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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

A pheromone-mediated mass-trapping program for three species of ambrosia beetle in a commercial sawmill

Shore, Terence Leckie January 1982 (has links)
A commercial sawmill in British Columbia, Canada, was surveyed in 1979 for the presence of the ambrosia beetles Trypodendron lineatum (Olivier) and Gnathotrichus retusus (LeConte) using pheromone-baited traps. The temporal and spatial distribution and relative abundance of these species were determined. This information was used during 1980 and 1981 to develop a mass-trapping program for these species while maintaining the integrity of an existing trapping program for a third ambrosia beetle species, G. sulcatus (LeConte). A fourth ambrosia beetle species, Platypus wilsoni (Swaine) responded in significantly larger numbers to traps baited with the pheromone sulcatol plus ethanol and α-pinene than to those baited with the pheromone lineatin or unbaited. Several experiments were conducted in order to improve or assess the trapping system. It was found that both G. retusus and T. lineatum response to their respective pheromones was increased by the inclusion of ethanol and α-pinene on the traps. T. lineatum response to lineatin was significantly reduced when sulcatol was included in the bait. An experiment conducted to determine optimum trap height showed that largest numbers of T. lineatum were caught on the lowest traps that cleared surrounding understory vegetation. A mark-recapture technique was tested as a potential means of assessing trapping efficiency. Recommendations were made that could result in this technique becoming a useful means of optimizing and evaluating ambrosia beetle mass-trapping programs. This concurrent mass-trapping program for three species of ambrosia beetles demonstrated that large numbers of beetles can be captured using pheromone-baited traps. The relatively low cost of this pest management tactic compared with the high values at risk has already resulted in much of the technology developed in this thesis being incorporated in ambrosia beetle management programs by forest industries in British Columbia. / Forestry, Faculty of / Graduate
12

The Impact of Ambrosia trifida (giant ragweed) on Native Prairie Species in an Early Prairie Restoration Project

Megyeri, Krisztian 01 December 2011 (has links)
As the ecological importance of prairies is becoming more recognized, the number of prairie restoration projects is increasing worldwide. One of the major challenges in restoring any disturbed ecosystem is the successful establishment of native species at the expensive of invasive species. While some weedy species are gradually replaced as other, more desired, species become established, there are invasive species that, due to their level of dominance, may out-compete native species indefinitely. The objectives of this study were 1) to quantify the impact of Ambrosia trifida (giant ragweed) on the plant community of a newsly established prairie, 2) to assess any difference in effectiveness between management practices (cutting versus pulling) of A. trifida, and 3) to establish a baseline vegetation survey to be used in future evaluations and research of the prairie. In March of 2011, 30 plots (each 3 m2) were established within the 20 acre prairie including 10 control plots [C], 10 plots where A. trifida was selectively cut approximately 10 cm above ground level [Rc], and 10 plots where A. trifida was selectively pulled [Rp]. Treatment (cutting/pulling) was applied three times (April, June, and August) during the study, and in order to compare the effectiveness of the treatments, the number of removed A. trifida was recorded for the first two applications. Between April and June, the number of A. trifida decreased by a mean of 34.9 individuals in the cut plots, and increased by a mean of 12.4 individuals in the pulled plots suggesting (albeit, not significantly) that pulling may disturb the ground and promote the germination of more seeds from the seedbed. Final biomass data collection was conducted in mid August by removing the above ground biomass of all plants excluding A. trifida from four subplots within each of the 30 main plots, followed by drying and weighing of all biomass. A total of 172 plants from 30 species were removed for a total biomass of 1735.10 grams. In the control plots the mean biomass was 6.73g and the species diversity (H') was 0.037. In the treatment plots, the corresponding values were 83.39g, and 2.093. This twelve-fold difference in biomass suggests that the presence of A. trifida has a remarkable impact on the overall community of this newly established prairie and that the correct management of A. trifida could expedite the restoration process.
13

Identification and characterization of glyphosate-resistant common ragweed

Pollard, Justin Michael. January 2007 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 10, 2009) Includes bibliographical references.
14

