIA database during this time period. A total of 548 naturalized and casual alien plant species were catalogued and invasion was recorded almost throughout the study area. Most invasion, in terms of both species numbers and total species abundance, was recorded along the southern, southwestern and eastern coastal belts and in the adjacent interior. This area includes the whole of the Fynbos and Forest Biomes, and the moister eastern parts of the Grassland and Savanna Biomes. This study reinforces previous studies that the Fynbos Biome is the most extensively invaded vegetation type in South Africa but it also shows that parts of Savanna and Grassland are as heavily invaded as parts of the Fynbos. The Fabaceae is prominent in all biomes and Acacia with 17 listed species, accounts for a very large proportion of all invasion. Acacia mearmii was by far the most prominent invasive species in the study area, followed by A. saligna, Lantana camara, A. cyclops, Opuntia ficus-indica. Solarium mauritianum, Populus alba/xcanescens, Melia azedarach, A. dealbata and species of Prosopis.

  9. The role of habitat factors in successful invasion of alien plant Acer negundo in riparian zones.

    Science.gov (United States)

    Sikorski, Piotr; Sikorska, Daria

    2016-04-01

    Ash-leaved maple (Acer negundo) is one of the most invasive species occurring in riparian zones. The invasion is especially effective in disturbed areas, as the plant favours anthropogenic sites. The plant was also observed to be able to penetrate into sandy bars, also those separated from the land, inaccessible to people. It's removal is time-consuming and laborious, often involves damage done to sensitive vegetation and the results are doubtful, as the plant quickly regenerates. The invasion patterns and establishment of ash-leaved maple in natural ecosystems are poorly investigated. The aim of this study was to test how habitat factors such as: light availability, soil characteristics and competition contribute to ash-leaved maple effective colonization of natural sand bars free from anthropogenic pressure. In 2014 sand bars located in Vistula River Valley in Warsaw were inventoried and classified basing on their development stage as 1 - initial, 2 - unstable, 3 - stable. Apart from the occurrence of the invasive ash-leaved maple the plants competing with it were recognized and the percentage of the shoots of shrubs and herbaceous plants was estimated. PAR was measured at ground level and 1 meter above ground, the thickness of organic layer formed on the top of the sand was also measured as the indicator of sand bar development stage. The maple's survival in extremely difficult conditions resembles the strategy of willows and poplars naturally occurring in the riparian zones, which are well adapted to this environment. The success of invasion strongly depends on the plants establishment during sand bars initial stage of development. The seedlings growth correlates with the age of the sand bar (r1=0,41, r2=0,42 i r3=0,57). The colonization lasts for 4-6 years and the individuals start to cluster in bigger parches. After that period the maple turns into the phase of competition for space. Habitat factors such as shading (r2=0,41 i r3=0,51) and organic layer

  10. The invasion of five alien species in the Delta do Parnaíba Environmental Protection Area, Northeastern Brazil.

    Science.gov (United States)

    Loebmann, Daniel; Mai, Ana Cecília G; Lee, James T

    2010-09-01

    Marine biological invasions have been regarded as one of the major causes of native biodiversity loss, with shipping and aquaculture being the leading contributors for the introductions of alien species in aquatic ecosystems. In the present study, five aquatic alien species (one mollusk, three crustaceans and one fish species) were detected during dives, shore searches and from the fisheries on the coast of the Delta do Parnaíba Environmental Protection Area, in the States of Piauí and Maranhão, Northeastern Brazil. The species were the bicolor purse-oyster Isognomon bicolor, the whiteleg shrimp Litopenaeus vannamei, the giant river prawn Macrobrachium rosenbergii, the Indo-Pacific swimming crab Charybdis hellerii and, the muzzled blenny Omobranchus punctatus. Ballast water (I. bicolor, C. hellerii, and O. punctatus) and aquaculture activities (L. vannamei and M. rosenbergii) in adjacent areas are the most likely vectors of introduction. All exotic species found have potential impact risks to the environment because they are able to compete against native species for resources (food and habitat). Isognomon bicolor share the same habitat and food items with the native bivalve species of mussels and barnacles. Litopenaeus vannamei share the same habitat and food items with the native penaeids such as the pinkspot shrimp Farfantepenaeus brasiliensis, the Southern brown shrimp Farfantepenaeus subtilis, and the Southern white shrimp Litopenaeus schmitti, and in the past few years L. vannamei was responsible for a viral epidemics in the cultivation tanks that could be transmitted to native penaeid shrimps. Charybdis hellerii is also able to cause impacts on the local fisheries as the species can decrease the populations of native portunid crabs which are commercialized in the studied region. Macrobrachium rosenbergii may be sharing natural resources with the Amazon River prawn Macrobrachium amazonicum. Omobranchus punctatus shares habit with the native redlip blenny

  11. Will climate change drive alien invasive plants into areas of high protection value? An improved model-based regional assessment to prioritise the management of invasions.

    Science.gov (United States)

    Vicente, J R; Fernandes, R F; Randin, C F; Broennimann, O; Gonçalves, J; Marcos, B; Pôças, I; Alves, P; Guisan, A; Honrado, J P

    2013-12-15

    Species distribution models (SDMs) studies suggest that, without control measures, the distribution of many alien invasive plant species (AIS) will increase under climate and land-use changes. Due to limited resources and large areas colonised by invaders, management and monitoring resources must be prioritised. Choices depend on the conservation value of the invaded areas and can be guided by SDM predictions. Here, we use a hierarchical SDM framework, complemented by connectivity analysis of AIS distributions, to evaluate current and future conflicts between AIS and high conservation value areas. We illustrate the framework with three Australian wattle (Acacia) species and patterns of conservation value in Northern Portugal. Results show that protected areas will likely suffer higher pressure from all three Acacia species under future climatic conditions. Due to this higher predicted conflict in protected areas, management might be prioritised for Acacia dealbata and Acacia melanoxylon. Connectivity of AIS suitable areas inside protected areas is currently lower than across the full study area, but this would change under future environmental conditions. Coupled SDM and connectivity analysis can support resource prioritisation for anticipation and monitoring of AIS impacts. However, further tests of this framework over a wide range of regions and organisms are still required before wide application. PMID:24161807

  12. Cabomba caroliniana A. Gray 1837: A new, alien and potentially invasive species in Serbia

    Directory of Open Access Journals (Sweden)

    Vukov Dragana

    2013-01-01

    Full Text Available During field studies of the vegetation in the canal network of the Hydro-System Danube-Tisa-Danube in Serbia, in 2008, 2011 and 2012, populations of Cabomba caroliniana A. Gray 1837 were recorded. Cabomba caroliniana was not previously recorded in the aquatic vegetation in Serbia. It is a popular aquarium plant native to South America (Brazil, Uruguay, Paraguay, and northeastern Argentina and, according to some authors, to southeastern United States. It was introduced into the rest of the USA, Canada, Australia, Asia (China, Malaysia, India, Japan, and in many regions of its new range it is considered an invasive and noxious aquatic weed. In Europe, it was found in the United Kingdom (introduced to England, Belgium, the Netherlands, and Hungary. Newly recorded populations in Serbia are restricted to the canals in Bačka. Populations are established only on two localities (Mali Stapar and Odžaci. [Projekat Ministarstva nauke Republike Srbije, br. III43002

  13. 外来种隐蔽入侵:类型及影响%Cryptic invasion of alien species: types and effects

    Institute of Scientific and Technical Information of China (English)

    褚栋; 国栋; 潘慧鹏; 张友军; 万方浩

    2012-01-01

    隐蔽入侵(cryptic invasion)是指在形态上与土著种(或早期建群种)不能或难以区分的外来种在人们未觉察的状态下成功入侵的过程.人们对这类入侵方式往往视而不觉.本文综述了外来种隐蔽入侵的类型以及生态影响.隐蔽入侵的类型主要包括外来姊妹种形式的隐蔽入侵、不同遗传支系的隐蔽入侵、不同地理种群的隐蔽入侵以及“返传入”.其中,“返传入”目前还是一种假说.由于这类入侵外来种更容易与土著种(或早期建群种)杂交或基因渗透,因而可对入侵种自身或土著种产生深远的生态影响.鉴于隐蔽入侵现象的广泛性,建议进一步加强该方面的研究.%The invasion of alien species that are morphologically indistinguishable, or hardly distinguishable, with the native species or earlier established species is regarded as cryptic invasion. This kind of invasion is often undetectable by human beings. The types of cryptic invasion include invasion of the alien sibling species, genetic lineages, geographic populations, and a hypothesized " back introduction". These alien species are more readily hybridize or introgress with native species or earlier established species and thus result in the long-term ecological effects on the invasive species or native species. The research related to cryptic invasion should be further strengthened in view of its widespread occurrence.

  14. Invasion by alien species in China, control methods and new directions of research%中国外来物种入侵的现状、对策及新的研究方向

    Institute of Scientific and Technical Information of China (English)

    范秀琴; 张雄帅; 舒景昌

    2011-01-01

    At present,most of the world have suffered the threat of invasive alien species, the extent of injury is increasingly severe. This paper described the reasons for the formation of biological invasion and the damage resulted from invasion of alien species, summed up the prevention measures of the invasion of alien species and explored new directions of researches.%目前,全球大部分地区都遭受到了外来生物入侵的威胁,危害程度也越来越严重。本文阐述了外来生物入侵形成的原因,入侵所造成的危害,总结了外来生物入侵的防治对策,并探讨了新的研究方向。

  15. Living with aliens: effects of invasive shrub honeysuckles on avian nesting.

    Directory of Open Access Journals (Sweden)

    Jason M Gleditsch

    Full Text Available Invasive species have come to the forefront of conservation biology as a major threat to native biodiversity. Habitats dominated by shrub honeysuckles (Lonicera spp. in the United States have been characterized as "ecological traps" by ecologists. Here we tested this hypothesis by investigating the effects of shrub honeysuckles on the nesting ecology of native birds in seven study sites in central Pennsylvania, USA. We examined how the abundance of shrub honeysuckles influenced the selection of nesting substrates and habitat for a community of common songbirds, and the parental-care behavior and nestling development of gray catbirds (Dumetella carolinensis. We found that birds had a strong bias towards nesting in honeysuckle shrubs, but not necessarily for nesting in honeysuckle-dominated habitats. Nest predation rates were affected by the density of nests in a habitat, but not by the overall abundance of honeysuckles in such habitats. Honeysuckle abundance in the habitat did show significant effects on some parental-care behavioral parameters: catbirds had higher nest visitation rates and shorter visit lengths in areas of high honeysuckle density. On average, Gray catbirds fed fruit 12%±0.31 s.e. of their nestling-feeding bouts, mostly fruits of shrub honeysuckles. Nestlings in sites with high honeysuckle density also showed higher mass:tarsus ratios, suggesting a good (possibly better physiological condition of catbird nestlings at the time of fledging. Our study shows that honeysuckle-dominated habitats could have equivocal effects on nesting parameters of common species of native birds. We advise more caution in the widespread denomination of novel plant communities with high densities of honeysuckle as "ecological traps" as effects can be null or positive on native birds in certain localities.

  16. Study on Alien Invasive Plants in Wuzhou City%梧州市外来入侵植物调查研究

    Institute of Scientific and Technical Information of China (English)

    马多; 和太平; 郑羡

    2012-01-01

    通过实地调查与文献查询相结合的方法,确认分析梧州市外来入侵植物种类、性状、起源地、传入途径和危害程度,结果表明:梧州市目前共有入侵植物27种,隶属于14科25属,其中以菊科植物种类最多,占总种数29.63%;草本植物20种占绝对优势,占总种数74.07%;24种起源地为美洲,占总种数88.89%;有意引种数量比例超过总种数一半;危害程度达到严重和较严重比例不高,少于总种数的1/4。目前梧州市入侵植物尚未引发严重的生态系统破坏问题,但存在较多潜在的生态安全隐患。最后对梧州市外来入侵植物的管理提出建议。%By the method of combining field investigation and literature review, the species, traits, o- rigin, invasive ways, and damage degree of the alien invasive plants in Wuzhou city were analyzed, the results showed that there were 27 invasive alien plants belonging to 14 families and 25 genera, among which the most specie was compositae accounting for 29.63 % (27 species), 20 species were herbs amounting for 74.07%, 24 species were from America accounting for 88.98 %, more than half of plants were intentional introduction, and the most harmful plants and the more harmful ones were less than 1/4 of total species. Serious damages to the ecosystem of Wuzhou caused by alien invasive plants haven' t been found, but there were still potential ecological security hidden troubles. The suggestions were put forward for the management of the alien invasive plants in Wuzhou.

  17. APPROACHES ON THE INVASIVE ALIEN TAXA IN ROMANIA - AMBROSIA ARTEMISIIFOLIA (RAGWEED II

    Directory of Open Access Journals (Sweden)

    Nicoleta IANOVICI

    2011-01-01

    Full Text Available In a previous paper we presented the localities in Romania where we identified populations of Ambrosia artemisiifolia. Between 2008-2011, investigations were continuing. Our data clearly show that Ambrosia is present throughout the country. The territories heavily infested are railway embankments, along traffic routes, gravel pits, building sites, forest edges, industrial areas, cemeteries and recreational areas. It is quite common to find ragweed in many private gardens, or flower pots in urban areas. The few foci observed along riversides got there by household waste and construction waste. In many rural communities find it on the drainage ditches. Disturbed and neglected land (on city limits and outside the city, abandonment of land without subsequent turning of stubble and another wrong agricultural practice, absence of ruderal weed control are the main causes that favor the dissemination of our country. Intensity of anthropogenic influence is manifested mainly by transport of materials and soil movement during road rehabilitation and construction of highways. The recent observations show that could be expected to appear on agricultural fields, now being found only on the outskirts of cultivated land, at 5-6 meters from high traffic roads. Ambrosia benefits from human activities to spread. This implies a strong control strategy. The main objective of the fighting activities need to be to reduce damages caused by its pollen and to limit its expansion. If invasion by Ambrosia is left uncontrolled, increase of allergies could heavily augment the treatments. Knowledge about mechanical or chemical control of ragweed could be very important for road and rail services, agricultural institutions, farmers, staff responsible for managing natural areas, institutions that approves and oversees residential sites and factories, responsible personnel of the administrations from cities and rural localities. Reducing the population is more required than

  18. Preliminary results of studies on the distribution of invasive alien vascular plant species occurring in semi-natural and natural habitats in NW Poland

    Directory of Open Access Journals (Sweden)

    Popiela Agnieszka

    2015-03-01

    Full Text Available In Western Pomerania, as in other areas of Europe, alien species play an increasingly important role. In particular, invasive plants tend to spread rapidly and in large numbers which may reduce diversity of native species, leading to the phenomenon of “trivialisation of flora”, and transform ecosystems. The list of invasive species (32 taxa includes alien species occurring throughout Western Pomerania, and penetrating natural or semi-natural habitats. The second group consists of potentially invasive species (23 taxa, i.e. those distributed across the area under study and tending to increase the number of their localities in semi-natural and natural habitats, taxa invasive only locally, as well as species with missing data, which does not currently allow including them into the first group. Invasive weeds, as well as some epecophytes and archaeophytes occurring only on anthropogenic sites and tending to spread, were not taken into account. Among hemiagriophytes, the most common and troublesome ones are: Conyza canadensis, Erigeron annuus, Lolium multiflorum, Lupinus polyphyllus, Solidago canadensis, S. gigantea. Among holoagriophytes, i.e. the taxa which received the highest naturalisation status, very expansive species, successful in land colonisation, like Acer negundo, Bidens frondosa, B. connata, Clematis vitalba, Elodea canadensis, Epilobium ciliatum, Heracleum sosnowskyi, Impatiens glandulifera, I. parviflora, Padus serotina, Quercus rubra and Robinia pseudoacacia, should be given particular attention. Among the invasive and potentially invasive species, most taxa penetrate plant communities of the Artemisietea and Molinio-Arrhenatheretea class, followed by Querco-Fagetea, Vaccinio-Piceetea, Stellarietea mediae, Salicetea purpurae and Koelerio-Corynophoretea. The number of invasive species is twice as high when compared to the situation of these species in Poland; on the contrary, the number of species inhabiting anthropogenic, semi

  19. The invasion of five alien species in the Delta do Parnaíba Environmental Protection Area, Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Daniel Loebmann

    2010-09-01

    Full Text Available Marine biological invasions have been regarded as one of the major causes of native biodiversity loss, with shipping and aquaculture being the leading contributors for the introductions of alien species in aquatic ecosystems. In the present study, five aquatic alien species (one mollusk, three crustaceans and one fish species were detected during dives, shore searches and from the fisheries on the coast of the Delta do Parnaíba Environmental Protection Area, in the States of Piauí and Maranhão, Northeastern Brazil. The species were the bicolor purse-oyster Isognomon bicolor, the whiteleg shrimp Litopenaeus vannamei, the giant river prawn Macrobrachium rosenbergii, the Indo-Pacific swimming crab Charybdis hellerii and, the muzzled blenny Omobranchus punctatus. Ballast water (I. bicolor, C. hellerii, and O. punctatus and aquaculture activities (L. vannamei and M. rosenbergii in adjacent areas are the most likely vectors of introduction. All exotic species found have potential impact risks to the environment because they are able to compete against native species for resources (food and habitat. Isognomon bicolor share the same habitat and food items with the native bivalve species of mussels and barnacles. Litopenaeus vannamei share the same habitat and food items with the native penaeids such as the pinkspot shrimp Farfantepenaeus brasiliensis, the Southern brown shrimp Farfantepenaeus subtilis, and the Southern white shrimp Litopenaeus schmitti, and in the past few years L. vannamei was responsible for a viral epidemics in the cultivation tanks that could be transmitted to native penaeid shrimps. Charybdis hellerii is also able to cause impacts on the local fisheries as the species can decrease the populations of native portunid crabs which are commercialized in the studied region. Macrobrachium rosenbergii may be sharing natural resources with the Amazon River prawn Macrobrachium amazonicum. Omobranchus punctatus shares habit with the native

  20. Long live the alien: is high genetic diversity a pivotal aspect of crested porcupine (Hystrix cristata) long-lasting and successful invasion?

    Science.gov (United States)

    Trucchi, Emiliano; Facon, Benoit; Gratton, Paolo; Mori, Emiliano; Stenseth, Nils Chr; Jentoft, Sissel

    2016-08-01

    Studying the evolutionary dynamics of an alien species surviving and continuing to expand after several generations can provide fundamental information on the relevant features of clearly successful invasions. Here, we tackle this task by investigating the dynamics of the genetic diversity in invasive crested porcupine (Hystrix cristata) populations, introduced to Italy about 1500 years ago, which are still growing in size, distribution range and ecological niche. Using genome-wide RAD markers, we describe the structure of the genetic diversity and the demographic dynamics of the H. cristata invasive populations and compare their genetic diversity with that of native African populations of both H. cristata and its sister species, H. africaeaustralis. First, we demonstrate that genetic diversity is lower in both the invasive Italian and the North Africa source range relative to other native populations from sub-Saharan and South Africa. Second, we find evidence of multiple introduction events in the invasive range followed by very limited gene flow. Through coalescence-based demographic reconstructions, we also show that the bottleneck at introduction was mild and did not affect the introduced genetic diversity. Finally, we reveal that the current spatial expansion at the northern boundary of the range is following a leading-edge model characterized by a general reduction of genetic diversity towards the edge of the expanding range. We conclude that the level of genome-wide diversity of H. cristata invasive populations is less important in explaining its successful invasion than species-specific life-history traits or the phylogeographic history in the native source range. PMID:27171527

  1. Past approaches and future challenges to the management of fire and invasive alien plants in the new Garden Route National Park

    Directory of Open Access Journals (Sweden)

    Richard M. Cowling

    2011-09-01

    Full Text Available The recently established Garden Route National Park (GRNP along the Cape south coast of South Africa occurs in a landscape where indigenous forests, fire-prone fynbos shrublands and fire-sensitive plantations of alien invasive trees are interspersed. We used the area as a case study in the challenges facing conservation managers in the achievement of biodiversity goals in a fire-prone environment. We explored the context within which fire management was practised during the past century by interviewing former catchment managers and reviewing forestry and catchment management policies. Mountain fynbos adjacent to plantations was subjected to burning regimes aimed at the protection of commercial timber resources rather than the preservation of fynbos biodiversity. Prescribed burning of fynbos adjacent to the plantations was typically done in multiple belt systems at rotations of about 4–8 years during spring, summer and autumn, to avoid the winter berg wind season. Such short-rotation and low-intensity fires favour resprouting graminoids over slow-maturing reseeders, and likely account for the compositional impoverishment observed in fynbos near plantations. Current and future challenges faced by the GRNP include (1 balancing conflicting fire management requirements for plantation safety against fynbos conservation; (2 the continual invasion of fynbos by fire-propagated alien pines sourced from plantations; (3 inadequate resources to redress the ‘invasion debt’ caused by the socio-economic legacy and past management neglect; and (4 fragmentation of land use between conservation and forestry threatening the sustainability of the region at large. We provide recommendations for management actions and research priorities to address these challenges.

  2. Changes in defense of an alien plant Ambrosia artemisiifolia before and after the invasion of a native specialist enemy Ophraella communa.

    Directory of Open Access Journals (Sweden)

    Yuya Fukano

    Full Text Available The evolution of increased competitive ability hypothesis (EICA predicts that when alien plants are free from their natural enemies they evolve lower allocation to defense in order to achieve a higher growth rate. If this hypothesis is true, the converse implication would be that the defense against herbivory could be restored if a natural enemy also becomes present in the introduced range. We tested this scenario in the case of Ambrosia artemisiifolia (common ragweed - a species that invaded Japan from North America. We collected seeds from five North American populations, three populations in enemy free areas of Japan and four populations in Japan where the specialist herbivore Ophraella communa naturalized recently. Using plants grown in a common garden in Japan, we compared performance of O. communa with a bioassay experiment. Consistent with the EICA hypothesis, invasive Japanese populations of A. artemisiifolia exhibited a weakened defense against the specialist herbivores and higher growth rate than native populations. Conversely, in locations where the herbivore O. communa appeared during the past decade, populations of A. artemisiifolia exhibited stronger defensive capabilities. These results strengthen the case for EICA and suggest that defense levels of alien populations can be recuperated rapidly after the native specialist becomes present in the introduced range. Our study implies that the plant defense is evolutionary labile depending on plant-herbivore interactions.

  3. Terminal slider control of nonlinear robotic systems

    Science.gov (United States)

    Venkataraman, Subaramanian T.; Gulati, Sandeep

    1992-06-01

    This invention provides robust nonlinear controllers for robotic operations in unstructured environments based upon a new class of sliding modes denoted terminal sliders that enforce closed loop system convergence to equilibrium in finite time. Improved performance results from the elimination of high frequency control switching previously employed for robustness to parametric uncertainties. Improved performance also results from the dependence of terminal slider stability upon the rate of change of uncertainties over the sliding surface rather than the magnitude of the uncertainty itself for robust control. Terminal sliding mode control also yields improved convergence where convergence time is finite and is to be controlled. This invention also applies terminal sliders to robot manipulator control and benchmark performance with the traditional computed torque control method and provides for design of control parameters.

  4. ALIEN SPECIES: THEIR ROLE IN AMPHIBIAN POPULATION DECLINES AND RESTORATION

    Science.gov (United States)

    Alien species (also referred to as exotic, invasive, introduced, or normative species) have been implicated as causal agents in population declines of many amphibian species. Herein, we evaluate the relative contributions of alien species and other factors in adversely affecting ...

  5. 中国外来入侵植物的学名考证%Nomenclatural Notes on Alien Invasive Vascular Plants in China

    Institute of Scientific and Technical Information of China (English)

    闫小玲; 马金双

    2011-01-01

    基于中国外来入侵植物的相关报道和文献,发现-些入侵植物的学名使用比较混乱,-个物种存在两个或两个以上的名称.依据最新植物志资料,对国内30种外来入侵植物学名进行了考证,包括中名、基名(若存在)、异名、原产地以及在中国的分布等.%Based on literatures of invasive plants, the scientific names of thirty alien invasive plants in China are reviewed here, since more than one name were used for one species by different anthers. The data from the floras updated were employed to compile the scientific name for each species. The vernacular name, basionym (if present),synonym (s) for each species, along with their distributions in China were provided.

  6. Reproductive assurance through self-fertilization does not vary with population size in the alien invasive plant Datura stramonium

    OpenAIRE

    van Kleunen, Mark; Fischer, Markus; Steven D. Johnson

    2007-01-01

    Autonomous self-fertilization is suggested to be associated with invasiveness in plants because it offers reproductive assurance when there is a shortage of suitable mates or pollinators. Given that shortages of mates and pollinators are a common cause of Allee effects in small plant populations, we predict that the benefits of self-fertilization in terms of reproductive assurance should be greatest in small populations. We tested this idea for the invasive herb Datura stramonium , a self-fer...

  7. Competitive replacement of the native Vitis and Hedera taxa by invasive aliens: morphological, cytological and molecular evidences

    Directory of Open Access Journals (Sweden)

    Maria HOHN

    2012-10-01

    Full Text Available We describe here case studies of two woody climber species native to the broadleaf forests of the Carpathian basin. Wild grape (Vitis sylvestris C.C.Gmel., considered to be one of the ancestors of the domesticated grapevine (Vitis vinifera L. became a highly threatened species since the introduction of the American grape species as rootstocks for grapevine. Among these, especially, Riparian grape (Vitis riparia Minchx. escaped from the wine yards and by invading the natural habitats replaced the autochthonous wild grape. In consequence of the competitive exclusion Vitis sylvestris suffered a strong withdrawal along its native habitats. 20 morphological traits, including leaf shape and trichome structure were studied to tackle evidence of the introgressive hybridization among the alien and native taxa. Most of the studied Hungarian habitats were already dominated by hybrid specimens of Vitis taxa. Molecular analysis based on 8 nuclear microsatellites markers supported the morphological results. 

  8. Niche-based modelling as a tool for predicting the risk of alien plant invasions at a global scale

    Czech Academy of Sciences Publication Activity Database

    Thuiller, W.; Richardson, D. M.; Pyšek, Petr; Midgley, G. F.; Hughes, G. O.; Rouget, M.

    2005-01-01

    Roč. 11, - (2005), s. 2234-2250. ISSN 1354-1013 R&D Projects: GA ČR GA206/03/1216 Institutional research plan: CEZ:AV0Z60050516 Keywords : bioclimatic modelling * biological invasions * risk assessment Subject RIV: EF - Botanics Impact factor: 4.075, year: 2005

  9. Catalogue of alien plants of the Czech Republic (2nd edition): checklist update, taxonomic diversity and invasion patterns

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Danihelka, Jiří; Sádlo, Jiří; Chrtek, Jindřich; Chytrý, M.; Jarošík, Vojtěch; Kaplan, Zdeněk; Krahulec, František; Moravcová, Lenka; Pergl, Jan; Štajerová, Kateřina; Tichý, L.

    2012-01-01

    Roč. 84, č. 2 (2012), s. 155-255. ISSN 0032-7786 R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional support: RVO:67985939 Keywords : invasive plants * checklist * Czech Republic Subject RIV: EF - Botanics Impact factor: 2.833, year: 2012

  10. Where do they come from and where do they go? European natural habitats as donors of invasive alien plants globally

    Czech Academy of Sciences Publication Activity Database

    Kalusová, V.; Chytrý, M.; Kartesz, J. T.; Nishino, M.; Pyšek, Petr

    2013-01-01

    Roč. 19, č. 2 (2013), s. 199-214. ISSN 1366-9516 R&D Projects: GA ČR(CZ) GAP505/11/1112 Institutional support: RVO:67985939 Keywords : habitat * invasibility * Europe Subject RIV: EF - Botanics Impact factor: 5.469, year: 2013

  11. Using Tournament Angler Data to Rapidly Assess the Invasion Status of Alien Sport Fishes (Micropterus spp. in Southern Africa.

    Directory of Open Access Journals (Sweden)

    John S Hargrove

    Full Text Available Fishes are one of the most commonly introduced aquatic taxa worldwide, and invasive fish species pose threats to biodiversity and ecosystem function in recipient waters. Considerable research efforts have focused on predicting the invasibility of different fish taxa; however, accurate records detailing the establishment and spread of invasive fishes are lacking for large numbers of fish around the globe. In response to these data limitations, a low-cost method of cataloging and quantifying the temporal and spatial status of fish invasions was explored. Specifically, angler catch data derived from competitive bass angling tournaments was used to document the distribution of 66 non-native populations of black bass (Micropterus spp. in southern Africa. Additionally, catch data from standardized tournament events were used to assess the abundance and growth of non-native bass populations in southern Africa relative to their native distribution (southern and eastern United States. Differences in metrics of catch per unit effort (average number of fish retained per angler per day, daily bag weights (the average weight of fish retained per angler, and average fish weight were assessed using catch data from 14,890 angler days of tournament fishing (11,045 days from South Africa and Zimbabwe; 3,845 days from the United States. No significant differences were found between catch rates, average daily bag weight, or the average fish weight between countries, suggesting that bass populations in southern Africa reach comparable sizes and numbers relative to waters in their native distribution. Given the minimal cost associated with data collection (i.e. records are collected by tournament organizers, the standardized nature of the events, and consistent bias (i.e. selection for the biggest fish in a population, the use of angler catch data represents a novel approach to infer the status and distribution of invasive sport fish.

  12. 梅州城市湿地外来入侵植物现状及防治对策%Alien Invasive Plants and Their Control in Urban Wetlands of Meizhou

    Institute of Scientific and Technical Information of China (English)

    曾兰华; 杨礼文; 俞万源; 李海山; 欧先交

    2013-01-01

    通过实地调查和文献检索,对梅州城市湿地外来入侵植物的组成、生活型、危害程度、原产地、入侵途径等进行了分析。结果表明:梅州城市湿地主要外来入侵植物有16科29属33种,其中菊科植物的数量最多,占入侵植物总数的27.3%;生活型以草本植物为主;有10种入侵植物给当地生态环境带来严重危害;原产地以美洲为主;引入途径主要以人为有意或无意引入为主。在分析城市湿地外来入侵植物现状的基础上,提出了建立入侵植物生态风险评估系统、加强入境检疫、加强地区合作、提高公众防范意识、有效防控和变害为宝等对策,为城市生态及经济的可持续发展提供参考。%The composition, life forms, damage degrees, original districts and invasive routes of alien invasive plant species in urban wetlands of Meizhou City are analyzed in this paper based on our field survey and literature review. The results show that 33 species from 16 families and 29 genera of alien invasive plant species are distributed in the urban wetlands of Meizhou. The Asteraceous plants are the most in number and take up 27.3%of the total species. Herbaceous plant is the dominant life form. In addition, there are 10 species that have caused high degree of threat to the local ecological environment. Most of the alien invasive plant species originally were from the Americas and were introduced intentionally or unintentionally by human beings. On the basis of the research, the strategies for controlling the alien invasive plants are proposed, such as establishing ecological risk evaluating system, enhancing entry quarantine, enhancing regional cooperation, increasing public awareness, effectively preventing and controlling the alien invasive plants, and transforming harmful plants into useful ones, etc. The results of this paper will provide reference for sustainable development of urban ecology and economy of the

  13. 海洋外来物种入侵对南海生态系统的影响及防控对策%Impacts of alien species invasion on the South China Sea ecosystem and related control strategies

    Institute of Scientific and Technical Information of China (English)

    陆琴燕; 刘永; 李纯厚; 魏小岚; 刘勇

    2013-01-01

    外来海洋物种入侵已成为继海洋栖息地破坏之后世界海洋生态环境面临的第二个重大威胁.为了全面了解我国南海外来物种的状况,本文阐述了南海主要外来物种的生物学和生态学特征及其对生态系统的影响,并提出相应的防控对策.结果表明:(1)在我国南海最主要分布和已经报道的外来物种共有35种,多为无意引进.其中,海洋外来藻类最多,为16种,占总种类数的45.7%;其次是海洋污损动物,为11种,占31.4%;外来微生物,为5种,占14.3%;潮间带滩涂植物主要有3种,占8.6%.(2)外来入侵物种主要通过4个方面危害海洋生态系统:弱化海洋生态系统群落结构,降低其物种多样性;改变海洋生态系统遗传多样性,降低其遗传变异性;影响海洋生态系统稳定性,造成外源病害肆虐;加剧海洋生态灾害.本文对南海不同种类外来物种生物学特征分析可为南海外来物种入侵的进一步研究提供基础资料,防控对策的提出可为管理部门制定海洋外来物种入侵管理策略提供参考,以期更好地保护南海海洋生态系统.%Alien species invasion is generally regarded as the second serious threat following habitat destruction to marine ecosystem.This paper elaborated the biological and ecological characters of marine alien species in the South China Sea and the impacts of these species invasion on the South China Sea ecosystem,and put forward the corresponding control strategies.There were totally 35 alien species in the South China Sea,most of which were accidentally introduced species.Among the alien species,alien algae were dominant (16 species,45.7% of the total),followed by fouling animals (11 species,31.4%),alien microorganisms (5 species,14.3%),and intertidal plants (3 species,8.6%).The alien species invasion weakened the community structure and reduced the biodiversity,altered the genetic diversity and decreased the genetic

  14. Ecological impacts of invasive alien plants: a meta-analysis of their effects on species, communities and ecosystems

    Czech Academy of Sciences Publication Activity Database

    Vila, M.; Espinar, J. L.; Hejda, Martin; Hulme, P. E.; Jarošík, Vojtěch; Maron, J. L.; Pergl, Jan; Schaffner, U.; Sun, Y.; Pyšek, Petr

    2011-01-01

    Roč. 14, č. 7 (2011), s. 702-708. ISSN 1461-023X R&D Projects: GA MŠk LC06073; GA ČR GA206/09/0563 Grant ostatní: European Comission(XE) 7E09072-(KBBE-212827) Institutional research plan: CEZ:AV0Z60050516 Keywords : biological invasions * impact * organisational level Subject RIV: EF - Botanics Impact factor: 17.557, year: 2011

  15. Contrasting patterns in the invasions of European terrestrial and freshwater habitats by alien plants, insects and vertebrates

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Bacher, S.; Chytrý, M.; Jarošík, Vojtěch; Wild, Jan; Celesti-Grapow, L.; Gassó, N.; Kenis, M.; Lambdon, P. W.; Nentwig, W.; Pergl, Jan; Roques, A.; Sádlo, Jiří; Solarz, W.; Vila, M.; Hulme, P. E.

    2010-01-01

    Roč. 19, č. 3 (2010), s. 317-331. ISSN 1466-822X R&D Projects: GA MŠk LC06073 Grant ostatní: ALARM(XE) GOCE-CT-2003-506675; European Comission(XE) SSPI-CT-2003-511202 Institutional research plan: CEZ:AV0Z60050516 Keywords : biological invasions * habitat affinities * Europe Subject RIV: EF - Botanics Impact factor: 5.273, year: 2010

  16. Survey and documentation of the potential and actual invasive alien plant species and other biological threats to biodiversity in Awash National Park, Ethiopia

    Directory of Open Access Journals (Sweden)

    Sebsebe DEMISSEW

    2011-01-01

    Full Text Available The study was conducted at the Awash National Park (ANP Ethiopia, todocument Invasive Alien Species (IAS and to assess the spread of Prosopis juliflora (Sw. DC. A total of 64 sample plots were laid systematically along the altitudinal gradient of 750 to 1916 m.Potential IAS were recorded. IAS which may threaten biodiversity of the park includes species such as Prosopis juliflora, Parthenium hysterophorus L., Cryptostegia grandiflora Roxb. ex R. Br., Parkinsonia aculeata L., Senna occidentalis (L. Link, Datura ferox L. and Xanthium strumarium L. Except P. juliflora and P. hysterophorus, all others were not recorded in Ethiopia as IAS. P.juliflora was recorded in three plots with cover of 1% to 10%. P. juliflora was also found spread in different parts of the park particularly following the route of cattle movement. P. hysterophoruswas recorded in and around nine sample plots. Plot 46, 47 and 48 werehighly infested by P. hysterophorus which covered more than 60, 70 and 80% of the ground layer respectively. C. grandiflora was recorded in 11 plots with cover ranging from 1% to 35%. In view of all the natural as well as anthropogenic threats to the biodiversity of the Park, the ANP is at high risk. The rich biodiversity needsimmediate management intervention.

  17. Strategy to control the invasive alien tree Miconia calvescens in Pacific islands: eradication, containment or something else?

    Science.gov (United States)

    Goarant, Anne-Claire; Meyer, Jean-Yves

    2011-01-01

     Miconia calvescens (Melastomataceae) is a notorious plant invader in the tropical islands of French Polynesia, Hawaii and New Caledonia. A small tree native to Central and South America, it was fi rst introduced as an ornamental in private botanic gardens in Tahiti (1937), Honolulu (1961), and Nouméa (1970s) where it escaped, became naturalised, and formed dense monospecifi c stands. More than 80,000 ha are currently invaded in French Polynesia, 10,000 ha in the Hawaiian Islands and 140 ha in New Caledonia. Control programmes have been under way in the Hawaiian Islands (Oahu, Maui, Hawaii, Kauai) and French Polynesia (Raiatea, Tahaa, Nuku Hiva, Fatu Hiva) since the early 1990s, and in New Caledonia (Province Sud) since 2006. Despite more than 15 years of intensive control efforts and millions of plants destroyed, eradication has not been achieved in any of these islands, mainly because the species has multiple features that thwart its elimination (e.g., prolific seed production, active dispersal by alien and native frugivorous birds, large and persistent soil seed bank, shade-tolerance), combined with the difficulty of detecting and destroying plants on rough terrain and steep slopes, insufficient control frequency, and limited financial and human resources. Miconia’s life cycle requires at least four years growth from seedling to fruiting. Consequently, prevention of fruit production may be an effective management strategy for small populations. This “juvenilization” process may allow the eradication of small populations when carefully conducted over a quarter century.

