Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Mark A. Isaacs, Dept. of Plant & Soil Sciences. Includes bibliographical references.

Thesis (doctoral)--Loughborough University, 1999. / BLDSC reference no.: DX207461.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 60-62). Also available on the World Wide Web.

Fallopia japonica (Houtt. Ronse Decraene) (syn. Reynoutria japonica syn. Polygonum cuspidatum, Japanese knotweed) is an aggressively invasive alien weed in the United Kingdom (UK) and throughout its introduced range. Its presence can herald considerable costs, both in terms of its ecological impact as a threat to biodiversity and economically due to the physical damage caused to property and the associated costs of treatment and disposal of the plant. There is therefore increasing interest in eradicating this alien species and as a result many different management techniques have been applied to try and control its spread. It is important to ascertain which of these are most appropriate in any given situation and so tools that can test the impact and efficiency of these techniques both quickly and cheaply would be extremely useful. In this thesis mathematical models are developed for the spatial spread of F. japonica on a local scale in the UK.

Stream channels and their corresponding riparian zones are composed of complex spatially and temporally dynamic systems. Changing land-use associated with urbanization has resulted in large shifts in riparian assemblages, stream hydraulics, and sediment dynamics leading to the degradation of the world’s waterways. To combat degradation, restoration and management of riparian zones is becoming increasingly common. However, the relationship between flora, especially the influence of invasive species, on sediment dynamics is poorly understood. This relationship must be studied further to ensure the success of management practices. Three methods were used to monitor erosion and turbidity within the Tookany Creek and its tributary Mill Run in the greater Philadelphia, PA region. To evaluate the influence of the invasive species Reynoutria japonica (Japanese knotweed) on erosion, reaches were chosen based on their riparian vegetation and degree of incision. Methods used to estimate sediment erosion included measuring changes in bank pins, repeated total station transects, and monitoring turbidity responses to storm events. While each method has been used in previous studies to monitor sediment flux, the combination of methods in this study allowed their applicability to be compared. Measurements taken with YSI turbidity loggers showed large fluctuations in turbidity based both on riparian conditions and geomorphic positioning, suggesting that future studies need to be careful with logger placement when using sediment calibration curves to estimate sediment yield within streams. There were pros and cons of using both total station and bank pins to estimate bank erosion. Total station has the potential to produce highly accurate measurements but a greater risk of loss of data if the control points used to establish the grid cannot be re-established from one measurement to the next. Bank pins are more likely to influence bank erosion and be affected by freeze-thaw conditions but provide a simple method of monitoring erosion at frequent intervals. Volume calculations based on total station transects along the main stem of the Tookany did not show a consistent relationship between riparian type and erosion rates. However, erosion calculations based on bank pins suggest greater erosion in reaches dominated by knotweed with 4.7x10-1 m3/m and 8.3x10-2 m3/m more erosion than those dominated by trees at Chelten Hills and Mill Run respectively. Turbidity responses to storm events were also higher (76.7 v 54.2 NTU) in reaches with knotweed, although this increase was found when the reach dominated by knotweed was also incised. Thus, this study linked knotweed to increased erosion using multiple methods. / Geology

Thesis (M.E.S.)--The Evergreen State College, 2006. / Title from title screen (viewed 3/11/2010). Includes bibliographical references (leaves 41-53).