The Chemical Ecology of Rapid Ohia Death

Kylle Alohilani Minei Roy (17538252) 02 December 2023 (has links)
<p dir="ltr">Rapid ʻōhiʻa death (ROD) is a disease complex caused by two <i>Ceratocystis fungi</i>, <i>C. lukuohia</i> and <i>C. huliohia</i>, that is devastating the keystone tree of the Hawaiian Islands, ʻōhiʻa lehua (<i>Metrosideros polymoropha</i>). The causal agents of ROD were identified in 2015 and I began researching entomological aspects of the complex in 2016. Much like other <i>Ceratocystis</i> diseases, my colleagues and I suspected that beetles and frass might be involved in the system. Together, we identified four species of invasive ambrosia beetles (Coleoptera: Curculionidae) that contribute to the spread of ROD: <i>Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus</i>, and <i>Xyleborus perforans</i>. Both ROD-<i>Ceratocystis</i> fungi and the ambrosia beetles inhabit the xylem of ʻōhiʻa. When these beetles create their home galleries, they produce frass particles infested with resting chlamydospores that can be transported in the environment through the soil, wind, and water. Secondly, the beetles are capable of vectoring the fungi directly to stressed trees via viable propagules attached to their exoskeleton. The natural progression of this research was to investigate the chemical ecology of the system, therefore building the foundations for management strategies to reduce the spread of ROD. In addition, I satisfied my curiosity to explore the fungal mutualisms of these beetles through the use of phylogenetics.</p><p dir="ltr">In Chapter 1, I review the literature describing ROD and the four ROD-associated ambrosia beetle species. I report all of the research to date regarding ROD, including current monitoring and management strategies. Then, I introduce ambrosia beetles and the Xyleborini tribe, focusing on the life history of the ROD-associated beetles and current literature describing the use of semiochemicals to control them.</p><p dir="ltr">In Chapter 2, I determine the volatile organic compounds associated with the ROD <i>Ceratocystis</i> – ʻōhiʻa pathosystem and the response of the associated beetles to those compounds. I investigated the volatiles produced by <i>C. lukuohia</i> and <i>C. hulihia</i> in culture in addition to when inoculated into ʻōhiʻa seedlings. Then, I describe olfactometer assays to determine if the ROD-associated beetles are attracted to the volatiles emitted from ROD-<i>Ceratocysti</i>s in culture.</p><p dir="ltr">In Chapter 3, I investigate semiochemicals for attracting and repelling ambrosia beetles in ʻōhiʻa forests. I describe separate trapping experiments, first, testing the attraction of beetles to 100% ethanol and 1:1 methanol ethanol. Second, we investigate the use of two beetle repellent products, one with verbenone and the other with verbenone + methyl salicylate active ingredients.</p><p dir="ltr">In Chapter 4, I describe the testing of the repellent, verbenone, in the SPLAT<sup>®</sup> Verb formulation, to deter ambrosia beetle attack from both healthy ʻōhiʻa trees and trees infested with ROD-<i>Ceratocystis</i>. Over two field seasons, we monitored ambrosia beetle attacks on trees treated with verbenone and measured the abundance of verbenone released from the repellents over time during the first season.</p><p dir="ltr">In Chapter 5, I investigate the ambrosia fungi of the ROD-associated beetles and native Hawaiian ambrosia beetles on the Island of Hawaiʻi. We isolated a dozen fungal symbionts from the mycetangia of ambrosia beetles, most of which are first reports in Hawaiʻi, and use phylogenetics to investigate putative new species of <i>Raffaelea</i> and <i>Ambrosiozyma.</i></p><p dir="ltr">Finally, in Chapter 6, I synthesize the results and future directions of the aforementioned chapters. Together, these dissertation chapters provide insights into ambrosia beetle monitoring and management strategies in Hawaiʻi and beyond. I describe the groundwork for understanding the pathosystem from a chemical ecology perspective and touch on the understudied world of Hawaiʻi fungi and potential pathogens.</p>
15