  18. The Problem and Status of the Alien Invasive Plants in China%中国外来入侵植物研究现状及存在的问题

    Institute of Scientific and Technical Information of China (English)

    闫小玲; 寿海洋; 马金双

    2012-01-01

    生物入侵是当今各国发展的一大挑战,特别是像中国这样的发展中国家.然而,我们对外来入侵种的本底资料还很不清楚,更缺乏相关的深入调查;对生物入侵所造成的生态和经济影响还没有引起足够的重视,同时也忽视了盲目引种可能带来的各种危害.本文在文献调研的基础上,从外来植物的入侵历史和文化、中国外来入侵植物的调查现状、外米植物入侵对生态安全及经济的影响等方面进行了全面系统的总结,并提出了中国外来入侵植物研究领域存在的问题及应对措施.%The biological invasion has become a major challenge on global development, especially for whole developing country like China. However, the background data of invasive species in China is still far from completed, and the relevant investigation of the Chinese invasive inforatmion has not been fully available yet today. The huge ecological and economic impacts caused by various invasive species have not been fully noticed or observed by the relative institutions and scientists, plus the ignorance of dangerous invasion with the introduction of alien species. Based on various literatures, the history and culture of invasive plant species, their invasive status and impact on ecological security and economic loss in China have been fully reviewed; and the problems existed and mangement measures of alien invasive plants in China have been fully proposed and summarized in order to provide basic information on the management of invasive plant species in China, and appeal to the government and the community to improve their Risk-Prevention strategies and great sense of urgency with alien invasive plants in China.

  19. New approaches to the management of golden apple snail, Pomacea canaliculata (Lamarck): An invasive alien pest species of rice

    International Nuclear Information System (INIS)

    Full text: Golden apple snail (GAS), Pomacea canaliculata (Lamarck) is native to South America. It was introduced to farmers in the Philippines in the 1980s from Argentina via Taiwan, and to other countries in Asia to increase their income and to enrich the protein intake in their diet, and also as an aquarium pet. The Global Invasive Species (IAS) FAO report that it causes 1.2 billion USD losses to aquatic crops particularly rice, taro and morning glory in Asian countries and the USA. Aside from being a serious agricultural pest, it is also an environmental pest. In an attempt to control GAS resource-poor-farmers resort to 'shot-gun approach' of using toxic and non specific agrochemicals thereby aggravating ecosystem pollution, risking their health and causing loss of aquatic biodiversity. GAS is expanding its distribution westwards in Asia and poses new threats of its invasion in Australia, India, Bangladesh and Pakistan. At the Philippine Rice Research Institute (PhilRice), my team focuses on two approaches. First we have to understand the field ecology of the GAS and identify weak-links in their life cycle. Then we use this basic information to manage GAS at the village level within the community in an ecologically sustainable socially acceptable and economically viable ways. I shall discuss how this LAS in transplanted lowland irrigated rice ecologies can be managed using locally available attractants during the vulnerable stage(s) of rice crop growth. New approaches will highlight the innovative and applied techniques on how to prevent the rampant abuse/misuse of agrochemicals, as well as GAS utilisation in weed management in rice fields and as aqua feed. In future, it is necessary to develop collaborative exploratory research with the IAEA and the Philippine Nuclear Research Institute (PNRI) to develop an effective area-wide management of GAS in direct-seeded rice systems that will capitalise on an integrated approach and environment-friendly technologies

  20. Alien Abductions

    Science.gov (United States)

    Nickell, Joe

    2000-03-01

    Since the beginning of the modern UFO craze in 1947, an elaborate mythology has developed concerning alleged extraterrestrial visitations. ``Flying saucer" sightings (typically involving misperceptions of such mundane phenomena as meteors and research balloons) began to be accompanied in the 1950s by reports from ``contactees," persons who claimed to have had close encounters with, even to have been transported to distant planets by, UFO occupants. By the 1960s came reports of sporadic ``abductions" which have proliferated in correlation with media interest. (Indeed, by interaction between claimants and media the portrayal of aliens has evolved from a multiplicity of types into the rather standardized big-eyed humanoid model.) While evidence of alien contact has often been faked--as by spurious photos, ``crop circles," and the notorious ``Alien Autopsy" film--few alien abduction reports appear to be hoaxes. Most seem instead to come from sincere, sane individuals. Nevertheless, not one has been authenticated, and serious investigation shows that such claims can be explained as sleep-related phenomena (notably ``waking dreams"), hypnotic confabulation, and other psychological factors. As is typical of other mythologies, the alien myth involves supernormal beings that may interact with humans, and it purports to explain the workings of the universe and humanity's place within it.

  1. ALIENS IN WESTERN STREAM ECOSYSTEMS

    Science.gov (United States)

    The USEPA's Environmental Monitoring and Assessment Program conducted a five year probability sample of permanent mapped streams in 12 western US states. The study design enables us to determine the extent of selected riparian invasive plants, alien aquatic vertebrates, and some ...

  2. Phyloecology of urban alien floras

    Czech Academy of Sciences Publication Activity Database

    Ricotta, C.; La Sorte, F. A.; Pyšek, Petr; Rapson, G. L.; Celesti-Grapow, L.; Thompson, K.

    2009-01-01

    Roč. 97, č. 6 (2009), s. 1243-1251. ISSN 0022-0477 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60050516 Keywords : urban aliens * biological invasions * phylogenetic similarity Subject RIV: EF - Botanics Impact factor: 4.690, year: 2009

  3. Invasive mechanism and manasement stratesy of Bemisia tabaci (Gennadius) biotype B: Progress report of 973 Program on invasive alien species in China

    Institute of Scientific and Technical Information of China (English)

    WAN FangHao; CUI XuHong; ZHANG LiPing; ZHANG Fan; ZHANG QingWen; LIU WanXue; LIANG Pei; LEI ZhongRen; ZHANG YongJun; ZHANG GuiFen; LIU ShuSheng; LUO Chen; CHU Dong; ZHANG YouJun; ZANG LianSheng; JIU Min; Lǖ ZhiChuang

    2009-01-01

    Bemisia tabaci (Gennadius) biotype B, called a "superbug", is one of the most harmful biotypes of this species complex worldwide. In this report, the invasive mechanism and management of B. tabaci bio-type B, based on our 5-year studies, are presented. Six B. tabaci biotypes, B, Q, ZHJ1, ZHJ2, ZHJ3 and FJ1, have been identified in China. Biotype B dominates the other biotypes in many regions of the country. Genetic diversity in biotype B might be induced by host plant, geographical conditions, and/or insecticidal application. The activities of CarE (carboxylesterase) and GSTs (glutathione-S-transferase) in biotype B reared on cucumber and squash were greater than on other host plants, which might have increased its resistance to insecticides. The higher activities of detoxification enzymes in biotype B might be induced by the secondary metabolites in host plants. Higher adaptive ability of biotype B adults to adverse conditions might be linked to the expression of heat shock protein genes. The in-digenous B. tabaci biotypes were displaced by the biotype B within 225 d. The asymmetric mating in-teractions and mutualism between biotype B and begomoviruses via its host plants speed up wide-spread invasion and displacement of other biotypes. B. tabaci biotype B displaced Trialeurodes vapo-rariorum (Westwood) after 4-7 generations under glasshouse conditions. Greater adaptive ability of the biotype B to adverse conditions and its rapid population increase might be the reasons of its suc-cessful displacement of T. vaporariorum. Greater ability of the biotype B to switch to different host plants may enrich its host plants, which might enable it to better compete with T. vaporariorum. Native predatory natural enemies possess greater ability to suppress B. tabaci under field conditions. The kairomones in the 3rd and 4th instars of biotype B may provide an important stimulus in host searching and location by its parasitoids. The present results provide useful information in

  4. Invasive mechanism and management strategy of Bemisia tabaci (Gennadius) biotype B: progress report of 973 Program on invasive alien species in China.

    Science.gov (United States)

    Wan, FangHao; Zhang, GuiFen; Liu, ShuSheng; Luo, Chen; Chu, Dong; Zhang, YouJun; Zang, LianSheng; Jiu, Min; Lü, ZhiChuang; Cui, XuHong; Zhang, LiPing; Zhang, Fan; Zhang, QingWen; Liu, WanXue; Liang, Pei; Lei, ZhongRen; Zhang, YongJun

    2009-01-01

    Bemisia tabaci (Gennadius) biotype B, called a "superbug", is one of the most harmful biotypes of this species complex worldwide. In this report, the invasive mechanism and management of B. tabaci biotype B, based on our 5-year studies, are presented. Six B. tabaci biotypes, B, Q, ZHJ1, ZHJ2, ZHJ3 and FJ1, have been identified in China. Biotype B dominates the other biotypes in many regions of the country. Genetic diversity in biotype B might be induced by host plant, geographical conditions, and/or insecticidal application. The activities of CarE (carboxylesterase) and GSTs (glutathione-S-transferase) in biotype B reared on cucumber and squash were greater than on other host plants, which might have increased its resistance to insecticides. The higher activities of detoxification enzymes in biotype B might be induced by the secondary metabolites in host plants. Higher adaptive ability of biotype B adults to adverse conditions might be linked to the expression of heat shock protein genes. The indigenous B. tabaci biotypes were displaced by the biotype B within 225 d. The asymmetric mating interactions and mutualism between biotype B and begomoviruses via its host plants speed up widespread invasion and displacement of other biotypes. B. tabaci biotype B displaced Trialeurodes vaporariorum (Westwood) after 4-7 generations under glasshouse conditions. Greater adaptive ability of the biotype B to adverse conditions and its rapid population increase might be the reasons of its successful displacement of T. vaporariorum. Greater ability of the biotype B to switch to different host plants may enrich its host plants, which might enable it to better compete with T. vaporariorum. Native predatory natural enemies possess greater ability to suppress B. tabaci under field conditions. The kairomones in the 3rd and 4th instars of biotype B may provide an important stimulus in host searching and location by its parasitoids. The present results provide useful information in

  5. Invasive mechanism and management strategy of Bemisia tabaci(Gennadius) biotype B:Progress report of 973 Program on invasive alien species in China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Bemisia tabaci(Gennadius) biotype B,called a "superbug",is one of the most harmful biotypes of this species complex worldwide.In this report,the invasive mechanism and management of B.tabaci biotype B,based on our 5-year studies,are presented.Six B.tabaci biotypes,B,Q,ZHJ1,ZHJ2,ZHJ3 and FJ1,have been identified in China.Biotype B dominates the other biotypes in many regions of the country.Genetic diversity in biotype B might be induced by host plant,geographical conditions,and/or insecticidal application.The activities of CarE(carboxylesterase) and GSTs(glutathione-S-transferase) in biotype B reared on cucumber and squash were greater than on other host plants,which might have increased its resistance to insecticides.The higher activities of detoxification enzymes in biotype B might be induced by the secondary metabolites in host plants.Higher adaptive ability of biotype B adults to adverse conditions might be linked to the expression of heat shock protein genes.The indigenous B.tabaci biotypes were displaced by the biotype B within 225 d.The asymmetric mating interactions and mutualism between biotype B and begomoviruses via its host plants speed up widespread invasion and displacement of other biotypes.B.tabaci biotype B displaced Trialeurodes vaporariorum(Westwood) after 4-7 generations under glasshouse conditions.Greater adaptive ability of the biotype B to adverse conditions and its rapid population increase might be the reasons of its successful displacement of T.vaporariorum.Greater ability of the biotype B to switch to different host plants may enrich its host plants,which might enable it to better compete with T.vaporariorum.Native predatory natural enemies possess greater ability to suppress B.tabaci under field conditions.The kairomones in the 3rd and 4th instars of biotype B may provide an important stimulus in host searching and location by its parasitoids.The present results provide useful information in explaining the mechanisms of genetic diversity

  6. Alien Invasive Plants in Nanchang Urban Green Land and Its Preventive Measures%南昌城市绿地外来入侵植物及其防治对策

    Institute of Scientific and Technical Information of China (English)

    朱碧华; 杨凤梅

    2012-01-01

    Alien plants invasion,which has caused wide public concern all over the world,threatening the stability and the bearing capability of ecosystem.Moreover,it harming the economic structure of human society and human health,and the loss is beyond estimation.The urban green land is easily influenced of alien plants invasion as a comparatively weaker self-regulate ecosystem.The common species of alien invasive plants in Nanchang urban green land were introduced in this paper,and its attacking ways and the harmful result to the urban green ecosystem were discussed,meanwhile,some relevant prevention measures were put forward.%植物入侵威胁生态系统的稳定性,影响生态系统的承载力,危害人类社会经济结构以及人类健康,造成了无法估量的损失,已经引起全球的普遍关注。城市绿地作为一个自我调节能力相对较弱的生态系统,对外来植物入侵的防范能力比较低,受影响的程度会更大。介绍南昌城市绿地中外来入侵植物的常见种类,探讨外来植物的入侵途径和对城市绿地生态系统的危害,并提出相应的预防措施。

  7. Investigation of slider surfaces after wear using photoemission electron microscopy

    International Nuclear Information System (INIS)

    The tribo-chemical interactions between the slider and the hard disk surface strongly influence the performance properties of a disk drive. To study these interactions, uncoated and carbon coated sliders were subjected to various wear tests using different disks. After the wear, the test slider surfaces were studied by photoemission electron microscopy (PEEM) using tunable x rays produced by a synchrotron. Using PEEM, one can identify the elemental and chemical state of the surfaces with a high spatial resolution. It was found that wear reduces the thickness of the carbon coating in some local areas of the slider surface. In particular, the coating was removed on elevated areas and in scratches. Scratches were found on the rails of the carbon coated and uncoated sliders after wear that showed the accumulation of a degraded (oxidized) lubricant which was transferred to the slider from the disk. It was also possible to analyze the chemical composition of the debris found on the slider surface. In the present case, the debris had the same chemical composition as the carbon coating of the slider. copyright 1999 American Vacuum Society

  8. Options in dealing with marine alien species

    NARCIS (Netherlands)

    Pelt-Heerschap, van H.M.L.; Sneekes, A.C.; Foekema, E.M.

    2015-01-01

    Invasive species can have strong impact on the local ecosystem, not only substantial impact on the local ecosystem, but also on economy and human health. This review on marine alien species outlines aspects of prevention, eradication and control strategies. When managing invasive species, prevention

  9. Widespread plant species: natives vs. aliens in our changing world

    Science.gov (United States)

    Stohlgren, Thomas J.; Pyšek, Petr; Kartesz, John; Nishino, Misako; Pauchard, Aníbal; Winter, Marten; Pino, Joan; Richardson, David M.; Wilson, John R.U.; Murray, Brad R.; Phillips, Megan L.; Ming-yang, Li; Celesti-Grapow, Laura; Font, Xavier

    2011-01-01

    Estimates of the level of invasion for a region are traditionally based on relative numbers of native and alien species. However, alien species differ dramatically in the size of their invasive ranges. Here we present the first study to quantify the level of invasion for several regions of the world in terms of the most widely distributed plant species (natives vs. aliens). Aliens accounted for 51.3% of the 120 most widely distributed plant species in North America, 43.3% in New South Wales (Australia), 34.2% in Chile, 29.7% in Argentina, and 22.5% in the Republic of South Africa. However, Europe had only 1% of alien species among the most widespread species of the flora. Across regions, alien species relative to native species were either as well-distributed (10 comparisons) or more widely distributed (5 comparisons). These striking patterns highlight the profound contribution that widespread invasive alien plants make to floristic dominance patterns across different regions. Many of the most widespread species are alien plants, and, in particular, Europe and Asia appear as major contributors to the homogenization of the floras in the Americas. We recommend that spatial extent of invasion should be explicitly incorporated in assessments of invasibility, globalization, and risk assessments.

  10. Widespread plant species: Natives versus aliens in our changing world

    Science.gov (United States)

    Stohlgren, T.J.; Pysek, P.; Kartesz, J.; Nishino, M.; Pauchard, A.; Winter, M.; Pino, J.; Richardson, D.M.; Wilson, J.R.U.; Murray, B.R.; Phillips, M.L.; Ming-yang, L.; Celesti-Grapow, L.; Font, X.

    2011-01-01

    Estimates of the level of invasion for a region are traditionally based on relative numbers of native and alien species. However, alien species differ dramatically in the size of their invasive ranges. Here we present the first study to quantify the level of invasion for several regions of the world in terms of the most widely distributed plant species (natives vs. aliens). Aliens accounted for 51.3% of the 120 most widely distributed plant species in North America, 43.3% in New South Wales (Australia), 34.2% in Chile, 29.7% in Argentina, and 22.5% in the Republic of South Africa. However, Europe had only 1% of alien species among the most widespread species of the flora. Across regions, alien species relative to native species were either as well-distributed (10 comparisons) or more widely distributed (5 comparisons). These striking patterns highlight the profound contribution that widespread invasive alien plants make to floristic dominance patterns across different regions. Many of the most widespread species are alien plants, and, in particular, Europe and Asia appear as major contributors to the homogenization of the floras in the Americas. We recommend that spatial extent of invasion should be explicitly incorporated in assessments of invasibility, globalization, and risk assessments. ?? 2011 Springer Science+Business Media B.V.

  11. Modelling Favourability for Invasive Species Encroachment to Identify Areas of Native Species Vulnerability

    OpenAIRE

    David Romero; José C Báez; Francisco Ferri-Yáñez; Bellido, Jesús J.; Raimundo Real

    2014-01-01

    We assessed the vulnerability of the native Mediterranean pond turtle to encroachment by the invasive red-eared slider in southern Spain. We first obtained an ecogeographical favourability model for the Mediterranean pond turtle. We then modelled the presence/absence of the red-eared slider in the Mediterranean pond turtle range and obtained an encroachment favourability model. We also obtained a favourability model for the red-eared slider using the ecogeographical favourability for the Medi...

  12. 北京松山自然保护区外来入侵植物研究%The Research of Alien Invasive Plant in Beijing Songshan Nature Reserve

    Institute of Scientific and Technical Information of China (English)

    刘佳凯; 姚可侃; 张容; 夏阳; 王慧慧; 张振明; 吴计贵; 蒋万杰

    2012-01-01

    为了对松山地区外来植物进行长期有效的监测和管理,防止其对当地的自然生态系统造成破坏,对松山国家级自然保护区的植物进行了详细的样方调查,并对保护区外来入侵植物的分布和相对盖度进行分析.结果表明:松山自然保护区共发现外来植物入侵植物23种,隶属于12科17属,其中大麻(Cannabis sativa)、反枝苋(Amaranthus retroflexus)、萱草(Hemerocallis fulva)、洋槐(Robinia pseudoacacia)、荷包豆(Phaseolus coccineus)等较为常见,影响外来植物入侵的主要因素是道路修建和坡向.该区域的外来物种的各种群规模不大,且多集中在人为活动较为频繁的实验区,对保护区内重点保护的天然次生油松林以及落叶阔叶次生林的生态系统并不存在特别大的威胁.%In order to establish a long-term monitoring mechanism of exotic plants in Songshan Nature Reserve, the author conducted this study, through the survey and the analysis of distribution and relative coverage of alien invasive plants in Songshan Nature Reserve, the results showed that 23 species of alien invasive plants were found, belonging to 12 families and 17 generas. Among them marijuana (Cannabis sativa), redroot amaranth (Amaranthus retroflexus), day lily (Hemerocallis fulva), acacia {Robinia pseudoacacia) and scarlet runner bean (Phaseolus coccineus) were more common. The road construction was the first factor, which influenced and promoted the distribution of alien plants. The next factor was the aspect. Research showed that the alien species population scale was not big and the adverse impact on the local ecological system was not obvious.

  13. Effect of friction on the performance of inertial slider

    Indian Academy of Sciences (India)

    K Anantheshwara; N S Murali; M S Bobji

    2008-06-01

    Inertial sliders are friction based drives used to position with a resolution of a few hundred of nanometers to over a range of few millimeters. The compactness and simple construction enabled it to be used as a coarse positioner in various Scanning Probe Microscopes (SPM). Even heavy masses has been thought off earlier to use the inertial slider to position precisely, lack of understanding in the dynamical friction behaviour has been the main reason why the inertial sliders potential has not been explored fully in any practical device. In this paper, we have studied the effect of different operating parameters on the step size of the slider. The inertial mass is kept on three sapphire balls, which are attached to shear piezoelectric material. The behaviour of inertial mass was studied for different input waveforms and different surface conditions that come in contact with the sapphire balls. It was observed that under lubricated conditions the step size was reduced.

  14. Dynamic synthesis of machine with slider-crank mechanism

    OpenAIRE

    Jomartov, A. A.; S. U. Joldasbekov; Drakunov, Yu. M.

    2015-01-01

    In this paper we consider the formulation and solution of the task of a dynamic synthesis machine with an asynchronous electric motor and a slider-crank mechanism. The constant parameters of the slider-crank mechanism (mass and moments of inertia and centers of gravity of links) and the parameters of the electrical motor are defined. The laws of motion of the machine and kinematic parameters of the mechanism are considered as given. We have developed the method of optimal dy...

  15. Considerations for the design of gas-lubricated slider bearings

    OpenAIRE

    Smith, Paul Wesley

    1988-01-01

    An approach is developed that simplifies calculation of the dynamic characteristics of a self-acting, gas-lubricated slider bearing system. This technique avoids a lengthy simultaneous solution of the equations of motion of the slider and the time-dependent Reynolds' equation, while providing additional design information that is otherwise unobtainable. The equilibrium pressure distribution in the gas film is obtained using the Bunov-Galerkin formulation of the finite element method. By c...

  16. Alien macroinvertebrates in Flanders (Belgium)

    OpenAIRE

    Boets, Pieter; Brosens, Dimitri; Lock, Koen; Adriaens, Tim; Aelterman, Bart; Mertens, Joost; Goethals, Peter

    2016-01-01

    Biological invasions of aquatic macroinvertebrates are gaining interest because of their potential for significant ecological and socio-economic impacts (positive and negative). In the present study, an inventory was made of the alien macroinvertebrates occurring in Flanders (northern Belgium) based on extensive existing collections of biological samples and supplemented with our additional sampling programs. Fresh and brackish waters as well as the Belgian coastal harbours, situated at the i...

  17. The bad biodiversity: alien plant species in Hong Kong

    OpenAIRE

    Ng, SC; Corlett, RT

    2002-01-01

    The flora of Hong Kong has been well-surveyed since the mid nineteenth century and has had a long history of alien plant invasions. To the present day, more than 2130 wild plant species have been recorded, including 238 species that are probably naturalized alien species. Among them, Mikania micrantha, Ipomoea cairica, Eupatorium catarium, and Panicum maximum are most abundant. Naturalized alien plants are most prominent in human-disturbed habitats, such as abandoned farmland, wasteland and r...

  18. Characterization of sliders for efficient force generation of electrostatically controlled linear actuator

    International Nuclear Information System (INIS)

    In this paper, the characterization of sliders for efficient force generation of an electrostatically controlled linear actuator (ECLIA) is investigated. The ECLIA consists of a piezoactuator (PZT), driving and holding electrodes, multiple sliders and a guide structure. The stepping motion of the sliders is driven by the PZT actuator via an electrostatic clutch mechanism. Thus, multiple sliders can achieve parallel, independent, precise motion, and a large stroke. Previous studies have indicated that the Si bulk slider and Si electrode created an air gap owing to the deformation of the Si electrode. Thus, the Si slider generated a low pushing force. In this study, we propose a fishbone structure mounted on a flexible slider to enhance the pushing force of the slider. The flexible slider, that can deform and fit into the Si electrode to reduce the air gap, results in highly efficient electrostatic-force generation. The fishbone structure improves the longitudinal stiffness of the flexible slider for high pushing-force generation. The results show that the pushing force created by the fishbone slider was three times greater than that of the conventional Si slider. The fishbone and flexible sliders exhibited a high performance for the ECLIA. (paper)

  19. Defining invasiveness and invasibility in ecological networks

    OpenAIRE

    C. Hui; Richardson, D. M.; Landi, P; H.O. Minoarivelo; Garnas, J.; Roy, H.E.

    2016-01-01

    The success of a biological invasion is context dependent, and yet two key concepts—the invasiveness of species and the invasibility of recipient ecosystems—are often defined and considered separately. We propose a framework that can elucidate the complex relationship between invasibility and invasiveness. It is based on trait-mediated interactions between species and depicts the response of an ecological network to the intrusion of an alien species, drawing on the concept of community satura...

  20. Alienation, Dogmatism and Acquiescence.

    Science.gov (United States)

    Ray, John J.

    1984-01-01

    Examined the issue of acquiescence by administering a balanced dogmatism scale and a balanced alienation scale to a random sample of Australians (N=118). Results showed that dogmatism and alienation did not correlate when acquiescence was controlled. (LLL)

  1. The coregulator Alien

    OpenAIRE

    Papaioannou, Maria; Melle, Christian; Baniahmad, Aria

    2007-01-01

    Alien has characteristics of a corepressor for selected members of the nuclear hormone receptor (NHR) superfamily and also for transcription factors involved in cell cycle regulation and DNA repair. Alien mediates gene silencing and represses the transactivation of specific NHRs and other transcription factors to modulate hormone response and cell proliferation. Alien is a highly conserved protein and is expressed in a wide variety of tissues. Knockout of the gene encoding Alien in mice is em...

  2. The role of the World Trade Organization and the 'three sisters' (the World Organisation for Animal Health, the International Plant Protection Convention and the Codex Alimentarius Commission) in the control of invasive alien species and the preservation of biodiversity.

    Science.gov (United States)

    Kahn, S; Pelgrim, W

    2010-08-01

    The missions of the World Organisation for Animal Health (OIE) include the design of surveillance and control methods for infectious transboundary animal diseases (including zoonoses), the provision of guarantees concerning animal health and animal production food safety, and the setting of standards for, and promotion of, animal welfare. The OIE role in setting standards for the sanitary safety of international trade in animals and animal products is formally recognised in the World Trade Organization (WTO) Agreement on the Application of Sanitary and Phytosanitary Measures (the SPS Agreement). While the primary focus of the OIE is on animal diseases and zoonoses, the OIE has also been working within the WTO framework to examine possible contributions the organisation can make to achieving the goals of the Convention on Biological Diversity, particularly to preventing the global spread of invasive alien species (IAS). However, at the present time, setting standards for invasive species (other than those connected to the cause and distribution of diseases listed by the OIE) is outside the OIE mandate. Any future expansion of the OIE mandate would need to be decided by its Members and resources (expertise and financial contributions) for an extended standard-setting work programme secured. The other international standard-setting organisations referenced by the SPS Agreement are the International Plant Protection Convention (IPPC) and the Codex Alimentarius Commission (CAC). The IPPC mandate and work programme address IAS and the protection of biodiversity. The CAC is not involved in this field. PMID:20919590

  3. Predicting vibration-induced displacement for a resonant friction slider

    DEFF Research Database (Denmark)

    Fidlin, A.; Thomsen, Jon Juel

    2001-01-01

    A mathematical model is set up to quantify vibration-induced motions of a slider, sandwiched between friction layers with different coefficients of friction, and equipped with an imbedded resonator that oscillates at high frequency and small amplitude. This model is highly nonlinear, involving non......-smooth functions with strong harmonic excitation terms. The method of averaging is extended to hold for systems of this class, and used to derive approximate expressions for predicting average velocities of the slider. These expressions are shown to produce results that agree very well with numerical integration...... of the full equations of motion. The expressions are used to estimate and explain the influence of system parameters....

  4. New Invasive Alien Plant Amaranthus polygonoides in Zhejiang%浙江新外来入侵植物--合被苋

    Institute of Scientific and Technical Information of China (English)

    张小伟; 谢文远; 张芬耀

    2015-01-01

    合被苋Amaranthus polygonoides L.原产加勒比海岛、美国、墨西哥等地,是新近传入浙江的外来植物。本文报道合被苋的植物学和生态学特性,介绍其在国内外分布和国内蔓延情况,为该种的早期控制提供基础资料。%Amaranthus polygonoides L., originated in the Caribbean island, American, Mexico etc, is a new alien plant found in Zhejiang. The article preliminarily introduced the biological and ecological characteristics, world distribution, its spread of the domestic, to provide basic data for preventing its spreading.

  5. Biological and Ecological Characteristics of an Invasive Alien Species Spartina in Yellow River Delta%黄河三角洲外来入侵物种米草的生物学与生态学特性

    Institute of Scientific and Technical Information of China (English)

    石东里; 田家怡; 陈印平

    2009-01-01

    In Yellow River Delta,the biological and ecological characteristics of an invasive alien spe-cies spartina were investigated. The results showed that the stem of spartina is tenacious and many gas chambers are in epidermal parencbyma of its rhizome. These characteristics ensure that it can live in flooding conditions. Salt gland that is under surface of its leaf and can secret and discharge salt. Water loss can make seed fail to germination. Its capability of asexual reproduction is strong and that is the bio-logical base of its spreading. Its euryhalinity, submergence tolerance, high adaptability and reproductive capacity,strong high invasion capacity and great ecological amplitude are the ecological base of its inva-sion and development.%对黄河三角洲外来入侵物种米草的生物学、生态学特性进行了观测和研究.结果表明:米草茎秆坚韧,不易倒伏;根状茎表皮薄壁组织内有许多气腔,与淹水条件下生活的习性相适应;米草叶背面有盐腺,便于泌盐和排盐;米草种子失水即失去萌发力,无性繁殖力强,是其扩散的生物学基础;米草的广盐性、耐淹性、高适应性、强繁殖扩散能力、强竞争入侵能力、生态幅宽,是其入侵和爆发的生态学基础.

  6. How many marine aliens in Europe?

    Directory of Open Access Journals (Sweden)

    Stelios Katsanevakis

    2013-01-01

    Full Text Available In the framework of the European Alien Species Information Network (EASIN; http://easin.jrc.ec.europa.eu/, an inventory of marine alienspecies in Europe was created by critically reviewing existing information in 34 global, European, regional and national databases. In total, 1369 marine alien species have been reported in the European seas (including 110 cryptogenic and 139 questionable species; this is a substantial increase from the 737 species previously reported in 2009 based on the DAISIE (Delivering Alien Invasive Species Inventories for Europe; http://www.europe-aliens.org dataset. Most of the reported species were invertebrates (63.3%, followed by chromists (13.7%, vertebrates (11.6%, and plants (10.1%. Mollusca is the most numerous phylum, followed by Arthropoda, Chordata, and Annelida. Thecountries with the highest reported numbers of marine alien species were Israel, Turkey, Italy, France, Egypt and Greece. A reporting bias is evident as efforts for monitoring and reporting alien species vary among countries.

  7. An assessment of the information content of South African alien species databases

    OpenAIRE

    Katelyn T. Faulkner; Dian Spear; Robertson, Mark P.; Mathieu Rouget; Wilson, John R. U.

    2015-01-01

    National alien species databases indicate the state of a country’s biodiversity and provide useful data for research on invasion biology and the management of invasions. In South Africa there are several different published alien species databases, but these databases were created for different purposes and vary in completeness and information content. We assessed the information content of published South African alien species databases in the context of other such databases globally, and ev...

  8. A Research Review of Invasive Mechanism of Alien Plant Ambrosia Artemisiifolia and Its Present Situation%外来植物豚草的入侵机理研究进展及其现状

    Institute of Scientific and Technical Information of China (English)

    柏祥; 刘传才; 塔莉; 王连龙

    2015-01-01

    从外来植物的入侵性和生境的可入侵性两方面综述了外来植物豚草的入侵机理研究进展,分析了豚草在秦皇岛地区的现状,以中国环境管理干部学院新校区为例调查了人类活动干扰对豚草的影响。豚草的入侵性与其自身所具有的生理生态学特性密切相关,生境的可入侵性则与其群落特征和受干扰程度等因素有关。目前豚草是秦皇岛地区自然群落的建群种,没有表现出入侵性。新校区调查结果表明:豚草在自然群落中零星分布,但受到人类活动干扰的生境中豚草表现出一定的优势度。因此,在豚草防治中应防止人类活动的过度干扰影响,以保护当地的生态环境。%A research review was presented on invasive mechanism of alien plant Ambrosia art-emisiifolia in terms of its invasiveness and the habitat invisibility. The present situation of the plant was analyzed in Qinhuangdao region, and the new campus was taken as an example to inves-tigate the effects of human activity disturbance on A. artemisiifolia. The invasiveness of A. artemisiifolia was closely related to its ecophysiological characteristics, while the habitat invisibility was impacted by community characteristics and disturbance degree. In present, the plant was a community construction species in this region, and showed no invasion. The investigated results showed that A. artemisiifolia distributed sporadically in the natural community. However, in the habitat disturbed by human activities, the plant had relatively high advantage. Therefore, excessive human activity disturbance should be prevented to control the invasive plant, by which to protect the local ecological environment.

  9. The Checklist of the Sardinian Alien Flora: an Update

    Directory of Open Access Journals (Sweden)

    Lina PODDA

    2012-11-01

    Full Text Available Alien plants colonization, due to the fast spreading of highly invasive taxa, is more and more a serious source of concerns for habitat and species conservation. Apart direct in situ intervention, it is of major importance to acquire the best and up to date knowledge about alien taxa that currently threaten the integrity of wild and valuable environments. In this light, here is presented the update to the checklist of alien vascular flora of the island of Sardinia (Italy on the basis of the new findings, nomenclatural adjustments, and revision of diffusion status of alien taxa. The checklist at present, consists of 541 taxa (84 doubtful which represent 17% of the whole flora of the island; 22 taxa are new to the island and 7 of them for Italy. Neophytes represent the majority of the whole alien flora (301, 66% of the total and, in confront to archaeophytes, gather nearly all invasive taxa (54 vs 4. The new findings are all neophytes. Phanerophytes (42% are the most representative biological form and Americas represents the region that mostly contributes to the Sardinian alien flora (33%. Further analysis highlights that, in terms of number of taxa, highly anthropically impacted environments such as synanthropic (36% and agricultural (23% are the eligible habitats for most of the alien species in Sardinia while coastal areas and wetlands, beyond hosting a lower number of taxa, are characterized by the relative highest number of invasives.

  10. INVASIVE ALIEN PLANTS ON DECAYING WOOD AND ON TREE-FALL DISTURBANCES IN FORESTS IN THE KARKONOSZE MTS (SUDETEN, SW POLAND

    Directory of Open Access Journals (Sweden)

    Monika Staniaszek-Kik

    2014-10-01

    Full Text Available Three invasive anthropophytes, i.e. two vascular plants Digitalis purpurea L. and Impatiens parviflora DC. as well as one moss Orthodontium lineare Schwägr, were recorded on decaying wood and tree-fall disturbances (pit-mound-root plate complex. It contributes only 1.9% to the flora of analyzed habitats (1.1% of moss flora, 2.9% of vascular plant flora and 3.5% of neophytes known in Sudeten Mts. They grew, sporadically and with a low frequency, on 3.5% of studied objects (on 3.1% of decaying logs and stumps and 5.6% of tree-fall disturbances in all types of forest communities in the area of Karkonosze National Park and in the vicinity. Nowadays, invasive neophytes do not pose a threat to diversity of endangered epixylic flora. Described habitats seem to be resistant to penetration by anthropophytes.

  11. The invasive alien leaf miner Cameraria ohridella and the native tree Acer pseudoplatanus: a fatal attraction?

    OpenAIRE

    Péré, Christelle; Augustin, Sylvie; Ted C J Turlings; Kenis, Marc

    2012-01-01

    1. The horse-chestnut leaf miner Cameraria ohridella is an invasive moth in Europe and a serious pest of horse-chestnut Aesculus hippocastanum. The moth also occasionally attacks sycamore maple Acer pseudoplatanus, when situated beside infested horse-chestnuts. 2. The main objective of the present study was to provide an overview of the relationship between C. ohridella and A. pseudoplatanus and to determine whether C. ohridella has the potential to shift to this native tree. 3. In the fiel...

  12. Dendroclimatological comparison of the alien invasive Pinus strobus and native Pinus sylvestris growing on ecological and geographical gradients in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Mácová, Marcela; Tichý, T.

    Praha : Academia, 2007 - (Hartel, H.; Cílek, V.; Herben, T.; Jackson, A.; Williams, R.), s. 225-229 ISBN 978-80-200-1577-8 R&D Projects: GA ČR(CZ) GA526/05/0430; GA AV ČR(CZ) IAA6005801; GA AV ČR(CZ) KJB6005302 Institutional research plan: CEZ:AV0Z60050516 Keywords : invasions * dendroclimatology * gradient Subject RIV: EF - Botanics

  13. Oviposition of the invasive two-spotted leafhopper on an endemic tree: Effects of an alien weed, foliar pubescence, and habitat humidity

    Directory of Open Access Journals (Sweden)

    Andrei V. Alyokhin

    2004-04-01

    Full Text Available The two-spotted leafhopper, Sophonia rufofascia (Kuoh and Kuoh, is an exotic pest from South-East Asia that attacks a wide variety of plant species in Hawaii. Myrica faya Aiton is an aggressive exotic weed that displaces and excludes native plants in Hawaiian forests. It has been argued that because of the high nutritional quality of its foliage, M. faya might facilitate leafhopper invasion of native Hawaiian ecosystems that were originally dominated by the endemic tree Metrosideros polymorpha (Gaudichaud. In the present study, we quantified suitability of M. faya and M. polymorpha as ovipositional hosts for S. rufofascia. Overall, leafhoppers preferred to deposit their eggs into the foliage of M. faya. M. faya presence in the area did not affect leafhopper oviposition on M. polymorpha. Foliar pubescence provided good protection of hirsute morphotypes of M. polymorpha. At the same time, glabrous M. polymorpha morphotypes were quite suitable for leafhopper oviposition. There was no difference in the abundance of leafhopper eggs along a precipitation gradient. Our results confirm that invasion of native Hawaiian forests by the weed M. faya will facilitate their invasion by S. rufofascia. Because of the broad host range characteristic of the two-spotted leafhopper, this build-up may adversely affect a number of endemic plant species growing in native forests.

  14. Chaotic And Periodic Dynamics Of A Slider-Crank Mechanism With Slider Clearance

    Science.gov (United States)

    Farahanchi, F.; Shaw, S. W.

