Food-Limited to Habitat-Limited: Predator-Prey Uncoupled

EPA Grant Number: U915806
Title: Food-Limited to Habitat-Limited: Predator-Prey Uncoupled
Investigators: Zaradic, Patricia A.
Institution: University of Pennsylvania
EPA Project Officer: Michaud, Jayne
Project Period: August 1, 2000 through August 1, 2003
Project Amount: $80,928
RFA: STAR Graduate Fellowships (2000) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Aquatic Ecosystems , Fellowship - Aquatic Ecology and Ecosystems


The objective of this research project is to examine the importance of predation for prey diversity in food-limited as compared to habitat-limited Northwest forest streams by: (1) determining if a dominant predator, the larval Pacific giant salamander, Dicamptodon tenebrosus, is more food-limited in old growth as compared to habitat-limited in logged; and (2) altering the predator density in each and observing the effects on prey abundance and diversity.


This research will build on 3 years of preliminary fieldwork at the HJ Andrews Experimental Forest, Oregon, long-term ecological research (LTER) site, evaluating the potential for habitat loss and prey enrichment to effectively uncouple predator-prey interactions, thereby shifting predation-structured communities to resource-structured communities. The study will determine to what degree prey as compared to habitat availability limits salamander larvae by supplemental feeding and by manipulating habitat abundance, adding artificial refugia to experimental reaches in old growth and logged streams. The relative importance of predation for structuring the invertebrate prey community also will be examined by following salamander populations in existing stream reaches and manipulating densities in other, experimentally enclosed stream reaches in old growth and logged stream habitats. Simpson's diversity index will be used to monitor changes in invertebrate prey number and diversity. Enclosed salamander densities will be altered to achieve old growth (high density), logged (low density), and salamander-free densities in a full factorial design under logged and old growth habitat types. By utilizing sites at the HJ Andrews Experimental Forest, data will be combined with other long-term data sets on forest productivity and species diversity. The HJ Andrews Experimental Forest has a long history of working with government agencies to actively incorporate research advances with applied management practices.

Expected Results:

This research will examine the effects of logging on old growth forest streams and suggest mitigating measures to reduce the impact on larval amphibians and their invertebrate prey.

Supplemental Keywords:

ecology, streams, sediment, amphibian, Dicamptodon tenebrosus, invertebrates, community composition, ecological effects, biodiversity, aquatic, habitat, ecosystem, indicators, restoration, Pacific Northwest, Oregon, OR, long-term ecological research, LTER, HJ Andrews Experimental Forest., RFA, Scientific Discipline, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Aquatic Ecosystems & Estuarine Research, exploratory research environmental biology, Ecosystem/Assessment/Indicators, Chemical Mixtures - Environmental Exposure & Risk, Ecosystem Protection, amphibians, State, Aquatic Ecosystem, Zoology, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Ecological Effects - Human Health, Habitat, Pacific Northwest, Biology, Exp. Research/future, Futures, Ecological Indicators, aquatic, ecological effects, larval Pacific giant salamander, biodiversity, streams, Oregon, old growth (high density), sediment, community composition, food limited, prey diversity, amphibian, habitat loss, salamanders, aquatic ecosytems, dominant predator, predator/prey interactions, logged (low density), aquatic ecosystems, ecosystem, restoration, Dicamptodon tenbrosus, habitat limited, ecosystems, aquatic ecology, indicators, amphibian population

Progress and Final Reports:

  • 2001
  • 2002
  • Final