Intérêt d'une approche évolutive pour l'étude des invasions biologiques. L'invasion d'Ambrosia artemisiifolia dans la vallée du Rhône

Genton, Benjamin 05 1900 (has links) (PDF)
Les invasions biologiques ont des conséquences écologiques et économiques considérables. Si leurs mécanismes démographiques, écologiques et génétiques sont maintenant connus, elles restent cependant difficiles à prédire. Les approches fondées sur la recherche des caractéristiques écologiques des espèces envahissantes ou des écosystèmes envahis n'ont pas encore abouti. Nous encourageons une approche évolutive pour mieux appréhender les mécanismes d'invasion, approche qui s'attache à la résolution de deux paradoxes. (1) Pourquoi une espèce "étrangère" réussit-elle à s'établir et à envahir un écosystème auquel elle n'est pas adaptée, surpassant parfois certaines espèces locales ? (2) Pourquoi les populations envahissantes réussissent-elles à s'adapter si rapidement à leur nouvel environnement malgré les effets de fondation ? L'ambroisie commune, envahissante dans la vallée du Rhône, est une Asteraceae d'origine nordaméricaine. Cet adventice des cultures pose d'importants problèmes de santé publique, son pollen étant très allergène. Pour tenter de résoudre les deux paradoxes évolutifs, nous avons mené plusieurs études comparant des populations envahissantes françaises à des populations nord-américaines de l'aire d'origine. Nous avons ainsi détecté un relâchement de la pression des herbivores qui pourrait avantager l'ambroisie dans l'aire d'invasion. En revanche, nous n'avons décelé aucune adaptation consécutive à cette diminution de pression d'herbivorie. Par ailleurs, après avoir développé des marqueurs microsatellites spécifiques, nous avons mis en évidence une diversité génétique plus élevée dans les populations françaises que dans les populations nord-américaines. Les effets de fondation furent probablement limités par l'introduction en France d'individus provenant de plusieurs populations sources. Enfin, nous proposons un cadre théorique évolutif où nous distinguons trois types d'invasion: celles ne nécessitant aucun changement de l'environnement ou de l'espèce, celles qui sont la conséquence d'un changement de l'environnement et celles qui résultent de l'adaptation de l'espèce.
16

The Effects of Biotic Interactions on Ambrosia artemisiifolia L.

MacDonald, Arthur Andrew Meahan 22 September 2009 (has links)
Plant invasions can ensue when plants are introduced to regions without their specialist enemies (the Enemy Release Hypothesis). This assumes natural enemies limit survival and fecundity in an invader's native range. I tested this assumption for a native invasive species, Common Ragweed (Ambrosia artemisiifolia), by excluding natural enemies from seeds, seedlings and adults. At the adult stage, I added disturbance and conspecific density treatments. Protection from herbivores slightly improved performance at the seedling stage only, while disturbance greatly increased survival and fecundity. Increasing conspecific density reduced performance only in disturbed plots. I also tested herbivore tolerance using simulated damage. Heavy (75%) damage did not reduce fecundity; light damage even increased seed production. These results suggest enemies do not limit Ambrosia in its native range, especially compared to the effects of habitat disturbance. While enemy release may have occurred during Ambrosia’s invasions, it is not likely to be their principal cause.
17

The Effects of Biotic Interactions on Ambrosia artemisiifolia L.

MacDonald, Arthur Andrew Meahan 22 September 2009 (has links)
Plant invasions can ensue when plants are introduced to regions without their specialist enemies (the Enemy Release Hypothesis). This assumes natural enemies limit survival and fecundity in an invader's native range. I tested this assumption for a native invasive species, Common Ragweed (Ambrosia artemisiifolia), by excluding natural enemies from seeds, seedlings and adults. At the adult stage, I added disturbance and conspecific density treatments. Protection from herbivores slightly improved performance at the seedling stage only, while disturbance greatly increased survival and fecundity. Increasing conspecific density reduced performance only in disturbed plots. I also tested herbivore tolerance using simulated damage. Heavy (75%) damage did not reduce fecundity; light damage even increased seed production. These results suggest enemies do not limit Ambrosia in its native range, especially compared to the effects of habitat disturbance. While enemy release may have occurred during Ambrosia’s invasions, it is not likely to be their principal cause.
18