    1994-10-01

    The problem of a planar slider-crank mechanism with clearance at the sliding (prismatic) joint is investigated. In this study the influence of the clearance gap size, bearing friction, crank speed and impact parameters on the response of the system are investigated. Three types of responses are observed: chaotic, transient chaos and periodic. It is shown that chaotic motion is prevalent over a range of parameters which corresponds to high crank speeds and/or low values of bearing friction with relatively ideal impacts. Periodic response is generally observed at low crank speeds and also at low values of the coefficient of restitution. Poincaré maps and statistical profiles of the impact locations and severity are used to characterize the motion and to obtain information regarding possible patterns of wear due to repeated impacts. As expected, chaotic motions lead to quite uniform distributions of impacts, while periodic motions lead to highly localized impact locations. It is also shown that the system response is essentially unpredictable over a wide range of parameters, thus casting doubt on the usefulness of such models for accurate prediction purposes.

  15. Genomics: an important tool for understanding plant invasiveness

    OpenAIRE

    Lei Shang; Yangjin Zhuoga; Ji Yang; Bo Li

    2010-01-01

    Invasive alien species threaten both native ecosystems and local economies and thus, considerable efforts have been expended to understand why certain alien species invade their non-native ecosystems so successfully and what consequences their successful invasions have for the invaded ecosystems. However, the mechanisms underlying the successful invasions by alien plants remain highly controversial as little is known about the determinants of plant invasiveness; this information is critical i...

  16. Impact of alien terrestrial arthropods in Europe. Chapter 5

    Directory of Open Access Journals (Sweden)

    Marc Kenis

    2010-07-01

    Full Text Available This chapter reviews the effects of alien terrestrial arthropods on the economy, society and environment in Europe. Many alien insect and mite species cause serious socio-economic hazards as pests of agriculture, horticulture, stored products and forestry. They may also affect human or animal health. Interestingly, there is relatively little information available on the exact yield and financial losses due to alien agricultural and forestry pests in Europe, particularly at continental scale. Several alien species may have a positive impact on the economy, for example parasitoids and predators introduced for the biological control of important pests. Invasive alien arthropods can also cause environmental hazards. They may affect native biodiversity through various mechanisms, including herbivory, predation, parasitism, competition for resource and space, or as vectors of diseases. They can also affect ecosystem services and processes through cascading effects. However, these ecological impacts are poorly studied, particularly in Europe, where only a handful cases have been reported.

  17. Dynamic Simulation of a Smart Crank and Slider Mechanism

    Institute of Scientific and Technical Information of China (English)

    ZHU Hai-tao; ZHANG Xu; ZHANG Jia-tai; HU Sheng-hai

    2002-01-01

    In this paper, a smart crank and slider mechanism is analyzed mostly from a dynamic view. By means of dynamic explicit finite element method, 3D nonlinear structure is simulated. It is proved that the mechanism can effectively accomplish smart movement prescribed. And in order to ensure reciprocal movement with higher frequency, measures should be taken to avoid over heating of parts. Compared with internal energy, kinetic energy of total rigid body is dominating, and Ydirection equivalent rigid velocity is much higher than X direction velocity. Equivalent rigid velocity of all parts is consistent with respective movement condition. For both energy and velocity, slider effect is dominating. Three direction equivalent inertia force oscillates. Force amplitude in Y-direction is comparitively the greatest.

  18. Dynamic simulation of a smart crank and slider mechanism

    Science.gov (United States)

    Zhu, Hai-Tao; Zhang, Xu; Zhang, Jia-Tai; Hu, Sheng-Hai

    2002-12-01

    In this paper, a smart crank and slider mechanism is analyzed mostly from a dynamic view. By means of dynamic explicit finite element method, 3D nonlinear structure is simulated. It is proved that the mechanism can effectively accomplish smart movement prescribed. And in order to ensure reciprocal movement with higher frequency, measures should be taken to avoid over heating of parts. Compared with internal energy, kinetic energy of total rigid body is dominating, and Y direction equivalent rigid velocity is much higher than X direction velocity. Equivalent rigid velocity of all parts is consistent with respective movement condition. For both energy and velocity, slider effect is dominating. Three direction equivalent inertia force oscillates. Force amplitude in Y-direction is comparitively the greatest.

  19. Hosts and parasites as aliens.

    Science.gov (United States)

    Taraschewski, H

    2006-06-01

    Over the past decades, various free-living animals (hosts) and their parasites have invaded recipient areas in which they had not previously occurred, thus gaining the status of aliens or exotics. In general this happened to a low extent for hundreds of years. With variable frequency, invasions have been followed by the dispersal and establishment of non-indigenous species, whether host or parasite. In the literature thus far, colonizations by both hosts and parasites have not been treated and reviewed together, although both are usually interwoven in various ways. As to those factors permitting invasive success and colonization strength, various hypotheses have been put forward depending on the scientific background of respective authors and on the conspicuousness of certain invasions. Researchers who have tried to analyse characteristic developmental patterns, the speed of dispersal or the degree of genetic divergence in populations of alien species have come to different conclusions. Among parasitologists, the applied aspects of parasite invasions, such as the negative effects on economically important hosts, have long been at the centre of interest. In this contribution, invasions by hosts as well as parasites are considered comparatively, revealing many similarities and a few differences. Two helminths, the liver fluke, Fasciola hepatica, of cattle and sheep and the swimbladder nematode, Anguillicola crassus, of eels are shown to be useful as model parasites for the study of animal invasions and environmental global change. Introductions of F. hepatica have been associated with imports of cattle or other grazing animals. In various target areas, susceptible lymnaeid snails serving as intermediate hosts were either naturally present and/or were introduced from the donor continent of the parasite (Europe) and/or from other regions which were not within the original range of the parasite, partly reflecting progressive stages of a global biota change. In several

  20. Alienation from School

    Science.gov (United States)

    Hascher, Tina; Hagenauer, Gerda

    2010-01-01

    Two studies aimed at understanding the time course of alienation from school and school factors that may influence alienation from school during early adolescence. In Study 1, 434 students from grade 5-8 participated (cross-sectional design). In Study 2, we followed 356 students from grade 6-7 (longitudinal design). The results confirm the…

  1. The aliens are hiding

    Science.gov (United States)

    2015-06-01

    In reply to the physicsworld.com news story “Trail goes cold on alien hotspots, for now” (28 April, http://ow.ly/MeOpZ; see also p5), which described the results of a survey that looked for unexplained pockets of infrared radiation that could have been produced by advanced alien civilizations.

  2. Variable viscosity condition in the modeling of a slider bearing

    OpenAIRE

    Uprety, Kedar Nath; Mancas, Stefan C.

    2014-01-01

    To reduce tear and wear of machinery lubrication is essential. Lubricants form a layer between two surfaces preventing direct contact and reduce friction between moving parts and hence reduce wear. In this short letter the lubrication of two slider bearings with parallel and nonparallel is studied. First, we show that bearings with parallel plates cannot support any load. For bearings with nonparallel plates we are interested on how constant and temperature dependent viscosity affects the pro...

  3. An Alternative Simulation Method for Calculation of Microgas Flows under Flying Head Sliders

    Directory of Open Access Journals (Sweden)

    Ching Shen

    2009-01-01

    Full Text Available The precise knowledge of the force and moment generated by the air squeezed under the read-write slider by the rotating disc is an engineering necessity in designing the air bearing surface slider. This paper reviews methods addressing the thin gas film bearings problem. It firstly reviews briefly the relatively well-known two methods of calculations of the microgas flows under flying head sliders, the generalized Reynolds equation, having given a number of useful results of slider design, and the DSMC method, which is precise and appropriate for the flow of complex configurations but is restricted to miniature (~micrometer size sliders. The main purpose of the paper is to introduce to the reader an alternative method, the information preservation (IP method, for use in simulation of the flows under air bearing surfaces. Some recent results of IP simulation of slider flows published on conference proceedings are introduced here.

  4. Dynamic modeling and identification of a slider-crank mechanism

    Science.gov (United States)

    Ha, Jih-Lian; Fung, Rong-Fong; Chen, Kun-Yung; Hsien, Shao-Chien

    2006-02-01

    In this paper, Hamilton's principle, Lagrange multiplier, geometric constraints and partitioning method are employed to derive the dynamic equations of a slider-crank mechanism driven by a servomotor. The formulation is expressed by only one independent variable and considers the effects of mass, external force and motor electric inputs. Comparing the dynamic responses between the experimental results and numerical simulations, the dynamic modeling gives a wonderful interpretation of a slider-crank mechanism. The parameters of many industrial machines are difficult to obtain if these machines cannot be taken apart. In this paper, a new identification method based on the real-coded genetic algorithm (RGA) is presented to identify the parameters of a slider-crank mechanism. The method promotes the calculation efficiency very much, and is calculated by the real-code without the operations of encoding and decoding. The results of numerical simulations and the experiments prove that the identification method is feasible. Finally, the experimental results by the RGA and the recursive least squares (RLS) are also compared.

  5. Use of non-timber forest products from invasive alien Prosopis species(mesquite) and native trees in South Africa: implications for management

    Institute of Scientific and Technical Information of China (English)

    Ross; T; Shackleton; David; C; Le; Maitre; Brian; W; van; Wilgen; David; M; Richardson

    2015-01-01

    Background: Prosopis species have been introduced to many areas outside their native range to provide benefits to local communities. Several Prosopis species and their hybrids(hereafter "mesquite") have, however, become naturalised and invasive and now generate substantial costs. Management options are limited because of the complex conflicts of interest regarding benefits and costs. Management policies and strategies must take account of such conflicts, but further insights are needed on the dimensions of uses and impacts before such information can be usefully applied. Current policy in South Africa allows for the growth and use of mesquite in one province,but not in others where its control is mandatory. We report on a study to quantify the direct use and perceptions of non-timber forest products(NTFPs) from mesquite and native trees in South Africa.Methods: Semi-structures household interviews were conducted with various stakeholder groups to identify what tree products are used, to ascertain amounts used as well as to gauge perceptions of natural resource use between different tree species and use over time.Results: The direct household use value of native trees was higher than that of mesquite, and local stakeholders attached greater value to products from native trees than from mesquite. Therefore, native trees are and will still be preferentially harvested, and mesquite is unlikely to offer protection to native species by providing an alternative source of products. Mesquite pods do, however, provide valuable additional resources(fodder and medicinal products). The use of both native trees and mesquite is decreasing as the incomes of poorer households rise and as alternative energy sources become available. The benefits and reliance on mesquite are not as high as previously assumed and the impacts from mesquite invasions create large problems for local communities.Conclusion: This study provides further evidence that the impacts of mesquite exceed the

  6. Aliens on Earth. Are reports of close encounters correct?

    OpenAIRE

    Sobkowicz, Pawel

    2012-01-01

    Popular culture (movies, SF literature) and witness accounts of close encounters with extraterrestrials provide a rather bizarre image of Aliens behavior on Earth. It is far from stereotypes of human space exploration. The reported Aliens are not missions of diplomats, scientists nor even invasion fleets; typical encounters are with lone ETs (or small groups), and involve curious behavior: abductions and experiments (often of sexual nature), cattle mutilations, localized killing and mixing in...

  7. Alien marine fishes in Cyprus: update and new records

    OpenAIRE

    Iglésias, Samuel; Frotté, Lou

    2015-01-01

    International audience The Mediterranean Sea, due to its connection to the Red Sea via the Suez Canal, its heavy maritime traffic, and the effects of climate change is a hotspot of invasion by alien species. A survey carried out around Cyprus during September 2014 documented the occurrence of 25 alien fishes. Seven Lessepsian migrants (Hippocampus fuscus Rüppell, 1838, Nemipterus randalli Russell, 1986, Ostorhinchus fasciatus (Shaw, 1790), Parupeneus forsskali (Fourmanoir & Guézé, 1976), P...

  8. A DYNAMIC MODEL FOR A DISC EXCITED BY VERTICALLY MISALIGNED, ROTATING, FRICTIONAL SLIDERS

    Institute of Scientific and Technical Information of China (English)

    OUYANG Huajiang; GU Yuanxian; YANG Haitian

    2004-01-01

    This paper presents a dynamic model for a disc subjected to two sliders rotating in the circumferential direction over the top and bottom surfaces of the disc. The two sliders are vertically misaligned and each is a mass-spring-damper system with friction between the slider and the disc.The moving loads produced by misaligned sliders can destabilise the whole system. Stability analysis is carried out in a simulated example. This model is meant to explain the friction mechanism for generating unstable vibration in many applications involving rotating discs.

  9. 中国西南纵向岭谷区外来入侵植物对生物多样性的影响%The Impacts of the Alien Invasive Plants on Biodiversity in Longitudinal Range-Gorge Region of Southwest China

    Institute of Scientific and Technical Information of China (English)

    陆树刚; 徐成东; 董晓东; 段玉清; 王奕

    2006-01-01

    This paper deals with the impacts of the alien invasive plants on biodiversity in longitudinal range-gorge region of Southwest China. The longitudinal range-gorge region of Southwest China is a critical region for reserving biodiversity and now this region has become a highly endangered region with more than 70 species of alien invasive plants. Among these invasive plants, Ageratina adenophora ( Eupatorium adeophorum ), Chromolaena odorata ( Eupatorium odoratum ), and Tithonia diversifolia are severely imperiling this region. The structure and functions of ecosystems in this region are badly destroyed with the consequences that, the native species are in the face of extinction, and thai agricultural producers, animal husbandry, and forestry activities or even the ecological security are in danger. The damage of alien invasive plants in this region led to a great attention in our country. It is of great practical significance and scientific value to make a comprehensive study of the alien invasive plants of this region, to discover their principles of activity, to slow down their imperiling speed, to wipe out them from this region, and eventually to restore the ecological equilibrium. This paper gives a detailed description of the impacts of the alien invasive plants on the plants species diversity, plants community diversity, ecosystem diversity, agricultural producers, animal husbandry, and forestry. In the end, the authors suggested several solutions to control and wipe out the alien invasive plants.%论述中国西南纵向岭谷区外来入侵植物对生物多样性的影响.中国西南纵向岭谷区是我国生物多样性保护的关键地区.目前,该区域已成为外来植物入侵的重灾区,外来入侵植物种类多达70余种,其中,紫茎泽兰Ageratina adenophora(Eupatorium adenophorum)、飞机草Chromolaena odorata(Eupatorium odoratum)和肿柄菊Tithonia diversifolia等在该区域危害严重,该区域的生态系统的结构与功能遭

  10. Recreational trails as corridors for alien plants in the Rocky Mountains, USA

    Science.gov (United States)

    Wells, Floye H.; Lauenroth, William K.; Bradford, John B.

    2012-01-01

    Alien plant species often use areas of heavy human activity for habitat and dispersal. Roads and utility corridors have been shown to harbor more alien species than the surrounding vegetation and are therefore believed to contribute to alien plant persistence and spread. Recreational trails represent another corridor that could harbor alien species and aid their spread. Effective management of invasive species requires understanding how alien plants are distributed at trailheads and trails and how their dispersal may be influenced by native vegetation. Our overall goal was to investigate the distribution of alien plants at trailheads and trails in the Rocky Mountains of Colorado. At trailheads, we found that although the number of alien species was less than the number of native species, alien plant cover ( x̄=50%) did not differ from native plant cover, and we observed a large number of alien seedlings in the soil seed bank, suggesting that alien plants are a large component of trailhead communities and will continue to be so in the future. Along trails, we found higher alien species richness and cover on trail (as opposed to 4 m from the trail) in 3 out of 4 vegetation types, and we observed higher alien richness and cover in meadows than in other vegetation types. Plant communities at both trailheads and trails, as well as seed banks at trailheads, contain substantial diversity and abundance of alien plants. These results suggest that recreational trails in the Rocky Mountains of Colorado may function as corridors that facilitate the spread of alien species into wildlands. Our results suggest that control of alien plants should begin at trailheads where there are large numbers of aliens and that control efforts on trails should be prioritized by vegetation type.

  11. Functional changes due to invasive species: Food web shifts at shallow Posidonia oceanica seagrass beds colonized by the alien macroalga Caulerpa racemosa

    Science.gov (United States)

    Deudero, S.; Box, A.; Alós, J.; Arroyo, N. L.; Marbà, N.

    2011-06-01

    Multiple stable isotope analyses were used to examine the trophic shifts at faunal assemblages within the invading macroalga Caulerpa racemosa in comparison to established communities of Posidonia oceanica seagrass meadows. Sampling of macrobenthic invertebrates and their potential food sources of algal mats and seagrass meadows in Mallorca (NW Mediterranean) showed differences in species composition of faunal and primary producers among seagrass and C. racemosa. Accordingly, changes in food web structure and trophic guilds were observed, not only at species level but also at community level. The carbon and nitrogen isotope signatures of herbivores, detritivores and deposit feeders confirmed that the seagrass provided a small contribution to the macrofaunal organisms. δ 13C at the P. oceanica seagrass and at the C. racemosa assemblages differed, ranging from -6.19 to -21.20‰ and -2.67 to -31.41‰, respectively. δ 15N at the Caulerpa mats was lower (ranging from 2.64 to 10.45‰) than that at the seagrass meadows (3.51-12. 94‰). Significant differences in isotopic signatures and trophic level among trophic guilds at P. oceanica and C. racemosa were found. N fractionation at trophic guild level considerable differed between seagrass and macroalgae mats, especially for detritivores, deposit feeders, and herbivores. Filter feeders slightly differed with a relatively lower N signal at the seagrass and CR values at community level and at trophic guild level were higher in the C. racemosa invaded habitats indicating an increase in diversity of basal resource pools. C. racemosa did seem to broaden the niche diversity of the P. oceanica meadows it colonised at the base of the food web, may be due to the establishment of a new basal resource. The extent of the effects of invasive species on ecosystem functioning is a fundamental issue in conservation ecology. The observed changes in invertebrate and macrophytic composition, stable isotope signatures of concomitant

  12. Parental Alienation Syndrome

    Directory of Open Access Journals (Sweden)

    Fuat Torun

    2011-09-01

    Full Text Available Children who have been programmed by one parent to be alienated from the other parent are commonly seen in the context of child-custody disputes. Its primary manifestation is the child’s campaign of denigration against a parent, a campaign that has no justification. It is said to result from a combination of a programming (brainwashing parent’s indoctrinations and the child’s own contributions to the vilification of the targeted parent. Many evaluators use the term parental alienation syndrome to refer to the disorder engendered in such children. However, there is significant controversy going on about the validity of parental alienation syndrome. The purpose of this article has been to describe and help to differentiate parental alienation syndrome and abuse for mental health professionals working in the field, and discuss the arguments about the validity of this syndrome.

  13. Parental Alienation Syndrome

    OpenAIRE

    Torun, Fuat

    2011-01-01

    Children who have been programmed by one parent to be alienated from the other parent are commonly seen in the context of child-custody disputes. Its primary manifestation is the child's campaign of denigration against a parent, a campaign that has no justification. It is said to result from a combination of a programming (brainwashing) parent's indoctrinations and the child's own contributions to the vilification of the targeted parent. Many evaluators use the term parental alienation syndro...

  14. Alien plant species list and distribution for Camdeboo National Park, Eastern Cape Province, South Africa

    Directory of Open Access Journals (Sweden)

    Mmoto L. Masubelele

    2009-01-01

    Full Text Available Protected areas globally are threatened by the potential negative impacts that invasive alien plants pose, and Camdeboo National Park (CNP, South Africa, is no exception. Alien plants have been recorded in the CNP since 1981, before it was proclaimed a national park by South African National Parks in 2005. This is the first publication of a list of alien plants in and around the CNP. Distribution maps of some of the first recorded alien plant species are also presented and discussed. To date, 39 species of alien plants have been recorded, of which 13 are invasive and one is a transformer weed. The majority of alien plant species in the park are herbaceous (39% and succulent (24% species. The most widespread alien plant species in the CNP are Atriplex inflata (= A. lindleyi subsp. inflata, Salsola tragus (= S. australis and cacti species, especially Opuntia ficus-indica. Eradication and control measures that have been used for specific problematic alien plant species are described. Conservation implications: This article represents the first step in managing invasive alien plants and includes the collation of a species list and basic information on their distribution in and around the protected area. This is important for enabling effective monitoring of both new introductions and the distribution of species already present. We present the first species list and distribution information for Camdeboo National Park.

  15. The occurrence of alien plant species in field margins in Finland

    OpenAIRE

    Jauni, Miia; Hyvönen, Terho

    2009-01-01

    The results suggest that alien plant species comprise an important part of the biodiversity of Finnish field margins and semi-natural agricultural habitats. The role of field margins as dispersal corridors for invasive alien plants is limited for certain species.

  16. 8 CFR 211.5 - Alien commuters.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Alien commuters. 211.5 Section 211.5 Aliens...: IMMIGRANTS; WAIVERS § 211.5 Alien commuters. (a) General. An alien lawfully admitted for permanent residence.... An alien commuter engaged in seasonal work will be presumed to have taken up residence in the...

  17. Review of alien marine macrophytes in Tunisia

    Directory of Open Access Journals (Sweden)

    Y. R. SGHAIER

    2014-06-01

    Full Text Available In the present study, the list of alien marine macrophytes introduced into Tunisia was updated in the light of available data and new observations. A total of 27 alien marine macrophytes have been recorded so far from Tunisia: 18 Rhodophyta, 3 Ochrophyta, 5 Chlorophyta and 1 Magnoliophyta. For each species, the locality (-ies, the year (or period and the source of the first observation in Tunisia are given. The distribution and the status (casual, cryptogenic, established or questionable of species in Tunisia were evaluated and, where appropriate, discussed. Among them, Hypnea cornuta is reported for the first time from Tunisia. Fourteen alien marine macrophytes are established, whereas seven cryptogenic and two casual species require further investigation. Eleven species are considered as invasive or potentially invasive in the Mediterranean Sea: Acrothamnion preissii, Asparagopsis armata, A. taxiformis Indo-Pacific lineage, Hypnea cornuta, Lophocladia lallemandii, Womersleyella setacea, Caulerpa chemnitzia, C. cylindracea, C. taxifolia, Codium fragile subsp. fragile and Halophila stipulacea. Finally, the case of four questionable species is also discussed.

  18. Inventory of alien marine species of Cyprus (2009

    Directory of Open Access Journals (Sweden)

    S. KATSANEVAKIS

    2012-12-01

    Full Text Available An updated inventory of alien marine species from coastal and offshore waters of Cyprus is presented. Records were compiled based on the existing scientific and grey literature, including HCMR database of Mediterranean alien species, technical reports, scientific congresses, academic dissertations, and websites, as well as on unpublished/personal observations. The listed species were classified in one of five categories: established, invasive, casual, cryptogenic, and questionable. The mode of introduction and the year of first sighting were also reported for each species. Eight new records based on personal observations of the authors were reported (Chondria coerulescens, Neosiphonia sphaerocarpa, Enchelycore anatina, Lagocephalus spadiceus, Lagocephalus suezensis, Scomberomorus commerson, Sillago sihama, and Sphoeroides pachygaster. Nine species, previously reported as aliens in Cypriot waters, were excluded from the inventory for various reasons. Ten established species were characterized as invasive (Caulerpa racemosa var. cylindracea, Cerithium scabridum, Strombus persicus, Trochus erythraeus, Brachidontes pharaonis, Pinctada radiata, Fistularia commersonii, Lagocephalus sceleratus, Siganus luridus, and Siganus rivulatus as they have a substantial impact on biodiversity and/or local economy. The impact of alien marine species in Cyprus is expected to grow in the close future, and further effort directed towards recording alien invasions and their impact will be needed.

  19. The problematic of the geographical expansion of invasive alien species. Analysis and distribution of two species in the province of Avila and initiatives for the minimization of their effects; La problematica de la expansion geografica de las especies exoticas invasoras. Analisis y distribucion de dos especies en la provincia de Avila e iniciativas para la minimizacion de sus efectos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Quiroga, F.

    2012-07-01

    Invasive alien species currently constitute a serious threat for biodiversity and large economic losses. The risks associated to its introduction are in constant growth due to the increase of trade, tourism, transport and market globalization. Examples of these species can be found in the fauna such as the red swamp or Louisiana crawfish and in the flora as the ailanthus, which affect a great deal of the Spanish provinces, as that of Avila where they will be analyzed in greater detail. Because of it, the development of an effective action against its invasion through a series of measures, as well as the development and implementation of a legal framework, in addition to the information of the citizens are essential aspects for eradication or to mitigate its expansion. (Author)

  20. Comparative study of closely related \\kur{Asteraceae} species with different invasive status

    OpenAIRE

    ŠAFARČÍKOVÁ, Simona

    2008-01-01

    Complex of 4 closely related Asteraceae species with different invasive status (native Bidens tripartita, casual aliens Cosmos bipinnatus, Coreopis tinctoria and invasive alien Bidens frondosa) was studied to clarify the invasive success of Bidens frondosa and to assess the invasive potential of both unsuccessful aliens. Among studied characteristics were included: reproductive traits (germination in different regimes, seed viability and seed production), growth characteristics (relative grow...

  1. Poles Apart: Comparing Trends of Alien Hymenoptera in New Zealand with Europe (DAISIE)

    OpenAIRE

    Ward, Darren; Edney-Browne, Emma

    2015-01-01

    Developing generalisations of invasive species is an important part of invasion biology. However, trends and generalisations from one part of the world may not necessarily hold elsewhere. We present the first inventory and analysis of all Hymenoptera alien to New Zealand, and compare patterns from New Zealand with those previously published from Europe (DAISIE). Between the two regions there was broad correlation between families with the highest number of alien species (Braconidae, Encyrtida...

  2. Parental Alienation Syndrome

    OpenAIRE

    Fuat Torun

    2011-01-01

    Children who have been programmed by one parent to be alienated from the other parent are commonly seen in the context of child-custody disputes. Its primary manifestation is the child’s campaign of denigration against a parent, a campaign that has no justification. It is said to result from a combination of a programming (brainwashing) parent’s indoctrinations and the child’s own contributions to the vilification of the targeted parent. Many evaluators use the term parental alienation syndro...

  3. The cobblers stick to their lasts : pollinators prefer native over alien plant species in a multi-species experiment

    OpenAIRE

    Chrobock, Thomas; Winiger, Pius; Fischer, Markus; van Kleunen, Mark

    2013-01-01

    The majority of plant species rely, at least partly, on animals for pollination. Our knowledge on whether pollinator visitation differs between native and alien plant species, and between invasive and non-invasive alien species is still limited. Additionally, because numerous invasive plant species are escapees from horticulture, the transition from human-assisted occurrence in urbanized habitats to unassisted persistence and spread in (semi-)natural habitats requires study. To address whethe...

  4. Retractable tool bit having slider type catch mechanism

    Science.gov (United States)

    Voellmer, George M.

    1992-12-01

    A retractable tool bit assembly utilized in connection with a robotic gripper type end-effector is presented. The apparatus includes one or more spring loaded nestable or telescoping tubular sections together with a catch mechanism for capturing and holding the toll, such as an allen key, in its retracted position. The innermost tubular section includes a threshold cap and engages and holds the tool. The catch mechanism consists of a slider type mechanism located adjacent a relatively larger outer base section and includes means for engaging a conically or mushroom shaped rear end portion of the tool when the telescoping sections are moved to a retracted or parked position. The catch mechanism is released upon actuation of a rotary tool drive motor coupled to a circular mount and which holds the base section. When released all the telescoping sections including the tool extends fully outward to a use position.

  5. Alien plant species along watercourses in the Natura 2000 network

    OpenAIRE

    Monty, Arnaud; Aimont, Hélène; Mahy, Grégory

    2014-01-01

    Natura 2000 is the centerpiece of EU nature and biodiversity policy. It is a European wide network of nature protection areas aiming at assuring the long-term survival of Europe's most valuable and threatened species and habitats. However, alien plants do not stop their spread at the border of protection areas and invasive plants are reported to threaten aquatic and riparian ecosystems. Our study aimed at assessing the plant invasion threat along watercourses within the Natura 2000 in Sout...

  6. Aliens and atheism

    Science.gov (United States)

    Campos, Sergio; de Muynck, Willem; Virginia; Peerally, Abed; Tyler, David; Stephen

    2014-11-01

    In reply to the physicsworld.com blog post "Aliens and atheists" (2 October, http://ow.ly/CQzu4), about a survey that found that atheists are more likely than religious people to believe that life exists on other planets.

  7. Monitoring Biological Invasions in Freshwater Habitats

    OpenAIRE

    Vilà, Montserrat; García-Berthou, Emili

    2010-01-01

    Alien species invading freshwater systems are causing major changes in biodiversity worldwide. Some alien species have been used as indicators of water quality and environmental degradation. We discuss the reasons for monitoring invasive species beyond their use as ecological indicators, and offer guidance on the design of appropriate long-term monitoring schemes. Monitoring plays an essential role in providing an early warning system, because eradication of alien species at the early stages ...

  8. Characteristics of HgCdTe epilayer grown by LPE using horizontal slider

    Indian Academy of Sciences (India)

    J K Radhakrishnan; S Sitharaman; S C Gupta

    2002-11-01

    The characteristics of HgCdTe epilayers grown in a modified horizontal slider system, are reported here. The surface morphology of the grown layers, their IR transmission characteristics, depth and lateral compositional uniformity, structural and electrical characteristics are discussed.

  9. Characterising performance of TEM compatible nanomanipulation slip-stick inertial sliders against gravity

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, A J; Wang, J J; Gay, R; Inkson, B J [Department of Engineering Materials, University of Sheffield. Sheffield SI 3JD (United Kingdom)], E-mail: a.lockwood@sheffield.ac.uk

    2008-08-15

    Slick-stick inertial sliders have been used in the manufacture of a novel miniaturised nanomanipulation and nanoindentation system. This has been designed to perform sub-micron localised in-situ deformation studies in a high resolution transmission electron microscope (HRTEM). Coarse position is realised by three independent sliders which are set mutually perpendicular to one another (x, y and z) with a range > lmm and resolution <100nm In this paper we discuss the effect that gravity has on the performance of the nanomanipulation slip-stick inertial drives by monitoring displacement rate, resolution and the effect of the normal force across the slip-stick slider. We report on the successful actuation of slip-stick sliders operated in a vertical orientation.

  10. Lubrication of a Porous Exponential Slider Bearing by Ferrofluid with Slip Velocity

    OpenAIRE

    SHAH, Rajesh C.

    2003-01-01

    A bearing with its slider in exponential form and stator with a porous facing of uniform thickness was analysed using a ferrofluid lubricant and considering slip velocity. Expressions for dimensionless pressure, load capacity, friction on the slider, coefficient of friction and for the position of the centre of pressure were obtained. Computed values of load capacity, friction, coefficient of friction and the position of the centre of pressure are displayed in graphical form. The lo...

  11. Modeling and Simulation of a Slider Crank Mechanism with a Flexible Extensible Link

    Science.gov (United States)

    Dupac, M.; Noroozi, S.

    In this paper the modelling of a slider-crank mechanism with an extensible flexible link is presented and its dynamical behaviour analyzed. The link flexibility is modelled using extensible rigid links and rotational springs. The equations of motion with and without slider clearance are written. Accurate simulation of the extensible mechanism is performed to study its possible performance and behaviour under the combined effect of different parameters. A dynamic analysis is carried out in order to understand its behaviour under motion reconfiguration.

  12. ELNAIS meets EASIN: distribution of marine alien species in Greece using EASIN mapping services and ELNAIS spatial data

    OpenAIRE

    Katsanevakis, S.; Zenetos, A.; D. POURSANIDIS; A.L. NUNES; Deriu, I.; Bogucarskis, K.; A. C. Cardoso

    2013-01-01

    The European Alien Species Information Network (EASIN) was created with the aim to provide easy access to accurate information on alien species in Europe. EASIN allows the retrieval of spatial information from existing online data providers in order to produce integrated georeferenced distribution maps of alien species in Europe. In November 2012, a new data provider, the Ellenic Network on Aquatic Invasive Species (ELNAIS), joined EASIN; this has significantly increased the available georefe...

  13. 22 CFR 41.71 - Transit aliens.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Transit aliens. 41.71 Section 41.71 Foreign... NATIONALITY ACT, AS AMENDED Transit Aliens § 41.71 Transit aliens. (a) Transit aliens—general. An alien is classifiable as a nonimmigrant transit alien under INA 101(a) (15) (C) if the consular officer is...

  14. 8 CFR 244.4 - Ineligible aliens.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Ineligible aliens. 244.4 Section 244.4 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS TEMPORARY PROTECTED STATUS FOR NATIONALS OF DESIGNATED STATES § 244.4 Ineligible aliens. An alien is ineligible for...

  15. 8 CFR 236.13 - Ineligible aliens.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Ineligible aliens. 236.13 Section 236.13 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF INADMISSIBLE AND DEPORTABLE ALIENS; REMOVAL OF ALIENS ORDERED REMOVED Family Unity Program §...

  16. 8 CFR 232.3 - Arriving aliens.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL AND MENTAL EXAMINATION § 232.3 Arriving aliens. When a district director has reasonable...

  17. Floristic analysis and distribution pattern of alien plants in Shandong Province,eastern China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Alien plants,along with their ecological invasion and negative impacts on indigenous species diversity and ecosystems,are one of the major topics of current ecological research.The background investigation and floristic analysis of alien plants are very important and form an essential database for invasive species research,control and management.In our study these alien plants,mainly collected from the Flora of Shandong Province,combined with a field survey,were studied and analyzed.We also established a floristic database.Our findings are as follows:1) there are a total of 827 alien species,belonging to 122 families and 416 genera of which 348 species were imported from other countries;2) a high proportion,39.0% of the flora in Shandong Province,is accounted for by alien species,of which 21 dominant families largely belong to the Rosaceae,Leguminosae,Asteraceae and Gramineae;3) the diverse geographical distribution of the genera is characterized by species dominant in the temperate zone which accounts for 52.5% of the alien plants and 44.1% of the plants from the tropics;4) the origins of alien species and their centralized distribution in Shandong together show the anthropogenic effect and unnatural impacts on the environment and 5) in Shandong Province,alien plants originate more from temperate zones than from any other areas of the world.

  18. A Letter to Alien

    Institute of Scientific and Technical Information of China (English)

    邱政榜

    2012-01-01

    Dear Alien, 1 am sorry to hear that you have some problems. I hear you argued with your best friend. 1 think you could call him up or go to his home. You could write him a letter. And you could tell him you are sony. Or maybe you could give him a ticket to a ball game. I am sure you will get on well with him again.

  19. Alien plant species in Svalbard

    OpenAIRE

    Roalsø, Erik Roall

    2012-01-01

    Increased introductions combined with favorable growing conditions may enhance the presence and increase the success of alien plant species in High Arctic settlements. With global warming, the presence and success of alien plants in Polar Regions might expand beyond the confinement of human settlements and cause problems for native species and ecosystems. Presence and abundance of alien and native vascular plant species were recorded, from chosen study sites, in the Svalbard settlements of Ba...

  20. Bending mechanics of the red-eared slider turtle carapace.

    Science.gov (United States)

    Achrai, Ben; Bar-On, Benny; Wagner, H Daniel

    2014-02-01

    The turtle shell is a natural shield that possesses complex hierarchical structure, giving rise to superior mechanical properties. The keratin-covered boney top (dorsal) part of the shell, termed carapace, is composed of rigid sandwich-like ribs made of a central foam-like interior flanked by two external cortices. The ribs are attached to one another in a 3-D interdigitated manner at soft unmineralized collagenous sutures. This unique structural combination promotes sophisticated mechanical response upon predator attacks. In the present study mechanical bending tests were performed to examine the static behavior of the red-eared slider turtle carapace, in different orientations and from various locations, as well as from whole-rib and sub-layer regions. In addition, the suture properties were evaluated as well and compared with those of the rib. A simplified classical analysis was used here to rationalize the experimental results of the whole rib viewed as a laminated composite. The measured strength (~300MPa) and bending modulus (~7-8.5GPa) of the rib were found to be of the same order of magnitude as the strength and modulus of the cortices. The theoretical prediction of the ribs' moduli, predicted in terms of the individual sub-layers moduli, agreed well with the experimental results. The suture regions were found to be more compliant and weaker than the ribs, but comparatively tough, likely due to the interlocking design of the boney zigzag elements. PMID:24333673

  1. Bark beetles and pinhole borers (Curculionidae, Scolytinae, Platypodinae alien to Europe

    Directory of Open Access Journals (Sweden)

    Lawrence Kirkendall

    2010-09-01

    Full Text Available Invasive bark beetles are posing a major threat to forest resources around the world. DAISIE’s web-based and printed databases of invasive species in Europe provide an incomplete and misleading picture of the alien scolytines and platypodines. We present a review of the alien bark beetle fauna of Europe based on primary literature through 2009. We find that there are 18 Scolytinae and one Platypodinae species apparently established in Europe, from 14 different genera. Seventeen species are naturalized. We argue that Trypodendron laeve, commonly considered alien in Europe, is a native species; conversely, we hypothesize that Xyleborus pfeilii, which has always been treated as indigenous, is an alien species from Asia. We also point out the possibility that the Asian larch bark beetle Ips subelongatus is established in European Russia. We show that there has been a marked acceleration in the rate of new introductions to Europe, as is also happening in North America: seven alien species were first recorded in the last decade. We present information on the biology, origins, and distributions of the alien species. All but four are polyphagous, and 11 are inbreeders: two traits which increase invasiveness. Eleven species are native to Asia, six to the Americas, and one is from the Canary Islands. The Mediterranean is especially favorable for invasives, hosting a large proportion of the aliens (8/18. Italy, Spain and France have the largest numbers of alien species (15, 10 and 7 respectively. We point out that the low numbers for at least some countries is likely due to under-reporting. Finally, we discuss the difficulties associated with identifying newly invasive species. Lack of good illustrations and keys hinder identification, particularly for species coming from Asia and Oceania.

