Skip to Main Content
Potential effects of an invasive nitrogen-fixing tree on a Hawaiian stream food webAuthor(s): Trisha B. Atwood; Tracy N. Wiegner; Jason P. Turner; Richard A. MacKenzie
Source: Pacific Science
Publication Series: Scientific Journal (JRNL)
View PDF (264.09 KB)
DescriptionFalcataria moluccana (albizia) is an exotic nitrogen (N)-fixing tree currently invading riparian forests in Hawai'i, U.S.A. This study examined how this invasion is impacting stream ecosystems by using naturally occurring stable isotopes of carbon (C) and N to compare food web structure between a noninvaded and an albizia-invaded stream reach on the island of Hawai'i. Isotopic signatures of particulate organic matter (POM), macroalgae, invertebrates, and fishes were collected and compared between the two stream reaches. Stable C isotopic signatures of organic matter sources (POM and macroalgae) and consumers (amphipods, caddisflies, crayfish, and fishes) from the invaded site were depleted in 13C compared with the noninvaded site. In contrast, all samples from the invaded site were enriched in 15N compared with the noninvaded site. Results from IsoSource and two-source mixing models suggested that albizia was a major contributor to diets of lower-level consumers within the invaded site, displacing POM and macroalgae as their major food sources. Albizia was also an indirect C and N source for higher-level consumers within the invaded site because albizia was the major dietary constituent of their prey. In addition, 15N enrichment of the macroalgae at the invaded site suggests that albizia may be an important N source to benthic primary producers and could be further altering the food web from bottom up. Our study provides some of the first evidence that invasive riparian N-fixing trees can potentially alter the structure of stream food webs.
- You may send email to firstname.lastname@example.org to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- 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.
CitationAtwood, Trisha B. ; N. Wiegner, Tracy; P. Turner, Jason; MacKenzie, Richard A. 2010. Potential effects of an invasive nitrogen-fixing tree on a Hawaiian stream food web. Pacific Science 64(3):367-379. doi: 10.2984/64.3.367
- Benefits of Eucalyptus-Albizia mixtures vary by site on Hawaii Island
- You are not always what we think you eat: selective assimilation across multiple whole-stream isotopic tracer studies
- Impacts of an invasive N2-fixing tree on Hawaiian stream water quality
XML: View XML