Diversidade de Curculionidae (Scolytinae, Platypodinae) e Bostrichidae em plantios de teca, Tectona grandis L.f., 1782, no Estado do Pará, Brasil

Ferreira, Carla Samara dos Santos 16 September 2016 (has links)
Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2017-01-05T11:14:19Z No. of bitstreams: 1 DissCSSF.pdf: 5294769 bytes, checksum: 0ab390d8f532ae94a15a76179151fb32 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2017-01-16T13:15:25Z (GMT) No. of bitstreams: 1 DissCSSF.pdf: 5294769 bytes, checksum: 0ab390d8f532ae94a15a76179151fb32 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2017-01-16T13:15:33Z (GMT) No. of bitstreams: 1 DissCSSF.pdf: 5294769 bytes, checksum: 0ab390d8f532ae94a15a76179151fb32 (MD5) / Made available in DSpace on 2017-01-16T13:15:40Z (GMT). No. of bitstreams: 1 DissCSSF.pdf: 5294769 bytes, checksum: 0ab390d8f532ae94a15a76179151fb32 (MD5) Previous issue date: 2016-09-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The teak wood is one of the most valuable in the world, creating interest among producers in its quality and great commercial value. In Brazil plantations are concentrated in the Midwest and North, and due to the increase in these exotic plantations, monitoring is necessary to learn about their insect diversity. In 2008 a program to monitor the quarantine pest Sinoxylon unidentatum (Coleoptera: Bostrichidae) in Tectona grandis was started in the state of Pará, Brazil, because of the proximity to the state of Mato Grosso, area of occurrence of this pest. The general objective of this research was to monitor S. unidentatum and other beetle borers in Canaã dos Carajás, Cumaru do Norte, Pau D’ Arco, Rio Maria, São Domingos do Araguaia and Ulianópolis. Our specific objectives were to determine the richness and diversity of Curculionidae (Scolytinae, Platypodinae) and Bostrichidae in these plantations, and to know if there was a seasonal variation for their most abundant species. Trappings were done biweekly with ethanol-baited flight intercept traps from June 2011 to April 2013, totaling 115 collections. We captured 10147 specimens of beetle borers, distributed in eight sub-tribes, and totaling 90 species. In Rio Maria we found the greatest diversity of beetles and in São Domingos do Araguaia the greatest richness. There was a predominance of Scolytinae of the sub-tribe Cryphalina, which probably develop in the understory or dry material above the soil. We trapped significantly more Bostrichidae and Hypothenemus during the dry season. Sinoxylon unidentatum, target species that started this research, was not detected. / A madeira de teca é uma das mais valiosas do mundo, despertando interesse entre os produtores pela sua qualidade e grande valorização comercial. No Brasil as plantações estão concentradas na região Centro-Oeste e Norte, e devido ao aumento destes plantios exóticos, o monitoramento faz-se necessário para o conhecimento da diversidade de insetos. No ano de 2008, iniciou-se um programa de fiscalização da praga quarentenária Sinoxylon unidentatum (Coleoptera: Bostrichidae) em plantios de Tectona grandis no estado do Pará, devido à proximidade com o estado de Mato Grosso, área de ocorrência desta praga. O objetivo geral desta pesquisa foi realizar o monitoramento de S. unidentatum e demais brocas capturadas nos municípios de Canaã dos Carajás, Cumaru do Norte, Pau D’ Arco, Rio Maria, São Domingos do Araguaia e Ulianópolis. Os objetivos específicos foram determinar a riqueza e diversidade, e verificar se há variação sazonal para as principais espécies de Curculionidae (Scolytinae, Platypodinae) e Bostrichidae em oito áreas experimentais no Pará. O experimento foi conduzido com armadilhas de intercepção de voo iscadas com etanol. As coletas foram realizadas a cada 15 dias, de junho de 2011 a abril de 2013, totalizando 115 coletas. Foram capturados 10147 espécimes de brocas, distribuídos em oito sub-tribos, totalizando 90 espécies. Em Rio Maria foi encontrada a maior diversidade de brocas e em São Domingos do Araguaia a maior riqueza. Houve predomínio de Scolytinae da sub-tribo Cryphalina, que se desenvolvem provavelmente no subbosque ou em material seco sobre o solo. Foram capturados significativamente mais Bostrichidae e Hypothenemus durante o período seco. Sinoxylon unidentatum, espécie alvo que iniciou esta pesquisa, não foi coletada.
19

