Abstract/Details

Ecological and evolutionary responses of native species to exotic community members


2005 2005

Other formats: Order a copy

Abstract (summary)

Biological invasions can have dramatic impacts on the ecology of native communities by altering population dynamics, species interactions, and community composition. Because of these strong ecological effects, invasion by exotic species may also provoke striking evolutionary responses in native species. Here I investigate how the presence of an exotic plant competitor and an exotic insect herbivore interact to affect both the ecology and the evolution of a common native plant species.

Chapter One demonstrates that invasion by the exotic plant Medicago polymorpha has strong direct competitive effects and strong indirect effects, mediated by the exotic herbivore Hypera brunneipennis, on the co-occurring native plant Lotus wrangelianus. These results suggest that exotic plants and exotic herbivores can interact to exacerbate the ecological consequences of invasion. Furthermore, rather than limiting the success of exotics, introduced herbivores that feed on exotic plants may provide additional, indirect avenues through which exotic plants can reduce the fitness of native species.

Chapter Two investigates the mechanisms underlying potential evolutionary responses of native species to biological invasions and demonstrates that patterns of natural selection on native plant traits vary dramatically, depending on the presence or absence of novel species. Here I show that the exotic plant M. polymorpha and the common exotic herbivore H. brunneipennis interact to produce strong novel selection pressures on the competitive response and anti-herbivore defenses of the native L. wrangelianus .

Chapter Three explores whether exotic plant competitors and exotic insect herbivores provoke evolutionary responses in native plants. L. wrangelianus has failed to respond evolutionarily to the serial invasion of M. polymorpha followed by H. brunneipennis. However, when herbivory from H. brunneipennis is experimentally reduced, Lotus appears to exhibit an evolutionary response to invasion by M. polymorpha. Thus, the presence of an exotic insect herbivore counteracts adaptation by the native L. wrangelianus to invasion by the exotic plant M. polymorpha, suggesting that serial invasions by many exotic species may limit the ability of natives to respond evolutionarily to the novel and frequently changing selection pressures that arise with each new invasion.

Indexing (details)


Subject
Ecology
Classification
0329: Ecology
Identifier / keyword
Biological sciences; Hypera brunneipennis; Invasive species; Lotus wrangelianus; Medicago polymorpha; Native species
Title
Ecological and evolutionary responses of native species to exotic community members
Author
Lau, Jennifer Ann
Number of pages
85
Publication year
2005
Degree date
2005
School code
0029
Source
DAI-B 66/07, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780542237386, 0542237385
Advisor
Strauss, Sharon Y.
University/institution
University of California, Davis
University location
United States -- California
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3182504
ProQuest document ID
305041737
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305041737
Access the complete full text

You can get the full text of this document if it is part of your institution's ProQuest subscription.

Try one of the following:

  • Connect to ProQuest through your library network and search for the document from there.
  • Request the document from your library.
  • Go to the ProQuest login page and enter a ProQuest or My Research username / password.