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Impact of an Invasive Exotic Species on Stream Nitrogen Levels in Southern Illinois 1
Author(s) -
Goldstein Christine L.,
Williard Karl W.J.,
Schoonover Jon E.
Publication year - 2009
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.2009.00314.x
Subject(s) - nitrate , environmental science , streams , ecosystem , watershed , ephemeral key , cover crop , ecology , biology , hydrology (agriculture) , agronomy , geology , computer network , machine learning , computer science , geotechnical engineering
Autumn‐olive ( Elaeagnus umbellata Thunb.) is an invasive, exotic shrub that has become naturalized in the eastern United States. Autumn‐olive fixes nitrogen (N) via a symbiotic relationship with the actinomycete Frankia . At the plot scale, the presence of autumn‐olive has been related to elevated soil water nitrate‐N (NO 3 − ‐N) concentrations. This study examined the relationship between autumn‐olive cover in a watershed and stream water quality. Stream water nitrate‐N (NO 3 − ‐N) and ammonium‐N (NH 4 + ‐N) concentrations were measured in 12 first order ephemeral streams draining watersheds with mixed forest cover and a range of 0‐35% autumn‐olive cover. Percent autumn‐olive cover was positively correlated with mean stream NO 3 − ‐N concentrations, but was not correlated with mean stream NH 4 + ‐N concentrations. While other studies have demonstrated a significant relationship between native N‐fixers and stream NO 3 − ‐N, this is the first study to document a relationship for an invasive, exotic N‐fixing species. Results suggest that this exotic species can be an additional source of NO 3 − in local and regional water bodies and demonstrates an additional negative ecosystem consequence of invasion beyond losses in biodiversity.