Populaciono-genetička karakterizacija ambrozije (Ambrosia artemisiifolia L.) južnog dela Panonske nizije i peripanonskog prostora centralnog Balkana / Population-genetic characterization of common ragweed (Ambrosia artemisiifoliaL.) from the southern part of the Pannonian Plain and the Peripannonian region of the Central Balkan

Kočiš-Tubić Nataša 22 September 2014 (has links)
<p>Vrsta&nbsp;<em> Ambrosia&nbsp; artemisiifolia&nbsp; L.&nbsp;</em> (fam.&nbsp; Asteraceae)&nbsp; je&nbsp; jedna&nbsp; od&nbsp; najagresivnijih&nbsp; invazivnih&nbsp;biljaka&nbsp; kako&nbsp; u&nbsp; Evropi,&nbsp; tako&nbsp; i&nbsp; na&nbsp; globalnom&nbsp; nivou.&nbsp; Kao&nbsp; korovska&nbsp; vrsta&nbsp; uzrokuje&nbsp; velike&nbsp;ekonomske&nbsp; gubitke&nbsp; redukujući&nbsp; prinos&nbsp; poljoprivrednih&nbsp; kultura,&nbsp; a&nbsp; njena&nbsp; masovna&nbsp; produkcija&nbsp;polena stvara ozbiljne alergijske probleme kod ljudi. Kao invazivna vrsta, predstavlja dobar&nbsp;model za proučavanje procesa uključenih u biolo&scaron;ke invazije, koje se danas prepoznaju kao&nbsp;deo globalnih promena, predstavljajući jednu od glavnih pretnji biodiverzitetu, funkcionisanju&nbsp;ekosistema,&nbsp; poljoprivredi,&nbsp; ali&nbsp; i&nbsp; ljudskom&nbsp; zdravlju.&nbsp; U&nbsp; Evropi,&nbsp; ambrozija&nbsp; je&nbsp; &scaron;iroko&nbsp;rasprostranjena,&nbsp; ali&nbsp; jedno&nbsp; od&nbsp; područja&nbsp; sa&nbsp; najvećom&nbsp; incidencom&nbsp; ovog&nbsp; invazivnog&nbsp; korova&nbsp; je&nbsp;Panonska&nbsp; nizija.&nbsp; Po&nbsp; svom&nbsp; položaju,&nbsp; kao&nbsp; i&nbsp; karakteristikama&nbsp; samog&nbsp; područja,&nbsp; ovaj&nbsp; region&nbsp;predstavlja&nbsp; povoljno&nbsp; stani&scaron;te&nbsp; kako&nbsp; za&nbsp; introdukciju&nbsp; ambrozije&nbsp; iz&nbsp; različitih&nbsp; pravaca,&nbsp; tako&nbsp; i&nbsp; za&nbsp;njenu brzu ekspanziju u pomenutom području i &scaron;ire.&nbsp; U proteklih 30-40 godina ambrozija se&nbsp;&scaron;iri&nbsp; na&nbsp; peripanonsko&nbsp; područje,&nbsp; tačnije&nbsp; ka&nbsp; centralnim&nbsp; i&nbsp; južnim&nbsp; delovima&nbsp; Srbije.&nbsp; Uzimajući&nbsp; u&nbsp;obzir sve činjenice,&nbsp; cilj ovog istraživanja je bio genetička karakterizacija populacija ambrozije&nbsp;<br />sa područja Panonske nizije i peripanonskog prostora centralnog&nbsp; dela Balkanskog poluostrva.&nbsp;U&nbsp; svrhu&nbsp; ovoga,&nbsp; upotrebljeni&nbsp; su&nbsp; jedni&nbsp; od&nbsp; najpopularnijih&nbsp; i &nbsp;ajinformativnijih&nbsp; molekularnih&nbsp;markera u polju populacione genetike, mikrosateliti. Na području Panonske nizije utvrđen je&nbsp;visok nivo genetičke varijabilnosti i nizak nivo genetičke diferencijacije i struktuiranosti među&nbsp;ispitivanim&nbsp; populacijama, a najverovatnije kao posledica multiplih introdukcija i