Southern Research Station

Title: Bottom-up limitation of a stream salamander in a detritus-based food web

Author: Johnson, Brent R.; Wallace, J. Bruce

Date: 2005

Source: Can. J. Fish. Aquat. Sci., Vol. 62: 301-311

Description: The indirect effects that resources can have on higher trophic levels remain poorly understood for detritus-based ecosystems. Our objective was to examine effects of long-term terrestrial litter exclusion on a larval salamander, Eurycea wilderae, in a detritus-based stream. After 4 years of exclusion treatment, we conducted a mark-recapture study and analyzed gut contents of E. wilderae larvae in the litter exclusion reach, a reach downstream of treatment, and in a reference stream. Eurycea wilderae growth rate (per day), density (individuals per square metre), biomass (milligrams ash-free dry mass per square metre), and production (milligrams ash-free dry mass per square metre per year) were all significantly reduced in the litter exclusion reach. Reduced density in the treatment reach was likely due to elevated hatchling drift driven by reduced prey availability. Larvae from the treatment reach had fewer prey items per gut than larvae in the reference stream and their diet consisted of fewer copepods but more midge larvae, nematodes, and terrestrial insects. The reach downstream of treatment was intermediate between reference and litter exclusion reaches for most measured parameters, indicating residual effects of upstream treatment. Our results provide the first comprehensive evidence of bottom-up limitation of a vertebrate predator in a detritus-based ecosystem and further demonstrate the importance of the terrestrial-aquatic linkage.

Keywords: 

View and Print this Publication (1.19 MB)

Pristine Version:  An uncaptured or "pristine" version of this publication is available. It has not been subjected to OCR (Optical Character Recognition) and therefore does not have any errors in the text. However it is a larger file size and some people may experience long download times. The "pristine" version of this publication is available here:

View and Print the PRISTINE copy of this Publication (1.46 MB)

Publication Notes: 

• 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.

 Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

Citation

Johnson, Brent R.; Wallace, J. Bruce  2005.  Bottom-up limitation of a stream salamander in a detritus-based food web.   Can. J. Fish. Aquat. Sci., Vol. 62: 301-311