Effects of Japanese Knotweed (Fallopia japonica) Detritus on Benthic Macroinvertebrate Communities of the Susquehanna River Main Stem

Elaine Langone Center, Terrace Room

Japanese knotweed (Fallopia japonica) is an invasive species rapidly spreading throughout the understory of riparian forests in Central Pennsylvania. There are concerns that this species may impact aquatic ecosystems. Allocthonous material, originating from outside the system, is the basis for aquatic food webs and can impact benthic communities. This study assesses the affects of Japanese knotweed leaf litter on the benthic macroinvertebrate communities of the Susquehanna River. Three chemically and physically distinct sites within the Susquehanna were chosen to compare benthic macroinvertebrate communities within Japanese knotweed and American sycamore (Platanus occidentalis) leaf packs. In addition, we are quantifying the accumulation of Japanese knotweed and American sycamore biomass naturally occurring leaf packs in the Susquehanna River. We predict that macroinvertebrate communities within low-quality knotweed litter will have relatively low diversity compared to high-quality native sycamore litter. This study will begin to evaluate how the riparian invader, Japanese knotweed, influences the benthic communities of the Susquehanna River.