Invasiva främmande arter (IFA) har negativa effekter på biologisk mångfald och inhemska ekosystem. Parkslide (Reynoutria japonica Houtt.)  är en svårutrotad IFA som har fått stor spridning i delar av Europa, och även i södra och mellersta Sverige, framförallt i kustområden. Den konkurrerar ut inhemska arter, framför allt genom att begränsa tillgången av ljus och näringsämnen för andra växter. Syftet med denna studie var att undersöka tillväxten hos parkslide med vattentillgång som parameter, för att förstå mer om arten och förutsäga hur förändring av denna abiotiska faktor kan påverka dess framtida spridning. Sex grupper med sticklingar och sex grupper med rhizomer analyserades vid olika bevattningsbehandlingar under 21 dagar, mellan kontrollbehandlingen 0 ml H2O/3e dag till 50 ml H2O/3e dag. Före plantering mättes vikt, längd och antal blad och noterades för sticklingarna - för rhizomer mättes vikt och antal groddögon. Överlevnaden bland sticklingar var 13.3% och bland rhizomer 95.0%. För rhizomerna skilde sig kontrollbehandlingen (0 ml H2O /3:e dag) med en genomsnittlig tillväxt på 3.0 cm signifikant i längdtillväxt från behandlingen med 15 ml H2O /3:e dag med en genomsnittlig tillväxt på 26.3 cm, i övrigt fanns inga signifikanta skillnader i längdtillväxt mellan de andra behandlingarna för rhizomerna. För tillväxt av massa bland rhizomer fanns det en signifikant skillnad mellan kontrollbehandlingen 0 ml H2O /3:e dag (29,4 % viktminskning) och all annan behandling utom 5 ml H2O /3:e dag. Behandlingen med 5 ml H2O /3:e dag hade också en signifikant skillnad mot 40 ml H2O /3:e dag (83,9 % viktökning), som var gruppen med högst viktökning bland rhizomer. Överlevnadsgraden var totalt sett låg för sticklingarna, och alla behandlingar hade 0 % levande sticklingar i slutet av experimentet, förutom behandlingen 25 ml H2O /3:e dag, 40 ml H2O /3:e dag och 50 H2O /3:e dag som hade en överlevnadsgrad på 30, 40 respektive 10 %. Studien visar att parkslide har mycket god förmåga till överlevnad vid varierande tillgång till vatten, då den grupp som inte alls vattnats under perioden var den enda som väsentligen särskilde sig från de andra. På grund av den höga överlevnaden bland rhizomer bör man iaktta stor försiktighet vid förflyttning av jordmassor för att begränsa denna spridningsväg och förebygga framtida nyetablering av parkslide. / Invasive alien species (IAS) have negative effects on biodiversity and native ecosystems. Japanese knotweed (Reynoutria japonica Houtt.) is an IAS that is difficult to eradicate, and it has become widespread in Europe and in the coastal and south-central Sweden. It outcompetes native species primarily by limiting the light and nutrients availability. The aim of this study was to investigate growth of Japanese knotweed under different watering conditions, to understand more about the species and if change of this abiotic factor can impact its future spread. Six groups of shoot cuttings and six groups of rhizomes fragments were planted and analyzed under different watering treatments for 21 days with water amount ranging from 0 ml H2O/3rd day for the control treatment up to 50 ml H2O/3rd day. Before planting, weight, length and number of leaves was measured for the shoot cuttings; for the rhizomes weight and number of sprout nodes was measured. The survival for the shoot cuttings was 13.3% and for the rhizomes 95.0%. For the rhizomes, the control treatment (0 ml H2O/3rd day) with an average of 3.0 cm growth differed significantly in length growth from the treatment with 15 ml H2O/3rd day with an average of 26.3 cm growth. There were no significant differences in length growth between the other rhizome treatments. For the mass growth of rhizomes, there was a significant difference between the control treatment 0 ml H2O/3rd day (29.4% weight loss) and all other treatment except 5 ml H2O/3rd day. The 5 ml H2O/3rd day treatment was also significantly different from the 40 ml H2O/3rd day (83.9% weight gain), which was the group with the highest weight gain. Survival rates were overall low for the shoot cuttings, and all treatments had 0% living shoot cuttings at the end of the experiment, except for the treatment of 25 ml H2O/3rd day, 40 ml H2O /3rd day and 50 ml H2O/3rd that had a survival rate of 30%, 40%, 10% respectively. The study shows that Japanese knotweed has a very good ability to survive with varying access to water, as the group that was not watered at all during the period was the only that essentially differed from the others. The high survival of the rhizomes calls for caution when moving soil masses in order to prevent further spread of the Japanese knotweed.

No description available.