  2. Aliens on Earth. Are reports of close encounters correct?

    CERN Document Server

    Sobkowicz, Pawel

    2012-01-01

    Popular culture (movies, SF literature) and witness accounts of close encounters with extraterrestrials provide a rather bizarre image of Aliens behavior on Earth. It is far from stereotypes of human space exploration. The reported Aliens are not missions of diplomats, scientists nor even invasion fleets; typical encounters are with lone ETs (or small groups), and involve curious behavior: abductions and experiments (often of sexual nature), cattle mutilations, localized killing and mixing in human society using various methods. Standard scientific explanations of these social memes point to influence of cultural artifacts (movies, literature) on social imagination, projection of our fears and observations of human society, and, in severe cases, psychic disorder of the involved individuals. In this work we propose an alternate explanation, claiming that the memes might be the result of observations of actual behavior of true Aliens, who, visiting Earth behave in a way that is then reproduced by such memes. Th...

  3. Functional differences between native and alien species : a global-scale comparison

    NARCIS (Netherlands)

    Ordonez, Alejandro; Wright, Ian J.; Olff, Han; Kitajima, Kaoru

    2010-01-01

    1. A prevalent question in the study of plant invasions has been whether or not invasions can be explained on the basis of traits. Despite many attempts, a synthetic view of multi-trait differences between alien and native species is not yet available. 2. We compiled a database of three ecologically

  4. Brechtian Alienation in Videogames

    Directory of Open Access Journals (Sweden)

    Daniel Joseph Dunne

    2014-11-01

    Full Text Available Immersion is constantly being broken in video games via the intrusion of mechanics and features that cause no end of distraction, breaking the player’s engagement in both the game’s narrative and in the gameplay. Yet these breaks are an integral part of games, whether through loading, saving or any other mechanical system that detracts from the playing the core game. These aren’t analysed as thoroughly as they could be in current game academia. However Bertolt Brecht’s “Verfremdungseffekt”, or distancing effect, provides a much needed foundation in the analysis of these sections within games that provoke a feeling of alienation.

  5. Analysis of the slider force calibration procedure for the British Pendulum Skid Resistance Tester

    Science.gov (United States)

    Hiti, Miha; Ducman, Vilma

    2014-02-01

    British Pendulum Skid Resistance Testers are being used for the determination of the slip/skid resistance of surfaces by laboratories all around the world in different fields. The instrument itself can give reproducible results; however, the comparison of results obtained by different instruments can show large deviations. This paper presents a comparison of the performance of four pendulum testers, the investigation of requirements in international standards and the analysis of the calibration procedure for the determination of the slider force/deflection characteristics. The slider force/deflection characteristics were measured manually and also automatically with a uniaxial tensile/compression testing machine using different techniques. The results highlight the importance of the slider force/deflection characteristic shape and its influence on the results indicated by the pendulum tester and outline inconsistencies in different international standards describing the same device and its requirements. Presented results show good reproducibility and comparability of the pendulum test results when calibration is performed with the assembled pendulum either manually or automatically, provided the stricter slider force characteristic envelope requirements are taken into consideration. The actual slider force should be stable from 1.5 mm deflection onwards.

  6. Analysis of the slider force calibration procedure for the British Pendulum Skid Resistance Tester

    International Nuclear Information System (INIS)

    British Pendulum Skid Resistance Testers are being used for the determination of the slip/skid resistance of surfaces by laboratories all around the world in different fields. The instrument itself can give reproducible results; however, the comparison of results obtained by different instruments can show large deviations. This paper presents a comparison of the performance of four pendulum testers, the investigation of requirements in international standards and the analysis of the calibration procedure for the determination of the slider force/deflection characteristics. The slider force/deflection characteristics were measured manually and also automatically with a uniaxial tensile/compression testing machine using different techniques. The results highlight the importance of the slider force/deflection characteristic shape and its influence on the results indicated by the pendulum tester and outline inconsistencies in different international standards describing the same device and its requirements. Presented results show good reproducibility and comparability of the pendulum test results when calibration is performed with the assembled pendulum either manually or automatically, provided the stricter slider force characteristic envelope requirements are taken into consideration. The actual slider force should be stable from 1.5 mm deflection onwards. (paper)

  7. Toxicokinetics of selenium in the slider turtle, Trachemys scripta.

    Science.gov (United States)

    Dyc, Christelle; Far, Johann; Gandar, Frédéric; Poulipoulis, Anastassios; Greco, Anais; Eppe, Gauthier; Das, Krishna

    2016-05-01

    Selenium (Se) is an essential element that can be harmful for wildlife. However, its toxicity in poikilothermic amniotes, including turtles, remains poorly investigated. The present study aims at identifying selenium toxicokinetics and toxicity in juvenile slider turtles (age: 7 months), Trachemys scripta, dietary exposed to selenium, as selenomethionine SeMet, for eight weeks. Non-destructive tissues (i.e. carapace, scutes, skin and blood) were further tested for their suitability to predict selenium levels in target tissues (i.e. kidney, liver and muscle) for conservation perspective. 130 juvenile yellow-bellied slider turtles were assigned in three groups of 42 individuals each (i.e. control, SeMet1 and SeMet2). These groups were subjected to a feeding trial including an eight-week supplementation period SP 8 and a following 4-week elimination period EP 4 . During the SP8, turtles fed on diet containing 1.1 ± 0.04, 22.1 ± 1.0 and 45.0 ± 2.0 µg g(-1) of selenium (control, SeMet1 and SeMet2, respectively). During the EP4, turtles fed on non-supplemented diet. At different time during the trial, six individuals per group were sacrificed and tissues collected (i.e. carapace, scutes, skin, blood, liver, kidney, muscle) for analyses. During the SP8 (Fig. 1), both SeMet1 and SeMet2 turtles efficiently accumulated selenium from a SeMet dietary source. The more selenium was concentrated in the food, the more it was in the turtle body but the less it was removed from their tissues. Moreover, SeMet was found to be the more abundant selenium species in turtles' tissues. Body condition (i.e. growth in mass and size, feeding behaviour and activity) and survival of the SeMet1 and SeMet2 turtles seemed to be unaffected by the selenium exposure. There were clear evidences that reptilian species are differently affected by and sensitive to selenium exposure but the lack of any adverse effects was quite unexpected. Fig. 1 Design of the feeding trial. T, Time of

  8. Unveiling the status of alien animals in the arid zone of Asia

    Science.gov (United States)

    Zhang, Lyubing

    2016-01-01

    Biological invasion is one of the most threatening factors for biodiversity conservation. Lacking information on alien species in certain regions of the world hampers a balanced understanding of invasion processes and efficient data exchange among stakeholders. Current knowledge gaps are in need of urgent concern. We therefore conducted a review on alien animals in Xinjiang, an unknown region of invasion ecology. Xinjiang lies in the heartland of the Asian continent, covering an area of 1,664,900 km2. In the past 64 years, 128 alien animal species were recorded in this region, 39% of which became invasive and led to loss of native biodiversity. Most of these species were introduced through diversification of local agriculture and aquaculture. This process was aggravated by improving transportation and flourishing trade. Multiple linear regression models and correlation analysis were run for explaining influence of environmental and anthropogenic factors on status of alien animals: economically developed areas with abundant water resource, oases in particular, were prone to be hotspots of alien animal species in this arid and semi-arid region. This study also revealed that taxonomically biased and lagged research were critical problems that impeded studies on biological invasions in Xinjiang, and proposed feasible solutions. PMID:26793423

  9. Structure design and establishment of database application system for alien species in Shandong Province, China

    Institute of Scientific and Technical Information of China (English)

    GUO Wei-hua; LIU Heng; DU Ning; ZHANG Xin-shi; WANG Ren-qing

    2007-01-01

    This paper presents a case study on structure design and establishment of database application system for alien species in Shandong Province, integrating with Geographic Information System, computer network, and database technology to the research of alien species. The modules of alien species database, including classified data input, statistics and analysis, species pictures and distribution maps,and out date input, were approached by Visual Studio.net 2003 and Microsoft SQL server 2000. The alien species information contains the information of classification, species distinction characteristics, biological characteristics, original area, distribution area, the entering fashion and route, invasion time, invasion reason, interaction with the endemic species, growth state, danger state and spatial information, i.e.distribution map. Based on the above bases, several models including application, checking, modifying, printing, adding and returning models were developed. Furthermore, through the establishment of index tables and index maps, we can also spatially query the data like picture,text and GIS map data. This research established the technological platform of sharing information about scientific resource of alien species in Shandong Province, offering the basis for the dynamic inquiry of alien species, the warning technology of prevention and the fast reaction system. The database application system possessed the principles of good practicability, friendly user interface and convenient usage. It can supply full and accurate information inquiry services of alien species for the users and provide functions of dynamically managing the database for the administrator.

  10. Space, time and aliens: Charting the dynamic structure of Galápagos pollination networks

    OpenAIRE

    Traveset, Anna; Chamorro, Susana; Olesen, Jens M.; Heleno, Rubén H.

    2015-01-01

    © The Authors 2015. Oceanic archipelagos are threatened by the introduction of alien species which can severely disrupt the structure, function and stability of native communities. Here we investigated the pollination interactions in the two most disturbed Galápagos Islands, comparing the three main habitats and the two seasons, and assessing the impacts of alien plant invasions on network structure.We found that the pollination network structure was rather consistent between the two islands,...

  11. Insights into invasion and restoration ecology: Time to collaborate towards a holistic approach to tackle biological invasions

    Directory of Open Access Journals (Sweden)

    Mirijam Gaertner

    2012-02-01

    Full Text Available The aim of our study is to provide an integrated framework for the management of alien plant invasions, combining insights and experiences from the fields of invasion and restoration ecology to enable more effective management of invasive species. To determine linkages between the scientific outputs of the two disciplines we used an existing data base on restoration studies between 2000 and 2008 and did a bibliometric analysis. We identified the type of restoration applied, determined by the aim of the study, and conducted a content analysis on 208 selected studies with a link to biological invasions (invasion-restoration studies. We found a total of 1075 articles on ecosystem restoration, with only eight percent of the studiesthe main objective to control alien invasions. The content analysis of 208 invasion-restoration studies showed that the majority of the studies focused on causes of degradation other than alien invasions. If invaders were referred to as the main driver of degradation, the prevalent cause for degradation was invaders outcompeting and replacing native species. Mechanical control of alien plant invasions was by far the most common control method used. Measures that went beyond the removal of alien plants were implemented in sixty-five percent of the studies.Although invasion control was not as common as other types of restoration, a closer look at the sub-group of invasion-restoration studies shows a clear link between restoration and invasion ecology. Concerns, as identified in the literature review, are firstly that restoration activities mostly focus on controlling the invader while other underlying causes for degradation are neglected, and secondly that the current approach of dealing with alien invasions lacks a combination of theoretical and practical aspects. We suggest that closer collaboration between invasion and restoration ecologists can help to improve the management of alien plant invasions. We conclude with a

  12. The occurrence of alien species in the settlement areas of the Kampinos National Park and its vicinity (Central Poland)

    OpenAIRE

    Kirpluk Izabella; Bomanowska Anna

    2015-01-01

    Studies aimed at the identification of the range and method of spread of alien plant species in settlement areas in Kampinos National Park (KNP) and its immediate vicinity were carried out in years 2012-2014. Special emphasis was put on surveying the sites of invasive alien species (IAS), and diagnosing potential threats posed to the natural and semi-natural vegetation of the national park by the IAS present in rural areas. We found 53 alien vascular plant species, including 40 invasive taxa ...

  13. 8 CFR 245a.32 - Ineligible aliens.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Ineligible aliens. 245a.32 Section 245a.32 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS ADJUSTMENT OF STATUS TO... IMMIGRATION AND NATIONALITY ACT LIFE Act Amendments Family Unity Provisions § 245a.32 Ineligible aliens....

  14. 8 CFR 1244.4 - Ineligible aliens.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Ineligible aliens. 1244.4 Section 1244.4 Aliens and Nationality EXECUTIVE OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT OF JUSTICE IMMIGRATION REGULATIONS TEMPORARY PROTECTED STATUS FOR NATIONALS OF DESIGNATED STATES § 1244.4 Ineligible aliens. An...

  15. 28 CFR 21.3 - Aliens.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Aliens. 21.3 Section 21.3 Judicial Administration DEPARTMENT OF JUSTICE WITNESS FEES § 21.3 Aliens. (a) Aliens entitled to payment of $30 per day. The following aliens are entitled to witness fees and allowances provided in § 21.4: (1)...

  16. Wanted and unwanted nature: Invasive plants and the alien–native dichotomy

    OpenAIRE

    Qvenild, Marte

    2013-01-01

    This thesis explores how plants are perceived and categorised as alien, invasive and native respectively at individual, professional, and political levels. The thesis demonstrates how perceptions of and interactions with plants happen in ways that do not always correspond to the environmental authorities definitions of alienness and nativeness. As alienness and nativeness are concepts that are spatiotemporal in character, the labelling of plants as alien or native often involve value-laden di...

  17. Geographical Constraints Are Stronger than Invasion Patterns for European Urban Floras

    OpenAIRE

    Ricotta, Carlo; Celesti-Grapow, Laura; Kühn, Ingolf; Rapson, Gillian; Pyšek, Petr; La Sorte, Frank A.; Thompson, Ken

    2014-01-01

    Understanding the mechanisms that affect invasion success of alien species is an important prerequisite for the effective management of present and future aliens. To gain insight into this matter we asked the following questions: Are the geographical patterns of species distributions in urban floras different for native compared with alien plant species? Does the introduction of alien species contribute to the homogenization of urban floras? We used a Mantel test on Jaccard dissimilarity matr...

  18. Entropy generation in non-Newtonian fluid flow in a slider bearing

    Indian Academy of Sciences (India)

    M Pakdemirli; B S Yilbas; M Yurusoy

    2004-12-01

    In the present study, entropy production in flow fields due to slider bearings is formulated. The rate of entropy generation is computed for different fluid properties and geometric configurations of the slider bearing. In order to account for the non-Newtonian effect, a special type of third-grade fluid is considered. It is found that the rate of entropy generation is influenced significantly by the height of the bearing clearance and the non-Newtonian parameter of the fluid.

  19. Radiation resistivity characteristics of a linear motion guide using the rice-bran-ceramic slider

    International Nuclear Information System (INIS)

    High power proton beam in the J-PARC accelerator raises heavy radiation in the accelerator's tunnel in case of beam manipulation at the injection or the extraction section. Stable operation with reliable devices is one of the important themes of the J-PARC although the high dose situation. This report shows a result of gamma ray irradiation examination about a linear motion guide using a unique slider, called RB-ceramic slider, to stand the high dose condition. The drive performance has been confirmed no deterioration through the dose of up to 50 MGy. (author)

  20. Impacts écologiques d'espèces invasives étrangères sur les abeilles

    OpenAIRE

    Stout, Jane C.; Morales, Carolina L.

    2009-01-01

    International audience We review direct and indirect impacts of invasive alien species (focussing on plants and insects) on native bees worldwide. Although there is a rapidly growing body of research into the effects of invasive alien plants on native plant pollination via disruption of native mutualisms, there has been little research on the impacts of invasive alien plants directly on bees. Such impacts are likely to vary according to the taxon of plant, the functional specificity of the...

  1. Alien Hand Syndrome.

    Science.gov (United States)

    Hassan, Anhar; Josephs, Keith A

    2016-08-01

    Alien hand syndrome (AHS) is a rare disorder of involuntary limb movement together with a sense of loss of limb ownership. It most commonly affects the hand, but can occur in the leg. The anterior (frontal, callosal) and posterior variants are recognized, with distinguishing clinical features and anatomical lesions. Initial descriptions were attributed to stroke and neurosurgical operations, but neurodegenerative causes are now recognized as most common. Structural and functional imaging and clinical studies have implicated the supplementary motor area, pre-supplementary motor area, and their network connections in the frontal variant of AHS, and the inferior parietal lobule and connections in the posterior variant. Several theories are proposed to explain the pathophysiology. Herein, we review the literature to update advances in the understanding of the classification, pathophysiology, etiology, and treatment of AHS. PMID:27315251

  2. The zone of alienation

    International Nuclear Information System (INIS)

    Ten years after the nuclear disaster, people still live and die in Chernobyl. Thousands of people continue to live and work there. Roughly 500 have moved back into their old homes inside the alienation zone. Fewer than half still alive. Medical researchers in the area insist that immune systems are weakened by doses of radiation far lower than previously thought. However, an European Union sponsored study concluded that Chernobyl's toll has been exaggerated. Thus, while 760 children in the contaminated area have developed thyroid cancer, only three have died as a result. Yet in and around Chernobyl, people carry on their lives and the Ukrainian Government says it can't afford to close the plant without billions of dollars in Western aid. ills

  3. Complete mitochondrial genomes of the yellow-bellied slider turtle Trachemys scripta scripta and anoxia tolerant red-eared slider Trachemys scripta elegans.

    Science.gov (United States)

    Yu, Danna; Fang, Xindong; Storey, Kenneth B; Zhang, Yongpu; Zhang, Jiayong

    2016-05-01

    The complete mitochondrial genomes of the yellow-bellied slider (Trachemys scripta scripta) and anoxia tolerant red-eared slider (Trachemys scripta elegans) turtles were sequenced to analyze gene arrangement. The complete mt genomes of T. s. scripta and elegans were circular molecules of 16,791 bp and 16,810 bp in length, respectively, and included an A + 1 frameshift insertion in ND3 and ND4L genes. The AT content of the overall base composition of scripta and elegans was 61.2%. Nucleotide sequence divergence of the mt-genome (p distance) between scripta and elegans was 0.4%. A detailed comparison between the mitochondrial genomes of the two subspecies is shown. PMID:25541313

  4. A piezoelectric linear ultrasonic motor with the structure of a circular cylindrical stator and slider

    Science.gov (United States)

    Sun, Dongming; Wang, Sheng; Sakurai, Junpei; Choi, Kee-Bong; Shimokohbe, Akira; Hata, Seiichi

    2010-04-01

    A piezoelectric linear ultrasonic motor is proposed, with a cylindrical stator and slider structure. The length and diameter of the motor are about 10 and 1.5 mm, respectively. The stator consists of two piezoelectric ceramic (PZT) tubes connected by a thin film metallic glass (TFMG) pipe. The stator is designed based on theoretical analyses and finite element method (FEM) simulation. The traveling wave propagation is obtained in the FEM simulation under the proper geometrical sizes, suitable boundary conditions and driving voltage signals. The trajectories of particles on the TFMG pipe are elliptical motion. In the experiment, a 25 µm thick TFMG pipe is fabricated using the rotating magnetron sputtering technique and the vibration characteristics of the stator are measured by a laser Doppler vibrometer (LDV) system. Bidirectional motion of the slider is observed around 600 kHz, the maximum velocity is near to 40 mm s - 1 at 50 Vp-p for the loose slider and the maximum output force is 6 mN at 70 Vp-p for the tight slider.

  5. Dynamic Balancing of a Single Crank-Double Slider Mechanism with Symmetrically Moving Couplers

    NARCIS (Netherlands)

    Wijk, van der V.; Herder, J.L.; Pisla, Doina; Ceccarelli, Marco; Husty, Manfred; Corves, Burkhard

    2010-01-01

    This article presents a systematic investigation of the dynamic balancing of a singlecrank-double slider mechanism of which the coupler links have symmetric motion. From the equationsof the linear momentum and angular momentum the force balance conditions and momentbalance conditions are derived. Bo

  6. A self-running standing wave-type bidirectional slider for the ultrasonically levitated thin linear stage.

    Science.gov (United States)

    Koyama, Daisuke; Takei, Hiroyuki; Nakamura, Kentaro; Ueha, Sadayuki

    2008-08-01

    A slider for a self-running standing wave-type, ultrasonically levitated, thin linear stage is discussed. The slider can be levitated and moved using acoustic radiation force and acoustic streaming. The slider has a simple configuration and consists of an aluminum vibrating plate and a piezoelectric zirconate titanate (PZT) element. The large asymmetric vibration distribution for the high thrust and levitation performance was obtained by adjusting the configuration determined by finite elemental analysis (FEA). As a preliminary step, the computed results of the sound pressure distribution in the 1-mm air gap by FEA was com pared with experimental results obtained using a fiber optic probe. The direction of the total driving force for the acoustic streaming in the small air gap was estimated by the sound pressure distribution calculated by FEA, and it was found that the direction of the acoustic streaming could be altered by controlling the vibration mode of the slider. The flexural standing wave could be generated along the vibrating plate near the frequencies predicted based on the FEA results. The slider could be levitated by the acoustic radiation force radiated from its own vibrating plate at several frequencies. The slider could be moved in the negative and positive directions at 68 kHz and 69 kHz, which correspond to the results computed by FEA, with the asymmetric vibration distribution of the slider's vibrating plate. Larger thrust could be obtained with the smaller levitation distance, and the maximum thrust was 19 mN. PMID:18986924

  7. Communication on invasive species

    OpenAIRE

    2014-01-01

    Like any other environmental problem, control of invasive species needs to be based on awareness of the implications by the public and by private enterprise. Active, informed public support is a major factor for success in managing a pest crisis; regulations and coercive measures alone do not succeed. Which raises the question of what to communicate, and how. There may be conflicts of interest where alien species are concerned because some of them are a source of income, pleasure or even a st...

  8. Ancient aliens on mars

    CERN Document Server

    Bara, Mike

    2013-01-01

    Best-selling author and Secret Space Program researcher Bara brings us this lavishly illustrated volume on alien structures on Mars. Was there once a vast, technologically advanced civilization on Mars, and did it leave evidence of its existence behind for humans to find eons later? Did these advanced extraterrestrial visitors vanish in a solar system wide cataclysm of their own making, only to make their way to Earth and start anew? Was Mars once as lush and green as the Earth, and teeming with life? Did Mars once orbit a missing member of the solar system, a "Super Earth” that vanished in a disaster that devastated life on Earth and Venus and left us only the asteroid belt as evidence of its once grand existence? Did the survivors of this catastrophe leave monuments and temples behind, arranged in a mathematical precision designed to teach us the Secret of a new physics that could lift us back to the stars? Does the planet have an automated defense shield that swallows up robotic probes if they wander int...

  9. Approaching invasive species in Madagascar

    OpenAIRE

    Kull, Christian A.; Jacques Tassin; Carrière, Stéphanie M.

    2014-01-01

    While a number of plants, animals, and insects in Madagascar have been called 'invasive', the topic of invasive species has until recently received less attention here than in other island contexts. Some species, often alien to Madagascar and introduced by humans, have expanded their range rapidly and have had both negative and positive effects on landscapes, on native biodiversity, and on livelihoods. Examples include the prickly pear (raketa), the silver wattle (mimosa), and, recently, the ...

  10. Fire management impacts on invasive plants in the western United States.

    Science.gov (United States)

    Keeley, Jon E

    2006-04-01

    Fire management practices affect alien plant invasions in diverse ways. I considered the impact of six fire management practices on alien invasions: fire suppression, forest fuel reduction, prescription burning in crown-fire ecosystems, fuel breaks, targeting of noxious aliens, and postfire rehabilitation. Most western United States forests have had fire successfully excluded for unnaturally long periods of time, and this appears to have favored the exclusion of alien plant species. Forest fuel reduction programs have the potential for greatly enhancing forest vulnerability to alien invasions. In part this is due to the focus on reestablishing pre-Euro-American fire regimes on a landscape that differs from pre-Euro-American landscapes in the abundance of aggressive non-native species. We may be forced to choose between restoring "natural"fire regimes or altering fire regimes to favor communities of native species. Intensive grazing in many western forests may exacerbate the alien problem after fire and temporally decoupling grazing and fire restoration may reduce the alien threat. Many shrubland ecosystems such as the Intermountain West sagebrush steppe or California chaparral have a natural, high-intensity crown fire regime that is less amenable to forest restoration tactics. Historical use of prescribed fire for type conversion of shrublands to more useful grazing lands has played some role in the massive annual grass invasion that threatens these shrublands. Fuel breaks pose a special invasive plant risk because they promote alien invasion along corridors into wildland areas. Use of prescription burning to eliminate noxious aliens has had questionable success, particularly when applied to disturbance-dependent annuals, and success is most likely when coupled with ecosystem restoration that alters the competitive balance between aliens and natives. Artificial seeding of alien species as a form of postfire stabilization appears to cause more problems than it

  11. Records of alien marine species in the shallow coastal waters of Chios Island (2009

    Directory of Open Access Journals (Sweden)

    S. KATSANEVAKIS

    2012-12-01

    Full Text Available The shallow coastline of Chios Island was surveyed for the presence of any alien marine benthic species, during August 2009. Fourteen randomly selected sites were surveyed by snorkeling during standardized one-hour transects at depths between 0 and 10 m, and the presence of all identified alien benthic species was recorded. Six alien species were identified: Asparagopsis taxiformis, Caulerpa racemosa var. cylindracea, Stypopodium schimperi, Halophila stipulacea, Percnon gibbesi, and Siganus luridus. The green alga C. racemosa var. cylindracea was found in high densities in all the surveyed sites and was characterized as invasive in the island. The brown alga S. schimperi, the crab P. gibbesi, and the fish S. luridussustain established populations in the area. For three of the recorded marine alien species (S. schimperi, P. gibbesi, and S. luridus,Chios Island seems to be the northernmost margin of their geographical range in the Aegean Sea.

  12. What makes the plant invasion possible? Paradigm of invasion mechanisms, theories and attributes

    OpenAIRE

    Prabhat Kumar Rai

    2015-01-01

    Plant invasion is the second most severe threat to biodiversity after habitat fragmentation. Invasive species are alien species whose introduction and spread threatens ecosystems, habitats or species with socio-cultural, economic and/or environmental harm, and harm to human health. Present review precisely describes the global problems of invasion in different ecosystems, continents and its multifaceted impacts. Plant invasion is now increasingly being recognized as global problem and various...

  13. Evaluation of Online Information Sources on Alien Species in Europe: The Need of Harmonization and Integration

    Science.gov (United States)

    Gatto, Francesca; Katsanevakis, Stelios; Vandekerkhove, Jochen; Zenetos, Argyro; Cardoso, Ana Cristina

    2013-06-01

    Europe is severely affected by alien invasions, which impact biodiversity, ecosystem services, economy, and human health. A large number of national, regional, and global online databases provide information on the distribution, pathways of introduction, and impacts of alien species. The sufficiency and efficiency of the current online information systems to assist the European policy on alien species was investigated by a comparative analysis of occurrence data across 43 online databases. Large differences among databases were found which are partially explained by variations in their taxonomical, environmental, and geographical scopes but also by the variable efforts for continuous updates and by inconsistencies on the definition of "alien" or "invasive" species. No single database covered all European environments, countries, and taxonomic groups. In many European countries national databases do not exist, which greatly affects the quality of reported information. To be operational and useful to scientists, managers, and policy makers, online information systems need to be regularly updated through continuous monitoring on a country or regional level. We propose the creation of a network of online interoperable web services through which information in distributed resources can be accessed, aggregated and then used for reporting and further analysis at different geographical and political scales, as an efficient approach to increase the accessibility of information. Harmonization, standardization, conformity on international standards for nomenclature, and agreement on common definitions of alien and invasive species are among the necessary prerequisites.

  14. 海南岛入侵植物的分布特点及其对本地植物的影响%Distribution patterns of alien invasive plants and their influences on native plants of Hainan Island

    Institute of Scientific and Technical Information of China (English)

    罗文启; 符少怀; 杨小波; 陈玉凯; 周威; 杨琦; 陶楚; 周文嵩

    2015-01-01

    Aims Our objective was to explore the distribution patterns of 20 noxious invasive plants in Hainan Island notified by the National Ministry of Agriculture, and their influences on native plants. We also focused on investigating the traits of six most widely spread invasive plants and plant distributions in seven types of terrestrial ecosystems. Three hypotheses were deployed in this study: (1) the ecological effects of plant invasion were related to the characteristics of invaded ecosystems and successional phases of invaded communities; (2) the invasive plants rather affected certain functional groups than the whole communities;(3) and most invasive plant species tended to colonize frequently disturbed ecosystems, while they were usually excluded by intact forest ecosystems. Methods The plot survey was conducted to investigate the distributions of the 20 target invasive plants. The ap-pearance frequency of the six most widely spread invasive plants (i.e., Chromolaena odorata, Praxelis clem-atidea, Mimosa pudica, Wedelia trilobata, Conyza sumatrensis, and Lantana camara) was compared among seven terrestrial ecosystems (i.e., secondary forest, farmland, grassland, abandoned land, plantation, village, and forest edge) to evaluate the invasibility of different ecosystems. The plots invaded by target species were classified, and species richness of native species in these invaded plots was compared using one-way ANOVAS. Relationships between the total coverage of invasive plants and the species richness of native plants were assessed using a linear regression model. Important findings (1) A total of 11 noxious invasive plants were found in Hainan Island, accounting for 55%of the target specie. (2) The target invasive species were mostly distributed in the northeastern and southwestern regions of Hainan Island, less in the southeastern region, and least in the central region. (3) An order of the inten-sity regarding plant invasiveness was expressed as Praxelis

  15. 8 CFR 1214.2 - Review of alien victims of severe forms of trafficking in persons; aliens in pending immigration...

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Review of alien victims of severe forms of trafficking in persons; aliens in pending immigration proceedings. 1214.2 Section 1214.2 Aliens and... NONIMMIGRANT CLASSES § 1214.2 Review of alien victims of severe forms of trafficking in persons; aliens...

  16. Cardan gear mechanism versus slider-crank mechanism in pumps and engines

    Energy Technology Data Exchange (ETDEWEB)

    Karhula, J.

    2008-07-01

    In machine design we always want to save space, save energy and produce as much power as possible. We can often reduce accelerations, inertial loads and energy consumption by changing construction. In this study the old cardan gear mechanism (hypocycloid mechanism) has been compared with the conventional slider-crank mechanism in air pumps and four-stroke engines. Comprehensive Newtonian dynamics has been derived for the both mechanisms. First the slidercrank and the cardan gear machines have been studied as lossless systems. Then the friction losses have been added to the calculations. The calculation results show that the cardan gear machines can be more efficient than the slider-crank machines. The smooth running, low mass inertia, high pressures and small frictional power losses make the cardan gear machines clearly better than the slider-crank machines. The dynamic tooth loads of the original cardan gear construction do not rise very high when the tooth clearances are kept tight. On the other hand the half-size crank length causes high bearing forces in the cardan gear machines. The friction losses of the cardan gear machines are generally quite small. The mechanical efficiencies are much higher in the cardan gear machines than in the slider-crank machines in normal use. Crankshaft torques and power needs are smaller in the cardan gear air pumps than in the equal slider-crank air pumps. The mean crankshaft torque and the mean output power are higher in the cardan gear four-stroke engines than in the slider-crank four-stroke engines in normal use. The cardan gear mechanism is at its best, when we want to build a pump or an engine with a long connecting rod (approx 5.crank length) and a thin piston (approx 1.5.crank length) rotating at high angular velocity and intermittently high angular acceleration. The cardan gear machines can be designed also as slide constructions without gears. Suitable applications of the cardan gear machines are three-cylinder half

  17. Geographical constraints are stronger than invasion patterns for European urban floras.

    Directory of Open Access Journals (Sweden)

    Carlo Ricotta

    Full Text Available Understanding the mechanisms that affect invasion success of alien species is an important prerequisite for the effective management of present and future aliens. To gain insight into this matter we asked the following questions: Are the geographical patterns of species distributions in urban floras different for native compared with alien plant species? Does the introduction of alien species contribute to the homogenization of urban floras? We used a Mantel test on Jaccard dissimilarity matrices of 30 urban floras across the British Isles, Italy and central Europe to compare the spatial distribution of native species with four classes of alien species: archaeophytes, all neophytes, non-invasive neophytes, and invasive neophytes. Archaeophytes and neophytes are species that were introduced into Europe before and after 1500 AD, respectively. To analyze the homogenizing effect of alien species on the native urban floras, we tested for differences in the average dissimilarity of individual cities from their group centroid in ordination space. Our results show that the compositional patterns of native and alien species seem to respond to the same environmental drivers, such that all four classes of alien species were significantly related to native species across urban floras. In this framework, alien species may have an impact on biogeographic patterns of urban floras in ways that reflect their history of introduction and expansion: archaeophytes and invasive neophytes tended to homogenize, while non-invasive neophytes tended to differentiate urban floras.

  18. Geographical constraints are stronger than invasion patterns for European urban floras.

    Science.gov (United States)

    Ricotta, Carlo; Celesti-Grapow, Laura; Kühn, Ingolf; Rapson, Gillian; Pyšek, Petr; La Sorte, Frank A; Thompson, Ken

    2014-01-01

    Understanding the mechanisms that affect invasion success of alien species is an important prerequisite for the effective management of present and future aliens. To gain insight into this matter we asked the following questions: Are the geographical patterns of species distributions in urban floras different for native compared with alien plant species? Does the introduction of alien species contribute to the homogenization of urban floras? We used a Mantel test on Jaccard dissimilarity matrices of 30 urban floras across the British Isles, Italy and central Europe to compare the spatial distribution of native species with four classes of alien species: archaeophytes, all neophytes, non-invasive neophytes, and invasive neophytes. Archaeophytes and neophytes are species that were introduced into Europe before and after 1500 AD, respectively. To analyze the homogenizing effect of alien species on the native urban floras, we tested for differences in the average dissimilarity of individual cities from their group centroid in ordination space. Our results show that the compositional patterns of native and alien species seem to respond to the same environmental drivers, such that all four classes of alien species were significantly related to native species across urban floras. In this framework, alien species may have an impact on biogeographic patterns of urban floras in ways that reflect their history of introduction and expansion: archaeophytes and invasive neophytes tended to homogenize, while non-invasive neophytes tended to differentiate urban floras. PMID:24465640

  19. 22 CFR 62.27 - Alien physicians.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Alien physicians. 62.27 Section 62.27 Foreign... Provisions § 62.27 Alien physicians. (a) Purpose. Pursuant to the Mutual Educational and Cultural Exchange... Foreign Medical Graduates must sponsor alien physicians who wish to pursue programs of graduate...

  20. Alienation, Dogmatism, and Related Personality Characteristics.

    Science.gov (United States)

    Sexton, Miriam E.

    1983-01-01

    Examined the relationship between alienation and dogmatism, as measured by shared personality characteristics. Scores from the Rokeach Dogmatism Scale, the Keniston Alienation Scale, the California Test of Personality, and the Omnibus Personality Inventory were obtained for 92 college freshmen. Alienation and dogmatism were positively related…

  1. 33 CFR 125.25 - Aliens.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Aliens. 125.25 Section 125.25 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) WATERFRONT....25 Aliens. Alien registration records together with other papers and documents which indicated...

  2. Do abundance and proximity of the alien Impatiens glandulifera affect pollination and reproductive success of two sympatric co-flowering native species?

    OpenAIRE

    Anne-Laure Jacquemart; Carolin Mayer; Mathieu Jonard; Valérie Cawoy

    2012-01-01

    In invasion ecology, potential impacts of aliens on native flora are still under debate. Our aim was to determine the pollinator mediated effects of both proximity and abundance of an alien species on the reproductive success of natives. We chose the highly invasive Impatiens glandulifera and two native species: Epilobium angustifolium and Aconitum napellus ssp. lusitanicum. These species share characteristics allowing for pollination interactions: similar biotopes, overlapping flowering peri...

  3. Functional differences between native and alien species: a global-scale comparison

    DEFF Research Database (Denmark)

    Ordonez Gloria, Alejandro

    2010-01-01

    1. A prevalent question in the study of plant invasions has been whether or not invasions can be explained on the basis of traits. Despite many attempts, a synthetic view of multi-trait differences between alien and native species is not yet available.2. We compiled a database of three ecologically...... important traits (specific leaf area, typical maximum canopy height, individual seed mass) for 4473 species sampled over 95 communities (3784 species measured in their native range, 689 species in their introduced range, 207 in both ranges).3. Considering each trait separately, co-occurring native and alien...... species significantly differed in their traits. These differences, although modest, were expressed in a combined 15% higher specific leaf area, 16% lower canopy height and 26% smaller seeds.4. Using three novel multi-trait metrics of functional diversity, aliens showed significantly smaller trait ranges...

  4. Effects of Nitrogen Deposition on Invasive and Competitive Abilities of an Alien Plant Ambrosia artemisüfolia%氮沉降对外来种豚草入侵能力与竞争能力的影响

    Institute of Scientific and Technical Information of China (English)

    陆光亚; 王晋萍; 桑卫国

    2012-01-01

    An experiment was conducted to study the effects of nitrogen deposition on morphological indices, biomass and its allocation , and interspecies competition of an invasive plant Ambrosia artemisii/olia (common ragweed) and two native plants Artemisia anmia and Artemisia mongolica. Results show that the invasive species is more plastic in response to nitrogen availability, compared with the two native species. With increasing nitrogen levels, the plant height, basal diameter, total biomass , supporting organs mass ratio ( SMR) of the invasive species significantly increased, while root biomass ratio (RMR) and root-to-shoot ratio decreased obviously. Nitrogen deposition had no significant effects on the morphological indices , biomass and its allocation of the native species except plant height and root-to-shoot ratio. Nitrogen deposition was beneficial for the invasive species to gain advantage in interspecies competition. The competitive ability of the invasive species enhanced with increasing nitrogen levels when mixed planting with Artemisia annua; however, A. mongolica was more competitive than A. artemisiifolia under low nitrogen levels, and less competition of .4. artemisiifolia was observed under high nitrogen levels when mixed planting with A. mongolica. The results show that nitrogen deposition is in favor of the invasive species, resulting in a wide dispersal of A artemisiifolia in Beijing region.%通过温室控制实验,模拟不同的氮沉降量对外来种豚草和本地种黄花蒿、蒙古蒿形态、生物量及其分配以及种间竞争的影响.结果表明:外来种豚草对氮素变化表现出很高的可塑性,而本地种可塑性不高.随氮素的增加,豚草的株高、基茎、总生物量、支持结构生物量比显著增加,根生物量比、根冠比明显降低;本地种除株高、根冠比等少数指标外,多数指标无显著差异.氮沉降有利于外来种豚草在种间竞争中取得优势.豚草和黄花蒿的混栽

  5. Tetrahedral Amorphous Carbon (ta-C) Ultra Thin Films for Slider Overcoat Application

    Science.gov (United States)

    Shi, X.; Hu, Y. H.; Hu, L.

