Dissertation Research: Aquatic effects of a terrestrial invasion: a riparian tree subsidizes carbon and nitrogen with differential consequences for stream ecosystems.
Invasive species can affect ecosystem functions such as productivity or processing of nutrients. These effects can beyond the habitat where the invasion occurs extend. The goal of this research is to evaluate the effects of an invasive non-native tree species (Russian olive, Elaeagnus angustifolia) on aquatic ecosystem processes. Unlike the native riparian vegetation that it replaces, Russian olive is able to fix nitrogen (N) transforming it into a form usable by itself and other plants. As a result, Russian olive trees can supply N to streams, altering nutrient uptake and algal growth. This altered processing of N in streams could result in greater export of N from invaded watersheds to downstream systems which could result in nutrient pollution problems. Research funded by this award will evaluate if this effect of Russian olive is manifested at a regional scale by comparing measurements of nitrogen input and biological demand for N in 10 invaded and 10 non-invaded streams in the Intermountain-West region.
Little is known about how invasive species affect the exchange of nutrients and food sources to adjacent ecosystems. If Russian olive alters N processing in streams this could represent a major unforeseen effect of riparian plant invasions. The results from this research will inform management of Russian olive which is in its infancy, despite the invasion's extent and potential impacts. The investigators will include undergraduate researchers and will mentor a high school intern from the nearby Shoshone-Bannock reservation where some of this work will be conducted. This study will address water quality and human health concerns affecting rural communities in the West. Results of this research will be communicated broadly to the scientific community, local managers and the general public.
