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.

Japanese knotweed is an invasive plant that grows in disturbed sites across Nova Scotia. This study recorded an average spring growth rate of 6cm per day until reaching a canopy height exceeding 2m in June. Knotweed stands contained on average 17 stems and 8.0kg of fresh biomass per m2. Leaf cover was significantly greater in knotweed patches versus grass and shrub habitats in riparian ecosystems. Plant diversity in knotweed patches was nil, yet invertebrate diversity and abundances were similar across habitats. Small mammal tracks were more abundant in knotweed than shrub patches, but not as much as grass plots. Two herbicides were applied at four different dates in 2011. The following year, Aminopyralid was ineffective while Imazapyr treatments successfully reduced knotweed biomass, density, height, and leaf cover. Imazapyr application is recommended at full growth (June) or flowering (August). This project provides new information on an invasive weed in eastern Canada.

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.

Abstract Japanese knotweed (Reynoutria japonica) is an invasive alien species which is difficult to control as it is a hardy perennial that recovers easily. In Västra Götaland County, Sweden, there are a total of 7 416 documented observations in the SLU Biodiversity Data Analysis Portal. This study examines Japanese knotweed in Västra Götaland County with the aim of investigating whether the occurrence can be linked to a certain type of land cover or soil moisture. National Land Cover Data and SLU Soil Moisture Map were used to investigate which land cover and soil moisture classes that occur within buffered species observations (with a radius of 6 m) as well as in the entire county. The results of this study show that the occurrence of Japanese knotweed is related to land cover. The area of land cover classes within reported Japanese knotweed observations was not proportional to the area of the respective land cover classes within Västra Götaland County. The species occurs most commonly within land cover classes such as forest (deciduous and pine forests), other open land and exploited land. Occurrence of Japanese knotweed was also related to a certain soil moisture class. The area of a certain soil moisture class within reported observations of Japanese knotweed was not proportional to the area of the respective soil moisture class within Västra Götaland County. Analysis shows that Japanese knotweed within Västra Götaland County has a preference for areas with mesic-dry soil. The results show that Japanese knotweed has a strong association with places associated with human activities and lower level of soil moisture. This can be used to predict which habitats are at high risk of invasion by the Japanese knotweed. / Sammanfattning Parkslide (Reynoutria japonica) är en invasiv främmande art som är svårbekämpad då den är en tålig perenn som lätt återhämtar. I Västra Götalands län, Sverige, finns det totalt 7416 dokumenterade artfynd i SLU Analysportalen för biodiversitetsdata. Den här studien går ut på att undersöka parkslide i Västra Götalands län, i syfte att utreda om förekomsten kan kopplas till viss typ av marktäcke eller markfuktighet. Nationella Marktäckedata och SLU Markfuktighetskarta användes för att undersöka vilka marktäcke- och markfuktighetsklasser förekommer inom buffrade artobservationer (med radie på 6 m) såväl som i hela länet. Resultaten av denna studie visar det förekomsten av parkslide är relaterad till marktäckning. Arean av marktäckeklasser inom rapporterade parkslide observationer var inte proportionell mot arean för respektive marktäckeklasser inom Västra Götalands län. Arten förekommer vanligast vid marktäckeklasser som skog (löv- och tallskogar), övrig öppen mark och exploaterad mark. Förekomst av parkslide var också relaterad till viss markfuktighetsklass. Arean av viss markfuktighetsklass inom rapporterade observationer av parkslide var inte proportionell till arean av respektive markfuktighetsklass inom Västra Götalands län. Analys visar att parkslide inom Västra Götalands län har en preferens för områden med markfuktighets nivån frisk-fuktig. Resultaten visar att parkslide har ett starkt samband med platser förknippade med mänskliga aktiviteter och lägre nivå av markfuktighet. Detta kan användas för att förutsäga vilka livsmiljöer som löper hög risk för invasion av parkslide.

La croissance d'une plante est un processus dynamique qui répond aux différentes caractéristiques de l'environnement. La baisse de production de biomasse induite par les différents stress, les perturbations ou la compétition détermine la tolérance des plantes à ces contraintes. Dans le cas d'une plante invasive, caractériser cette tolérance est crucial pour déterminer les habitats sensibles et rechercher des moyens de prévention ou de lutte. Les taxa du genre Fallopia sont ici étudiés dans le cadre de l'invasion du département de la Loire. Leurs réponses au stress nutritif, salin, et à une perturbation sont associées aux conditions environnementales favorisant ou limitant l'invasion. Les résultats obtenus apportent des éléments de réflexion sur les mécanismes à l'origine de l'invasion par les renouées et sur l'efficience de différentes méthodes de lutte et de prévention de l'invasion / Plant growth is a dynamic process that responds to environmental characteristics. The decrease of the plant biomass production induced by various stresses, disturbance, or competition, determines the tolerance to these constraints. In the case of invasive plants, assessing this tolerance is crucial to determine invasibility and to find prevention or control methods. The taxa of the genus Fallopia are here considered in the context of the invasion of the Loire department. Their responses to nutrient stress, salt stress, and disturbance are associated with environmental conditions favouring or limiting the invasion. The results give some evidences about mechanisms implied in the success of Fallopia spp and about the effectiveness of different prevention or control methods