    Tetrahedral Amorphous Carbon (ta-C) thin film by using Filtered Cathodic Vacuum Arc (FCVA) technique has proven to be wear-resistive and corrosion resistant for a wide range of electrical, optical, and mechanical applications. Many investigations have shown that the ta-C film prepared by the FCVA technique can provide a superior ultra thin overcoat for the sliders and media compared to ECR-CVD and IBD coating technology. The ta-C film excels in terms of the film density, hardness, surface roughness and corrosion resistance. Nanofilm Technology International (NTI) has successfully developed and commercialized the FCVA coating system (FS series) for the slider overcoat application, which provides a good quality film with a high hardness (~50 GPa), low stress (2~3 GPa), low macro-particle density (~1/cm2 for particles > 0.3 μm), good uniformity (production repeatability (< 5%).

  6. Tracking Control of the Flexible SLIDER-CRANK Mechanism System Under Impact

    Science.gov (United States)

    FUNG, R.-F.; SUN, J.-H.; WU, J.-W.

    2002-08-01

    The variable structure control (VSC) and the stabilizer design by using pole placement technique are applied to the tracking control of the flexible slider-crank mechanism under impact. The VSC strategy is employed to track the crank angular position and speed, while the stabilizer design is involved to suppress the flexible vibrations simultaneously. From the theoretical impact consideration, three approaches including the generalized momentum balance (GMB), the continuous force model (CFM), and the CFM associated with the effective mass compensation EMC are adopted, and are derived on the basis of the energy and impulse-momentum conservations. Simulation results are provided to demonstrate the performance of the motor-controller flexible slider-crank mechanism not only accomplishing good tracking trajectory of the crank angle, but also eliminating vibrations of the flexible connecting rod.

  7. DOUBLE FOUR-BAR CRANK-SLIDER MECHANISM DYNAMIC BALANCING BY META-HEURISTIC ALGORITHMS

    Directory of Open Access Journals (Sweden)

    Habib Emdadi

    2013-09-01

    Full Text Available In this paper, a new method for dynamic balancing of double four-bar crank slider mechanism by metaheuristic-based optimization algorithms is proposed. For this purpose, a proper objective function which is necessary for balancing of this mechanism and corresponding constraints has been obtained by dynamic modeling of the mechanism. Then PSO, ABC, BGA and HGAPSO algorithms have been applied for minimizing the defined cost function in optimization step. The optimization results have been studied completely by extracting the cost function, fitness, convergence speed and runtime values of applied algorithms. It has been shown that PSO and ABC are more efficient than BGA and HGAPSO in terms of convergence speed and result quality. Also, a laboratory scale experimental doublefour-bar crank-slider mechanism was provided for validating the proposed balancing method practically.

  8. Double Four-Bar Crank-Slider Mechanism Dynamic Balancing by Meta-Heuristic Algorithms

    Directory of Open Access Journals (Sweden)

    Habib Emdadi

    2013-09-01

    Full Text Available In this paper, a new method for dynamic balancing of double four-bar crank slider mechanism by meta-heuristic-based optimization algorithms is proposed. For this purpose, a proper objective function which is necessary for balancing of this mechanism and corresponding constraints has been obtained by dynamic modeling of the mechanism.Then PSO, ABC, BGA and HGAPSO algorithms have been applied for minimizing the defined cost function in optimization step. The optimization results have been studied completely by extracting the cost function, fitness, convergence speed and run time values of applied algorithms. It has been shown that PSO and ABC are more efficient than BGA and HGAPSO in terms of convergence speed and result quality. Also, a laboratory scale experimental double four-bar crank-slider mechanism was provided for validating the proposedbalancing method practicall

  9. Finding and Exploring Health Information with a Slider-Based User Interface.

    Science.gov (United States)

    Pang, Patrick Cheong-Iao; Verspoor, Karin; Pearce, Jon; Chang, Shanton

    2016-01-01

    Despite the fact that search engines are the primary channel to access online health information, there are better ways to find and explore health information on the web. Search engines are prone to problems when they are used to find health information. For instance, users have difficulties in expressing health scenarios with appropriate search keywords, search results are not optimised for medical queries, and the search process does not account for users' literacy levels and reading preferences. In this paper, we describe our approach to addressing these problems by introducing a novel design using a slider-based user interface for discovering health information without the need for precise search keywords. The user evaluation suggests that the interface is easy to use and able to assist users in the process of discovering new information. This study demonstrates the potential value of adopting slider controls in the user interface of health websites for navigation and information discovery. PMID:27440297

  10. Optimal Resource Management in the Presence of a Deleterious Alien Species

    NARCIS (Netherlands)

    Batabyal, A.A.; Nijkamp, Peter

    2007-01-01

    Various plants and resources such as orchards are vulnerable to the detrimental effects of successful invasions by alien animal or plant species. To outline an appropriate policy response, we first use renewal theory to construct a stochastic model of optimal orchard management in the presence of a

  11. Czech alien flora and the historical pattern of its formation: what came first to Central Europe?

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Sádlo, Jiří; Mandák, Bohumil; Jarošík, V.

    2003-01-01

    Roč. 135, - (2003), s. 122-130. ISSN 0029-8549 R&D Projects: GA AV ČR KSK6005114; GA ČR GA206/99/1239 Institutional research plan: CEZ:AV0Z6005908 Keywords : alien flora * immigration pattern * invasion history Subject RIV: EF - Botanics Impact factor: 3.128, year: 2003

  12. Land use intensification differentially benefits alien over native predators in agricultural landscape mosaics

    Science.gov (United States)

    Aim: Both anthropogenic habitat disturbance and the breadth of habitat use by alien species have been found to facilitate invasion into novel environments, and these factors have been hypothesized to be important within coccinellid communities specifically. In this study, we address two questions: (...

  13. A List of Alien Plants in the Kruger National Park

    Directory of Open Access Journals (Sweden)

    I.A.W. Macdonald

    1988-10-01

    Full Text Available The alien vascular plant flora of the Kruger National Park is listed. Annotations cover the invasive status, modes of introduction and dispersal, dates of first recording, ecological impacts and control status of each species. The list comprises 156 species of which 113 are considered invasive within the park. Most of the species have been accidentally introduced to the park. The ecological impacts of 27 species (of which 11 are trees and shrubs were rated as moderate or high. By 1985 only 10 species are thought to have been eradicated from the park. Most of the invasive species are herbaceous weeds of man-disturbed sites and the eradication of these is generally considered impossible. Most of the important species are dispersed by water and animals. The significance of limiting reinvasion of the park down the rivers flowing into the park, is stressed.

  14. Shliomis Model Based Ferrofluid Lubrication of a Rough Porous Convex Pad Slider Bearing

    OpenAIRE

    G. M. Deheri; Patel, J.R.; N.D. Patel

    2016-01-01

    An attempt has been made to analyze the performance characteristics of a Shliomis model based ferrofluid lubrication of a rough porous convex pad slider bearing. Regarding roughness, the stochastic method adopted by Christensen and Tonder finds the application here in statistical averaging of the associated Reynolds equation. The graphical representation suggests that the adverse effect of surface roughness can be reduced to certain extent by the positive effect of Shliomis model based ferrof...

  15. Morphometric characterization of the mesoamerican slider (trachemys venusta, emydidae) from the atrato river basin, colombia.

    OpenAIRE

    Claudia P. Ceballos; William A. Brand

    2014-01-01

    A group of 89 sliders, Trachemys venusta, were confiscated by the local authorities in the Atrato river basin of Colombia. The life history of this species has known from populations in different countries but in Colombia there is only one anecdotic report that is 50 years old. Given the wide biogeography and diversity of forms of this species throughout its range from Mexico to Colombia, we report this case of turtle confiscation and use this opportunity to document the morphometry that this...

  16. Morphometric Characterization of the Mesoamerican Slider (Trachemys venusta, Emydidae) from the Atrato river basin, Colombia.

    OpenAIRE

    Claudia P. Ceballos; William A. Brand

    2014-01-01

    A group of 89 sliders, Trachemys venusta, were confiscated by the local authorities in the Atrato river basin of Colombia. The life history of this species has known from populations in different countries but in Colombia there is only one anecdotic report that is 50 years old. Given the wide biogeography and diversity of forms of this species throughout its range from Mexico to Colombia, we report this case of turtle confiscation and use this opportunity to document the morphometry that this...

  17. Double Four-Bar Crank-Slider Mechanism Dynamic Balancing by Meta-Heuristic Algorithms

    OpenAIRE

    Habib Emdadi; Mahsa Yazdanian; Mir Mohammad Ettefagh; Mohammad-Reza Feizi-Derakhshi

    2013-01-01

    In this paper, a new method for dynamic balancing of double four-bar crank slider mechanism by meta- heuristic-based optimization algorithms is proposed. For this purpose, a proper objective function which is necessary for balancing of this mechanism and corresponding constraints has been obtained by dynamic modeling of the mechanism. Then PSO, ABC, BGA and HGAPSO algorithms have been applied for minimizing the defined cost function in optimization step. The optimization results have been stu...

  18. Analytical Solution of a Nonlinear Index-Three DAEs System Modelling a Slider-Crank Mechanism

    OpenAIRE

    Brahim Benhammouda; Hector Vazquez-Leal

    2015-01-01

    The slider-crank mechanism (SCM) is one of the most important mechanisms in modern technology. It appears in most combustion engines including those of automobiles, trucks, and other small engines. The SCM model considered here is an index-three nonlinear system of differential-algebraic equations (DAEs), and therefore difficult to integrate numerically. In this work, we present the application of the differential transform method (DTM) to obtain an approximate analytical so...

  19. Invasive species unchecked by climate - response

    DEFF Research Database (Denmark)

    Burrows, Michael T.; Schoeman, David S.; Duarte, Carlos M.;

    2012-01-01

    Hulme points out that observed rates of range expansion by invasive alien species are higher than the median speed of isotherm movement over the past 50 years, which in turn has outpaced the rates of climate-associated range changes of marine and terrestrial species. This is not surprising, given...... the many ecological and anthropogenic processes that combine to facilitate the translocation of invasive species and the subsequent expansion of their populations. Successful alien species have been observed to rapidly expand their ranges until some limit, typically climate-imposed, is reached. Comparisons...... of climate-change-induced range shifts between native and alien species are meaningful only after the initial invasive spread has reached a stable range boundary. A focus on regions with high velocities of climate change, and on regions such as the tropics where novel thermal niches are being created, should...

  20. The Mexican "Illegal Alien" Commute.

    Science.gov (United States)

    Decker, Phil

    1986-01-01

    A photo report of the following three treks by illegal aliens across the border from Mexico to work in Arizona reveals the dangers and disappointments the migrants are exposed to: (1) a "carpool" from Southern Mexico; (2) a train ride from Sinaloa; and (3) a 40-mile hike through the Arizona desert. (PS)

  1. Invasive ornamental fish: a potential threat to aquatic biodiversity in peninsular India

    Directory of Open Access Journals (Sweden)

    J.D.M. Knight

    2010-02-01

    Full Text Available Alien fish find their way into newer habitats and ecosystems opportunistically. Once in a new habitat, these species try to occupy empty niches and compete with native species. An alien species becomes invasive wherever it has a competetive advantage over native species. Ecology of aquatic invasive alien species is rather poorly understood as most attention has been on invertebrates as that which spread through ballast water. Invasive alien species of fish that have taken advantage of the aquarium trade are emerging as the most important threats to fragile aquatic habitats. Regulations to this trade are rather weak and there is a general lack of data on the ecological impact of alien fish species despite the fact that a third of the world’s worst aquatic invasive species are aquarium or ornamental species.

  2. Searching for Alien Life Having Unearthly Biochemistry

    Science.gov (United States)

    Jones, Harry

    2003-01-01

    The search for alien life in the solar system should include exploring unearth-like environments for life having an unearthly biochemistry. We expect alien life to conform to the same basic chemical and ecological constraints as terrestrial life, since inorganic chemistry and the laws of ecosystems appear to be universal. Astrobiologists usually assume alien life will use familiar terrestrial biochemistry and therefore hope to find alien life by searching near water or by supplying hydrocarbons. The assumption that alien life is likely to be based on carbon and water is traditional and plausible. It justifies high priority for missions to search for alien life on Mars and Europa, but it unduly restricts the search for alien life. Terrestrial carbon-water biochemistry is not possible on most of the bodies of our solar system, but all alien life is not necessarily based on terrestrial biochemistry. If alien life has a separate origin from Earth life, and if can survive in an environment extremely different from Earth's, then alien life may have unearthly biochemistry. There may be other solvents than water that support alien life and other elements than carbon that form complex life enabling chain molecules. Rather than making the exploration-restricting assumption that all life requires carbon, water, and terrestrial biochemistry, we should make the exploration-friendly assumption that indigenous, environmentally adapted, alien life forms might flourish using unearthly biochemistry in many places in the solar system. Alien life might be found wherever there is free energy and a physical/chemical system capable of using that energy to build living structures. Alien life may be discovered by the detection of some general non-equilibrium chemistry rather than of terrestrial biochemistry. We should explore all the potential abodes of life in the solar system, including those where life based on terrestrial biochemistry can not exist.

  3. Seedling traits, plasticity and local differentiation as strategies of invasive species of Impatiens in central Europe

    OpenAIRE

    Skálová, Hana; Havlíčková, Vendula; Pyšek, Petr

    2012-01-01

    Background and Aims Invasiveness of some alien plants is associated with their traits, plastic responses to environmental conditions and interpopulation differentiation. To obtain insights into the role of these processes in contributing to variation in performance, we compared congeneric species of Impatiens (Balsaminaceae) with different origin and invasion status that occur in central Europe. Methods Native I. noli-tangere and three alien species (highly invasive I. glandulifera, less inva...

  4. 22 CFR 42.22 - Returning resident aliens.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Returning resident aliens. 42.22 Section 42.22... Returning resident aliens. (a) Requirements for returning resident status. An alien shall be classifiable as... presented that: (1) The alien had the status of an alien lawfully admitted for permanent residence at...

  5. 8 CFR 236.2 - Confined aliens, incompetents, and minors.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Confined aliens, incompetents, and minors. 236.2 Section 236.2 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF INADMISSIBLE AND DEPORTABLE ALIENS; REMOVAL OF ALIENS ORDERED REMOVED...

  6. Life-history traits of alien and native senecio species in the Mediterranean region

    Science.gov (United States)

    Sans, F. X.; Garcia-Serrano, H.; Afán, I.

    2004-12-01

    Two related shrubs, Senecio inaequidens and S. pterophorus, both introduced to western Mediterranean Europe from South Africa, were compared with a native Mediterranean shrub, S. malacitanus, to identify life-history traits that confer invasive ability. We examined ecological interactions that affect seedling emergence and establishment, flowering time, growth and reproduction and competitive ability in these three closely related species. Seeds were planted, the seedlings were then transplanted and individual performance was evaluated with respect to: (1) competition with plant neighbours and (2) resource addition. Senecio inaequidens had higher rates of seedling establishment and a shorter pre-reproductive period. Competition with neighbours had a considerable impact on S. malacitanus, delaying flowering time and reducing growth and reproduction. S. pterophorus showed inefficient seedling establishment compared to the other two species, but performed better in terms of growth and reproduction. The two alien species were markedly more competitive than the native one. However, differences in competitiveness among S. malacitanus and the two aliens varied depending on resource availability. Thus, Senecio inaequidens and S. pterophorus were more affected by competition in subplots with resource addition and by competition in those without addition, respectively. The latter showed a greater capacity to respond to additional resources in competitive environments and, in addition, its reproductive effort was unrelated to habitat conditions. The invasive potential of the alien species was higher than that of the native. This was a result of various biological characteristics and specific interactions between invader and environment, which made the invasiveness of alien species unpredictable.

  7. Epstein on alienation: a rejoinder

    OpenAIRE

    Walter Block

    2006-01-01

    Purpose – The purpose of this paper is to counteract Epstein's views on the alienability of property. Epstein favors limitations of laissez-faire capitalism regarding such things as guns, liquor, narcotics, certain books and voting and this paper aims to criticize them from the perspective of full, free enterprise. Design/methodology/approach – The main method is that of the reductio ad absurdum. For example, Epstein favors prior restraint on books giving information as to how an atomic bomb ...

  8. Invasive mechanism and control strategy of Ageratina adenophora (Sprengel)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation,the formation of single dominant population, displacement of native plants and sustainable management strategies were investigated. The present results helped to clarify and explain such issues as the adaptability post invasion,interaction and competition between inter-and intra-species and community resistance, thereby providing important references to researches on other invasive alien species.

  9. How many marine aliens in Europe?

    OpenAIRE

    Stelios Katsanevakis; Francesca Gatto,; Argyro Zenetos; Ana Cristina Cardoso

    2012-01-01

    In the framework of the European Alien Species Information Network (EASIN; http://easin.jrc.ec.europa.eu/), an inventory of marine alien species in Europe was created by critically reviewing existing information in 34 global, European, regional and national databases. In total, 1369 marine alien species have been reported in the European seas (including 110 cryptogenic and 139 questionable species); this is a substantial increase from the 737 species previously reported in 2009 based on the ...

  10. Alienation in educational organizations and its’ management

    OpenAIRE

    Sadi Yılmaz; Pınar Sarpkaya

    2009-01-01

    The purpose of this study was to study the alienation in educational organizations carefully and to call attention to this subject which was studied insufficiently. Descriptive method was used in the study. The concept of alienation was brought up with philosophical and sociological principals and then common inferences about the educational organizations were made within the help of studies which were about the alienation in educational institutions. Hegel was the first to consider the fact ...

  11. Index of Alien Impact: A method for evaluating potential ecological impact of alien plant species

    Science.gov (United States)

    Alien plant species are stressors to ecosystems and indicators of reduced ecosystem integrity. The magnitude of the stress reflects not only the quantity of aliens present, but also the quality of their interactions with native ecosystems. We develop an Index of Alien Impact (IAI...

  12. Alienation in educational organizations and its’ management

    Directory of Open Access Journals (Sweden)

    Sadi Yılmaz

    2009-09-01

    Full Text Available The purpose of this study was to study the alienation in educational organizations carefully and to call attention to this subject which was studied insufficiently. Descriptive method was used in the study. The concept of alienation was brought up with philosophical and sociological principals and then common inferences about the educational organizations were made within the help of studies which were about the alienation in educational institutions. Hegel was the first to consider the fact of “alienation” philosophically in his book “Phenomenology of Spirit  ”. To Hegel human history is also the history of human being’s becoming alienated to himself. After Hegel, Ludwig Feuerbach considered this fact in his book “Essence of Christianity” in 1841. According to Marx, alienation is a compulsory phase that development of human being must have. Marx emphasizes that in capitalist society which is named as modern society man with his labor in production relations becomes alienated to his labor, then to his social relationships, and finally to himself. In his opinion, man is desired to pull in to the consumption helical that is obstinately insisted as necessity. In this way, consumption and dissatisfaction are two elements which set off and product each other. Alienation is deterioration and decay conceit of human existence’s natural, social, psychological and cultural dimensions. It is human being’s separating from each other and becoming alienated to each other. In this respect, alienation means that man survives by becoming distant to himself, to the product he produces, to his natural, social, psychological and cultural environment but under the control of their dominance and decisiveness. Seeman distinguishes alienation into five; Powerlessness, Meaninglessness, Normlessness, Isolation and self-estrangement. The studies that are made in educational organizations about alienation focus on alienation of teacher and student. There

  13. Alienation in educational organizations and its’ management

    Directory of Open Access Journals (Sweden)

    Pınar Sarpkaya

    2009-09-01

    Full Text Available The purpose of this study was to study the alienation in educational organizations carefully and to call attention to this subject which was studied insufficiently. Descriptive method was used in the study. The concept of alienation was brought up with philosophical and sociological principals and then common inferences about the educational organizations were made within the help of studies which were about the alienation in educational institutions. Hegel was the first to consider the fact of “alienation” philosophically in his book “Phenomenology of Spirit ”. To Hegel human history is also the history of human being’s becoming alienated to himself. After Hegel, Ludwig Feuerbach considered this fact in his book “Essence of Christianity” in 1841. According to Marx, alienation is a compulsory phase that development of human being must have. Marx emphasizes that in capitalist society which is named as modern society man with his labor in production relations becomes alienated to his labor, then to his social relationships, and finally to himself. In his opinion, man is desired to pull in to the consumption helical that is obstinately insisted as necessity. In this way, consumption and dissatisfaction are two elements which set off and product each other. Alienation is deterioration and decay conceit of human existence’s natural, social, psychological and cultural dimensions. It is human being’s separating from each other and becoming alienated to each other. In this respect, alienation means that man survives by becoming distant to himself, to the product he produces, to his natural, social, psychological and cultural environment but under the control of their dominance and decisiveness. Seeman distinguishes alienation into five; Powerlessness, Meaninglessness, Normlessness, Isolation and self-estrangement. The studies that are made in educational organizations about alienation focus on alienation of teacher and student. There

  14. ELNAIS meets EASIN: distribution of marine alien species in Greece using EASIN mapping services and ELNAIS spatial data

    Directory of Open Access Journals (Sweden)

    S. KATSANEVAKIS

    2013-04-01

    Full Text Available The European Alien Species Information Network (EASIN was created with the aim to provide easy access to accurate information on alien species in Europe. EASIN allows the retrieval of spatial information from existing online data providers in order to produce integrated georeferenced distribution maps of alien species in Europe. In November 2012, a new data provider, the Ellenic Network on Aquatic Invasive Species (ELNAIS, joined EASIN; this has significantly increased the available georeferenced information on marine/estuarine alien species in Greek waters. Here, we use maps created by EASIN to show differences in patterns of distribution in Greece for the most abundant Phyla of marine alien species - Mollusca, Arthropoda, Chordata and Annelida. We also show that the two main pathways of introduction of marine alien species (Lessepsian migration and Shipping are related to different patterns of species spatial distribution in Greece. Overall, the tools provided by EASIN can greatly aid scientists and policy makers in obtaining high quality information on marine alien species in Greece, especially after the association with ELNAIS.

  15. Dynamic Performance Characteristics of a Curved Slider Bearing Operating with Ferrofluids

    Directory of Open Access Journals (Sweden)

    Udaya P. Singh

    2012-01-01

    Full Text Available In the present theoretical investigation, the effect of ferrofluid on the dynamic characteristics of curved slider bearings is presented using Shliomis model which accounts for the rotation of magnetic particles, their magnetic moments, and the volume concentration in the fluid. The modified Reynolds equation for the dynamic state of the bearing is obtained. The results of dynamic stiffness and damping characteristics are presented. It is observed that the effect of rotation of magnetic particles improves the stiffness and damping capacities of the bearings.

  16. Shliomis Model Based Ferrofluid Lubrication of a Rough Porous Convex Pad Slider Bearing

    Directory of Open Access Journals (Sweden)

    G.M. Deheri

    2016-03-01

    Full Text Available An attempt has been made to analyze the performance characteristics of a Shliomis model based ferrofluid lubrication of a rough porous convex pad slider bearing. Regarding roughness, the stochastic method adopted by Christensen and Tonder finds the application here in statistical averaging of the associated Reynolds equation. The graphical representation suggests that the adverse effect of surface roughness can be reduced to certain extent by the positive effect of Shliomis model based ferrofluid lubrication. Further, for this type of bearing system, this model remains more effective as compared to Neuringer-Rosensweig model.

  17. Position Fuzzy Control for a Two-Axis Shaking Table based on Slider-Crank Mechanism

    Directory of Open Access Journals (Sweden)

    Carlos H. Esparza-Franco

    2013-11-01

    Full Text Available Different mechanisms have been designed to generate vibratory motion to test the evaluation of seismic control systems to be used in structural buildings. These systems are called "shaking-tables" and they are usually designed with linear actuators which facilitate the implementation of classical control systems for its proper operation. This paper presents a position fuzzy control system designed to control the displacement behavior of earthquakes on the shaking-table based on a slider-crank mechanism. The results show repeatability greater than 97%, adequate to the validation of anti-seismic controllers on small-scale models.

  18. A method to calculate and counterbalance the inertia force of slider-crank mechanisms in high-speed presses

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A new method to calculate and counterbalance the inertia force of slider-crank mechanisms in high-speed mechanical presses was put forward. By analyzing the kinematic characteristics of a center-located slider-crank mechanism whose crank rotates at a constant angular velocity,the kinematic parameters of the slide,connecting rod and crank were formulated approximately. On the basis of the results above,three inertia forces and the input moment in the mechanism during its idle running were investigated and fo...

  19. Economic essays on marine invasive species and international fisheries agreements

    NARCIS (Netherlands)

    Walker, A.N.

    2016-01-01

    This thesis is divided into two parts, as explained in Chapter 1, which focus on different aspects of marine ecological change. Part A considers marine Invasive Alien Species (IAS), which are taxa introduced outside of their native range. The detrimental consequences of invasions for human welfare n

  20. Survey of roadside alien plants in Hawai`i Volcanoes National Park and adjacent residential areas 2001-2005

    Science.gov (United States)

    Bio, Keali'i F.; Pratt, Linda W.; Jacobi, James D.

    2012-01-01

    The sides of all paved roads of Hawai`i Volcanoes National Park (HAVO) were surveyed on foot in 2001 to 2005, and the roadside presence of 240 target invasive and potentially invasive alien plant species was recorded in mile-long increments. Buffer zones 5–10 miles (8–16 km) long along Highway 11 on either side of the Kīlauea and Kahuku Units of the park, as well as Wright Road that passed by the disjunct `Ōla`a Tract Unit, were included in the survey. Highway 11 is the primary road through the park and a major island thoroughfare. Three residential subdivisions adjacent to the park were similarly surveyed in 0.5–1 mile (0.8–1.6 km) intervals in 2003, and data were analyzed separately. Two roads to the east and northeast were also surveyed, but data from these disjunct areas were analyzed separately from park roads. In total, 174 of the target alien species were observed along HAVO roads and buffers, exclusive of residential areas, and the mean number of target aliens per mile surveyed was 20.6. Highway 11 and its buffer zones had the highest mean number of target alien plants per mile (26.7) of all park roads, and the Mauna Loa Strip Road had the lowest mean (11.7). Segments of Highway 11 adjacent to HAVO and Wright Road next to `Ōla`a Tract had mean numbers of target alien per mile (24–47) higher than those of any internal road. Alien plant frequencies were summarized for each road in HAVO. Fifteen new records of vascular plants for HAVO were observed and collected along park roads. An additional 28 alien plant species not known from HAVO were observed along the buffer segments of Highway 11 adjacent to the park. Within the adjacent residential subdivisions, 65 target alien plant species were sighted along roadsides. At least 15 potentially invasive species not currently found within HAVO were observed along residential roads, and several other species found there have been previously eliminated from the park or controlled to remnant populations

  1. The assessment of hull fouling as a mechanism for the introduction and dispersal of marine alien species in the main Hawaiian Islands through surveys at harbors on Oahu's southern and southwestern coasts during 2003 (NODC Accession 0001455)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surveys for adult invertebrates that were part of the hull fouling communities were done to determine to what extent marine alien invasive species (AIS) are being...

  2. The assessment of hull fouling as a mechanism for the introduction and dispersal of alien species in the main Hawaiian Islands through surveys at harbors on Oahu's Southern and Southwestern Coasts during 2003 (NODC Accession 0001455)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surveys for adult invertebrates that were part of the hull fouling communities were done to determine to what extent marine alien invasive species (AIS) are being...

  3. An updated review of alien species on the coasts of Turkey

    Directory of Open Access Journals (Sweden)

    M.E. CINAR

    2012-12-01

    Full Text Available This 2010 review of alien species along the coasts of Turkey represents a total of 400 alien species belonging to 14 systematic groups. The present paper also reports the first findings ofVanderhorstia mertensi in the Aegean Sea (Gökova Bay, Chama adspersa in the Sea of Marmara andMya arenaria in the Aegean Sea. A total of 124 new alien species was determined within the last 5 years. Mollusca had the highest number of species (105 species, followed by Polychaeta (75 species, Crustacea (64 species and Pisces (58 species. The highest number of alien species (330 species were encountered on the Levantine coast of Turkey, followed by the Aegean Sea (165 species, Sea of Marmara (69 species and Black Sea (20 species. The Suez Canal (66% of the total number of alien species is the main vector for species introductions to the coasts of Turkey, followed by the ship-mediated transport (30%. The majority of species (306 species, 76% of total number of species have become established in the area, while 59 species are classified as casual (15%, 23 species as questionable (6% and 13 species as cryptogenic (3%. One new alien species was introduced to the coasts of Turkey every 4 weeks between 1991 and 2010. The majority of aliens were found on soft substratum (198 species in shallow waters (0-10 m (319 species. Some species such asCaulerpa racemosa, Amphistegina lobifera, Amphisorus hemprichii, Rhopilema nomadica, Mnemiopsis leidyi, Hydroides spp., Ficopomatus enigmaticus, Charybdis longicollis, Rapana venosa, Asterias rubens, Siganus spp. and Lagocephalus sceleratus show high invasive characters, and have great impacts both on the prevailing ecosystems and humans.

  4. Alienating Students: Marxist Theory in Action

    Science.gov (United States)

    Thiele, Megan; Pan, Yung-Yi Dian; Molina, Devin

    2016-01-01

    Karl Marx's revolutionary call, "Workers of the World Unite," resonates with many in today's society. This article describes and assesses an easily reproducible classroom activity that simulates both alienating, and perhaps more importantly, non-alienating states of production as described by Marx. This hands-on learning activity gives…

  5. Alienation, Mass Society and Mass Culture.

    Science.gov (United States)

    Dam, Hari N.

    This monograph examines the nature of alienation in mass society and mass culture. Conceptually based on the "Gemeinschaft-Gesellschaft" paradigm of sociologist Ferdinand Tonnies, discussion traces the concept of alienation as it appears in the philosophies of Hegel, Marx, Kierkegaard, Sartre, and others. Dwight Macdonald's "A Theory of Mass…

  6. Update of alien fauna and new records from Tunisian marine waters

    Directory of Open Access Journals (Sweden)

    K. OUNIFI- BEN AMOR

    2014-06-01

    Full Text Available An updated inventory of alien marine fauna in coastal and offshore Tunisian waters is presented. Records were compiled from scientific and ‘grey’ publications, presentations at scientific meetings, theses presented in fulfillment of requirements towards MSc and PhD degrees, websites and personal observations. 136 alien species were recorded in Tunisian waters, 60 records in northern coasts, West Mediterranean and 76 in central and southern coasts, Central Mediterranean. Nearly half of the first sightings in Tunisian waters took place in the Gulf of Gabès. The dominant taxa are Crustancean (24%, Molluscs (23%, Fishes (19% and Annelida (13%. Twenty one species previously reported as aliens, were upon consideration, reclassified as range-expanding Atlantic species. Amathia verticillata, previously considered native to the Mediterranean, is reclassified as pseudoindigenous. Twenty one alien species are newly recorded from Tunisia, including 5 fish species, 5 polychaetes, 4 crustaceans, 4 molluscs, and one each schyphozoan, bryozoan and tunicate. The findings of Gibberulus gibberulus albus, Morula aspera and Calcinus latens, three species new to the Mediterranean, and of Actaedoes tomentosus, reported for the second time in the basin, are described. Species were classified according to their establishment status and their origins. This contribution highlights the dual origin of biological invasion in Tunisian waters (Red Sea and Atlantic, with slightly more species of Red Sea and Indo-Pacific origin (61,76%.  The impact of the alien species in Tunisian waters was discussed.

  7. An extensive alien plant inventory from the inhabited areas of galapagos.

    Directory of Open Access Journals (Sweden)

    Anne Guézou

    Full Text Available BACKGROUND: Plant invasions are causing habitat degradation in Galapagos. Problems are concentrated on the four inhabited islands. Plants introduced to rural areas in the humid highlands and urban areas on the arid coast act as foci for invasion of the surrounding Galapagos National Park. METHODOLOGY/PRINCIPAL FINDINGS: Here we present results of the most comprehensive inventory to date of alien vascular plants in the inhabited areas of Galapagos. The survey was conducted between 2002 and 2007, in 6031 properties (97% of the total on Floreana, Isabela, San Cristobal and Santa Cruz Islands. In total 754 alien vascular plant taxa were recorded, representing 468 genera in 123 families. Dicotyledons represented 554 taxa, monocotyledons 183, there were 7 gymnosperms and 10 pteridophytes. Almost half (363 of the taxa were herbaceous. The most represented families were Fabaceae (sensu lato, Asteraceae and Poaceae. The three most recorded species in the humid rural areas were Psidium guajava, Passiflora edulis and Bryophyllum pinnatum, and in the dry urban areas, Aloe vera, Portulaca oleracea and Carica papaya. In total, 264 (35% taxa were recorded as naturalized. The most common use for taxa was ornamental (52%. CONCLUSIONS/SIGNIFICANCE: This extensive survey has increased the known alien vascular flora of Galapagos by 257 species, giving a ratio of alien to native taxa of 1.57:1. It provides a crucial baseline for plant invasion management in the archipelago and contributes data for meta analyses of invasion processes worldwide. A repeat of the survey in the future would act as an effective early detection tool to help avoid further invasion of the Galapagos National Park.

  8. A Generic Friction Model for Radial Slider Bearing Simulation Considering Elastic and Plastic Deformation

    Directory of Open Access Journals (Sweden)

    Günter Offner

    2015-06-01

    Full Text Available The investigation of component dynamics is one of the main tasks of internal combustion engine (ICE simulation. This prediction is important in order to understand complex loading conditions, which happen in a running ICE. Due to the need for fuel saving, mechanical friction, in particular in radial slider bearings, is one important investigation target. A generic friction modeling approach for radial slider bearings, which can be applied to lubricated contact regimes, will be presented in this paper. Besides viscous friction, the approach considers in particular boundary friction. The parameterization of the friction model is done using surface material and surface roughness measurement data. Furthermore, fluid properties depending on the applied oil additives are being considered. The application of the model will be demonstrated for a typical engineering task of a connecting rod big end study to outline the effects of contact surface texture. AlSn-based and polymer coated bearing shells will be analyzed and compared with respect to friction reduction effects, running-in behavior and thermal load capabilities.

  9. Preventing, controlling, and managing alien species introduction for the health of aquatic and marine ecosystems

    Science.gov (United States)

    Short, C.I.; Gross, S.K.; Wilkinson, D.

    2004-01-01

    The introduction and spread of invasive species is an emerging global problem. As economic and ecological impacts continue to grow, there will be an increasing need to develop innovative solutions and global partnerships to combat the increasing rate of invasions and their accompanying impacts. Threats to sustainable fisheries in North America associated with alien species come from many global directions and sources and can be deliberate or the unintended consequence of other actions. Decisions about the role of sustainable fisheries in protecting and restoring the health of aquatic ecosystems become even more complex when economic and social factors are considered along with environmental impacts, because many intentionally introduced species also have associated economic and community costs and benefits. Actions designed to prevent or control alien species in an aquatic ecosystem are often complicated by these nonenvironmental factors as well as public perception and opinion. Aquatic ecosystems are disturbed to varying degrees by alien species, including disease organisms. Prevention is the first and best line of defense. Determining likely pathways and effective countermeasures is more cost-effective than either eradication or control. Our ability to quickly identify new species and their associated risk to ecosystems is critical in designing and implementing effective control and management actions. Lack of infrastructure and necessary resources, clear-cut authority for regulation and action, and scientific information about the biology of alien species and effective control techniques are often limiting factors that prevent the needed action to protect aquatic ecosystems.

  10. Alien seas oceans in space

    CERN Document Server

    Lopes, Rosaly

    2013-01-01

    In the early days of planetary observation, oceans were thought to exist in all corners of the Solar System. Carbonated seas percolated beneath the clouds of Venus. Features on the Moon's surface were given names such as "the Bay of Rainbows” and the "Ocean of Storms." With the advent of modern telescopes and spacecraft exploration these ancient concepts of planetary seas have been replaced by the reality of something even more exotic. Alien Seas serves up the current research, past beliefs, and new theories to offer a rich array of the "seas" on other worlds. It is organized by location and by the material composing the oceans under discussion, with expert authors penning chapters on their  specialty. Each chapter features new original art depicting alien seas, as well as the latest ground-based and spacecraft images. With the contributors as guides, readers can explore the wild seas of Jupiter's watery satellite Europa, believed similar in composition to battery acid. Saturn's planet-sized moon Titan see...

  11. Alien encounter a scientific novel

    CERN Document Server

    Schulze-Makuch, Dirk

    2014-01-01

    It has been nearly 100 years since the Apollo moon landings, when Jack and Vladimir, two astronauts on a mission to Venus, discover a mysterious void related to indigenous life on the planet. Subsequently more voids are detected on Earth, Mars, Titan, and, quite ominously, inside a planetoid emerging from the Kuiper belt. Jack is sent to investigate the voids in the Solar System and intercept the planetoid - which, as becomes increasingly clear, is inhabited by alien life forms. Jack and his crew will have little time to understand their alien biochemistry, abilities, behavior patterns, resilience, and technology, but also how these life forms relate to the voids. Humankind's first encounter with these exotic life forms couldn't be more fateful, becoming a race against time to save life on Earth and to reveal the true nature of the voids, which seem to be intrinsically related to life and the universe itself. In this novel, the author combines many topics related to state-of-the-art research in the field of...

  12. Papahanaumokuakea - Laysan Island Invasive Plant Monitoring and Control with Volunteers 2012

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This project supports restoration activities at Laysan Island. Staff and volunteers continue efforts to eradicate alien invasive species Indian dropseed (Sporobolus...

