Community and ecosystem consequences of giant knotweed (Polygonum sachalinense) invasion into riparian forests of western Washington, USA

An assessment of invasive plant species monitored by the Northern Research Station Forest Inventory and Analysis Program, 2005 through 2010

“…P. x bohemicum; Fallopia x bohemica; F. x bohemicum; Reynoutria x bohemica; R. x bohemicum) POBO10 Background and characteristics: Bohemian knotweed is an herbaceous perennial of the buckwheat family (Polygonaceae). It is a hybrid between Japanese knotweed and giant knotweed which are native to northeastern Asia and were introduced as ornamentals to Europe in the second half of the 19th century and to North America as ornamentals and fodder in the late 19th century (Murrell et al 2011, Urgenson et al 2009). Bohemian knotweed grows best in full sun (Fig.…”

“…It was introduced in the second half of the 19th century to Europe from Japan and in the late 19th century to North America as an ornamental and for fodder (Urgenson et al 2009). Floristic records in the northwestern United States suggest this IPS, along with Bohemian and Japanese knotweed, are among the most rapidly spreading plant invaders (Urgenson et al 2009). Humans have facilitated the spread of this species by planting it in gardens where they enjoy the white flowers (Fig.…”

“…42). Another important spread mechanism is flood waters which transport rhizome fragments (Urgenson et al 2009). …”

“…Urgenson et al (2009) found that this plant has the ability to alter the structure and function of riparian forests due to its high rate of resorption of foliar nitrogen which results in less nitrogen being added to the soil.…”

A Model Approach for Estimating Colony Size, Trends, and Habitat Associations of Burrow-Nesting Seabirds

“…When invasive nonnative species displace natives within the riparian zone, these introduced species have the potential to cause long-term cascading changes in the structure and functioning of both the riparian zone and adjacent aquatic habitat. A study by Urgenson et al (2009) found the invasive non-native giant knotweed (Polygonum sachalinense) caused such changes in community function and structure of western Washington riparian zones. Richness and abundance of native herbs, shrubs, and juvenile trees were negatively correlated with knotweed density, with a 70% reduction of native leaf litter mass.…”