intenzivnog&nbsp;protoka gena među populacijama ispitivanog regiona. Suprotno, populacije sa peripanonskog&nbsp;prostora&nbsp; centralnog&nbsp; Balkana&nbsp; su&nbsp; pokazale&nbsp; niži&nbsp; nivo&nbsp; genetičkog&nbsp; diverziteta&nbsp; u&nbsp; odnosu&nbsp; na&nbsp;panonske populacije, sa izraženom inter-populacionom diferencijacijom. Potvrđeno je &scaron;irenje&nbsp;ambrozije&nbsp; u&nbsp; pravcu&nbsp; sever-jug&nbsp; na&nbsp; području&nbsp; peripanonskog&nbsp; prostora,&nbsp; kao&nbsp; i&nbsp; poreklo&nbsp; ovih&nbsp;populacija&nbsp; od&nbsp; populacija&nbsp; iz&nbsp; regiona&nbsp; Panonske&nbsp; nizije,&nbsp; ali&nbsp; bez&nbsp; isključivanja&nbsp; mogućeg&nbsp; upliva&nbsp;ambrozije&nbsp; iz&nbsp; drugih&nbsp; pravaca.&nbsp; Ova&nbsp; saznanja&nbsp; doprinose&nbsp; rasvetljavanju&nbsp; procesa&nbsp; introdukcije&nbsp; i&nbsp;ekspanzije&nbsp; ispitivane&nbsp; invazivne&nbsp; vrste&nbsp; na&nbsp; ovom&nbsp; području&nbsp; Evrope.&nbsp; Utvrđen&nbsp; visok&nbsp; potencijal&nbsp; u&nbsp;ekspanziji ambrozije i potencijalni pravci &scaron;irenja u ispitivanom području, mogu da doprinesu&nbsp;predviđanju dalje potencijalne ekspanzije ove vrste, &scaron;to bi moglo unaprediti mere kontrole i&nbsp;strategiju za suzbijanje &scaron;irenja ambrozije.</p> / <p><em>Ambrosia&nbsp; artemisiifolia&nbsp;</em> L.&nbsp; (fam.&nbsp; Asteraceae)&nbsp; is&nbsp; one&nbsp; of&nbsp; the&nbsp; most&nbsp; aggressive&nbsp; invasive&nbsp; plant&nbsp;species&nbsp; in&nbsp; Europe&nbsp; and&nbsp; globally.&nbsp; As&nbsp; weed&nbsp; species,&nbsp; common&nbsp; ragweed&nbsp; causes&nbsp; great&nbsp; economic&nbsp;losses by reducing the yield of agricultural crops, and its mass production&nbsp; of pollen produces&nbsp;severe allergic problems in humans. As an invasive species,&nbsp; <em>Ambrosia artemisiifolia&nbsp;</em> is&nbsp; a good&nbsp;model for studying the processes of biological invasions, which are today recognized as part&nbsp;of&nbsp; global&nbsp; changes,&nbsp; presenting&nbsp; a&nbsp; major&nbsp; threat&nbsp; to&nbsp; biodiversity,&nbsp; the&nbsp; functioning&nbsp; of &nbsp; ecosystems,&nbsp;agriculture and human health. In Europe, <em>Ambrosia artemisiifolia</em> is widespread, but one of the&nbsp;most&nbsp; infested&nbsp; area&nbsp; is&nbsp; the&nbsp; Pannonian&nbsp; Plain.&nbsp; According&nbsp; to&nbsp; location&nbsp; and&nbsp; characteristics&nbsp; of&nbsp; the&nbsp;area,&nbsp; this&nbsp; region&nbsp; represents&nbsp; a&nbsp; favorable&nbsp; habitat&nbsp; for&nbsp; introduction&nbsp; of&nbsp; common&nbsp; ragweed&nbsp; from&nbsp;different&nbsp; directions&nbsp; and&nbsp; rapid&nbsp; expansion&nbsp; in&nbsp; these&nbsp; areas&nbsp; as&nbsp; well&nbsp; as&nbsp; further.