, Volume 133, Issue 4, pp 573–582

Salmon and alder as nitrogen sources to riparian forests in a boreal Alaskan watershed

  • James M. Helfield
  • Robert J. Naiman
Ecosystems Ecology

DOI: 10.1007/s00442-002-1070-x

Cite this article as:
Helfield, J.M. & Naiman, R.J. Oecologia (2002) 133: 573. doi:10.1007/s00442-002-1070-x


Anadromous Pacific salmon (Oncorhynchus spp.) transport marine-derived nitrogen (MDN) to the rivers in which they spawn. Isotopic analyses of riparian vegetation in a boreal Alaskan watershed indicate that trees and shrubs near spawning streams derive ~24–26% of their foliar nitrogen (N) from salmon. Basal area growth of white spruce (Picea glauca) is enhanced at sites receiving MDN inputs. This marine N subsidy appears to be less important to riparian ecosystems where symbiotic N fixation by alder (Alnus crispa) is prevalent, although salmon carcasses may nonetheless be an important source of other marine-derived nutrients affecting productivity in these forests. These findings illustrate the complexity of interactions surrounding riparian forests and the interconnectedness of river and riparian ecosystems.

Alnus crispa Marine-derived nutrients Oncorhynchus Picea glauca Riparian Stable isotopes

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • James M. Helfield
    • 1
  • Robert J. Naiman
    • 2
  1. 1.College of Forest Resources, University of Washington, Box 352100, Seattle, WA 98195, USA
  2. 2.School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98195, USA