Grantee Research Project Results

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: Hahn, Intaek
Project Period: August 1, 2000 through August 1, 2003
Project Amount: $80,928
RFA: STAR Graduate Fellowships (2000) RFA Text | Recipients Lists
Research Category: Fellowship - Aquatic Ecology and Ecosystems , Academic Fellowships

Objective:

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.

Approach:

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

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.