Impacts of invasive riparian knotweed on litter decomposition, aquatic fungi, and macroinvertebratesAuthor(s): Shannon M. Claeson; Carri J. LeRoy; Jacob R. Barry; Kevin A. Kuehn
Source: Biological Invasions. 16(7): 1531-1544
Publication Series: Scientific Journal (JRNL)
Station: Pacific Northwest Research Station
Download Publication (808.88 KB)
DescriptionBohemian knotweed (Polygonum X bohemicum), the hybrid between Japanese and giant knotweed, is the most common invasive knotweed species in western North America and the most difficult to control. Invasive knotweed congeners spread aggressively along streams and establish dense monotypic stands, reducing riparian plant species diversity. Allochthonous organic matter inputs from riparian plants are an important source of energy and nutrients for organisms in small streams. However, little information exists concerning the influence of knotweed on stream processes. This study examines the quality of Bohemian knotweed leaves compared to native red alder and black cottonwood leaves, along with leaf-associated fungal biomass accumulation, macroinvertebrate communities, and decay rates from three forested streams in western Washington State. Senesced knotweed leaves were lower in nitrogen and phosphorus, and higher in cellulose, fiber, and lignin content than alder leaves, but were more similar to cottonwood leaves. Fungal biomass differed among species and changed over time. Macroinvertebrate shredders collected from leaf packs after 31 days were proportionately more abundant on alder leaves than knotweed and cottonwood. Decay rates were not significantly different among leaf species, but during the first 31 days alder broke down faster than knotweed. After 56 days, all of the leaf packs were mostly decomposed. Overall, these findings do not show major discrepancies between leaf species except those related to initial litter structural and chemical quality. However, changes in the timing and quantity of litter inputs are also important factors to be considered in understanding the impact of invasive knotweed on stream ecosystem processes.
- Visit PNW's Publication Request Page to request a hard copy of this publication.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationClaeson, Shannon M.; LeRoy, Carri J.; Barry, Jacob R.; Kuehn, Kevin A. 2014. Impacts of invasive riparian knotweed on litter decomposition, aquatic fungi, and macroinvertebrates. Biological Invasions. 16(7): 1531-1544.
KeywordsBohemian knotweed, Japanese knotweed, Polygonum, Fallopia, freshwater, exotic
- Knocking out knotweed: research pins down a rogue invasive
- Passive reestablishment of riparian vegetation following removal of invasive knotweed (Polygonum)
- Eriogonum Michx.: wild-buckwheat, buckwheatbrush
XML: View XML