Les espèces exotiques envahissantes végétales sont des plantes introduites et naturalisées hors de leur aire de répartition native et capables de maintenir et d’accroitre leur population. Certaines sont considérées comme transformatrices de par leur effet sur les écosystèmes : leur structure, leur fonctionnement ainsi que leur communauté végétale et animale. Ces transformations peuvent rendre certaines de ces espèces nuisibles de par leurs impacts écologiques et économiques important. Les travaux réalisés dans le cadre de cette thèse et présentés ici ont pour objectif d’approfondir les connaissances sur l’impact des invasions biologiques. La faune du sol, la végétation native et leur substrat ainsi que son fonctionnement ont été étudiés à différentes échelles spatiales. Deux espèces exotiques, envahissantes en Europe, ont été considérées comme modèles pour ces travaux : le robinier faux-acacia (Robinia pseudoacacia) et la renouée du japon (Reynoutria japonica). Premièrement, une méta-analyse globale a permis de démontrer l’effet positif des invasions biologiques végétales sur l’abondance de certains groupes de la faune du sol, notamment les consommateurs primaires, en fonction de la structure de l’habitat (ouvert ou fermé). Ensuite, une étude à large échelle sur le robinier faux-acacia a permis d’illustrer les différences qui peuvent exister dans la réponse des écosystèmes forestiers aux invasions le long d’un gradient latitudinal. Ce gradient, composé de quatre régions distinctes en Europe de l’Ouest présente des différences de climat et de végétation dominante, ces différences modifiant l’impact du robinier faux-acacia. Une étude approfondie sur le robinier faux-acacia en Normandie a permis de mieux comprendre l’effet du robinier faux-acacia sur les communautés animales et végétales ainsi que sur le fonctionnement des écosystèmes par comparaison avec deux essences natives dominantes. Finalement, une manipulation expérimentale en laboratoire a démontré l’impact des composés allélopathiques de la renouée du Japon sur une partie de la faune du sol. Cette étude a montré que certaines espèces exotiques envahissantes sont susceptibles d’influencer la faune, et les réseaux trophiques, du sol par leur métabolisme secondaire. Ces travaux illustrent l’intérêt, dans le contexte des invasions biologiques végétales, de l’étude simultanée des compartiments aériens et souterrains à différentes échelles spatiales. / Invasive alien plants are species introduced and naturalized outside of their native distribution range and which have the capacity to maintain and expand their population. Some of these species are considered to be ecosystem transformers by altering their structure, functioning as well as resident animal and plant communities. These induced alterations make some of these species undesirable through their ecological and economical impacts. The work presented in this thesis aimed at a better understanding of the impact of biological invasions by alien plants. The soil fauna, native vegetation and their substrate, as well as ecosystem functioning, were studied at different spatial scales. Two exotic alien species, invasive in Europe, were considered as biological models for this work: the black locust (Robinia pseudoacacia) and the Japanese knotweed (Reynoutria japonica). Firstly, a global meta-analysis demonstrated the positive impact that plant invasions can exert on the abundance of some groups within the soil fauna, notably primary consumers, within different types of habitats (open or closed). Then, a large-scale study on the black locust revealed the differences that can can occur in the response of forest ecosystems to invasions along a latitudinal gradient. Study sites along this gradient, distributed amog four distinct regions in western Europe, exhibit differences in climate and dominant native vegetation which can alter the impact of the black locust. A detailed study on black locust impact in Normandy demonstrated the impact of R. pseudoacacia on native plant and soil fauna communities, as well as some ecosystem functions, in comparison to two native tree species. Finally, a laboraty experiment demonstrated the impact that allelopathic compounds extracted from Japanese knotweed rhizomes can have on some organisms within the soil fauna. This study showed that some invasive alient plants can influence the soil fauna, and soil food webs, through their secondary metabolism. This thesis illustrates that simultaneous study of both aboveground and belowground ecosystem compartments at different spatial scales is of interest in the context of biological invasions.

Fallopiajaponica (Houtt.) Ronse Decraene (Japanese knotweed), an introduced, invasive, rhizomatous perennial plant, has become an increasing problem for nature conservation and land management in both rural and urban areas in the British Isles. In the native range of the plant, Japan, Taiwan and northern China, a number of varieties are recorded. Three congeners of F. japonica are present in the British Isles, F. sachalinensis, F. japonica var. conipacta and F. baldschuanica in addition to a hybrid F. x bohemica. An investigation by postal survey of the distribution of the hybrid F. x bohemica has identified 131 records for the British Isles. Both male and female plants of F. x bohemica have been recorded. Current understanding suggests that only female plants of F. japonica are present in the British Isles, inferring that the only means of reproduction is through vegetative regeneration. High rates of regeneration were recorded in this study for stem and rhizome material for both F. japonica and F. x bohemica in an aquatic and terrestrial environment. Implications of vegetative regeneration are discussed in terms of current management practices and future methods of control. A combination of digging with a mechanical excavator followed by spraying with the herbicide glyphosate decreased the time required to achieve an effective level of control of F. japonica compared to spraying alone. Fragmentation of the rhizome system through digging resulted in an increase in stem density allowing a more effective delivery of herbicide. Implications in terms of costs for F. japonica treatment on sites awaiting re-development are discussed. Analysis of data collated from surveys of F. japonica in Swansea using a Geographical Information System suggest that the primary habitats infested are waste ground and stream and river banks. Results suggest that disturbance, both by natural means and by human intervention has been the primary cause of spread of F. japonica in the British Isles. Management strategies are proposed which take account of these results and measures are put forward to help prevent future infestations.