&nbsp; In&nbsp; the&nbsp; past&nbsp; 30-40&nbsp;years,&nbsp; common&nbsp; ragweed&nbsp; was&nbsp; spreading&nbsp; across&nbsp; Peripannonian&nbsp; region,&nbsp; more&nbsp; precisely,&nbsp; to&nbsp; the&nbsp;Central and Southern parts of Serbia. According the facts, the aim of this study was the genetic&nbsp;characterization&nbsp; of&nbsp; populations&nbsp; of&nbsp; <em>Ambrosia&nbsp; artemisiifolia&nbsp;</em> from&nbsp; the&nbsp; Southern&nbsp; part&nbsp; of&nbsp; the&nbsp;Pannonian Plain and the&nbsp; Peripannonian region of the Central Balkan.&nbsp; One of the most popular&nbsp;and most informative molecular markers in&nbsp; population genetics, microsatellites&nbsp; were&nbsp; used. In&nbsp;the area of the Pannonian Plain, a high level of&nbsp; genetic variability and low&nbsp; level of&nbsp; genetic&nbsp;differentiation and structure&nbsp; among the study population have detected, probably as a&nbsp; result of&nbsp;multiple&nbsp; introduction&nbsp; and&nbsp; intensive&nbsp; gene&nbsp; flow&nbsp; between&nbsp; populations.&nbsp; In&nbsp; the&nbsp; other&nbsp; hand,&nbsp; the&nbsp;populations from the Peripannonian region have shown lower level of genetic diversity related&nbsp;to&nbsp; populations&nbsp; from&nbsp; Pannonin&nbsp; Plain,&nbsp; with&nbsp; moderate&nbsp; level&nbsp; of&nbsp; inter-population&nbsp; differentiation.&nbsp;Obtained&nbsp; results&nbsp; have&nbsp; confirmed&nbsp; that&nbsp; the&nbsp; spread&nbsp; of&nbsp; common&nbsp; ragweed&nbsp; across&nbsp; Peripannonian&nbsp;region was&nbsp; in the north-south direction, as &nbsp;well as that the populations from the considered&nbsp;area originated from the populations of Pannonian Plain.&nbsp; However, in this claim we can not&nbsp;exclude&nbsp; the&nbsp; possible&nbsp; influence&nbsp; of&nbsp; <em>Ambrosia&nbsp; artemisiifolia</em>&nbsp; from&nbsp; other&nbsp; directions.&nbsp; This&nbsp; study&nbsp;contributes&nbsp; to&nbsp; better understuding of&nbsp; the process of introduction and expansion of&nbsp; <em>Ambrosia&nbsp;artemisiifolia&nbsp;</em> in&nbsp; considered part&nbsp; of Europe.&nbsp; Detected&nbsp; high potential for &nbsp;expansion of&nbsp; common&nbsp;ragweed and possible directions of spreading in the study area, can contribute to the prediction&nbsp;of&nbsp; potential&nbsp; further&nbsp; expansion&nbsp; of&nbsp; <em>Ambrosia&nbsp; artemisiifolia</em>,&nbsp; which&nbsp; could&nbsp; improve&nbsp; control&nbsp;measures and strategies for preventing the spreading of this invasive species.&nbsp;</p>
20

Vegetation of the eastern Cabeza Prieta NWR and adjacent BLM lands, Arizona

Malusa, Jim 31 December 2003 (has links)
A report on the vegetation of the Cabeza Prieta NWR, with tables giving statistical representations of the vegetation associations.

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