  13. INVENTORY OF THE INVASIVE ALIE N PLANT SPECIES IN INDONESIA

    Directory of Open Access Journals (Sweden)

    SRI S UDARMIYATI T JITROSOEDIRDJO

    2005-01-01

    Full Text Available An inventory of the alien plant species in Indone sia based on the existing references and herbarium specimens concluded that 1936 alien plant species ar e found in Indonesia which belong to 187 families. Field studies should be done to get the complete figur es of alien plant species in Indonesia. Based on the existing figures of the plant species, the invasive alien plant species can be iden tified, followed by studies on the assessment of losses, biology, management and their possible utilizations. Alien plant species are imported to Indonesia for cultivation, collection of the botanical garden, as experimental plants or other curiosities. Aside from plants purposely imported, there are also introduced plant propagules conta-minating imported agricultural products. These alien plant species can be beneficial or have a potential of being invasive. The alien cultivated species consisted of 67% of the total number. More than half of the cultivated plants are ornamental plants. Some of th e species are naturalized or escaped from cultivation and become wild and invasive. Some other natura lized species, adapted well without any problems of invasion. There are 339 species or 17% of the species r ecorded as weeds. The highest record of weeds is found in the family of Poaceae (57 species, follo wed by Asteraceae (53 species and Cyperaceae (35 species. There are 6 families having more than 10 species of weeds: Amaranthaceae, Asteraceae, Cyperaceae, Euphorbiaceae, Poaceae, and Rubiaceae. Three families have more than 100 species: Asteraceae 162 species, Poaceae 120 species, and Papillionaceae 103 species. Five species of aquatic and 20 species of terrestrial plants considered as important alien plant species in Indonesia were identified and some of their distributions noted

  14. A method to calculate and counterbalance the inertia force of slider-crank mechanisms in high-speed presses

    Institute of Scientific and Technical Information of China (English)

    Jim Wang; Sheng-dun Zhao; Hu-shan Shi; Chun-jian Hua

    2009-01-01

    A new method to calculate and counterbalance the inertia force of slider-crank mechanisms in high-speed mechanical presses was put forward. By analyzing the kinematic characteristics of a center-located slider-crank mechanism whose crank rotates at a constant angular velocity, the kinematic parameters of the slide, connecting rod and crank were formulated approximately. On the basis of the results above, three inertia forces and the input moment in the mechanism during its idle running were investigated and formulated by dynamic analysis. A verification experiment was performed on a slider-crank mechanism at a high-speed press machine. The forces derived from the established formulas were compared respectively with those obtained by the ADAMS software and the classical method of connecting rod mass substitution. It was experimentally found that the proposed formulas have an improved performance over related earlier techniques. By use of these results, a 1000 kN 1250 rpm four-point high-speed press machine was designed and manufactured. The slide of this press is driven by four sets of slider-crank mechanisms with symmetrical layout and opposite rotation directions to counterbalance the horizontal inertia forces. Four eccentric counterbalance blocks were designed to counterbalance the vertical force after their mass and equivalent eccentric radius were formulated. The high-speed press machine designed by the proposed counterbalance method has worked with satisfactory performance and good dynamic balance for more than four years in practical production.

  15. The occurrence of alien species in the settlement areas of the Kampinos National Park and its vicinity (Central Poland

    Directory of Open Access Journals (Sweden)

    Kirpluk Izabella

    2015-09-01

    Full Text Available Studies aimed at the identification of the range and method of spread of alien plant species in settlement areas in Kampinos National Park (KNP and its immediate vicinity were carried out in years 2012-2014. Special emphasis was put on surveying the sites of invasive alien species (IAS, and diagnosing potential threats posed to the natural and semi-natural vegetation of the national park by the IAS present in rural areas. We found 53 alien vascular plant species, including 40 invasive taxa which may potentially pose a threat to the ecosystems of KNP. Species encroaching from settlement areas to semi-natural and natural communities included: Bidens frondosa, Echinocystis lobata, Impatiens glandulifera, I. parviflora, Juncus tenuis, Lupinus polyphyllus, Reunoutria japonica and Solidago gigantea. Most of them were species from the highest invasiveness (IV and III classes in Poland. Similarity analysis carried out for all investigated localities with regard to all alien species, and only for invasive ones showed a clear division into separate groups: villages within the boundaries of the national park and villages outside the park.

  16. Alien interference: disruption of infochemical networks by invasive insect herbivores

    NARCIS (Netherlands)

    Desurmont, Gaylord A.; Harvey, Jeff A.; van Dam, Nicole M.; Cristescu, Simona M.; Schiestl, Florian P.; Cozzolino, Salvatore; Anderson, Peter; Larsson, Mattias C.; Kindlmann, Pavel; Danner, Holger; Turlings, Ted C. J.

    2014-01-01

    Insect herbivores trigger various biochemical changes in plants, and as a consequence, affect other organisms that are associated with these plants. Such plant-mediated indirect effects often involve herbivore-induced plant volatiles (HIPVs) that can be used as cues for foraging herbivores and their

  17. Aliens as an Invasive Reproductive Power in Science Fiction

    OpenAIRE

    Moisseeff, Marika

    2013-01-01

    International audience In Brave New World (1932), children are created in test tubes and maternity is held to be a disgraceful remnant of the past that only subsists in reservations for "savages". Eroticism, the privilege of civilized humanity, is part of culture, whereas natural procreation reduces one to sheer animal state. In works of contemporary science fiction, viviparity is depicted as a form of animalizing parasitism. Underlying these representations is the idea that the more "evol...

  18. How Far Could the Alien Boatman Trichocorixa verticalis verticalis Spread? Worldwide Estimation of Its Current and Future Potential Distribution

    OpenAIRE

    Guareschi, Simone; Coccia, Cristina; Sánchez-Fernández, David; Carbonell, José Antonio; Boyero, Luz; Green, Andy J.; Millán, Andrés

    2013-01-01

    Invasions of alien species are considered among the least reversible human impacts, with diversified effects on aquatic ecosystems. Since prevention is the most cost-effective way to avoid biodiversity loss and ecosystem problems, one challenge in ecological research is to understand the limits of the fundamental niche of the species in order to estimate how far invasive species could spread. Trichocorixa verticalis verticalis (Tvv) is a corixid (Hemiptera) originally distributed in North Ame...

  19. Getting the Right Traits: Reproductive and Dispersal Characteristics Predict the Invasiveness of Herbaceous Plant Species

    OpenAIRE

    Moravcová, Lenka; Pyšek, Petr; Jarošík, Vojtěch; Pergl, Jan

    2015-01-01

    To better understand the effect of species traits on plant invasion, we collected comparative data on 20 reproductive and dispersal traits of 93 herbaceous alien species in the Czech Republic, central Europe, introduced after 1500 A. D. We explain plant invasion success, expressed by two measures: invasiveness, i.e. whether the species is naturalized but non-invasive, or invasive; and dominance in plant communities expressed as the mean cover in vegetation plots. We also tested how important ...

  20. 26 CFR 1.871-3 - Residence of alien seamen.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 9 2010-04-01 2010-04-01 false Residence of alien seamen. 1.871-3 Section 1.871... (CONTINUED) INCOME TAXES Nonresident Aliens and Foreign Corporations § 1.871-3 Residence of alien seamen. In order to determine whether an alien seaman is a resident of the United States for purposes of the...

  1. 26 CFR 1.6654-6 - Nonresident alien individuals.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 13 2010-04-01 2010-04-01 false Nonresident alien individuals. 1.6654-6 Section....6654-6 Nonresident alien individuals. (a) In general. A nonresident alien individual is required to... gross income of a nonresident alien individual is such as to require making a payment of...

  2. 45 CFR 1626.5 - Alien status and eligibility.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Alien status and eligibility. 1626.5 Section 1626... RESTRICTIONS ON LEGAL ASSISTANCE TO ALIENS § 1626.5 Alien status and eligibility. Subject to all other... may provide legal assistance to an alien who is present in the United States and who is within one...

  3. 47 CFR 90.115 - Foreign government and alien eligibility.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Foreign government and alien eligibility. 90... government and alien eligibility. (a) No station authorization in the radio services governed by this part....9(c) of this chapter) if such entity is: (1) An alien or the representative of any alien; (2)...

  4. 45 CFR 1626.7 - Verification of eligible alien status.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Verification of eligible alien status. 1626.7... CORPORATION RESTRICTIONS ON LEGAL ASSISTANCE TO ALIENS § 1626.7 Verification of eligible alien status. (a) An alien seeking representation shall submit appropriate documents to verify eligibility, unless the...

  5. 28 CFR 0.47 - Alien property matters.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Alien property matters. 0.47 Section 0.47....47 Alien property matters. The Office of Alien Property shall be a part of the Civil Division: (a... Alien Property: (1) Exercising or performing all the authority, rights, privileges, powers, duties,...

  6. 31 CFR 515.335 - Permanent resident alien.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Permanent resident alien. 515.335... Definitions § 515.335 Permanent resident alien. As used in § 515.208, the term permanent resident alien means an alien lawfully admitted for permanent residence into the United States....

  7. 8 CFR 1240.38 - Fingerprinting of excluded aliens.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Fingerprinting of excluded aliens. 1240.38 Section 1240.38 Aliens and Nationality EXECUTIVE OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT OF JUSTICE IMMIGRATION REGULATIONS PROCEEDINGS TO DETERMINE REMOVABILITY OF ALIENS IN THE UNITED STATES Exclusion...

  8. 8 CFR 1236.2 - Confined aliens, incompetents, and minors.

    Science.gov (United States)

    2010-01-01

    ...(c) of 8 CFR chapter I. (b) Service custody and cost of maintenance. An alien confined because of... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Confined aliens, incompetents, and minors. 1236.2 Section 1236.2 Aliens and Nationality EXECUTIVE OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT...

  9. 22 CFR 40.92 - Aliens unlawfully present.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Aliens unlawfully present. 40.92 Section 40.92... UNDER THE IMMIGRATION AND NATIONALITY ACT, AS AMENDED Aliens Previously Removed § 40.92 Aliens unlawfully present. (a) 3-year bar. An alien described in INA 212(a)(9)(B)(i)(I) shall be ineligible for...

  10. 45 CFR 233.52 - Overpayment to aliens.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Overpayment to aliens. 233.52 Section 233.52... ELIGIBILITY IN FINANCIAL ASSISTANCE PROGRAMS § 233.52 Overpayment to aliens. A State Plan under title IV-A of the Social Security Act, shall provide that: (a) Any sponsor of an alien and the alien shall...

  11. 8 CFR 274a.3 - Continuing employment of unauthorized aliens.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Continuing employment of unauthorized aliens. 274a.3 Section 274a.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS CONTROL OF EMPLOYMENT OF ALIENS Employer Requirements § 274a.3 Continuing employment...

  12. 22 CFR 40.91 - Certain aliens previously removed.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Certain aliens previously removed. 40.91... IMMIGRANTS UNDER THE IMMIGRATION AND NATIONALITY ACT, AS AMENDED Aliens Previously Removed § 40.91 Certain aliens previously removed. (a) 5-year bar. An alien who has been found inadmissible, whether as a...

  13. Aliens.

    Directory of Open Access Journals (Sweden)

    Juliet Fall

    2008-06-01

    Full Text Available Berce du Caucase, Renouée du Japon, Séneçon du Cap, Solidage du Canada : le monde s’invite dans nos jardins et nos paysages. Or, cet exotisme botanique, longtemps valorisé et promu par les Sociétés d’acclimatation, est aujourd’hui perçu comme un important problème écologique. Hors des limites contrôlées de nos jardins publics ou privés, ces plantes nous envahissent. Elles se mobilisent, concurrencent nos espèces indigènes, se dotent de pouvoirs allergènes et nous nuisent. ...

  14. Alienation in Irvine Welsh’s Trainspotting

    Directory of Open Access Journals (Sweden)

    B.A. Senekal

    2010-07-01

    Full Text Available This article examines how Melvin Seeman’s theory of alienation (1959 and modern alienation research manifest in Irvine Welsh’s “Trainspotting”. This is an important novel, not only because of its commercial success, but also because it depicts a specific marginalised subculture. Postmodernism and systems theory approaches, as well as changes in the social and political spheres have motivated researchers such as Geyer (1996, Kalekin-Fishman (1998 and Neal and Collas (2000 to reinterpret Seeman’s theory. This article attempts to incorporate this new theory of alienation in the analysis of contemporary fiction. Seeman identifies five aspects of alienation, namely powerlessness, meaninglessness, normlessness, social isolation and self-estrangement. Following Neal and Collas (2000, in particular, this article omits self-estrangement, but shows how the other four aspects of alienation have changed since Seeman’s formulation. It is argued that “Trainspotting” depicts a specific occurrence of alienation in modern western society, besides normlessness, meaninglessness, and social isolation, highlighting Seeman’s concept of powerlessness, in particular. The article further argues that applying Seeman’s theory of alienation in the study of contemporary literature provides a fresh theoretical approach that contributes to the understanding of how fiction engages with its environment.

  15. Effects of Structural Deformations of the Crank-Slider Mechanism on the Estimation of the Instantaneous Engine Friction Torque

    Science.gov (United States)

    CHALHOUB, N. G.; NEHME, H.; HENEIN, N. A.; BRYZIK, W.

    1999-07-01

    The focus on the current study is to assess the effects of structural deformations of the crankshaft/connecting-rod/piston mechanism on the computation of the instantaneous engine friction torque. This study is performed in a fully controlled environment in order to isolate the effects of structural deformations from those of measurement errors or noise interference. Therefore, a detailed model, accounting for the rigid and flexible motions of the crank-slider mechanism and including engine component friction formulations, is considered in this study. The model is used as a test bed to generate the engine friction torque,Tfa, and to predict the rigid and flexible motions of the system in response to the cylinder gas pressure. The torsional vibrations and the rigid body angular velocity of the crankshaft, as predicted by the detailed model of the crank-slider mechanism, are used along with the engine load torque and the cylinder gas pressure in the (P-ω) method to estimate the engine friction torque,Tfe. This method is well suited for the purpose of this study because its formulation is based on the rigid body model of the crank-slider mechanism. The digital simulation results demonstrate that the exclusion of the structural deformations of the crank-slider mechanism from the formulation of the (P-ω) method leads to an overestimation of the engine friction torque near the top-dead-center (TDC) position of the piston under firing conditions. Moreover, for the remainder of the engine cycle, the estimated friction torque exhibits large oscillations and takes on positive numerical values as if it is inducing energy into the system. Thus, the adverse effects of structural deformations of the crank-slider mechanism on the estimation of the engine friction torque greatly differ in their nature from one phase of the engine cycle to another.

  16. Myth And Migration: Alienation And Belonging In Recent Asian-Australian Picture Books

    OpenAIRE

    Wenche Ommundsen

    2009-01-01

    From Exodus to the American Dream, from Terra Nulli us to the Yellow Peril to multicultural harmony, migration has provided a rich source of myth throughout human history. It engenders dreams, fears and memor ies in both migrant and resident populations; giving rise to hope for a new start an d a bright future, feelings of exile and alienation, nostalgia for lost homelands, dreams of belonging and entitlement, fears of invasion, dispossession and cultural extinct...

  17. Competition between the alien Bidens frondosa and its native congener Bidens tripartita

    Czech Academy of Sciences Publication Activity Database

    Gruberová, Helena; Prach, Karel

    Leiden : Backhuys Publishers, 2003 - (Child, L.; Brock, J.; Brundu, G.; Prach, K.; Pyšek, P.; Wade, P.; Williamson, M.), s. 227-235 ISBN 90-5782-135-4. [International Conference on the Ecology and Management of Alien Plant Invasions (EMAPI)/6./. Loughborough (GB), 12.09.2001-15.09.2001] R&D Projects: GA AV ČR KSK6005114 Keywords : Bidens frondosa * Bidens tripartita Subject RIV: EF - Botanics

  18. Alien flora of Europe: Species diversity, temporal trends, geographical patterns and research needs

    OpenAIRE

    Lambdon, Philip; Pyšek, Petr; Basnou, Corina; Hejda, Martin; Arianoutsou, Margarita; Essl, Franz; Jarošík, Vojtěch; Pergl, Jan; Winter, M.; Anastasiu, P.; Andriopoulos, P.; Bazos, I.; Brundu,Giuseppe; Celesti-Grapow, Laura; P. Chassot

    2008-01-01

    The paper provides the first estimate of the composition and structure of alien plants occurring in the wild in the European continent, based on the results of the DAISIE project (2004-2008), funded by the 6th Framework Programme of the European Union and aimed at >creating an inventory of invasive species that threaten European terrestrial, freshwater and marine environments>. The plant section of the DAISIE database is based on national checklists from 48 European countries/ regions and Isr...

  19. Alien species on the coasts of Turkey

    OpenAIRE

    M.E. CINAR; Bilecenoglu, M; Ozturk, B.; T. KATAGAN; V. AYSEL

    2012-01-01

    The compilation of data on alien species reported from the Turkish coasts yielded a total of 263 species belonging to 11 systematic groups, of which Mollusca had the highest number of species (85 species), followed by Crustacea (51), fishes (43) and phytobenthos (39). The Black Sea is represented by a total of 20 alien species, the Sea of Marmara by 48 species, the Aegean Sea by 98 species and the Levantine Sea by 202 species. The majority of aliens found in the Black Sea and the Sea of Marma...

  20. God-Belief, Self- Detection, Alienation

    OpenAIRE

    Dr Majid Sadeghi Hasan Abadi; Mahdi Ganjvar

    2010-01-01

    According to some Western thinkers, considering earthy and compelled human alongside with the heavenly and compelling God can result in nothing but human’s alienation and transduction of alien personality in his mind and spirit. Basically, man’s realization of alienation and its type has a close relationship with the way of consideration of human and his nature. Of course type of human regard to God and kind of God that a religion defines, is another altered factor that into the s...

  1. Resource competition in plant invasions: emerging patterns and research needs

    OpenAIRE

    Margherita eGioria; Bruce Arthur Osborne

    2014-01-01

    Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relatively to that of other mechanisms, at different stages of an invasion ...

  2. Impact of invasive plants on food webs and pathways

    OpenAIRE

    Sikai Wang; Qiang Sheng; Tianjiang Chu; Bo Li; Jiakuan Chen; Jihua Wu

    2013-01-01

    In natural ecosystems, energy mainly flows along food chains in food webs. Numerous studies have shown that plant invasions influence ecosystem functions through altering food webs. In recent decades, more attention has been paid to the effects of alien plants on local food webs. In this review, we analyze the influence of exotic plants on food webs and pathways, and explore the impacts of local food web characteristics on community invasibility. Invasive plants alter food webs mainly by chan...

  3. Resource competition in plant invasions: emerging patterns and research needs

    OpenAIRE

    Gioria, Margherita; Osborne, Bruce A.

    2014-01-01

    Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion pr...

  4. Rocky shores of a major southern African Marine Protected Area are almost free from intertidal invertebrate alien species

    Directory of Open Access Journals (Sweden)

    Hanlie Malherbe

    2014-02-01

    Full Text Available A major threat to marine ecosystems is the establishment and proliferation of invasive alien species. This study addresses gaps in our knowledge regarding marine alien invertebrate species in the Kogelberg Biosphere Reserve (KBR and adjacent Betty’s Bay Marine Protected Area (MPA in the Western Cape of South Africa, together a potentially important area for south-coast marine conservation. Understanding the distribution and geographical expansion of these species is critical for conservation planning. A quantitative systematic survey of the intertidal rocky shore region was undertaken. The mytilid Mediterranean mussel, Mytilus galloprovincialis, and the bryozoan Watersipora subtorquata were the only alien species recorded along the coastline, which included the MPA. The abundance of M. galloprovincialis was significantly higher outside the MPA, and the abundance of W. subtorquata was significantly higher inside the MPA. With only two alien species recorded, the Betty’s Bay MPA and its surroundings support relatively few marine alien species with regards to rocky shore invertebrate biodiversity. Conservation implications: It is important that the Betty’s Bay MPA and its adjacent coastline maintain its current status as an area with relatively few marine alien species. The conservation implications on management require routine surveys of this region to detect early introductions of any additional species.

  5. The alien terrestrial invertebrate fauna of the High Arctic archipelago of Svalbard: potential implications for the native flora and fauna

    Directory of Open Access Journals (Sweden)

    Stephen J. Coulson

    2015-09-01

    Full Text Available Experience from the Antarctic indicates that the establishment of alien species may have significant negative effects on native flora and fauna in polar regions and is considered to be amongst the greatest threats to biodiversity. But, there have been few similar studies from the Arctic. Although the terrestrial invertebrate inventory of the Svalbard Archipelago is amongst the most complete for any region of the Arctic, no consideration has yet been made of alien terrestrial invertebrate species, their invasiveness tendencies, threat to the native biology or their route of entry. Such baseline information is critical for appropriate management strategies. Fifteen alien invertebrate species have established in the Svalbard environment, many of which have been introduced via imported soils. Biosecurity legislation now prohibits such activities. None of the recorded established aliens yet show invasive tendencies but some may have locally negative effects. Ten species are considered to be vagrants and a further seven are classified as observations. Vagrants and the observations are not believed to be able to establish in the current tundra environment. The high connectivity of Svalbard has facilitated natural dispersal processes and may explain why few alien species are recorded compared to isolated islands in the maritime Antarctic. The vagrant species observed are conspicuous Lepidoptera, implying that less evident vagrant species are also arriving regularly. Projected climate change may enable vagrant species to establish, with results that are difficult to foresee.

  6. Alien Marine Species in the Mediterranean - the 100 ‘Worst Invasives’ and their Impact

    Directory of Open Access Journals (Sweden)

    N. STREFTARIS

    2012-12-01

    Full Text Available A number of marine alien species have been described as invasive or locally invasive in the Mediterranean because of their proliferation, and/or their geographical spread and/or impact on native populations. Based on that information and on the documented impact they have on the biodiversity and socioeconomics of the basin, a preliminary list of the 100 ‘worst’ Invasive Alien Species (IAS in the Mediterranean has been produced and presented in this work along with details on their impact. Emphasis is given to their impact on socioeconomics (fi sheries/aquaculture, health & sanitation, infrastructure & building, documented for 43 species. Such selection of the ‘worst’ IAS was diffi cult and controversial and is expected to attract much attention and scientifi c criticism since not only can the documentation of the impact of IAS be controversial, but also their inventory can be biased towards the effort and resources devoted to the study of the impact of certain species/taxonomic groups. Thus, while marine plants (phytobenthos and phytoplankton are fairly well studied, less attention has been paid to the impact of vertebrates and even less to invertebrates. Nevertheless, the list highlights the need for continued research on the issue (monitoring aliens and their impact for an integrated ecosystem based management approach over the entire area. The preliminary list can provide the basis for selecting indicator species within the Mediterranean and thus be the common ground to build cooperation about IAS within countries in the region.

  7. Ferrofluid Lubrication of a Rough Porous Hyperbolic Slider Bearing with Slip Velocity

    Directory of Open Access Journals (Sweden)

    S.J. Patel

    2014-09-01

    Full Text Available An attempt has been made to study and analyze the combined effect of roughness and slip velocity on the performance of a ferrofluid based rough porous hyperbolic slider bearing. Beavers and Joseph’s slip model has been used to evaluate the effect of slip velocity. The stochastic modeling of Christensen and Tonder has been employed to estimate the effect of transverse surface roughness. The associated Reynolds’ type equation is solved with suitable boundary conditions to obtain the pressure distribution leading to the calculation of load carrying capacity. Further, the expressions for friction and position of centre of pressure are obtained. It is observed that the bearing system gets adversely affected by the transverse surface roughness. The slip velocity further enhances this adverse effect. However, the magnetization saves the situation in the case of negatively skewed roughness when variance (-ve occurs. But for an overall improved performance of the bearing the lower values of slip parameter may be favorable.

  8. On the Performance of Pivoted Curved Slider Bearings: Rabinowitsch Fluid Model

    Directory of Open Access Journals (Sweden)

    U.P. Singh

    2012-09-01

    Full Text Available The present theoretical analysis is to investigate the effect of nonNewtonian Pseudoplastic & Dilatant lubricants (lubricant blended with viscosity index improver–Rabinowitsch fluid model on the dynamic stiffness and damping characteristics of pivoted curved slider bearings. The modified Reynolds equation has been obtained for steady and damping states of the bearing. To analyze the steady state characteristics and dynamic characteristics, small perturbation theory has been adopted. The results for the steady state bearing performance characteristics (steady state film pressure, load carrying capacity and centre of pressure as well as dynamic stiffness and damping characteristics have been calculated numerically for various values of viscosity index improver using Mathematical 7.0 and it is concluded that these characteristics vary significantly with the non-Newtonian behavior of the fluid consistent with the real nature of the problem.

  9. Energy Extraction from a Slider-Crank Wave Energy under Irregular Wave Conditions: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun; Zhang, James Z.; Muljadi, Eduard; Yu, Yi-Hsiang

    2015-08-24

    A slider-crank wave energy converter (WEC) is a novel energy conversion device. It converts wave energy into electricity at a relatively high efficiency, and it features a simple structure. Past analysis on this particular WEC has been done under regular sinusoidal wave conditions, and suboptimal energy could be achieved. This paper presents the analysis of the system under irregular wave conditions; a time-domain hydrodynamics model is adopted and a rule-based control methodology is introduced to better serve the irregular wave conditions. Results from the simulations show that the performance of the system under irregular wave conditions is different from that under regular sinusoidal wave conditions, but a reasonable amount of energy can still be extracted.

  10. Non-linear effects in the support motion of an elastically mounted slider crank mechanism

    Science.gov (United States)

    Davidson, I.

    1983-01-01

    A study is made of an in-line slider crank mechanism in which the sliding mass is elastically supported. The ratio of crank length to connecting rod length is not assumed small and relatively large displacements of the support are allowed. Ordinary and parametric non-linear terms are thus retained in the equations of motion. It is shown that the presence of parametric terms gives rise to additional conditions for resonance in the support motion. Approximate solutions are obtained for the fundamental and half subharmonic steady state responses and the effect of the non-linear and parametric terms examined. The stability of the steady state responses is considered and it is shown that instability is associated with a negative slope of the amplitude frequency characteristic.

  11. Reliability analysis of kinematic accuracy for the elastic slider-crank mechanism

    Institute of Scientific and Technical Information of China (English)

    TUO Yaofei; CHEN Jianjun; ZHANG Chijiang; CHEN Yongqin

    2007-01-01

    This paper deals with the static and dynamic output kinematic accuracy of a group of elastic slider-crank mechanisms with the same design parameters by taking the bar length,the joint-gaps,the mass density,and the sectional and the physical parameters as random variables.According to the principle of linear pile-up of small displacement,the static and dynamic output kinematic errors are synthesized,and the reliability model of the kinematic accuracy of the mechanism is built.Through an example,a study of the influencing factors on the reliability of the output kinematic accuracy of the mechanism is made.The results obtained reveal the following facts:with the increase of the crank's rotating speed,the dynamic elastic deformation of the mechanism becomes the principal factor that greatly affects the reliability of the output kinematic accuracy of the mechanism.

  12. Energy Extraction from a Slider-Crank Wave Energy Converter under Irregular Wave Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun; Zhang, James Z.; Muljadi, Eduard; Yu, Yi-Hsiang

    2015-10-19

    A slider-crank wave energy converter (WEC) is a novel energy conversion device. It converts wave energy into electricity at a relatively high efficiency, and it features a simple structure. Past analysis on this particular WEC has been done under regular sinusoidal wave conditions, and suboptimal energy could be achieved. This paper presents the analysis of the system under irregular wave conditions; a time-domain hydrodynamics model is adopted and a rule-based control methodology is introduced to better serve the irregular wave conditions. Results from the simulations show that the performance of the system under irregular wave conditions is different from that under regular sinusoidal wave conditions, but a reasonable amount of energy can still be extracted.

  13. Irregular Wave Energy Extraction Analysis for a Slider Crank WEC Power Take-Off System

    Energy Technology Data Exchange (ETDEWEB)

    Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun; Zhang, James Z.; Muljadi, Eduard

    2015-09-02

    Slider crank Wave Energy Converter (WEC) is a novel energy conversion device. It converts wave energy into electricity at a relatively high efficiency, and it features a simple structure. Past analysis on this WEC has been done under regular sinusoidal wave conditions, and a suboptimal energy could be achieved. This paper presents the analysis of the system under irregular wave conditions; a time-domain hydrodynamics model is adopted and the control methodology is modified to better serve the irregular wave conditions. Results from the simulations show that the performance of the system under irregular wave conditions is different from that under regular sinusoidal wave conditions, but still a reasonable amount of energy can be extracted.

  14. The Affective Slider: A Digital Self-Assessment Scale for the Measurement of Human Emotions

    Science.gov (United States)

    Betella, Alberto; Verschure, Paul F. M. J.

    2016-01-01

    Self-assessment methods are broadly employed in emotion research for the collection of subjective affective ratings. The Self-Assessment Manikin (SAM), a pictorial scale developed in the eighties for the measurement of pleasure, arousal, and dominance, is still among the most popular self-reporting tools, despite having been conceived upon design principles which are today obsolete. By leveraging on state-of-the-art user interfaces and metacommunicative pictorial representations, we developed the Affective Slider (AS), a digital self-reporting tool composed of two slider controls for the quick assessment of pleasure and arousal. To empirically validate the AS, we conducted a systematic comparison between AS and SAM in a task involving the emotional assessment of a series of images taken from the International Affective Picture System (IAPS), a database composed of pictures representing a wide range of semantic categories often used as a benchmark in psychological studies. Our results show that the AS is equivalent to SAM in the self-assessment of pleasure and arousal, with two added advantages: the AS does not require written instructions and it can be easily reproduced in latest-generation digital devices, including smartphones and tablets. Moreover, we compared new and normative IAPS ratings and found a general drop in reported arousal of pictorial stimuli. Not only do our results demonstrate that legacy scales for the self-report of affect can be replaced with new measurement tools developed in accordance to modern design principles, but also that standardized sets of stimuli which are widely adopted in research on human emotion are not as effective as they were in the past due to a general desensitization towards highly arousing content. PMID:26849361

  15. The Affective Slider: A Digital Self-Assessment Scale for the Measurement of Human Emotions.

    Directory of Open Access Journals (Sweden)

    Alberto Betella

    Full Text Available Self-assessment methods are broadly employed in emotion research for the collection of subjective affective ratings. The Self-Assessment Manikin (SAM, a pictorial scale developed in the eighties for the measurement of pleasure, arousal, and dominance, is still among the most popular self-reporting tools, despite having been conceived upon design principles which are today obsolete. By leveraging on state-of-the-art user interfaces and metacommunicative pictorial representations, we developed the Affective Slider (AS, a digital self-reporting tool composed of two slider controls for the quick assessment of pleasure and arousal. To empirically validate the AS, we conducted a systematic comparison between AS and SAM in a task involving the emotional assessment of a series of images taken from the International Affective Picture System (IAPS, a database composed of pictures representing a wide range of semantic categories often used as a benchmark in psychological studies. Our results show that the AS is equivalent to SAM in the self-assessment of pleasure and arousal, with two added advantages: the AS does not require written instructions and it can be easily reproduced in latest-generation digital devices, including smartphones and tablets. Moreover, we compared new and normative IAPS ratings and found a general drop in reported arousal of pictorial stimuli. Not only do our results demonstrate that legacy scales for the self-report of affect can be replaced with new measurement tools developed in accordance to modern design principles, but also that standardized sets of stimuli which are widely adopted in research on human emotion are not as effective as they were in the past due to a general desensitization towards highly arousing content.

  16. Language skills and earnings among legalized aliens

    OpenAIRE

    Miller, Paul W.; Chiswick, Barry R.

    1999-01-01

    This paper uses the data on males and females from the 1989 Legalized Population Survey (LPS), a sample of aliens granted amnesty under 1986 Immigration Reform and Control Act, to analyse English language proficiency and earnings. We use a model of English language proficiency that is based on economic incentives, exposure and efficiency variables that measure the costs and benefits of aquiring English language skills. Consistent with the model, in this sample of former illegal aliens, Englis...

  17. PHEMERANTHUS CONFERTIFLORUS: NEW ALIEN SPECIES TO EUROPE

    OpenAIRE

    NAGODĂ Eugenia; COMĂNESCU Petronela; ANASTASIU Paulina

    2013-01-01

    Phemeranthus confertiflorus (Montiaceae) is reported as a new alien species to Europe. It is native to North America and used as decorative in rock gardens. The specimens of this plant were collected in Bucharest (Romania) and deposited in BUC. The mode of introduction of the plant is unknown, most likely escaped from cultivation. Data about habitat and population of the taxon are presented. One of the plants that accompany Phemeranthus confertiflorus is also an alien to Europe – Portulaca pi...

  18. Alien species on the coasts of Turkey

    Directory of Open Access Journals (Sweden)

    M.E. CINAR

    2012-12-01

    Full Text Available The compilation of data on alien species reported from the Turkish coasts yielded a total of 263 species belonging to 11 systematic groups, of which Mollusca had the highest number of species (85 species, followed by Crustacea (51, fishes (43 and phytobenthos (39. The Black Sea is represented by a total of 20 alien species, the Sea of Marmara by 48 species, the Aegean Sea by 98 species and the Levantine Sea by 202 species. The majority of aliens found in the Black Sea and the Sea of Marmara were transported via shipping, whereas the Levantine coast is extensively subjected to Lessepsian migration. Benthic habitats (soft and hard substrata comprise 76% of the total alien species and the pelagic environment is inhabited by thirty-nine species. Almost 50% of aliens collected from the Turkish coasts were found only at 0-10 m depth. Eight species occur at depths deeper than 100 m. The impacts of aliens on the benthic and pelagic ecosystems are presented.

  19. Alien plants in urban nature reserves: from red-list species to future invaders?

    Directory of Open Access Journals (Sweden)

    Vojtěch Jarošik

    2011-10-01

    Full Text Available Urban reserves, as other protected areas, are aimed at preserving species richness but the conservation effort in these protected areas is complicated by a high proportion of alien species. We examined which environmental factors determine the representation of alien species in 48 city reserves of Prague, Czech Republic, distinguishing between archaeophytes, i.e. alien species introduced since the beginning of Neolithic agriculture up to 1500 A. D., and neophytes, i.e. modern invaders introduced after that date, with the former group separately analysed for endangered archaeophytes (listed as C1 and C2 categories on national red list. Archaeophytes responded positively to the extent of arable land that was in place at the time of the reserve establishment, and to a low altitudinal range. Neophytes, beside soil properties responded to recent human activities proxied by current proportion of built-up area in the reserves. Endangered archaeophytes, besides the same affinity for past arable land as other archaeophytes, were supported by the presence of current wasteland habitats in the reserve. This suggests that for endangered archaeophytes it might have been difficult to adapt to changing agricultural practices, and ruderal wasteland might act as a refugium for them. From the viewpoint of conservation, ruderal habitats of nature reserves thus can be more important than was previously though. Forty-six of the 155 neophytes recorded in the reserves are classified as invasive. The reserves thus harbour 67% of the 69 invasive neophytes recorded in the country, and particularly warning is that among the most invasive species are many shrubs and trees, a life form that is known to account for widespread invasions with high impacts. Our results thus strongly suggest that in Prague nature reserves there is a warning potential for future invasions.

  20. Modified technique of using conventional slider boat for liquid phase epitaxy of silicon for solar cell application

    Indian Academy of Sciences (India)

    D Majumdar; S Chatterjee; U Gangopadhyay; H Saha

    2003-10-01

    Epitaxial layers of silicon are grown on single crystal Si-substrate from a solution of silicon in indium using conventional graphite slider boat technique. The important problems of natural convection due to lower density of silicon compared to indium, poor wetting of substrate due to high angle of contact of indium solution on silicon substrate resulting in poor nucleation, melt removal from the growth substrate and saturation wafer associated with LPE in this technique are practically eliminated using sandwich method with simple modifications of the boat and the method of growth. Some experimental studies on the effect of different surface preparations of growth substrate are also reported. Growth results are shown and discussed. Further, improvization of slider boat to facilitate better study of growth parameters is suggested in the line of modification already carried out.

  1. PC-based pseudo-model following discrete integral variable structure control of positions in slider-crank mechanisms

    Science.gov (United States)

    Chuang, Chin-Wen

    2007-04-01

    This paper proposes a pseudo-model following (PMF) discrete integral variable structure control (DIVSC) scheme to control the position of a slider crank coupled with a pseudo-model (PM) synchronous motor. Applying the Grey modeling method, the reference model and plant are on-line converted to pseudo-reference model and accumulated model, respectively. The advantage is that the least data and memory are used in this modeling procedure. The DIVSC is introduced to guide the model following motion. The integral controller is used to reduce the steady-state error. The switching controller is used to finish the sliding motion. The two existing condition of the discrete sliding mode are introduced in this paper, too. Finally, the position control of the slider crank is used to show the performance of the proposed control scheme. The simulation and experimental results show the robustness and the practicability.

  2. Traits of reproductive biology associated with invasiveness in alien invasive plant Phytolacca americana%外来入侵植物美洲商陆的繁殖生物学特性及其与入侵性的关系

    Institute of Scientific and Technical Information of China (English)

    周兵; 闫小红; 肖宜安; 张争光; 李晓红; 杨佳琴

    2013-01-01

    Phytolacca americana is one of the widespread invasive weeds in Phytolaccaceae in China. The reproductive traits of this species such as phenology of flowering, floral syndrome, breeding system and seed germination characteristics were studied by experimental observation and bagging treatment to assess the association of these reproductive traits with invasiveness. P. americana flowered during June to August every year in Ji’an city. The lifespan of a single capitulum was approximately 6 to 7 days, 2 to 4 days for a single flower. The diameter, stamen length, style length and stigma diameter were (6.43 ± 0.15), (2.83 ± 0.10), (0.92 ± 0.06) and (1.02 ± 0.08) mm respectively. Bagged flowers without emasculation showed high maturing rate (93.33±1.92)% which means a high self-compatibility, but it also exhibited a certain cross-compatibility with a maturing rate of (42.22±2.22)% in the emasculation treatment, its P/O ratio was 372.37 ± 31.24, and out-crossing index was 3, which suggests that the breeding system of P. americana is facultative selfing, and sometimes needs pollinators. The main floral visitors were insects of Apidae, Vespidae, Sarcophagidae, Syrphidae. The thousand seed weight was 6.43 g, the seed emerged relatively lowly, but orderly and with a long life activity. Our experimental findings suggested that the reproductive traits such as the versatile mating system of self- and cross-pollination, high seed production, long seed life span and strong asexual capacity might contribute to the invasive capability of P. americana.%  美洲商陆(Phytolacca americana)是一种我国广泛分布的商陆科入侵植物。通过实验观察和人工控制套袋等方法,对其开花动态、花部综合特征、繁育系统和种子萌发率等与繁殖相关的特性进行了研究,探讨了这些繁殖特性与入侵性的关系。结果表明,美洲商陆每年6—8月开花,单花序的花期为6~7 d,单花的花期为2~4 d。其花

  3. Socioeconomic and livelihood impact of invasive species on marginal homesteads: the case of aceria guerreronis on coconut palms in India

    OpenAIRE

    Aravindakshan, Sreejith

    2011-01-01

    Alien invasive species are non-native organisms that occur outside their natural adapted habitat and dispersal potential. They are seen as a threat not only to biodiversity and ecosystems, but also to socioeconomic development, livelihood and human well-being. In India, the bioinvasion of coconut palms by an alien invasive mite species Aceria guerreronis, popularly known as ‘Coconut mite’ accounting for enormous economic loss was first noticed just before the start of the new millennium. Amon...

