The Role of Introduced Trout in Altering Native Lentic Communities in the Sierra Nevada, California

EPA Grant Number: U915804
Title: The Role of Introduced Trout in Altering Native Lentic Communities in the Sierra Nevada, California
Investigators: Leyse, Karen E.
Institution: University of California - Davis
EPA Project Officer: Packard, Benjamin H
Project Period: August 1, 2000 through August 1, 2003
Project Amount: $80,187
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 determine the extent to which the distribution patterns of native aquatic invertebrate and amphibian species are altered by introductions of nonnative fish.


I am combining field surveys with comparative techniques, and with field and lab experiments that will test possible mechanisms for the effects of fish on native species. I am researching museum records and resource agency documents to: (1) determine the past presence of three amphibian species (Rana muscosa, Ambystoma macrodactylum sigillatum, and Hyla regilla) and key macroinvertebrates in lakes within the study area; and (2) verify lakes stocked with trout. This information will establish a baseline that can be used to assess changes in community composition within the study area. I also am conducting surveys of alpine and subalpine lakes (with and without fish) in the Sierra Nevada to quantify environmental parameters, and to document the presence of invertebrate and amphibian species at each lake. Invertebrate and zooplankton samples are collected at a subset of lakes and identified to species, genus, or family depending on the taxon. All species locations are mapped using geographic information systems. I will compare species distributions versus abiotic factors and fish presence using multivariate techniques. The field experiment will consist of duplicate sets of enclosures set in lakes, with and without fish, to test predictions that fish presence will negatively affect larval amphibian (A.m. sigillatum) survival and growth, and to compare the effects of fish on other macroinvertebrates. I also will use replicated, small-scale experiments to test mechanisms that might underlie changes in amphibian occurrence. Prey choice experiments will document the extent to which A.m. sigillatum larvae and trout may compete for the same prey species. Behavioral experiments will document interactions between trout and amphibian larvae.

Supplemental Keywords:

fellowship, amphibians, Rana muscosa, Ambystoma macrodactylum sigillatum, introduced fish, Sierra Nevada, trout, introduced predator, invertebrate, aquatic, ecology, conservation, surveys, monitoring, California, CA.

Progress and Final Reports:

  • 2001
  • 2002
  • Final