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When can herbivores slow or reverse the spread of an invading plant? A test case from Mount St. Helens

  • Author(s) / Creator(s)
  • Here we study the spatial dynamics of a coinvading consumer-resource pair. We present a theoretical treatment with extensive empirical data from a long-studied field system in which native herbivorous insects attack a population of lupine plants recolonizing a primary successional landscape created by the 1980 volcanic eruption of Mount St. Helens. Using detailed data on the life history and interaction strengths of the lupine and one of its herbivores, we develop a system of integrodifference equations to study plant-herbivore invasion dynamics. Our analyses yield several new insights into the spatial dynamics of coinvasions. In particular, we demonstrate that aspects of plant population growth and the intensity of herbivory under low-density conditions can determine whether the plant population spreads across a landscape or is prevented from doing so by the herbivore. In addition, we characterize the existence of threshold levels of spatial extent and/or temporal advantage for the plant that together define critical values of “invasion momentum,” beyond which herbivores are unable to reverse a plant invasion. We conclude by discussing the implications of our findings for successional dynamics and the use of biological control agents to limit the spread of pest species.

  • Date created
    2005
  • Subjects / Keywords
  • Type of Item
    Article (Published)
  • DOI
    https://doi.org/10.7939/R3P26QF11
  • License
    Copyright 2005 by The University of Chicago
  • Language
  • Citation for previous publication
    • Fagan, W. F., Lewis, M., Neubert, M. G., Aumann, C., Apple, J. L., & Bishop, J. G. (2005). When can herbivores slow or reverse the spread of an invading plant? A test case from Mount St. Helens. The American naturalist, 166(6), 669-685.