  4. Do abundance and proximity of the alien Impatiens glandulifera affect pollination and reproductive success of two sympatric co-flowering native species?

    Directory of Open Access Journals (Sweden)

    Anne-Laure Jacquemart

    2012-12-01

    Full Text Available In invasion ecology, potential impacts of aliens on native flora are still under debate. Our aim was to determine the pollinator mediated effects of both proximity and abundance of an alien species on the reproductive success of natives. We chose the highly invasive Impatiens glandulifera and two native species: Epilobium angustifolium and Aconitum napellus ssp. lusitanicum. These species share characteristics allowing for pollination interactions: similar biotopes, overlapping flowering periods and same main pollinators. The effects of abundance (5, 25 and 100 individuals and proximity (0 and 15 m of the alien on visitation rate, insect behaviour, pollen deposition and reproductive success of both natives were investigated during 2 flowering seasons. We used centred visitation rates as they can be directly interpreted as a positive or negative effect of the invasive.Both abundance and proximity of the alien increased bumblebee visitation rates to both natives. On the other hand, abundance of the exotic species had a slight negative effect on honeybee visits to natives while its proximity had no effect. The behaviour of bumblebees changed as visitors left significantly more often the native plants for I. glandulifera when its abundance increased. As a consequence of this “inconstancy”, bees deposited considerable quantities of alien pollen on native stigmas. Nevertheless, this interspecific pollen transfer did not decrease seed set in natives. Self-compatibility and high attractiveness of both native species probably alleviate the risk of altered pollinator services and reproductive success due to the invader in natural populations.

  5. Transferring alien genes to wheat

    International Nuclear Information System (INIS)

    In broad terms an alien gene can be considered to be any gene transferred to wheat from a related species. As described above by Maan (section 7D) the genus Triticum contains a broad range of species, some of which cross readily with the cultivated tetraploid (T. Turgidum L.) or hexaploid (T. aestivum L.) wheats, and others only with great difficulty. In addition, wheat will also cross with species in a number of other genera including Agropyron, Elymus, Elytrigia (=Agropyron), Haynaldia, Hordeum, and Secale (Riley and Kimber, 1966; Knobloch, 1968; Feldman and Sears, 1981). In discussing the Triticum and Aegilops spp., the classification by Kimber and Sears, section SA-I, above, will be followed. For the Agropyron and related species the classification described by Dewey (1983) will be used. To avoid confusion, in referring to the literature the designations used by the authors will be given, followed by the new designation. The wild relatives of wheat are adapted to a broad range of environments and carry a large reservoir of useful genes (Zohary et al., 1969; Kerber and Dyck, 1973; Brezhnev, 1977; Feldman and Sears, 1981; Limin and Fowler, 1981; Sharma et aI., 1981; McGuire and Dvorak, 1981). Initially they were considered to be primarily sources of disease resistance, but more recently they have been recognized as potential sources of genes for high protein, cold tolerance, salt tolerance, drought tolerance, lodging resistance, early maturity, and even yield. Extensive screening of the wild relatives of wheat needs to be done before their useful genes can be fully utilized

  6. Alien hand syndrome: Contradictive movement and disorder of color discrimination

    OpenAIRE

    Wang X; Fan C; Zhou J

    2004-01-01

    A senile Chinese female patient with alien hand syndrome of vascular etiology is reported. This case exhibited contradictive movement, left-lateral paresis and disorder of color discrimination, which might be a new subtype of the alien limb syndrome.

  7. Updated review of marine alien species and other ‘newcomers’ recorded from the Maltese Islands (Central Mediterranean

    Directory of Open Access Journals (Sweden)

    J. EVANS

    2015-01-01

    Full Text Available An updated review of marine alien species and other ‘newcomers’ recorded from the Maltese Islands is presented on account of new records and amendments to a previous review in 2007. Species were classified according to their establishment status (‘Questionable’, ‘Casual’, ‘Established’, ‘Invasive’ and origin (‘Alien’, ‘Range expansion’, ‘Cryptogenic’. A total of 31 species were added to the inventory, while 6 species have been removed, bringing the total number of species to 73. Of these, 66 are considered to be aliens (or putative aliens but with uncertain origin with the remaining 7 resulting from range expansion. Six records are considered to be questionable and hence unverified. For verified records, the dominant taxonomic groups are Mollusca (represented by 21 species and Actinopterygii (15 species, followed by Crustacea (8 species and Rhodophyta (7 species. Eight of these species (aliens: Caulerpa cylindracea, Lophocladia lallemandi, Womersleyella setacea, Brachidontes pharaonis, Percnon gibbesi, Fistularia commersonii, Siganus luridus; range extender: Sphoeroides pachygaster are considered to be invasive. The introduction pathway for 30 species is unknown. Amongst the alien species, ‘Shipping’ is the most common introduction pathway, followed by ‘Secondary dispersal’ from elsewhere in the Mediterranean Sea. An increasing trend in the number of alien marine species reported from the Maltese Islands is evident, with a peak of 22 species recorded during the last decade (2001–2010. A discussion on the rationale for including range-expanding species in national inventories of recent arrivals, and in the analysis of trends in records from the Maltese Islands, is included. In particular, the general warming trend of Mediterranean surface waters appears to be facilitating the westward spread of thermophilic alien species from the Eastern to the Central Mediterranean, and the eastward range expansion of

  8. Drivers and Outcomes of Work Alienation: Reviving a Concept

    OpenAIRE

    Shantz, Amanda; Alfes, K.; Bailey, C; E. Soane

    2015-01-01

    This article sheds new light on an understudied construct in mainstream management theory, namely, work alienation. This is an important area of study because previous research indicates that work alienation is associated with important individual and organizational outcomes. We tested four antecedents of work alienation: decision-making autonomy, task variety, task identity, and social support. Moreover, we examined two outcomes of alienation: deviance and performance, the former measured...

  9. Simulation of a head slider considering a discrete track recording technology

    International Nuclear Information System (INIS)

    Discrete track recording (DTR) is a new application technology that utilizes a separate physical storage disk with grooves and ridges comprised of radial and circumferential direction in order to achieve higher data transfer rates and storage densities on a hard disk drive (HDD). However, the grooves and ridges on the DTR media cause flying stability issues. Therefore, we analyze and compare the dynamic performance of a head slider with three types of DTR media in which different DTR parameters are defined, such as groove width and pitch. Prior to simulations, we propose the DTR flying height (FH) loss equation which estimates a loss of FH on the DTR media using the defined DTR parameters. The accuracy and creditability of this equation is then predicted by comparing the results of the equation to those of the simulation. Consequently, we propose a method for designing the air bearing surface (ABS) on the DTR media using the static performance of the ABS on a continuous track recording (CTR) along with the proposed DTR FH loss equation

  10. THE DEFORMATION EFFECT OF VM SLIDER MULTI COMPLEX MACHINE SERIES ON PRECISION MACHINING

    Directory of Open Access Journals (Sweden)

    Berezhnoy S. B.

    2015-09-01

    Full Text Available The article is devoted to the problems of increasing the economic growth of the Russian Federation, the development of high-tech knowledge-intensive manufacturing industries on the basis of a fundamentally new technological order, new unmanned technologies. The measures to improve the accuracy of manufacturing of complex and large-sized parts. Currently, the technical level of many sectors of the economy is largely determined by the level of production of means of production. The basis of these means is the machine tool industry. On the basis of machine tool development we handle a comprehensive mechanization and automation of production processes in industry, construction, agriculture, transport and other industries. We completed a comprehensive analysis of the errors affecting the manufacturing precision parts. The activities for improving the accuracy of manufacture based on VM 32 multi-machine complex series were proposed. We made the analysis of the cutting forces influence and the cross-sectional shape of the slide on its deformation for various types of processing. We determined the optimal shape of the cross section of the slider to increase stiffness and reduce deformation of the slide in metal cutting

  11. Mitochondrial responses to prolonged anoxia in brain of red-eared slider turtles.

    Science.gov (United States)

    Pamenter, Matthew E; Gomez, Crisostomo R; Richards, Jeffrey G; Milsom, William K

    2016-01-01

    Mitochondria are central to aerobic energy production and play a key role in neuronal signalling. During anoxia, however, the mitochondria of most vertebrates initiate deleterious cell death cascades. Nonetheless, a handful of vertebrate species, including some freshwater turtles, are remarkably tolerant of low oxygen environments and survive months of anoxia without apparent damage to brain tissue. This tolerance suggests that mitochondria in the brains of such species are adapted to withstand prolonged anoxia, but little is known about potential neuroprotective responses. In this study, we address such mechanisms by comparing mitochondrial function between brain tissues isolated from cold-acclimated red-eared slider turtles (Trachemys scripta elegans) exposed to two weeks of either normoxia or anoxia. We found that brain mitochondria from anoxia-acclimated turtles exhibited a unique phenotype of remodelling relative to normoxic controls, including: (i) decreased citrate synthase and F1FO-ATPase activity but maintained protein content, (ii) markedly reduced aerobic capacity, and (iii) mild uncoupling of the mitochondrial proton gradient. These data suggest that turtle brain mitochondria respond to low oxygen stress with a unique suite of changes tailored towards neuroprotection. PMID:26763217

  12. Transient alien limb phenomenon in right frontoparietal infarction

    OpenAIRE

    Panda Samhita

    2010-01-01

    Alien limb phenomenon is associated with different neurological disorders, such as stroke and corticobasal degeneration. It is usually caused by involvement of the corpus callosum, with or without the frontal regions. Rarely, it can result from insult in the posterior cerebral artery territory. Alien limb phenomenon is generally persistent. Here, an unusual case of transient alien hand phenomenon is reported.

  13. 7 CFR 273.4 - Citizenship and alien status.

    Science.gov (United States)

    2010-01-01

    ....” means that the alien is lawfully present as defined at 8 CFR 103.12(a). (b) Reporting illegal aliens. (1... participating in the Program from any demand made under 8 CFR 213a.4(a) for the value of food stamp benefits... 7 Agriculture 4 2010-01-01 2010-01-01 false Citizenship and alien status. 273.4 Section...

  14. Transient alien limb phenomenon in right frontoparietal infarction

    Directory of Open Access Journals (Sweden)

    Panda Samhita

    2010-01-01

    Full Text Available Alien limb phenomenon is associated with different neurological disorders, such as stroke and corticobasal degeneration. It is usually caused by involvement of the corpus callosum, with or without the frontal regions. Rarely, it can result from insult in the posterior cerebral artery territory. Alien limb phenomenon is generally persistent. Here, an unusual case of transient alien hand phenomenon is reported.

  15. 32 CFR 1630.46 - Class 4-T: Treaty alien.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Class 4-T: Treaty alien. 1630.46 Section 1630.46 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM CLASSIFICATION RULES § 1630.46 Class 4-T: Treaty alien. In Class 4-T shall be placed any registrant who is an alien...

  16. 32 CFR 1602.3 - Aliens and nationals.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Aliens and nationals. 1602.3 Section 1602.3 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM DEFINITIONS § 1602.3 Aliens and nationals. (a) The term alien means any person who is not a citizen or national of...

  17. 22 CFR 41.55 - Aliens with extraordinary ability.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Aliens with extraordinary ability. 41.55... IMMIGRATION AND NATIONALITY ACT, AS AMENDED Business and Media Visas § 41.55 Aliens with extraordinary ability. (a) Requirements for O classification. An alien shall be classifiable under the provisions of INA...

  18. 22 CFR 41.58 - Aliens in religious occupations.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Aliens in religious occupations. 41.58 Section... IMMIGRATION AND NATIONALITY ACT, AS AMENDED Business and Media Visas § 41.58 Aliens in religious occupations. (a) Requirements for “R” classification. An alien shall be classifiable under the provisions of...

  19. 42 CFR 436.128 - Coverage for certain qualified aliens.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Coverage for certain qualified aliens. 436.128... Mandatory Coverage of the Categorically Needy § 436.128 Coverage for certain qualified aliens. The agency... § 440.255(c) of this chapter to those aliens described in § 436.406(c) of this subpart....

  20. 45 CFR 233.51 - Eligibility of sponsored aliens.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Eligibility of sponsored aliens. 233.51 Section... CONDITIONS OF ELIGIBILITY IN FINANCIAL ASSISTANCE PROGRAMS § 233.51 Eligibility of sponsored aliens... affidavit(s) of support or similar agreement on behalf of an alien (who is not the child of the sponsor...

  1. 43 CFR 426.8 - Nonresident aliens and foreign entities.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Nonresident aliens and foreign entities..., DEPARTMENT OF THE INTERIOR ACREAGE LIMITATION RULES AND REGULATIONS § 426.8 Nonresident aliens and foreign... reclamation law or these regulations, a nonresident alien or foreign entity that directly holds land in...

  2. 8 CFR 1241.20 - Aliens ordered excluded.

    Science.gov (United States)

    2010-01-01

    ..., see 8 CFR 241.20 through 241.25. ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Aliens ordered excluded. 1241.20 Section 1241.20 Aliens and Nationality EXECUTIVE OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT OF...

  3. 20 CFR 404.1036 - Certain nonresident aliens.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Certain nonresident aliens. 404.1036 Section... Employment § 404.1036 Certain nonresident aliens. (a) Foreign students. (1) Foreign students (nonimmigrant aliens) may be temporarily in the United States under subparagraph (F) of section 101(a)(15) of...

  4. 42 CFR 436.330 - Coverage for certain aliens.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Coverage for certain aliens. 436.330 Section 436... Coverage of the Medically Needy § 436.330 Coverage for certain aliens. If an agency provides Medicaid to... condition, as defined in § 440.255(c) of this chapter to those aliens described in § 436.406(c) of...

  5. 42 CFR 435.139 - Coverage for certain aliens.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Coverage for certain aliens. 435.139 Section 435... Aliens § 435.139 Coverage for certain aliens. The agency must provide services necessary for the treatment of an emergency medical condition, as defined in § 440.255(c) of this chapter, to those...

  6. 22 CFR 40.9 - Classes of inadmissible aliens.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Classes of inadmissible aliens. 40.9 Section 40.9 Foreign Relations DEPARTMENT OF STATE VISAS REGULATIONS PERTAINING TO BOTH NONIMMIGRANTS AND... inadmissible aliens. Subparts B through L describe classes of inadmissible aliens who are ineligible to...

  7. 8 CFR 1241.30 - Aliens ordered deported.

    Science.gov (United States)

    2010-01-01

    ... ordered deported, see 8 CFR 241.30 through 241.33. ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Aliens ordered deported. 1241.30 Section 1241.30 Aliens and Nationality EXECUTIVE OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT OF...

  8. Gulliver’s Alienation from A Total Rationalist

    Institute of Scientific and Technical Information of China (English)

    周月

    2015-01-01

    Taken the historical background of this novel into consideration, the present essay presents a text-based analysis of Gulliver's alienation. It analyzes the process of Gulliver's alienation from a total rationalist to an anti-rationalist. Gulliver's alienation shows Swift's his deep reflection on the 18th Century total rationalism.

  9. 26 CFR 301.7701(b)-1 - Resident alien.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Resident alien. 301.7701(b)-1 Section 301.7701... ADMINISTRATION PROCEDURE AND ADMINISTRATION Definitions § 301.7701(b)-1 Resident alien. (a) Scope. Section 301.7701(b)-1(b) provides rules for determining whether an alien individual is a lawful permanent...

  10. AliEn - EDG Interoperability in ALICE

    OpenAIRE

    Bagnasco, S.; Barbera, R.(Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Catania, Italy); Buncic, P.; Carminati, F.; Cerello, P.(Sezione INFN, Turin, Italy); Saiz, P.

    2003-01-01

    AliEn (ALICE Environment) is a GRID-like system for large scale job submission and distributed data management developed and used in the context of ALICE, the CERN LHC heavy-ion experiment. With the aim of exploiting upcoming Grid resources to run AliEn-managed jobs and store the produced data, the problem of AliEn-EDG interoperability was addressed and an in-terface was designed. One or more EDG (European Data Grid) User Interface machines run the AliEn software suite (Cluster Monitor, Stora...

  11. Alienation in As I lay Dying

    Institute of Scientific and Technical Information of China (English)

    汪倩

    2013-01-01

    The enormous change of the earlier 20th century has not only brought false prosperity to the society but also pushed people into spiritual wasteland. Indifference and alienation have replaced communication and trust among people or between one and self. By analyzing the alienation among people, the self-split of oneself and the reasons resulting these in William Faulkner ’s As I lay Dying, the concern of Faulkner about the social phenomenon and his pursuit of transcending the personal to a universal level will be better presented to us.

  12. Approaching invasive species in Madagascar

    Directory of Open Access Journals (Sweden)

    Christian A. Kull

    2014-12-01

    Full Text Available While a number of plants, animals, and insects in Madagascar have been called ’invasive’, the topic of invasive species has until recently received less attention here than in other island contexts. Some species, often alien to Madagascar and introduced by humans, have expanded their range rapidly and have had both negative and positive effects on landscapes, on native biodiversity, and on livelihoods. Examples include the prickly pear (raketa, the silver wattle (mimosa, and, recently, the Asian common toad (radaka boka. Building on a conceptual approach to ’invasive species’, this paper emphasizes the importance of inclusive and deliberative site- and population - specific management of invasive species. It analyses three separate concepts commonly used in definitions of invasion: the origin, behaviour, and effects of particular species. It places these concepts in their broader social and ecological context, with particular attention to local perspectives on invasive species. We illustrate these concepts with Malagasy examples and data. The examples demonstrate that while invasions can have dramatic consequences, there can be multiple, often competing, interests as well as site - specific biophysical, environmental, and cultural considerations that need to be taken into account when designing policy and management interventions. We conclude with a number of lessons learned.

  13. Does residence time affect responses of alien species richness to environmental and spatial processes?

    Directory of Open Access Journals (Sweden)

    Matteo Dainese

    2012-08-01

    Full Text Available One of the most robust emerging generalisations in invasion biology is that the probability of invasion increases with the time since introduction (residence time. We analysed the spatial distribution of alien vascular plant species in a region of north-eastern Italy to understand the influence of residence time on patterns of alien species richness. Neophytes were grouped according to three periods of arrival in the study region (1500–1800, 1800–1900, and > 1900. We applied multiple regression (spatial and non-spatial with hierarchical partitioning to determine the influence of climate and human pressure on species richness within the groups. We also applied variation partitioning to evaluate the relative importance of environmental and spatial processes. Temperature mainly influenced groups with speciesa longer residence time, while human pressure influenced the more recently introduced species, although its influence remained significant in all groups. Partial regression analyses showed that most of the variation explained by the models is attributable to spatially structured environmental variation, while environment and space had small independent effects. However, effects independent of environment decreased, and spatially independent effects increased, from older to the more recent neophytes. Our data illustrate that the distribution of alien species richness for species that arrived recently is related to propagule pressure, availability of novel niches created by human activity, and neutral-based (dispersal limitation processes, while climate filtering plays a key role in the distribution of species that arrived earlier. This study highlights the importance of residence time, spatial structure, and environmental conditions in the patterns of alien species richness and for a better understanding of its geographical variation.

  14. They're Here: A Coast-to-Coast Investigation of Invasive Species

    Science.gov (United States)

    Hogan, Tracy; Craven, John

    2005-01-01

    According to the National Invasive Species Council, an "invasive species" is defined as a species that is (1) nonnative (or alien) to the ecosystem under consideration, and (2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health. In this article, the authors describe an activity that can be…

  15. Native and alien ichthyofauna in coastal fishery of Rhodes (eastern Mediterranean (2002-2010

    Directory of Open Access Journals (Sweden)

    Maria Corsini-Foka

    2015-11-01

    Full Text Available Rhodes Island (southeastern Aegean is located in a geographically crucial region subjected to biological invasions. Among the 108 alien species recorded, 30 are fish, all of Indo-Pacific/Red Sea origin introduced via Suez through Lessepsian migration (Corsini-Foka et al., 2015; Corsini-Foka and Kondylatos, In press; Kondylatos and Corsini-Foka, In press. In this oligotrophic area, fishery production is limited, due to the paucity of species of commercial interest and their low abundance, while adapted infrastructures for fish landing and marketing are absent. Coastal fishery has dominated during the last twenty years (ELSTAT, 2015. Within 2002-2010, the Hydrobiological Station of Rhodes conducted experimental boat seining surveys, using exclusively a professional 12m fishing boat, at 5-30 m depth, in the Gulf of Trianda (sandy mud, Posidonia meadows. The 94 carried out hauls (7-18 hauls/year, produced a total fish biomass of approximately 4400 Kg, recording 97 fish (86 native, 11 alien and 4 cephalopod species (3 native, 1 alien. Fish species ranged from 32 to 63/year, whereas aliens ranged from 5 to 8 species. Almost steadily present since 2002, were earlier colonizers such as Apogonichthyoides pharaonis, Siganus rivulatus, Siganus luridus, Stephanolepis diaspros and more recent ones as Pteragogus trispilus, Sphyraena chrysotaenia and Fistularia commersonii, while Lagocephalus sceleratus, firstly recorded in 2005, occurred regularly since 2007; the presence of Lagocephalus suezensis, Sphyraena flavicauda and Upeneus pori was scattered since their first records in 2004-2005. Alien fish commercially important are the Siganids, S. chrysotaenia and surprisingly F. commersonii. In terms of biomass per haul, alien fish ranged from 0 to 18.5 Kg, native from 1.5 to 182 Kg. Catches were dominated by Centracanthidae (Spicara spp. and Sparidae (Boops boops, sometimes by other native such as Oblada melanura, Diplodus spp., Chromis Chromis and others. The

  16. Investigating Invasives

    Science.gov (United States)

    Lightbody, Mary

    2008-01-01

    Invasive species, commonly known as "invasives," are nonnative plants, animals, and microbes that completely take over and change an established ecosystem. The consequences of invasives' spread are significant. In fact, many of the species that appear on the Endangered Species list are threatened by invasives. Therefore, the topic of invasive…

  17. Do species differ in their ability to coexist with the dominant alien Lupinus polyphyllus? A comparison between two distinct invaded ranges and a native range

    Czech Academy of Sciences Publication Activity Database

    Hejda, Martin

    2013-01-01

    Roč. 17, jun 2013 (2013), s. 39-55. ISSN 1619-0033 R&D Projects: GA ČR(CZ) GAP505/11/1112; GA ČR GA206/07/0668 Institutional support: RVO:67985939 Keywords : lupinus polyphyllus * invasive alien species * native range Subject RIV: EF - Botanics

  18. SHELTER COMPETITION BETWEEN TWO INVASIVE CRAYFISH SPECIES: A LABORATORY STUDY

    OpenAIRE

    Alonso, F.(Instituto de Física La Plata, Universidad Nacional de La Plata and CONICET, La Plata, Argentina); R. Martínez

    2006-01-01

    Alien crayfishes represent a common threat to aquatic ecosystems. Their spread in Europe is leading to more frequent contacts between different invasive species populations. Shelter can be an important factor in the resulting interactions. A laboratory experiment was designed to analyse the competition for shelter in similarly sized males of two species that show an invasive behaviour in Spain, Pacifastacus leniusculus and Procambarus clarkii. We carried out 24 heterospecific, six-hou...

  19. Seed rain pattern of the invasive weed Senecio inaequidens (Asteraceae)

    OpenAIRE

    Monty, Arnaud; Stainier, Charles; Lebeau, Frédéric; Pieret, Nora; Mahy, Grégory

    2008-01-01

    Dispersion capacity of alien invasive plants is a key feature for understanding invasion processes and risks. Here, we present an experimental study focussing on the seed rain pattern of Senecio inaequidens, an African plant widespread throughout Europe, under common favourable dispersal conditions. One hundred achenes from two Belgian populations underwent a drop time in still air experiment in order to assess linear correlation between several morphological traits and terminal velocity. Var...

  20. 基于 ADAMS 的曲柄滑块机构运动仿真研究%Motion Simulation of Slider Crank Based on ADAMS

    Institute of Scientific and Technical Information of China (English)

    何毅斌; 胡荣博; 刘慧; 杨兵宽; 张雨

    2014-01-01

    应用 ADAMS 软件建立曲柄滑块机构的虚拟样机,对曲柄滑块中做往复运动的滑块进行运动学分析。运动仿真表明,曲柄转速一定,曲柄大小的改变对滑块的速度和加速度有较显著影响,对连杆影响较小;此外,滑块加速度在近半个运动周期时间内基本保持稳定。这些结果对以曲柄滑块机构为原型的设备设计开发具有参考价值。%The ADAMS software was applied to establish the virtual prototype of crank slider mechanism, and the slider of crank slider to do reciprocating motion kinematics analysis was carried out.The motion simulation shows that,under the rotational speed of the crank,the change of the lider crank size had a sig-nificant effect on its velocity and acceleration and the linkage effects is small;in addition,the slider accel-eration in half a cycle time maintained the basic stability.These results are helpful f for the design and de-velopment of the devices using the crank slider mechanism as the prototype.

  1. Processes of Alienation: Marx, Orff and Kodaly

    Science.gov (United States)

    Benedict, Cathy

    2009-01-01

    Using Marx as a lens through which to interrogate music methodology, in particular those espoused by Orff and Kodaly, this article suggests that rather than the free play and creativity Orff and Kodaly intended, the implementation of these methods in a strict and unmindful manner, often alienates both teacher and student from musicking. Thus these…

  2. The use of alien gene transfers

    International Nuclear Information System (INIS)

    The present status of the gene transfers from alien species belonging to the sub-tribe Triticanae into wheat is reviewed, and the advantages and disadvantages of the different methods available for such transfers are examined. In general, the alien genes provide a high degree of resistance against a notably wide range of physiological races of wheat rusts, powdery mildew and other diseases. The alien resistance, like other sources of resistance, is known to break down for certain new races. This may happen more often when alien genes of resistance are widely incorporated in commercial cultivars and grown over large areas. So far, few of the available induced translocation stocks have contributed to the development of agronomically superior commercial cultivars, mainly due to the associated undesirable effects of the translocations on agronomic characters of the recipient variety. The deleterious effects appear in some genetic backgrounds and not in others. Extensive hybridization of translocation stocks with different genotypes has been emphasized by most investigators. Such programmes have led to the release of three commercial cultivars - 2 in Australia and 1 in the USA. On the other hand, spontaneous wheat-rye translocations carrying gene(s) for disease resistance have been unconsciously incorporated into several wheat cultivars, some of them are widely cultivated and were top in ranking based on grain yield. (author)

  3. Alien wavelength modeling tool and field trial

    DEFF Research Database (Denmark)

    Sambo, N.; Sgambelluri, A.; Secondini, M.;

    2015-01-01

    A modeling tool is presented for pre-FEC BER estimation of PM-QPSK alien wavelength signals. A field trial is demonstrated and used as validation of the tool's correctness. A very close correspondence between the performance of the field trial and the one predicted by the modeling tool has been...

  4. Staff Exchange or Legal Alien Programs

    DEFF Research Database (Denmark)

    Jørgensen, Rune Nørgaard

    2016-01-01

    SRA would very much like to support the exchange of best practice between members throughout the year and the Membership Committee is presently looking into the opportunities for a Staff Exchange or Legal Alien Program. However the International Section has already had the chance to provide this...

  5. Aliens Among Us : Are They Already Here ?

    Science.gov (United States)

    McGaha, J.

    2008-03-01

    Popular culture, science fiction and mainstream belief, says they are! What is the evidence? Astronomer, skeptic and retired USAF pilot James McGaha examines this "Space Age" Mythology. From years of investigation of the physical evidence of aliens and there spacecraft (UFO's) here on earth, McGaha presents the scientific facts.

  6. God-Belief, Self- Detection, Alienation

    Directory of Open Access Journals (Sweden)

    Majid Sadeghi Hasan Abadi

    2010-04-01

    Full Text Available According to some Western thinkers, considering earthy and compelled human alongside with the heavenly and compelling God can result in nothing but human’s alienation and transduction of alien personality in his mind and spirit. Basically, man’s realization of alienation and its type has a close relationship with the way of consideration of human and his nature. Of course type of human regard to God and kind of God that a religion defines, is another altered factor that into the side transaction, human and God has a decisive role. In Islamic teaching human nature and religion are defined as two truth corresponding together and in other words unique truth manifest into the sight of genesis and legislation as human nature and religion. In Islamic philosophy especially Hekmah Al-Motaaliyeh (transcendental wisdom human’s relationship with God and also universe with God, is the same as relation and dependency. In heavenly instructions, human nature is divine whiff. Therefore, it should have total congruity with divine nature. Since self- forgetfulness is the direct result of God- forgetfulness, God-belief and self- detection have strong relation with each other, too. Moreover, in the mystical instructions of the Muslims mystics, God is a truth that is closer to man than himself. And therefore, the more he is such proximity , attraction and rapture to God, not only the man becomes self- alien , but also he will recognize himself better than before and will approach to his own origin.

  7. God-Belief, Self- Detection, Alienation

    Directory of Open Access Journals (Sweden)

    Dr Majid Sadeghi Hasan Abadi

    2010-01-01

    Full Text Available According to some Western thinkers, considering earthy and compelled human alongside with the heavenly and compelling God can result in nothing but human’s alienation and transduction of alien personality in his mind and spirit. Basically, man’s realization of alienation and its type has a close relationship with the way of consideration of human and his nature. Of course type of human regard to God and kind of God that a religion defines, is another altered factor that into the side transaction, human and God has a decisive role. In Islamic teaching human nature and religion are defined as two truth corresponding together and in other words unique truth manifest into the sight of genesis and legislation as human nature and religion. In Islamic philosophy especially Hekmah Al-Motaaliyeh (transcendental wisdom human’s relationship with God and also universe with God, is the same as relation and dependency. In heavenly instructions, human nature is divine whiff. Therefore, it should have total congruity with divine nature. Since self- forgetfulness is the direct result of God- forgetfulness, God-belief and self- detection have strong relation with each other, too. Moreover, in the mystical instructions of the Muslims mystics, God is a truth that is closer to man than himself. And therefore, the more he is such proximity , attraction and rapture to God, not only the man becomes self- alien , but also he will recognize himself better than before and will approach to his own origin.

  8. Invasiveness Does Not Predict Impact: Response of Native Land Snail Communities to Plant Invasions in Riparian Habitats

    OpenAIRE

    Horáčková, Jitka; Juřičková, Lucie; Arnošt L. Šizling; Jarošík, Vojtěch; Pyšek, Petr

    2014-01-01

    Studies of plant invasions rarely address impacts on molluscs. By comparing pairs of invaded and corresponding uninvaded plots in 96 sites in floodplain forests, we examined effects of four invasive alien plants (Impatiens glandulifera, Fallopia japonica, F. sachalinensis, and F.×bohemica) in the Czech Republic on communities of land snails. The richness and abundance of living land snail species were recorded separately for all species, rare species listed on the national Red List, and small...

  9. Box Tree Moth (Cydalima perspectalis, Lepidoptera; Crambidae), New Invasive Insect Pest in Croatia

    OpenAIRE

    Dinka Matošević

    2013-01-01

    Background and Purpose: Alien invasive species have been described as an outstanding global problem. Hundreds of species are intentionally and unintentionally moved worldwide and and numbers of introductions to new habitats have been accelerated all over the world due to the increasing mobility of people and goods over the past decades. Numerous alien insect species, many of them introduced only in the last 20 years, have become successfully established in various ecosystems in Croatia. Box t...

  10. Crocodylian – chelonian carnivory: bitetraces of Dwarf Caiman, Paleosuchus palpebrosus in Red-eared slider, Trachemys scripta carapaces

    DEFF Research Database (Denmark)

    Milàn, Jesper; Kofoed, Jens; Bromley, Richard Granville

    2010-01-01

    Predatory acts of the Recent Dwarf Caiman, Paleosuchus palpebrosus, preying on Red-eared Sliders, Trachemys scripta, are investigated with regard to bite traces left in the turtle shells and the technique applied by the caiman to crack open the carapace of the turtle. The caiman manipulated the t...... rows; elongated scratch traces from the teeth scraping along the carapaces; and large crushed areas on the plastrons and carapaces from repeated bites applied to the same area. These are all traces that would be recognizable in fossil turtle material....

  11. A critical review of records of alien marine species from the Maltese Islands and surrounding waters (Central Mediterranean

    Directory of Open Access Journals (Sweden)

    M. SCIBERRAS

    2012-12-01

    Full Text Available An updated list of alien marine species recorded from the Maltese Islands and surrounding waters, compiled from scientific and ‘grey’ literature and from authenticated unpublished reports to the authors, is presented. The listed species are classified in one of four categories as regards establishment status: established, casual, invasive and questionable. Doubtful records are listed as ‘?’. A total of 48 species, including nine dubious ones, are included in the list. Of the accepted records, 64% are established, of which 15.4% are invasive, 18% are casual and 18% are questionable. The most represented groups are molluscs (14 species, fish (13 species and macrophytes (10 species. Six species are classified as invasive in Maltese waters: Lophocladia lallemandii, Womersleyella setacea, Caulerpa racemosa var. cylindracea, Percnon gibbesi, Fistularia commersonii and Sphoeroides pachygaster; impacts of some of these species on local ecosystems are discussed. Since the early 1900s, there has been an increasing trend in the number of alien marine species reported from the Maltese Islands. Transportation via shipping and in connection with aquaculture, as well as the range expansion of Lessepsian immigrants, appear to be the most common vectors for entry, accounting for 20%, 11% and 32% respectively of the alien species included in this review. The general warming trend of Mediterranean waters and increasing marine traffic may be facilitating the spread of warm-water Atlantic and Indo-Pacific species to the central Mediterranean, including the Maltese Islands.

  12. Invasiveness of Oenothera congeners alien to Europe: Jack of all trades, master of invasion?

    Czech Academy of Sciences Publication Activity Database

    Mihulka, Stanislav; Pyšek, Petr; Martínková, Jana; Jarošík, Vojtěch

    2006-01-01

    Roč. 8, - (2006), s. 83-96. ISSN 1433-8319 R&D Projects: GA ČR GP206/03/P155; GA ČR GA206/05/0323 Institutional research plan: CEZ:AV0Z60050516 Keywords : Competitive ability * Germination * Growth rate Subject RIV: EF - Botanics Impact factor: 2.905, year: 2006

  13. Alien flora of Europe: species diversity, temporal trends, geographical patterns and research needs

    Czech Academy of Sciences Publication Activity Database

    Lambdon, P. W.; Pyšek, Petr; Basnou, C.; Hejda, Martin; Arianoutsou, M.; Essl, F.; Jarošík, Vojtěch; Pergl, Jan; Winter, M.; Anastasiu, P.; Andriopoulos, P.; Bazos, I.; Brundu, G.; Celesti-Grapow, L.; Chassot, P.; Delipetrou, P.; Josefsson, M.; Kark, S.; Klotz, S.; Kokkoris, Y.; Kühn, I.; Marchante, H.; Perglová, Irena; Pino, J.; Vila, M.; Zikos, A.; Roy, D.; Hulme, P. E.

    2008-01-01

    Roč. 80, č. 2 (2008), s. 101-149. ISSN 0032-7786 R&D Projects: GA AV ČR(CZ) IAA600050811; GA MŠk(CZ) LC06073 Grant ostatní: DAISIE(XE) SSPI-CT-2003-511202 Institutional research plan: CEZ:AV0Z60050516 Keywords : alien plants * Europe * invasion Subject RIV: EF - Botanics Impact factor: 2.396, year: 2008 http://www.ibot.cas.cz/preslia/P082Lam.pdf

  14. Diversity of invasive species in Shanghai

    Directory of Open Access Journals (Sweden)

    Qingrou Zhang

    2013-11-01

    Full Text Available A list of invasive alien species (IAS is essential for initiating an analysis of the biological and ecological traits of such species and for improving our understanding of patterns of biological invasions. An inventory of IAS in Shanghai was prepared through a literature survey. A total of 212 IAS belonging to 63 orders and 87 families were recorded. Of these, 65% were plants, 29% were animals, and the rest were microorganisms. Dominant groups could be distinguished in both plant and animal groups. Species originating from the Americas made up 51% of the total, while 52% of plant species were introduced intentionally and 82% of animal species unintentionally. Of the invasive plants, 93% are distributed in highly disturbed habitats with rich resources, whereas 76% of invasive animals occur in storehouses and farmlands. The present information on diversity and ecological features of IAS is crucial for designing management strategies against the negative impacts of such species in Shanghai.

  15. The concept of alienation in educational psychology: History and perspectives

    Directory of Open Access Journals (Sweden)

    Osin E.N.,

    2016-01-01

    Full Text Available The paper focuses on the explanatory power and limitations of the concept of alienation in educational research. Psychological studies of the phenomena associated with alienation (burnout, extrinsic motivation, cynicism, etc. are limited by the context of individual mind, whereas the concept of alienation refers to a set of processes unfolding at both individual and sociocultural levels. The paper demonstrates the heuristic possibilities offered by the cultural-historical activity approach to meaning and meaning regulation in the analysis of alien-ation phenomena. The author reviews the findings of empirical studies of alienation in education, as well as existing theoretical works discussing the genesis of alienation and ways to overcome it. According to these works, the ongoing growth of the body of human knowledge results in increasing alienation in the educational context, but individual activity aimed at finding the meaning of collective action and of one’s place in it may help to overcome the challenge of alienation. Despite being too abstract to serve as a tool for designing psychological studies, the category of alienation may be useful for their interpretation, helping to integrate psychological findings into the interdisciplinary context, in order to review and improve existing educational institutions and practices.

  16. Plant invasions

    Czech Academy of Sciences Publication Activity Database

    Richardson, D. M.; Pyšek, Petr

    Ed. 2. Waltham: Academic Press Inc, 2013 - (Levin, S.), s. 90-102. (vol. 6). ISBN 978-0-12-384719-5 Institutional support: RVO:67985939 Keywords : species invasiveness * habitat invasibility * impact Subject RIV: EF - Botanics

  17. 8 CFR 241.24 - Notice to transportation line of alien's exclusion.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Notice to transportation line of alien's exclusion. 241.24 Section 241.24 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF ALIENS ORDERED REMOVED Deportation of Excluded Aliens (for...

  18. 8 CFR 241.21 - Stay of deportation of excluded alien.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Stay of deportation of excluded alien. 241.21 Section 241.21 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF ALIENS ORDERED REMOVED Deportation of Excluded Aliens (for Hearings...

  19. Invasive Candidiasis

    Science.gov (United States)

    ... Candidiasis Oropharyngeal / Esophageal Candidiasis Genital / vulvovaginal candidiasis Invasive candidiasis Definition Symptoms Risk & Prevention Sources Diagnosis Treatment Statistics Healthcare Professionals ...

  20. Impacts of invading alien plant species on water flows at stand and catchment scales.

    Science.gov (United States)

    Le Maitre, D C; Gush, M B; Dzikiti, S

    2015-01-01

    There have been many studies of the diverse impacts of invasions by alien plants but few have assessed impacts on water resources. We reviewed the information on the impacts of invasions on surface runoff and groundwater resources at stand to catchment scales and covering a full annual cycle. Most of the research is South African so the emphasis is on South Africa's major invaders with data from commercial forest plantations where relevant. Catchment studies worldwide have shown that changes in vegetation structure and the physiology of the dominant plant species result in changes in surface runoff and groundwater discharge, whether they involve native or alien plant species. Where there is little change in vegetation structure [e.g. leaf area (index), height, rooting depth and seasonality] the effects of invasions generally are small or undetectable. In South Africa, the most important woody invaders typically are taller and deeper rooted than the native species. The impacts of changes in evaporation (and thus runoff) in dryland settings are constrained by water availability to the plants and, thus, by rainfall. Where the dryland invaders are evergreen and the native vegetation (grass) is seasonal, the increases can reach 300-400 mm/year. Where the native vegetation is evergreen (shrublands) the increases are ∼200-300 mm/year. Where water availability is greater (riparian settings or shallow water tables), invading tree water-use can reach 1.5-2.0 times that of the same species in a dryland setting. So, riparian invasions have a much greater impact per unit area invaded than dryland invasions. The available data are scattered and incomplete, and there are many gaps and issues that must be addressed before a thorough understanding of the impacts at the site scale can be gained and used in extrapolating to watershed scales, and in converting changes in flows to water supply system yields. PMID:25935861

  1. Hitting the right target: taxonomic challenges for, and of, plant invasions

    OpenAIRE

    Pyšek, Petr; Hulme, Philip E.; Meyerson, Laura A.; Smith, Gideon F; James S Boatwright; Crouch, Neil R; Figueiredo, Estrela; Llewellyn C. Foxcroft; Jarošík, Vojtěch; Richardson, David M.; Suda, Jan; Wilson, John R. U.

    2013-01-01

    This paper explores how a lack of taxonomic expertise, and by implication a dearth of taxonomic products such as identification tools, has hindered progress in understanding and managing biological invasions. It also explores how the taxonomic endeavour could benefit from studies of invasive species. We review the literature on the current situation in taxonomy with a focus on the challenges of identifying alien plant species and explore how this has affected the study of biological invasions...

  2. Invasive species

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Richardson, D. M.

    Vol. 5. Great Barrington : Berkshire Publishing Group, 2012 - (Craig, R.; Nagle, J.; Pardy, B.; Schmitz, O.; Smith, W.), s. 211-219 ISBN 978-1-933782-16-4 Institutional support: RVO:67985939 Keywords : plant invasions * invasibility * invasiveness Subject RIV: EF - Botanics

  3. Posterior alien hand syndrome: case report

    Energy Technology Data Exchange (ETDEWEB)

    Rohde, S.; Weidauer, S.; Lanfermann, H.; Zanella, F. [Institute of Neuroradiology, Johann Wolfgang Goethe University, Schleusenweg 2-16, 60528 Frankfurt am Main (Germany)

    2002-11-01

    The alien hand syndrome (AHS) is involuntary uncontrolled movement of an arm with a sense of estrangement from the limb itself. AHS was initially used to describe interhemispheric disconnection phenomena in patients with lesions in the anterior corpus callosum, but it has been found in patients with posterior cerebral lesions without involvement of the corpus callosum, for example parietal infarcts or corticobasal degeneration. The posterior alien hand syndrome is less frequent and presents with nonpurposive behaviour like lifting the arm or writhing fingers. We report an 80-year-old woman with a posterior AHS of the dominant right hand. MRI showed atrophy of the pre- and postcentral gyri without involvement of the corpus callosum. We discuss the aetiology of the posterior AHS and the differences from the anterior varieties. (orig.)

  4. Posterior alien hand syndrome: case report

    International Nuclear Information System (INIS)

    The alien hand syndrome (AHS) is involuntary uncontrolled movement of an arm with a sense of estrangement from the limb itself. AHS was initially used to describe interhemispheric disconnection phenomena in patients with lesions in the anterior corpus callosum, but it has been found in patients with posterior cerebral lesions without involvement of the corpus callosum, for example parietal infarcts or corticobasal degeneration. The posterior alien hand syndrome is less frequent and presents with nonpurposive behaviour like lifting the arm or writhing fingers. We report an 80-year-old woman with a posterior AHS of the dominant right hand. MRI showed atrophy of the pre- and postcentral gyri without involvement of the corpus callosum. We discuss the aetiology of the posterior AHS and the differences from the anterior varieties. (orig.)

  5. Genomics of Wild Relatives and Alien Introgressions

    Czech Academy of Sciences Publication Activity Database

    Rey, Elodie; Molnár, I.; Doležel, Jaroslav

    Heidelberg: Springer Verlag, 2015, s. 347-381 ISBN 978-3-319-23493-9 R&D Projects: GA MŠk(CZ) LO1204; GA ČR GBP501/12/G090 Institutional support: RVO:61389030 Keywords : Wheat breeding * Alien gene function * Chromosome flow sorting Subject RIV: EB - Genetics ; Molecular Biology http://link.springer.com/chapter/10.1007%2F978-3-319-23494-6_13

  6. Exoplanets finding, exploring, and understanding alien worlds

    CERN Document Server

    Kitchin, Chris

    2012-01-01

    Since 1992 there has been an explosion in the discovery of planets orbiting stars other than the Sun. There are now around 600 alien planets that we know about and that number is likely to break through the 1,000 ‘barrier’ within a couple of years. The recent launch of the Kepler space telescope specifically to look for new worlds opens the prospect of hundreds, maybe thousands, of further exoplanets being found. Many of these planets orbits stars that are not too different from the Sun, but they are so close in to their stars that their surfaces could be flooded with seas of molten lead – or even molten iron. Others orbit so far from their stars that they might as well be alone in interstellar space. A planet closely similar to the Earth has yet to be detected, but that (to us) epoch-making discovery is just a matter of time. Could these alien worlds could provide alternative homes for humankind, new supplies of mineral resources and might they might already be homes to alien life? Exoplanets: Finding,...

  7. Czech alien flora and the historical pattern of its formation: what came first to Central Europe?

    Science.gov (United States)

    Pysek, Petr; Sádlo, Jirí; Mandák, Bohumil; Jarosík, Vojtech

    2003-03-01

    Temporal patterns of immigration to the country were analysed using 668 alien species in the flora of the Czech Republic for which the dates of the first record were available (64.8% of the total number of 1031 so-called neophytes, i.e. aliens introduced after the year 1500). After a period of initial slow increase lasting to the 1840s, the accumulation of neophytes over time could be best fitted by a linear model that explained 97% of the variance. The intensity of floristic research, which varied between periods, did not significantly affect the overall increase in the number of aliens. The effect of species traits on the year of introduction was evaluated, with continent of origin, introduction type (deliberate or accidental), life history, Grime's life strategy, onset of flowering, mode of dispersal and propagule size as explanatory variables. Species of European origin and CSR strategists arrived earlier than those with other origins and strategies. Deliberately introduced species appeared earlier than accidental arrivals, and those cultivated for utilitary reasons on average arrived earlier than ornamentals. Species capable of early flowering were remarkably more prevalent among early newcomers. A separate analysis of accidentally introduced American species also identified life history as a significant predictor of immigration time, with annuals being introduced earlier than biennials and perennials. The data contribute to an understanding of a crucial stage of the invasion process that has received little attention in the literature. The model "early alien" to Central Europe is a European species with a CSR strategy deliberately brought for cultivation as a utilitary plant. Once it escaped from cultivation, its establishment in the wild was favoured by its ability to flower early and, therefore, complete the life cycle. PMID:12647111

  8. Distribution and impact of the alien anemone Sagartia ornata in the West Coast National Park

    Directory of Open Access Journals (Sweden)

    Tamara B. Robinson

    2015-03-01

    Full Text Available Sagartia ornata is an alien anemone that occurs intertidally within the West Coast National Park (WCNP. Whilst baseline distributional data was gathered in 2001, the range and abundance of this alien has not been reassessed. The present study aimed to determine the current status and distribution of this anemone, to assess its diet so as to establish the role it may play as predator and to investigate its impact on sandy-shore communities. Sagartia ornata was found to be restricted to the WCNP, where it occurred in densities of up to 508 ± 218 individuals per m2 . Within the park the distribution of this anemone had changed. Populations were recorded in Nanozostera capensis seagrass beds for the first time and this alien was absent from two areas in which it had previously occurred. Diet analysis revealed indigenous polychaetes and amphipods as the dominant prey items consumed by S. ornata. This alien was found to significantly alter sandy-shore community structure, with differences caused primarily by increases in the abundance and biomass of the tanaid Anatanais gracilis and the polychaete Orbinia angrapequensis. Additionally, invaded areas supported significantly greater invertebrate diversity, density and biomass. It is concluded that whilst this anemone negatively affects native biota, its current dependence on restricted habitats precludes widespread impacts with the park.Conservation implications: With regard to conservation implications, this invasion should be routinely monitored outside the WCNP as in its native range S. ornata occurs on rocky shores and kelp holdfasts, suggesting a potential for spread along the west coast of South Africa.

  9. Alien Species and the Water Framework Directive - Questionnaire Results

    OpenAIRE

    VANDEKERKHOVE JOCHEN; Cardoso, Ana

    2010-01-01

    Alien species constitute a major pressure in aquatic environments, both ecologically and economically. This recognition has initiated a debate on the role of alien species in ecological status classifications. We distributed a questionnaire to review how EU Member States (MSs) deal with alien species in their national status assessments under the Water Framework Directive (WFD). The questionnaire was filled and returned by 23 EU MSs and Norway. Analysis of the questionnaire returns and referr...

  10. AliEn - ALICE environment on the GRID

    International Nuclear Information System (INIS)

    AliEn (http://alien.cern.ch) (ALICE Environment) is a Grid framework built on top of the latest Internet standards for information exchange and authentication (SOAP, PKI) and common Open Source components. AliEn provides a virtual file catalogue that allows transparent access to distributed datasets and a number of collaborating Web services which implement the authentication, job execution, file transport, performance monitor and event logging. In the paper we will present the architecture and components of the system

  11. Alien species as a driver of recent extinctions.

    Science.gov (United States)

    Bellard, Céline; Cassey, Phillip; Blackburn, Tim M

    2016-02-01

    We assessed the prevalence of alien species as a driver of recent extinctions in five major taxa (plants, amphibians, reptiles, birds and mammals), using data from the IUCN Red List. Our results show that alien species are the second most common threat associated with species that have gone completely extinct from these taxa since AD 1500. Aliens are the most common threat associated with extinctions in three of the five taxa analysed, and for vertebrate extinctions overall. PMID:26888913

  12. Alien terrestrial crustaceans (Isopods and Amphipods). Chapter 7.1

    OpenAIRE

    Pierre-Olivier Cochard; Ferenc Vilisics; Emmanuel Sechet

    2010-01-01

    A total of 17 terrestrial crustacean species aliens to Europe of which 13 isopods (woodlice) and 4 amphipods (lawn shrimps) have established on the continent. In addition, 21 species native to Europe were introduced in a European region to which they are not native. The establishment of alien crustacean species in Europe slowly increased during the 20th century without any marked changes during the recent decades. Almost all species alien to Europe originate from sub-tropical or tropical ar...

  13. Alien Presence in the Home : The Design of Tableau Machine

    OpenAIRE

    Romero, Mario; Pousman, Zachary; Mateas, Michael

    2008-01-01

    We introduce a design strategy, alien presence, which combines work in human---computer interaction, artificial intelligence, and media art to create enchanting experiences involving reflection over and contemplation of daily activities. An alien presence actively interprets and characterizes daily activity and reflects it back via generative, ambient displays that avoid simple one-to-one mappings between sensed data and output. We describe the alien presence design strategy for achieving enc...

  14. Past Arctic aliens have passed away, current ones may stay

    OpenAIRE

    2015-01-01

    Increased human activity and climate change are expected to increase the numbers and impact of alien species in the Arctic, but knowledge of alien species is poor in most Arctic regions. Through field investigations over the last 10 years, and review of alien vascular plant records for the high Arctic Archipelago Svalbard over the past 130 years, we explored long term trends in persistence and phenology. In total, 448 observations of 105 taxa have been recorded from 28 sites. Recent surveys a...

  15. Global change and marine communities: Alien species and climate change

    International Nuclear Information System (INIS)

    Anthropogenic influences on the biosphere since the advent of the industrial age are increasingly causing global changes. Climatic change and the rising concentration of greenhouse gases in the atmosphere are ranking high in scientific and public agendas, and other components of global change are also frequently addressed, among which are the introductions of non indigenous species (NIS) in biogeographic regions well separated from the donor region, often followed by spectacular invasions. In the marine environment, both climatic change and spread of alien species have been studied extensively; this review is aimed at examining the main responses of ecosystems to climatic change, taking into account the increasing importance of biological invasions. Some general principles on NIS introductions in the marine environment are recalled, such as the importance of propagule pressure and of development stages during the time course of an invasion. Climatic change is known to affect many ecological properties; it interacts also with NIS in many possible ways. Direct (proximate) effects on individuals and populations of altered physical-chemical conditions are distinguished from indirect effects on emergent properties (species distribution, diversity, and production). Climatically driven changes may affect both local dispersal mechanisms, due to the alteration of current patterns, and competitive interactions between NIS and native species, due to the onset of new thermal optima and/or different carbonate chemistry. As well as latitudinal range expansions of species correlated with changing temperature conditions, and effects on species richness and the correlated extinction of native species, some invasions may provoke multiple effects which involve overall ecosystem functioning (material flow between trophic groups, primary production, relative extent of organic material decomposition, extent of benthic-pelagic coupling). Some examples are given, including a special

  16. Displacement of a native by an alien bumblebee: lower pollinator efficiency overcome by overwhelmingly higher visitation frequency.

    Science.gov (United States)

    Madjidian, Josefin A; Morales, Carolina L; Smith, Henrik G

    2008-07-01

    Biological invasions might constitute a major threat to mutualisms. Introduced pollinators might competitively displace their native counterparts, which in turn affects the pollination of native plants, if native and alien visitors differ in pollinator effectiveness. Since its invasion in 1994 into south-west Argentina, the introduced European bumblebee Bombus ruderatus has continuously increased in abundance, along with a simultaneous decrease in the abundance of the native Bombus dahlbomii. The latter is the only native bumblebee species of the temperate forests of southern South America, and the main pollinator of the endemic herb Alstroemeria aurea. In order to evaluate the impact of the ongoing displacement of the native by the alien bumblebee, we compared the pollinator effectiveness (i.e., the combination of pollinator efficiency per visit and visitation frequency) between both bumblebee species, as well as related pollinator traits that might account for potential differences in pollinator efficiency. Native Bombus dahlbomii, which has a larger body and spent more time per flower, was the more efficient pollinator compared to Bombus ruderatus, both in terms of quantity and quality of pollen deposited per visit. However, Bombus ruderatus was a much more frequent flower visitor than Bombus dahlbomii. As a consequence, Bombus ruderatus is nowadays a more effective pollinator of A. aurea than its native congener. Despite the lack of evidence of an increase in seed set at the population level, comparisons with historical records of Bombus dahlbomii abundances prior to Bombus ruderatus' invasion suggest that the overall pollination intensity of A. aurea might in fact have risen as a consequence of this invasion. Field experiments like these, that incorporate the natural variation in abundance of native and alien species, are powerful means to demonstrate that the consequences of invasions are more complex than previous manipulated and controlled experiments have

  17. The Alienated Plot in The End of the Road

    Institute of Scientific and Technical Information of China (English)

    王丽娜

    2014-01-01

    The End of the Road is John Barth’s second novel, and it is the first novel that brought abortion to the focus of public attention, which proves to be a huge success. This paper intends to study the alienation in The End of the Road based on the alienation as a literary style and the alienation embodied in the literary context. Through the analysis of the alienated plot, the pa-per aims to emphasize the internal cause for the end of the different character ’s road.

  18. Threat and management strategies of potentially invasive insects in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG RunZhi; ZHANG YaPing; JIANG YouXu

    2009-01-01

    The Global Invasive Species Database, GISD, comprises 27 species of the most significant invasive alien insects in the world (through November, 2005), 6 of which are originally native to China, 11 are established in China, and 10 have a potential invasion threat to China. This paper discusses these species in terms of distribution, harmfulness and dispersal ways, and finds that: (ⅰ) Information regarding invasive insects in the GISD remains inadequate. Such harmful invasive species as Opogona sacchari (Bojer), Oracella acuta (Lobdell), and Dendroctonus valens LeConte are not included. (ⅱ) Ten species of invasive insects, particularly Lasius neglectus Van Loon and Linepithema humile (Mayr)which become established in areas near China, have the potential to become established in China. (ⅲ)Special attention should be paid to species from Asia and the Americas because of their greater Iikelihood of becoming established in China. Finally, some management strategies including legislation,quarantine, early warning, prevention and control are suggested.

  19. Threat and management strategies of potentially invasive insects in China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Global Invasive Species Database, GISD, comprises 27 species of the most significant invasive alien insects in the world (through November, 2005), 6 of which are originally native to China, 11 are established in China, and 10 have a potential invasion threat to China. This paper discusses these species in terms of distribution, harmfulness and dispersal ways, and finds that: (i) Information re-garding invasive insects in the GISD remains inadequate. Such harmful invasive species as Opogona sacchari (Bojer), Oracella acuta (Lobdell), and Dendroctonus valens LeConte are not included. (ii) Ten species of invasive insects, particularly Lasius neglectus Van Loon and Linepithema humile (Mayr) which become established in areas near China, have the potential to become established in China. (iii) Special attention should be paid to species from Asia and the Americas because of their greater likeli-hood of becoming established in China. Finally, some management strategies including legislation, quarantine, early warning, prevention and control are suggested.

  20. What makes the plant invasion possible? Paradigm of invasion mechanisms, theories and attributes

    Directory of Open Access Journals (Sweden)

    Prabhat Kumar Rai

    2015-06-01

    Full Text Available Plant invasion is the second most severe threat to biodiversity after habitat fragmentation. Invasive species are alien species whose introduction and spread threatens ecosystems, habitats or species with socio-cultural, economic and/or environmental harm, and harm to human health. Present review precisely describes the global problems of invasion in different ecosystems, continents and its multifaceted impacts. Plant invasion is now increasingly being recognized as global problem and various continents are adversely affected, although to a differential scale. Quest for the ecological mechanism lying behind the success of invasive species over native species has drawn the attention of researches worldwide particularly in context of diversity-stability relationship. Transport, colonization, establishment and landscape spread may be different steps in success of invasive plants and each and every step is checked through several ecological attributes. Further, several ecological attribute and hypothesis (enemy release, novel weapon, empty niche, evolution of increased competitive ability etc. were proposed pertaining to success of invasive plant species. However, single theory will not be able to account for invasion success among all environments as it may vary spatially and temporally. Therefore, in order to formulate a sustainable management plan for invasive plants, it is necessary to develop a synoptic view of the dynamic processes involved in the invasion process. Moreover, invasive species can act synergistically with other elements of global change, including land-use change, climate change, increased concentrations of atmospheric carbon dioxide and nitrogen deposition. Henceforth, a unified framework for biological invasions that reconciles and integrates the key features of the most commonly used invasion frame-works into a single conceptual model that can be applied to all human-mediated invasions.

  1. THE ALIEN STREET TREES OF FORTALEZA (NE BRAZIL: QUALITATIVE OBSERVATIONS AND THE INVENTORY OF TWO DISTRICTS

    Directory of Open Access Journals (Sweden)

    Marcelo Freire Moro

    2011-01-01

    Full Text Available Public tree planting is important for cities. It produces shadow, brings well-being for humans, and supports the urban fauna. But the cultivation of exotic plants can also be responsible for dissemination of invasive species. This paper aims to evaluate public tree planting in Fortaleza, Ceará state, in northeastern Brazil. From 2005 to 2009, qualitative observations on tree composition in the city were made. In 2006, a detailed inventory of all public trees was carried out in two districts of Fortaleza. Jointly, 2075 individuals grew here. Most of the tree species planted in Fortaleza are aliens, some are even invasive. The massive use of exotic plants in Fortaleza has negative consequences for the environmental education. People do not know the regional native trees, and thus are not concerned about the local biodiversity conservation. In spite of the huge amounts of native species available for ornamental purposes in the Brazilian flora, the street trees of Fortaleza are overwhelmingly aliens.

  2. Resource competition in plant invasions: emerging patterns and research needs

    Directory of Open Access Journals (Sweden)

    Margherita eGioria

    2014-09-01

    Full Text Available Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relatively to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, while invasive congeners are not necessarily competitively superior over native congeners, nor alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy. We then identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examinations of resource competition dynamics and of the impact of global environmental changes on competitive interactions between invasive and native

  3. Invasive plant integration into native plant-pollinator networks across Europe.

    Science.gov (United States)

    Vilà, Montserrat; Bartomeus, Ignasi; Dietzsch, Anke C; Petanidou, Theodora; Steffan-Dewenter, Ingolf; Stout, Jane C; Tscheulin, Thomas

    2009-11-01

    The structure of plant-pollinator networks has been claimed to be resilient to changes in species composition due to the weak degree of dependence among mutualistic partners. However, detailed empirical investigations of the consequences of introducing an alien plant species into mutualistic networks are lacking. We present the first cross-European analysis by using a standardized protocol to assess the degree to which a particular alien plant species (i.e. Carpobrotus affine acinaciformis, Impatiens glandulifera, Opuntia stricta, Rhododendron ponticum and Solanum elaeagnifolium) becomes integrated into existing native plant-pollinator networks, and how this translates to changes in network structure. Alien species were visited by almost half of the pollinator species present, accounting on average for 42 per cent of the visits and 24 per cent of the network interactions. Furthermore, in general, pollinators depended upon alien plants more than on native plants. However, despite the fact that invaded communities received more visits than uninvaded communities, the dominant role of alien species over natives did not translate into overall changes in network connectance, plant linkage level and nestedness. Our results imply that although supergeneralist alien plants can play a central role in the networks, the structure of the networks appears to be very permeable and robust to the introduction of invasive alien species into the network. PMID:19692403

  4. Invasive plant integration into native plant–pollinator networks across Europe

    Science.gov (United States)

    Vilà, Montserrat; Bartomeus, Ignasi; Dietzsch, Anke C.; Petanidou, Theodora; Steffan-Dewenter, Ingolf; Stout, Jane C.; Tscheulin, Thomas

    2009-01-01

    The structure of plant–pollinator networks has been claimed to be resilient to changes in species composition due to the weak degree of dependence among mutualistic partners. However, detailed empirical investigations of the consequences of introducing an alien plant species into mutualistic networks are lacking. We present the first cross-European analysis by using a standardized protocol to assess the degree to which a particular alien plant species (i.e. Carpobrotus affine acinaciformis, Impatiens glandulifera, Opuntia stricta, Rhododendron ponticum and Solanum elaeagnifolium) becomes integrated into existing native plant–pollinator networks, and how this translates to changes in network structure. Alien species were visited by almost half of the pollinator species present, accounting on average for 42 per cent of the visits and 24 per cent of the network interactions. Furthermore, in general, pollinators depended upon alien plants more than on native plants. However, despite the fact that invaded communities received more visits than uninvaded communities, the dominant role of alien species over natives did not translate into overall changes in network connectance, plant linkage level and nestedness. Our results imply that although supergeneralist alien plants can play a central role in the networks, the structure of the networks appears to be very permeable and robust to the introduction of invasive alien species into the network. PMID:19692403

  5. 22 CFR 41.24 - International organization aliens.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false International organization aliens. 41.24... IMMIGRATION AND NATIONALITY ACT, AS AMENDED Foreign Government Officials § 41.24 International organization aliens. (a) Definition of international organization. “International organization” means: (1) Any...

  6. Political Disenchantment: A Cognitive-Perceptual Theory of Political Alienation.

    Science.gov (United States)

    Long, Samuel

    An investigation of a cognitive-perceptual model to measure adolescents' feelings of political alienation is reported. The model hypothesizes that fundamental to the political alienation process is a feared actual or potential loss of freedom; this process is called psychological reactance. The sample consisted of 460 senior high school students…

  7. No Trespassing: What Every Alien Needs to Know.

    Science.gov (United States)

    Hyde, Sheila A.; Carpenter, D. Stanley

    1992-01-01

    Examines what might occur when staff members change positions and offers suggestions for the "alien" venturing into unfamiliar territory. Discusses ways in which an alien may trespass: inappropriate enthusiasm for the new place; failure to fit into the system; inappropriate comparisons; failure to define success; failure to deal with failing; and…

  8. 8 CFR 235.3 - Inadmissible aliens and expedited removal.

    Science.gov (United States)

    2010-01-01

    ... asylum officer in accordance with 8 CFR 208.30. The examining immigration officer shall record sufficient... the United States in accordance with section 241(c) of the Act and 8 CFR part 241. (9) Waivers of... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Inadmissible aliens and expedited...

  9. 8 CFR 204.6 - Petitions for employment creation aliens.

    Science.gov (United States)

    2010-01-01

    ... Commissioner for Examinations as provided in 8 CFR 103.3. (7) Requirements for alien entrepreneurs. An alien... this manner does not exempt the petitioner from the requirements of 8 CFR 204.6(j) (2) and (3) relating... meet the criteria set forth in 8 CFR 204.6(j)(4)(ii). (i) State designation of a high unemployment...

  10. 42 CFR 435.350 - Coverage for certain aliens.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Coverage for certain aliens. 435.350 Section 435... ISLANDS, AND AMERICAN SAMOA Optional Coverage of the Medically Needy § 435.350 Coverage for certain aliens... treatment of an emergency medical condition, as defined in § 440.255(c) of this chapter, to those...

  11. Making Marx Accessible: Understanding Alienated Labor through Experiential Learning

    Science.gov (United States)

    Parrotta, Kylie L.; Buck, Alison R.

    2013-01-01

    We introduce an exercise designed to make Marx's theory of alienated labor accessible to students in a Sociology of Work class. Through a role-playing activity where students create and sell goods under conditions of both alienated and nonalienated labor, students actually experience the different material and social consequences of these…

  12. ALIEN MARINE SPECIES OF LIBYA: FIRST INVENTORY AND NEW RECORDS IN EL-KOUF NATIONAL PARK (CYRENAICA AND THE NEIGHBOURING AREAS

    Directory of Open Access Journals (Sweden)

    H. BAZAIRI

    2013-07-01

    Full Text Available The presence of marine alien species in El-Kouf National Park and the neighbouring areas was assessed using a compilation of available information and observations, a field survey conducted on October 2010 in the framework of the MedMPAnet project and results of further monitoring during June and September 2012. A total of 9 alien species were reported: the Rhodophyta Asparagopsis taxiformis (Delile Trevisan de Saint-Léon, the Chlorophyta Caulerpa racemosa var. cylindracea (Sonder Verlaque, Huisman & Boudouresque, the crab Percnon gibbesi (H. Milne-Edwards, 1853 and the fishes Fistularia commersonii Rüppell, 1838, Siganus luridus (Rüppell, 1829, Siganus rivulatus Forsskål, 1775, Pempheris vanicolensis Cuvier, 1831, Lagocephalus sceleratus (Gmelin, 1789 and Sphyraena flavicauda Rüppell, 1838. Several of them were until now unknown for the National Park. The list of alien marine species of Libya is updated and discussed. Until now 63 marine aliens species were recorded along the Libyan coasts. These include 3 Foraminifera, 3 Ochrophyta, 5 Rhodophyta, 5 Chlorophyta, 1 Magnoliophyta, 11 Arthropoda, 13 Mollusca, 1 Echinodermata and 21 Chordata. Among these Non Indigenous Species, 43 are known as established along the Libyan coast including 8 invasive, 11 casual, 6 questionable, 3 cryptogenic and 1 unknown. An in-depth study of the marine organisms would substantially increase the number of alien species occurring in Libya. Monitoring of marine assemblages of MPAs is a valuable opportunity to go further into the knowledge of native and introduced species.

  13. Performance of a Ferrofluid Based Rough Parallel Plate Slider Bearing: A Comparison of Three Magnetic Fluid Flow Models

    Directory of Open Access Journals (Sweden)

    Jimit R. Patel

    2016-01-01

    Full Text Available Efforts have been made to present a comparison of all the three magnetic fluid flow models (Neuringer-Rosensweig model, Shliomis model, and Jenkins model so far as the performance of a magnetic fluid based parallel plate rough slider bearing is concerned. The stochastic model of Christensen and Tonder is adopted for the evaluation of effect of transverse surface roughness. The stochastically averaged Reynolds-type equation is solved with suitable boundary conditions to obtain the pressure distribution resulting in the calculation of load carrying capacity. The graphical results establish that for a bearing’s long life period the Shliomis model may be employed for higher loads. However, for lower to moderate loads, the Neuringer-Rosensweig model may be deployed.

  14. A STUDY OF THIN FILM LUBRICATION AT NANOSCALE FOR A FERROFLUID BASED INFINITELY LONG ROUGH POROUS SLIDER BEARING

    Directory of Open Access Journals (Sweden)

    Jimit R. Patel

    2016-04-01

    Full Text Available The study aims at analyzing the performance of a ferrofluid-based infinitely long rough porous slider bearing which makes use of thin film lubrication at nanoscale. The stochastic model of Christensen and Tonder has been employed to analyze the effect of surface roughness while the Neuringer-Rosensweig’s model has been adopted to study the magnetization effect. The pressure distribution in the bearing system has been obtained by solving the associated stochastically averaged Reynolds type equation. The results indicate that although the transverse roughness is supposed to affect the bearing system adversely, the situation remains fairly better in the case of thin film lubrication at nanoscale. In fact, the consideration of thin film lubrication at nanoscale results in an all round improved performance, even for lower strength of the magnetic intensity. However, the couple stress adds a little more to this positive effect.

  15. Ionic Conductivity and Mechanical Properties of Slide-Ring Gel Swollen with Electrolyte Solution Including Lithium Ions

    International Nuclear Information System (INIS)

    Polymer gel electrolytes with both high ionic conductivity and mechanical ductility are produced using a slide-ring (SR) gel swollen with an electrolyte solution (ES) composed of propylene carbonate (PC) and lithium salt. The SR gel was derived from polyrotaxane (PR), in which cyclic molecules known as cyclodextrins (CDs) are threaded on the axial polymer chain of polyethylene glycol (PEG) capped by bulky ends, through intermolecular crosslinking between the CDs. The molar conductivity of the SR gel electrolyte with a high swelling ratio and small crosslinking density was more than 95% for pristine ES, and the activation energy and potential window of the SR gel electrolyte was close to that of pristine ES. The compressive properties of the SR gel electrolyte were also investigated; the Young's modulus of the SR gel electrolyte decreased with the crosslinking density and the SR gel electrolyte with a low crosslinking density was not fractured under compression to almost half of the original thickness

  16. Dynamic Analysis and Vibration Control of a Flexible SLIDER-CRANK Mechanism Using PM Synchronous Servo Motor Drive

    Science.gov (United States)

    Fung, R.-F.; Chen, K.-W.

    1998-07-01

    Dynamic analysis and vibration control of a flexible slider-crank mechanism driven by a permanent magnet (PM) synchronous servo motor are studied in this paper. Geometric constraint at the end of a flexible connecting rod is derived and introduced into Hamilton's principle to formulate the governing equations of the connecting rod which is modelled by Timoshenko beam theory. The coupling equations describe the rigid-body motion, flexible vibrations and motor system. In order to control crank speed and reduce flexible vibrations simultaneously, speed and tracking controllers are designed through a reaching law variable structure control (VSC) method. By choosing proper parameters in control law, dynamic responses of the flexible system in reaching mode can be controlled. Numerical results show that the proposed controllers not only eliminate the dynamic deflections of the flexible connecting rod, but also keep good tracking performances. Moreover, the robustness against external disturbances can also be improved by employing the proposed control scheme.

  17. How far could the alien boatman Trichocorixa verticalis verticalis spread? Worldwide estimation of its current and future potential distribution.

    Science.gov (United States)

    Guareschi, Simone; Coccia, Cristina; Sánchez-Fernández, David; Carbonell, José Antonio; Velasco, Josefa; Boyero, Luz; Green, Andy J; Millán, Andrés

    2013-01-01

    Invasions of alien species are considered among the least reversible human impacts, with diversified effects on aquatic ecosystems. Since prevention is the most cost-effective way to avoid biodiversity loss and ecosystem problems, one challenge in ecological research is to understand the limits of the fundamental niche of the species in order to estimate how far invasive species could spread. Trichocorixa verticalis verticalis (Tvv) is a corixid (Hemiptera) originally distributed in North America, but cited as an alien species in three continents. Its impact on native communities is under study, but it is already the dominant species in several saline wetlands and represents a rare example of an aquatic alien insect. This study aims: i) to estimate areas with suitable environmental conditions for Tvv at a global scale, thus identifying potential new zones of invasion; and ii) to test possible changes in this global potential distribution under a climate change scenario. Potential distributions were estimated by applying a multidimensional envelope procedure based on both climatic data, obtained from observed occurrences, and thermal physiological data. Our results suggest Tvv may expand well beyond its current range and find inhabitable conditions in temperate areas along a wide range of latitudes, with an emphasis on coastal areas of Europe, Northern Africa, Argentina, Uruguay, Australia, New Zealand, Myanmar, India, the western boundary between USA and Canada, and areas of the Arabian Peninsula. When considering a future climatic scenario, the suitability area of Tvv showed only limited changes compared with the current potential distribution. These results allow detection of potential contact zones among currently colonized areas and potential areas of invasion. We also identified zones with a high level of suitability that overlap with areas recognized as global hotspots of biodiversity. Finally, we present hypotheses about possible means of spread, focusing on

  18. AliEn: ALICE environment on the GRID

    International Nuclear Information System (INIS)

    Starting from mid-2008, the ALICE detector at CERN LHC will collect data at a rate of 4PB per year. ALICE will use exclusively distributed Grid resources to store, process and analyse this data. The top-level management of the Grid resources is done through the AliEn (ALICE Environment) system, which is in continuous development since year 2000. AliEn presents several original solutions, which have shown their viability in a number of large exercises of increasing complexity called Data Challenges. This paper describes the AliEn architecture: Job Management, Data Management and UI. The current status of AliEn will be illustrated, as well as the performance of the system during the data challenges. The paper also describes the future AliEn development roadmap

  19. Alien macroalgae in Denmark - a broad-scale national perspective

    DEFF Research Database (Denmark)

    Thomsen, Mads S.; Wernberg, Thomas; Stæhr, Peter Anton;

    2007-01-01

    Most studies documenting the importance of alien macroalgae relative to native species are based on smaller-scale sampling programmes. Between 1989 and 2003, a Danish monitoring programme collected data on the percentage cover of macroalgae at more than 600 locations throughout the country. We...... examined this data set to estimate the relative abundance of alien species in the algal flora on large spatiotemporal scales, i.e. across depth ranges, regions and years. Of the 10 alien macroalgal species known to inhabit Danish coastal waters, nine were found in the survey. Most of the alien species were...... only present in low quantities (<1% of the entire flora). In contrast, the two most common alien species, Sargassum muticum and Bonnemaisonia hamifera, constituted 2-7% of the assemblages, depending on depth, region and year. Sargassum muticum was abundant from 0 to 5 m in the northwestern region...

  20. AliEn: ALICE Environment on the GRID

    CERN Multimedia

    Bagnasco, S; Buncic, P; Carminati, F; Cirstoiu, C; Grigoras, C; Hayrapetyan, A; Harutyunyan, A; Peters, A J; Saiz, P

    2007-01-01

    Starting from mid-2008, the ALICE detector at CERN LHC will collect data at a rate of 4PB per year. ALICE will use exclusively distributed Grid resources to store, process and analyse this data. The top-level management of the Grid resources is done through the AliEn (ALICE Environment) system, which is in continuous development since year 2000. AliEn presents several original solutions, which have shown their viability in a number of large exercises of increasing complexity called Data Challenges. This paper describes the AliEn architecture: Job Management, Data Management and UI. The current status of AliEn will be illustrated, as well as the performance of the system during the data challenges. The paper also describes the future AliEn development roadmap.